CSP-H-2 BASIC HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369H HELICOPTERS

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(b). Install the two screws, two bolts and

for deterioration and plastic cover for

nut and washers that secure the

cracks.

drain assembly to the structure,

shroud and scroll.

(3). Installation (Shaft−Driven Blower):

(a). Position cover over transmission.

NOTE: Do not overtighten the two bolts and

nut. Torque to 10 inch−pounds (1.13 Nm)

(b). Install heater duct bolt at lower left

maximum.

aft inside corner of cover if heating

system ducting is installed.

(c). If drain assembly is a replacement,

connect the flexible drain hose and

(c). Install the four screws and washers

secure with two wraps to lockwire (2,

fingertight. Check cover for proper fit

Table 2−4).

and that liquid level plug is visible.

C. Main Transmission Cover

(d). Tighten screws.

Different main transmission covers are used

(e). Set the nylon tape edging to the

with the shaft−driven and belt−driven oil

mating file fasteners by using hand

cooler blower installations. The main trans−

pressure.

mission cover is a polycarbonate plastic form

(f). Attach the main transmission drain

that essentially matches the transmission

assembly.

housing contour. The plastic form has a

permanently bonded insulation blanket cover

(4). Removal (Belt−Driven Blower):

with a fiberglass core and flexible vinyl

exterior. Plastic form gaskets cushion the cover

(a). Disconnect electrical wiring from

surfaces that mate with the adjacent struc−

transmission temperature sensor and

ture. When installed, there is space between

chip detector.

the cover and transmission to allow inlet air

flow for transmission cooling. With the

NOTE: The cover assembly may be installed

shaft−driven blower, a yoke−type drain

with sealant. To remove the cover, split the

assembly fits around the lower end of the

sealant with a sharp knife to protect seals

cover. A flexible hose connects to the drain

and surface finish from damage.

assembly outlet tube and pipes overboard any

water or oil that collects in the cover.

(b). Remove 14 washers and screws to

remove cover from fuselage structure,

(1). Removal (Shaft−Driven Blower):

trim support strips and upper

transmission baffle.

(a). Detach the main transmission drain

assembly.

(c). Remove cover from left and right

cooling ducts.

(b). Release nylon tape edging (Velcro

(5). Installation (Belt−Driven Blower):

hook tapes) from mating nylon pile

fasteners (Velcro piles) at aft edges of

(a). Apply parting agent (113, Table 2−4)

cover.

and sealant (106) to areas indicated

in Figure 2−6.

(c). Remove four screws and washers

from cover.

(b). Position cover over transmission and

install cooling ducts.

(d). Remove bolt from heater duct flange

at lower left aft inside corner of cover

(c). install 14 screws and washers to

if heating system ducting is installed;

secure cover and trim support strips.

then lower cover to remove it..

(d). Connect electrical wiring to transmis−

(2). Inspection (Shaft−Driven Blower):

sion temperature sensor and chip

Inspect foam gaskets and cover blanket

detector.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

D. Main Transmission Cover Assembly

(6). Apply adhesive (3, Table 2−4) to both

Seals Replacement

rubber seal and cover assembly. Align

seals and press into place.

(Ref. Figure 2−7) Cover seals PN

369H8063−85, 89, and −91 in the

(7). Allow bond to cure for 24 hours;

369H8063−505 polycarbonate type main

reinstall cover assembly.

transmission cover assembly may be removed

E. Cargo Compartment Aft Bulkhead Access

on a one time basis for inspection, and

Covers

reinstalled using a rubber adhesive to ensure

adequate bond between the seals and the

The cargo compartment aft bulkhead access

polycarbonate cover. This procedure, which

covers enclose essentially symmetrical

follows, does not apply to 369H8097 fiberglass

openings to the fuselage spaces at either side

type main transmission cover.

of the engine air inlet plenum chamber. The

right side cover provides access to the oil tank,

(1).

Remove main transmission cover

oil cooler and oil system drain valve. The left

assembly.

side cover provides access to elements of the

cabin heating installation on the helicopters so

(2).

Remove 369H8063−85, −89 and −91

equipped. Turnlock fasteners secure the outer

rubber seals from cover assembly.

edge of each cover to the fuselage.

Discard seal if any deterioration is

noted.

(1). Removal: Release turnlock fasteners

and lift cover from structure.

(3).

Use X−acto knife or equivalent to

remove loose adhesive material adher−

(2). Inspection:

ing to polycarbonate cover and rubber

seals. Use abrasive paper to remove

(a). Inspect turnlock fasteners and

remaining adhesive residue from cover

receptacles for condition.

and seals.

(b). Inspect cover for corrosion and

(4).

Abrade inside flange of rubber seals.

cracks.

(5).

Wipe clean the abraded areas of cover

(3). Installation: Position the cover over the

and seals, using naphtha and clean

opening in the structure and engage the

cloth.

turnlock fasteners.

369H8063−85 SEAL

369H8063−91 SEAL

369H8063−89 SEAL

MAIN TRANSMISSION

COVER ASSEMBLY

30−216

Figure 2-7. Main Rotor Transmission Cover Seals Installation

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Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

F. Pilot Compartment Floor Access Doors

(b). If removed, heel strips are reinstalled

by inserting hinge pins through

Each of the two pilot’s compartment access

brackets on forward end of strip and

doors are formed by two hinged aluminum or

antitorque pedal mounting bracket

fiberglass panels, hinged at the forward edge

and connecting springs to clips or

to the pilot’s compartment floor. A latch at the

brackets on underside of heel strips.

rear secures each door in place. Two aluminum

Crimp or stake end of pins slightly

heel strips, on which two stainless steel skids

after installation or use hinge pins

are bonded, are hinged and held in place over

secured by a cotter pin as follows:

each door by a spring. early type doors are a

single piece of fiberglass with heel strips

1). Detach spring from clip or bracket

bonded in place and the forward ends of the

on underside of each heel strip (not

strips hinged to permit opening the doors.

applicable to early type one−piece

pilot compartment floor access

(1). Removal: Remove either floor access

door).

door as follows.

2). Remove existing hinge pins secur−

NOTE: The one−piece door is removed accord−

ing forward end of heel strips.

ing to step (d).

3). Install new hinge pins and secure

end of each pin with washer and

(a). Release the latch at the rear of the

cotter pin. Direction of pinhead is

door.

optional.

(b). Raise and hold up the rear of the heel

4). Attach spring to clip or bracket on

strips for access to the long hinge pin

underside of each heel strip, as

at forward end of door.

applicable.

NOTE: Heel strips may be removed for ease of

5). Check installation of new hinge

access by detaching springs from clips (or

pins for discrepancies.

brackets) on underside of strips and remov−

ing hinge pins attaching forward ends of

(c). Position one−piece door and install

strips to the anti− torque pedal mounting

hinge pins through hinges and

bracket.

antitorque pedal mounting bracket.

(c). Remove the long hinge pin securing

Fuel Cell Access Doors

forward edge of door to pilot’s

The fuel cell access doors are stiffener−rein−

compartment floor; remove door.

forced aluminum plates that form a portion of

(d). Remove one−piece access door by

the cargo floor. the left access door provides

releasing the flush−mounted latch

access to the fuel quantity transmitter (tank

and removing the two hinge pins that

unit) and fuel shutoff valve and the fuel cell

secure the door at the forward end.

cover (for access to the engine start pump), as

well as the left fuel cell. A quick−release lock

(2). Inspection:

pin is secured with a 4 inch (10 cm) lanyard to

the outboard edge of each door. The pins retain

(a). Inspect doors for cracks and other

the removable jacking fittings that are used for

visible damage.

jacking, parking and mooring the helicopter. A

stud on the stiffener of current type doors

(b). Check security of heel strip bonding.

provides an attachment point for floor cushion

material.

(c). As applicable, inspect hinges and

hinge pins for damage.

These are stressed doors. The

CAUTION

helicopter must never be flown

(3). Installation:

with either door removed.

(a). Position door and secure forward

(1). Removal: Remove the 29 retaining

edge to floor using a long hinge pin.

screws and washers and lift out door.

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Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(2). Installation:

I. Engine Air Inlet Forward Fairings

(a). Position door over opening and

Ambient air is directed to the engine and the

secure in place with retaining screws

engine oil cooler through the two removable

and washers.

forward engine air inlet fairings and the aft

fairing that is riveted to the structure. The

(b). Stow quick−release lock pin in its

engine inlet fairings are fabricated of glass

hole.

cloth layers over polyurethane foam fillers.

The forward fairing halves establish the main

H. Controls Tunnel Cover

air inlet duct. Each half contains a smaller

Four tunnel−routed control rods exit the

duct on its inside leading edge that diverts

tunnel area through a cover mounted at the

cooling air to the main transmission and oil

top of the Sta. 78.50 canted frame. The cover

cooler blower. The forward fairings provide

or cover boots must be removed before any of

access to the main rotor mixer controls and the

the control rods are removed. The cover has

main rotor mast, its base and supporting

four naugahyde boots, two of which are sewed

structure.

together while the other two are individual. All

(1). Removal: A total of 32 screws with

boots are secured to the cover with self−clinch−

washers secure the fairing halves

ing nylon straps.

together and to the structure. Either

(1). Removal: The right− and left−side

half may be independently removed or

engine air inlet forward fairings should

the joined halves may be removed as an

be removed for best access to the

assembly. Two screws and washers join

controls tunnel cover.

the halves at the center splice.

(a). Remove the three screws, nuts, and

(a). Remove screws and washers attach−

six washers, and the four bolts and

ing forward fairing to fuselage.

washers from controls cover.

Remove forward fairing.

(b). Remove the cotter pin, nut, bolt and

(b). Remove two screws and washers at

washers that secure the upper end of

the splice if it is necessary to sepa−

each tunnel−routed control rod.

rate the two halves.

Disengage the rods ends from the

bellcranks.

(2). Inspection: Inspect the engine air inlet

fairings for structural damage. inspect

(c). Lift controls cover over rod ends.

for cracked or frayed glass cloth

(2). Installation:

surfaces and crushed fillers. Inspect

tape seals on closures inside fairings for

(a). Place controls tunnel cover over the

deformation and damage.

four control rods, with double boot

section fitting over the two right−side

(3). Repair: Make general repairs to the

control rods.

engine air inlet fairings according to

CSP−H−6. Replace the tape seals on

(b). Attach each control rod end to its

closures inside fairings with 0.25 x 0.50

bellcrank with bolt (head to left, two

inch (6.35 x 12.7 mm) pressure−sensi−

washers, nut and cotter pin.

tive tape (42, Table 2−4), cut to length

(c). Install controls tunnel cover with the

as required.

three screws, nuts and six washers

(4). Installation:

aft, and the four bolts and washers

forward. Tighten bolts and screws

(a). Position engine air inlet fairings on

evenly.

fuselage and align attachment holes.

(d). If removed, reinstall right− and

(b). Install attaching washers and screws

left−side engine inlet fairings.

in mounting flanges and through

(e). Check that control rods move freely

splice at top of left−side fairing, if

in the cover boots.

fairing halves separated.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

J. Engine Air Inlet Fairing Access Doors

and is secured in place with turnlock fasten−

ers. The current type access door is a flat cover

Access doors are provided on both the forward

on the mast support structure. Twelve screws

and aft engine air inlet fairings. The right side

secure the access cover in place. When an

of the forward fairing contains the tail rotor

engine air inlet vertical screen is installed, five

drive shaft access door. The right side of the

of the cover screws with washers also retain

aft fairing contains a removable or hinge−

the front of the screen base. Primarily in−

mounted plenum chamber access door.

tended for access to the front end of the tail

rotor shaft, the door/cover provides limited

(1). Removal: Remove screws and washers

access to the accessories mounted on the aft

or release turnlock fasteners to take off

end of the main transmission.

desired access door.

(1). Removal:

(2). Inspection:

(a). Remove engine air inlet forward

(a). Inspect turnlock fasteners and

fairing.

receptacles for proper fastening

action.

(b). Remove screws from cover or release

turnlock fasteners to release door.

(b). Inspect fiberglass doors for structural

damage such as cracked or frayed

(2). Inspection: Inspect turnlock fasteners

glass cloth surfaces.

and receptacles for proper fastening

action. Inspect door for structural

(c). Inspect the hinge−mounted door for

defects and door hinge for damage and

structural damage and loose or

operation.

missing latching mechanism hard−

(3). Installation:

ware.

Check that all areas of the air

(d). Check latching mechanism and door

CAUTION

inlet and plenum chamber are

hinges for proper operation and

clean and free of debris. Check that all pro−

locking capability.

tective covers are removed. Engine damage

(e). Inspect seal installed around aft

will result if these precautions are not ob−

fairing door for security and condi−

served.

tion.

(a). Close access door and engage turn−

lock fasteners or position access cover

(3). Installation:

on mast support structure and secure

Check that all areas of the air

with screws (and five washers as

CAUTION

inlet and plenum chambers are

applicable to inlet screen).

clean and free of debris. check that all pro−

(b). Install engine air inlet forward

tective covers are removed. Engine damage

fairing.

will result if these precautions are not ob−

served.

L. Controls Access Door and Foot Support

Fairings

(a). Position door on fairing and install

applicable screws and washers or

The controls access door and the two foot

engage turnlock fasteners.

support fairings provide access to the forward

landing gear struts and dampers, lower

(b). Close the hinge−mounted plenum

elements of the underseal installation for the

chamber access door and ensure that

engine and flight control systems and portions

locking mechanism locks in place.

of the electrical wiring routed beneath the

pilot’s seat structure. The foot fairings are

K. Aft Section Air Inlet (Tail Rotor Drive)

fiberglass assemblies, each having two small

Access Door

polycarbonate plastic windows. the outboard

The early type aft section air inlet (tail rotor

windows allow inspection of the forward

drive) access door is hinge−mounted to the aft

landing gear damper assemblies without prior

fuselage structure above the plenum chamber

removal of the fairings. The inboard windows

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

are not for inspection by establish left−or

(2). Installation: Check that there are no

right−hand interchangeability. The controls

foreign objects in the area shielded by

access door is aluminum plate that provides

the covers, position cover and secure

primary access to the lower end of the tunnel−

with screws and washers.

routed flight control push rods in addition to

O. Fuel Vent Cover

other elements of the control system.

The formed aluminum fuel vent cover provides

The controls access door is a

CAUTION

access to the fuel cell vent system crossover

stressed door. The helicopter

fitting that interconnects the forward top

must never be flown with this door removed.

inboard corners of the two cells.

(1). Removal: Remove eight screws and

(1). Removal: Remove four screws and

washers to release each foot fairing.

washers to release the fuel vent cover.

Remove 14 screws and washers, or 27

screws and washers as applicable, to

(2). Installation: Check that area to be

release controls access door.

covered is clean. Position cover and

secure with screws and washers.

(2). Installation: Position controls access

door (bevel at lower right corner) or foot

P. Fuel Filler Shield

support fairings and secure with screws

The polycarbonate plastic fuel filler shield

and washers.

protects the right fuel cell filler extension from

M. Pilot’s Seat Cover

possible damage from cargo impact, and also

covers the cargo floor opening for the filler.

The pilots seat cover is an aluminum alloy

panel assembly with a honeycomb core. The

(1). Removal:

seat cover provides primary access to the

(a). Remove five screws and washers that

upper elements of the underseat installation of

secure the fuel filler shield base to

engine and flight control systems.

the cargo floor.

(1). Removal: Remove 16 screws and

(b). Remove the two nuts, screws and

washers to release the pilot’s seat cover.

washers that secure the shield tabs

to the fuselage skin and fuel filler cap

Use all necessary precautions to

CAUTION

to release the shield.

prevent the possible entry of for−

eign objects into the controls linkage ex−

NOTE: Use care not to dislodge or damage the

posed by removal of the cover. Unnoticed de−

sealing grommet (if installed) that fits

bris in this area could jam or damage the

around the extended range fitting opening

controls when they are moved.

in the shield.

(2). Installation: Check that there are no

(2). Installation: Position the fuel filler

foreign objects present in the controls

shield and install the two screws,

linkage. Position pilot’s seat cover and

washers and nuts that secure the shield

secure with screws and washers.

tabs to the fuselage skin and fuel filler

cap; do not tighten.

N. Outboard (LH) Collective Stick Cover and

Wiring Cover

NOTE: Check that extended range fitting

grommet (if installed) provides a tight seal

The two small covers installed at the left side

between the shield and fitting. Replace

of the seat structure keep the left seat belt

grommet if deteriorated.

from fouling the aft end of the collective stick.

They also shield the electrical wiring where it

Q. Boom Bolts Access Doors and Tail Rotor

exits the seat structure and where it connects

Control Bellcrank Access Door

to the auxiliary circuit receptacles mounted in

The forward and aft boom bolts access doors

the left corner of the bulkhead.

provide access to the bolts that secure the

(1). Removal: Remove screws and washers

tailboom to the fuselage aft section. These

to release either cover.

doors are also removed for access to perform

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

removal and installation of the tail rotor drive

(b). Remove or release fasteners joining

shaft and/or tailboom (tail rotor blade angle)

the two side fairings.

control rod and to check drive shaft damper

(c). Detach side fairings from the canopy

friction or replace the damper. The tail rotor

structure by releasing accordion

control bellcrank access door provides primary

rivets or velcro fasteners.

access to the Sta. 142 bellcrank link between

the Sta. 100 tail rotor control rod and the

(d). Disconnect and tag−identify electrical

tailboom control rod.

loads from light/switch and horn

housing; then remove center fairing.

(1). Removal: Release turnblock fasteners

and lift boom bolts or controls access

(e). If required, remove attaching hard−

door from fuselage.

ware and horn and light assembly

from center fairing.

(2). Inspection: Inspect turnlock fasteners

and receptacles for proper fastening

(2). Installation: Install the instrument

action.

panel fairings in reverse order starting

with the last fairing section removed.

(3). Installation: Position boom bolts or

Refer to Section 19 for battery sensing

controls access door and engage

and engine out warning horn equip−

turnlock fasteners.

ment.

R. Exterior Lights Covers

U. Instrument Panel Lower Section Side

Cover Panels

Three fuselage openings for exterior lights are

closed off by round aluminum covers. Informa−

The two side cover panels that enclose the

tion on night lights is provided in CSP−H−3.

lower instrument panel support assembly

structure are aluminum alloy sheet. Removal

S. Cargo Swing/Hook Fairing Cover

of the covers provides access to wiring, tubing

and the fuel shutoff control cable routed

The well of the cargo swing/hook fairing is

upward to the instrument panel, as well as

closed off by a rectangular aluminum alloy

parts of the tail rotor control torque tube

cargo hook cover. Information on the cargo

installation. Refer to applicable configuration

swing and hook is provided in CSP−H−3.

supplement for removal of instrument panel

lower section.

T. Instrument Panel Fairings

(1). Removal: Remove five screws and

The three instrument panel fairings and hood

washers to release either side cover.

around the instrument panel are molded

thermoplastic enclosures that shield the area

NOTE: The running time meter is mounted in

froward of the panel from direct sunlight and

the left side cover and the landing light

foreign material. Removal of the side fairings

relay is mounted on the right side cover of

provides access to the shutoff valve controls,

helicopters equipped with either or both of

electrical and indicating system components

these options. For instructions or replace−

and any optional avionics equipment mounted

ment of either item, refer to CSP−H−3.

to the instrument panel and on the panel

support structure.

(2). Installation: Check that there are no

foreign Objects present in the controls

(1). Removal:

linkage, position the cover(s) and secure

with screws and washers.

NOTE: On helicopters equipped with a type B

instrument panel with full face hood, eight

V. Instrument Panel Lower Section Front

face attachment screws and two panel lights

Cover Panel

knife splices must be disconnected before

hood removal. Ref. Sec. 17 for attachment

The front panel inside the lower section of the

and disconnect points.

instrument panel support is aluminum alloy.

Removal of the cover provides access to

(a). Remove hood attachment screws and

electrical and avionics wiring at the lower

washers; remove hood.

forward area of the instrument panel.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(1). Removal: Remove five screws and

(1).

Removal (Current Type): Release the

washers to release the cover.

three latches to open access doors.

Index mark the hinge, shim and

(2). Installation: Position panel and secure

serrated plate to the door structure.

with screws and washers.

Remove the three engine access door

hinge attachment screws with washers.

W. Pilot and Cargo Doors

The forward screws are attached with

nuts and the aft screws attach to

The two pilot doors and two cargo doors are

rivnuts.

bonded aluminum alloy frames containing

large plastic windows. Current type doors are

(2).

Installation (Current Type): Position

auto−latching (automatically latch) when

door and temporarily install shim,

closed. Early type doors are latched manually.

serrated plate and attachment hard−

The door latching mechanism consists of four

ware. Align indexing marks on shim,

latches, two lengths of wire−reinforced cable

serrated plate and hinge with those on

within housings and a latch rod. The door

the door and then tighten the screws.

hinges on each door are provided with quick

Close and latch the doors and check for

removal type ball−lock hinge pins. The doors

firm fit with no deflection. If further

do not incorporate jettison provisions.

adjustment is required.

(3).

Removal (Early Type): Release the

(1). Removal:

three latches to open access doors.

Remove the pivot point attaching

(a). Open the door and individually pull

hardware from the door hinge and lift

the hinge pins up and out by the

door from fuselage hinge halves.

tabs.

(4).

Installation (Early Type): Lift access

(b). Hold door in alignment so that

door into position, align hinges and

hinges do not bind and slide door

install attaching hardware. Close and

hinges from hinge sockets to remove

latch the doors and check for firm fit

door.

with no deflection. If further adjust−

ment is required, refer to Section 3.

(2). Installation:

9. Helicopter Cleaning

(a). Lift door into position so that hinges

are aligned and engage door hinges

General cleaning of oil and dirt deposits from

with fuselage hinge sockets.

the helicopter and its components must be

accomplished by using dry−cleaning solvent (1,

(b). Hold door open and insert hinge pins

Table 2−4), standard commercial grade

far enough for the spring−loaded ball

kerosene or a solution of detergent soap and

detent to emerge past the lower side

water. The exceptions that must be observed

of the hinge socket. Close and latch

are specified in the following cleaning para−

the door.

graphs.

Some commercial cleaning

X. Engine Access Doors

CAUTION

agents, such as readily avail−

able household cleaners, contain chemicals

The two engine access doors are stamped and

that can cause corrosive action and/or leave

bonded aluminum alloy structures that form

residue that can result in corrosion. Exam−

the fuselage contour below the aft section

ples of cleaning agents that are not to be

engine compartment. The hinge−mounted

used are ‘‘Fantastik" and ‘‘409" type clean−

doors are secured in the closed position by

ers, or locally made strong soap cleaners.

three lever type, draw hook latches.

A. Fuselage Interior Trim and Upholstery

NOTE: For removal of current type doors, do

Cleaning

not attempt to remove hinge pivot bolts and

spacers. Refer to Section 3 for disassembly

(1). Clean dirt or dust accumulations from

at hinge points and for all door mainte−

floors and other metal surfaces with a

nance.

vacuum cleaner or small hand brush.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(2). Sponge soiled upholstery and trim

C. Transparent Plastic Cleaning

panels with a mild soap and lukewarm

water solution. Avoid complete soaking

(1). Clean the outside surfaces of plastic

of the upholstery and flocked trim

panels by rinsing with clean water and

panels. Wipe solution residue from

rubbing lightly with palm of hand.

upholstery with a cloth dampened by

(2). Use a mild soap and water solution or

clean water.

aircraft type plastic cleaner to remove

oil spots and similar residue.

(3). Remove imbedded grease or dirt from

upholstery and carpeting by sponging

Never attempt to dry plastic

CAUTION

or wiping with an upholstery cleaning

panels with a dry cloth; To do so

solvent recommended for nylon fabric.

will cause any abrasive particles lying on

the plastic to scratch or dull the surface.

Wiping with a dry cloth will also build up an

(4). Clean leather surfaces with saddle soap

electrostatic charge that will attract dust

and warm water. Wipe residue with a

particles from the air.

clean cloth and warm water.

(3). After dirt is removed from surface of

plastic, rinse with clean water and let

NOTE: If necessary, seat upholstery may be

air dry or dry with a soft, damp cham−

thoroughly dry−cleaned with solvent. When

ois.

complete dry−cleaning is performed, uphol−

stery must be re− flame− proofed in com−

(4). Clean the inside surfaces of plastic

pliance with FAR Part 27.

panels by using aircraft type plastic

cleaner and tissue quality paper wipers.

B. Airframe Exterior and Rotor Blade

Cleaning

D. Battery Cleaning

(1). Check that electrical power selector

Use care to prevent scratching

switch on instrument panel is OFF.

CAUTION

of the aluminum skin when

cleaning main rotor blades. Never use vola−

(2). Unlatch and raise pilot compartment

tile solvents or abrasive materials. Never

floor left side access door. Remove four

apply bending loads to blades or blade tabs

screws and washers securing battery

during the cleaning process.

cover and remove cover.

Use care to avoid damaging bat−

(1). Wash the helicopter exterior, including

CAUTION

tery temperature sensing wires

fiberglass components and rotor blades,

and switch connections during cleaning.

when necessary, by using a solution of

clean water and mild soap.

(3). Use a clean cloth dampened by clean

water to remove any accumulation of

dust, dirt or white powder (potassium

NOTE: Avoid directing soapy or clean water

carbonate).

concentrations toward the engine air intake

area and the instrument static source ports

(4). If battery is unusually dirty or shows

in the aft fairing.

evidence of caked crystals around the

cells it should be removed from the

(2). Clean those surfaces that are stained

helicopter for further cleaning with a

with fuel or oil by initial wiping with a

nylon (or other non−metallic) brush and

soft cloth dampened by solvent (1,

clean running water.

Table 2−4), followed by washing with

(5). Dry the top of the battery thoroughly

clean water and mild soap.

with a clean cloth.

(3). Rinse washed areas with clean water

(6). Reinstall battery cover, mounting

and dry with a soft cloth.

screws and washers.

Page 2-46

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(7). Lower and latch the floor access door.

(3).

Position a container of cloth to catch

residual oil. Loosen and remove filter

E. Battery Electrolyte Spillage Cleaning

housing by turning it counterclockwise.

Electrolyte is a strong alka−

(4).

Remove filter element and O−ring from

WARNING

line solution and is harmful

pump housing.

to the skin and clothing. Wear protec−

(5).

Inspect the filter element for metal

tive clothing that is used exclusively

particles. If metal particles are present,

for servicing nickel− cadmium batter−

remove the main transmission chip

ies. Neutralize and flush electrolyte

detectors and inspect for other evidence

from the skin or hands as described be−

of internal failure in the gearbox.

low. Where there is evidence of spewed

or spilled battery electrolyte, flush off

(6).

Clean the filter element and housing

the surface immediately with water

with solvent (1, Table 2−4) and ultra−

(cold if possible) and neutralize with a

sonic equipment, if available, or by

3 percent boric acid solution. Follow

reverse flushing using a solvent

with a thorough flushing of clean wa−

blowgun. Repeat cleaning until solvent

ter (cold if possible).

is clear and then let element dry.

F. Transmission Lubrication Pump Oil Filter

(7).

Inspect element for cracks or dents that

Cleaning

would make it unserviceable. Replace

element if condition is questionable.

(1). Remove, in order, sound insulation,

Check condition of O−rings and replace

gearbox access cover, transmission

if damaged.

drain assembly and main transmission

cover.

(8).

Lubricate O−rings with transmission oil

and install on end of filter and in pump

(2). Remove lockwire from filter housing.

housing.

ELEMENT

O−RING

PACKING

FILTER

ELEMENT

HOUSING

O−RING

PACKING

PUMP

HOUSING

SPRING

FILTER HOUSING;

TENSION

70−100 IN. LB. (7.91−11.30 NM)

WASHER

30−009B

Figure 2-8. Transmission Lubrication Pump Oil Filter

Page 2-47

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(9). Check that tension washer is in filter

NOTE: The current drawn by the starter−gen−

housing and install element in filter

erator to maintain 10% N₁ rpm should be

housing. Check that the O−ring on the

approximately 150 amperes with 12 Vdc in−

element will seat properly in the pump

put.

housing when element is installed.

I. Engine Air Inlet Screen Cleaning

(10). Turn filter housing clockwise and

(1). Remove vertical air inlet screen.

tighten to 70 − 100 inch−pounds (7.91

(2). Clean filter screen with a soft brush to

−

11.30 Nm). Safety the filter housing

remove dirt accumulations.

to the pump housing with lockwire (2).

(3). Immerse screen assembly in a solution

(11). Replenish transmission oil supply if

of detergent soap (63, Table 2−4) and

necessary; then perform ground runup

allow to soak approximately 15 min−

of helicopter and check splitline for oil

utes. Flush out with clear water. Allow

leakage.

screen assembly to drain and air−dry

thoroughly.

(12). Reinstall, in order, the main transmis−

sion cover, the drain assembly, the main

10. Corrosion Control

gearbox access cover and sound insula−

The airframe is fabricated mainly of aluminum

tion.

and some magnesium alloys, with selective use

of stainless steel and titanium, and should be

G. Engine Fuel and Oil Filter Cleaning

checked regularly for any signs of corrosion,

especially at points of dissimilar and overlap−

Refer to the appropriate Allison Operation and

ping metal contact.

Maintenance Manual.

(1). Corrosion of dissimilar metals is the

H. Engine Compression Cleaning

result of several conditions; lack of

sufficient insulation in the areas of

Clean engine compressor according to the

metal contact, tears or punctures in the

Allison Operation and Maintenance Manual

metal itself, and areas where the

and the following limits. The Lear−Siegler

protective finishes have been scuffed,

Model Number 23032−020 starter−generator

scratched, chipped or worn away.

can be used to motor the Allison 250 Series

engine for compressor cleaning cycles each 50

(2). Inspections and maintenance precau−

or more hours. Input voltage should be 24 Vdc,

tions should be performed to inhibit the

but it is permissible to use 12 Vdc. To prevent

start of corrosive action (Ref. Standard

starter−generator damage, the duty cycle

Practices for Corrosion Prevention).

(cranking) time limits that must not be

(3). Common types of corrosion that may be

exceeded are:

encountered are described in the

following paragraphs.

24 Vdc External

24 Vdc Helicopter

Auxiliary Power

Battery Power

(4). Restoration procedures for marred but

uncorroded surfaces, as well as surfaces

25 Seconds ON

40 Seconds ON

in which corrosion is found, are given in

30 Seconds OFF

60 Seconds OFF

the touch−up procedures.

25 Seconds ON

40 Seconds ON

(5). Refer to MDHI Publication No.

30 Seconds OFF

60 Seconds OFF

CSP−A−3 Corrosion Control Manual for

a more complete treatment of this

25 Seconds ON

40 Seconds ON

maintenance area.

30 Minutes

OFF

30 Minutes

OFF

A. Standard Practices for Corrosion

12 Vdc External Auxiliary Power

Prevention

2 Minutes ON

(1). Inspection of Interior Metal Surfaces:

30 Minutes OFF

(a). Inspect primer−painted surfaces for

2 Minutes ON

scratches and other damage.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(b). Inspect finish−painted (color coated)

(a). Check that seam or joint is clean and

surfaces for condition of finish.

free of foreign matter and moisture.

(c). Inspect areas of metal overlap (faying

(b). Apply sealant with a putty knife or

similar tool.

surfaces) for evidence of corrosion.

(c). Force the sealant well down into the

(d). Inspect the attachment area of bolts,

seam to eliminate any air pockets.

screws and other fasteners for

corrosion.

(d). Fillet the sealant to give the joint or

seam a smooth appearance.

(2). Inspection of Exterior Metal Surfaces:

(5). Removal of Salt Deposits: To inhibit

(a). Inspect finish for scratches, cracks,

corrosion, helicopters operating over

peeling, fading, or other damage,

salt water and those that come in

particularly around bolts, screws,

contact with salt water or spray should

and other fasteners.

be washed with fresh water as fre−

quently as possible.

(b). Inspect normally sealed seams and

B. Magnesium Alloy Corrosion

joints for loose or missing sealing

compound.

Corrosion will not normally be present on

painted, treated or protected surfaces.

(c). Inspect exposed skin edges for

condition of corrosion−protective

Corrosion will attack magnesium when nicks

finish or sealing compound and for

or scratches through the surface protection

evidence of corrosion.

expose the metal to moisture or air. Corrosion

is present if the following conditions are in

(d). Inspect areas of metal overlap for

evidence.

evidence of corrosion.

Bare magnesium alloys, when

CAUTION

(3). Insulation of Magnesium Alloys

exposed to salt− laden air, will

Against Corrosion: To prevent galvanic

corrode very rapidly. Adequate protective fi−

corrosion between magnesium and any

nishes must at all times be maintained on

dissimilar metals:

magnesium.

(1). Whitish powdered deposits.

(a). Coat contacting surfaces with a layer

of sealing compound (3, Table 2−4) in

(2). Zinc chromate primer discoloration over

addition to the primer (4 or 7).

an area.

(b). Use 5056S aluminum alloy washers

(3). Blistering or cracking of the finish

under boltheads and nuts that would

coating.

otherwise contact magnesium. If

5056S aluminum is not available, use

C. Aluminum Alloy Corrosion

5052S alloy washers.

Corrosion will not normally be present on

aluminum surfaces that have a chemical

CAUTION

protective finish; however, because moisture

Do not use steel washers.

can permeate paint that is nicked or scratched,

corrosion might attack the metal even though

(c). Apply primer (4) on the attaching

it is painted. In such cases, the affected areas

hardware before installation.

will generally be characterized by:

(4). Application of Sealing Compound: Use

(1). A scaly or blistered appearance of the

sealing compound (3) to replace loose or

finish surface.

missing sealant on exterior surfaces.

Sealant is used to fill seams and joints

(2). A dulling and pitting of the area.

that might trap water. Apply sealant as

follows:

(3). Whitish powdered deposits.

Page 2-49

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

NOTE: To differentiate between aluminum and

(4). If protective paint coatings are not

magnesium alloy, apply one drop of ordinary

available, liberally apply a corrosion−

sulfuric acid (dropped from a glass rod) to

preventive compound or any available

the surface of the metal being tested. If the

grease to affected areas.

alloy is magnesium, a foaming or boiling ac−

F. Corrosion Arresting on Main Rotor

tion of the liquid, accompanied by a black

Blades

discoloration of the metal, will immediately

occur. If the alloy is aluminum, no reaction

The following outlines a method of arresting a

to the acid will be evidenced.

corrosive condition on main rotor blades.

Do not apply sulfuric acid to or

Wear rubber gloves when using

CAUTION

near bolts, fasteners, seams, or

phosphoric solution in next step.

faying surfaces. Immediately after complet−

(1). Wipe down main rotor blades with a 10

ing the magnesium and aluminum test,

percent phosphoric acid solution (10,

wash the tested area with water to prevent

Table 2−4).

burns and continued acid action on the ma−

terial.

(2). Rinse main rotor blades immediately

with water and wipe dry.

D. Alloy Steel Corrosion

(3). Wax main rotor blades.

Corrosion (rust) will not normally be present

on steel surfaces that have been painted;

NOTE: As a preventive measure to assist in ar−

however, surfaces may corrode where moisture

resting further corrosion the main rotor

has permeated the paint. Such corrosion will

blades should be washed with water and

be characterized by:

waxed on a weekly basis.

G. Main Rotor Hub Corrosion Prevention

(1). A reddish or brownish blistered

(Tri-Flow Wash Procedure)

appearance in the corroded area.

The following procedure will help prevent

(2). Blistering of the painted surfaces.

corrosion of main rotor hub components,

especially on helicopters operated in marine

E. Temporary Anti-Corrosion Measures

environments. The procedure should be

The temporary anti−corrosion measures

accomplished following the last flight each day

outlined here are to be used only in cases

for helicopters operated in marine or other

where the proper materials or equipment are

corrosive environments, and at each 25 hour

not available.

inspection, or more often if desired, for

helicopters not operated in corrosive environ−

These temporary anti−corro−

ments.

WARNING

sion measures apply to the

Use care when working

helicopter airframe only. If a part of

WARNING

around turning rotor blades.

the structure is corroded too badly to

Stay low. Remain on right side of heli−

withstand normal loads before the heli−

copter to avoid tail rotor blades.

copter can reach a repair station, metal

patches will have to be installed before

NOTE: Perform the first step below prior to en−

the helicopter is flown

gine shutdown, following the last flight of

the day if possible. When the rotor stops

(1). Examine part or area in question for

turning, the laminates of the strap− pack

extent of corrosion.

spread apart slightly. Contaminates col−

lected on the edges of the strap−pack assem−

(2). Remove loose paint and powdery

bly can enter the area between the lami−

products of corrosion by scraping with a

nates as they spread apart. If the rotor

sharp phenolic scraper, or brushing the

continues turning until the contaminants

area with a heavy fiber brush.

are washed away, centrifugal force will keep

(3). Wash off the affected areas with mild

the laminates compressed and not allow the

soap and clean fresh water; rinse

corrosive substances to enter the area be−

thoroughly.

tween the laminates.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(1). Bring engine to ground idle; set SCAV

I. Aluminum Alloy Exterior Surface

AIR to ON (Ref. applicable PFM).

Touch-Up Treatment

Perform the following:

NOTE:

If there is any question of whether or

(a). Spray fine fresh water mist on main

not the protective coating is removed, it

rotor blades.

should always be assumed that bare metal

is exposed.

(b). Direct a strong stream of fresh water

(1). Wash affected area with a solution of

into main rotor hub and control

mild soap and fresh water. Rinse area

system at main rotor hub.

with clean water and wipe dry with a

clean soft lint−free cloth.

(c). Spray entire rotor hub with lubricant

(149, Table 2−4).

(2). Using a swab, liberally apply chemical

film solution (8, Table 2−4).

NOTE: Lift main rotor blades to separate strap

pack laminates in next step, and spray di−

(3). Allow solution to remain on surface for

rectly between individual laminates.

1 to 3 minutes, or until surface becomes

amber to brown in color.

(2). Shut down engine. When rotor blades

stop turning, spray strap−packs with

NOTE: Avoid letting the chemical mixture dry

lubricant.

on the surface. If it has dried, re−wet the

surface with the solution.

(3). Perform engine water wash.

(4). Rinse treated surface thoroughly with

clean water. After rinsing, wipe off

(4). Wash remainder of helicopter exterior

excess moisture with a clean lint−free

using fresh water spray.

cloth. If dry compressed air is available,

(5). Wash main rotor blades with Zip Wax

blow any moisture from joints or

(150), or equivalent, mixed per man−

crevices and allow to dry completely at

ufacturer’s instructions.

room temperature for approximately

one hour.

H. Magnesium Alloy Exterior Surface

(5). Apply paint finish touch−up.

Touch-Up Treatment

J. Steel Alloy Exterior Surface Touch-Up

(1). Prepare solution of chromic acid, 20

Treatment

ounces per gallon (150 g/L), ammonium

sulfate, 14 ounces per gallon (105 g/L),

(1). Remove loose paint and corrosion

and ammonium hydroxide, 12 fluid

products by scraping area with a sharp

ounces per gallon (94 g/L). Solution pH

phenolic scraper, brushing with a heavy

should be 2.6 − 3.4 and operating

fiber brush and light sanding with 320

temperature should be ambient.

grit or finer sandpaper (9, Table 2−4).

(2). Clean painted parts for three to five

(2). Wash off the area with mild soap and

minutes in alkaline solution (Oakite 61

clean fresh water; rinse thoroughly.

or equivalent); swab unpainted parts

(3). Treat surface with surface cleaner (10)

with MEK or aliphatic naphtha.

or equivalent.

(3). Dampen clean cloth or soft brush in

(4). Allow solution to remain on surface for

prepared solution and apply to touch−

approximately five minutes. Keep

up areas for ten to thirty minutes until

surfaces wet.

desired color is produced. Color range is

from gold through yellow to brown.

(5). Rinse thoroughly roughly with clean

water. Dry with a clean lint−free cloth

(4). Rinse or swab parts thoroughly in

and then allow to air−dry completely.

clean, room temperature water. Dry;

paint as required.

(6). Apply paint finish touchup.

Page 2-51

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

11. Paint Finish

If paint remover is used in the

CAUTION

vicinity of drive shaft couplings,

ensure the couplings are completely masked

Refer to the applicable configuration supple−

and covered. if paint remover contacts the

ment for details of standard production paint

coupling diaphragms, rust spots will devel−

finish, color and color scheme. (Customized

op and coupling replacement will be re−

paint schemes are not shown.)

quired.

B. Paint Touch-Up

A. Paint Removal

Whenever possible, paint touch up should be

performed in a dust−free shelter that is free of

excessive air currents and that has ventilation

(1).

Use paint remover (11, Table 2−4)when

provisions for adequate (safe) personal

it becomes necessary to remove the

respiration.

finish paint coatings. Ordinarily, the

use of paint remover should be limited

The following items should nev−

CAUTION

to stripping of paint from parts that

er be touched up, primed or fin−

require magnetic particle or fluores−

ish−painted: rod ends containing bearings;

cent−penetrant inspection and to parts

bolts and nuts securing rod ends; decals and

that require the removal of excessive

serialization plates; transparent surfaces

paint buildup.

(canopy, etc); parts made from natural, syn−

thetic or silicone rubber; electrical bonds;

close tolerance holes; and parts continuous−

(2).

Solvent type paint remover is usually

ly coated with grease, oil or fluid.

not capable of removing the primer

NOTE: Following procedures apply to applica−

coating. However, complete removal of

tion of both polyurethane and acrylic paints.

the epoxy primer coating may not be

The primary interior finish of the helicopter

required to perform dye−penetrant

is acrylic paint. Polyurethane paint is used

inspection.

for the exterior finish on a current 369HS/

HE helicopter. The exterior of a 369HM or

(3).

If necessary, it may be possible to

early 369HS/HE helicopter is finished with

remove small amounts of primer by

acrylic paint. Polyurethane paint may be

light scrubbing of the primer surface

applied directly over acrylic paint since the

with solvent type paint remover and a

two are compatible.

stiff bristle brush. No other means,

(1). Touch up − Small Sanded Areas

short of sanding or mechanical scrap−

(Reworked Scratches, Nicks, Gouges,

ing, will prove more suitable or effective

etc):

for removal of epoxy primer except use

(a). If metal protection is not adequate,

of the acid type remover.

apply applicable chemical surface

treatment.

(4).

Whenever the acid type remover is used

(b). If chemical surface treatment is

all special safety precautions noted on

undamaged or has already been

the container must be observed. Use all

applied, wipe the surface clean with

necessary precautions to prevent the

thinner (12, Table 2−4). Wipe dry

entry of any type paint remover into

immediately.

structural seams or joints, and the joint

lines of bearings and bushings that are

(c). Apply coat of epoxy primer (7).

still assembled with the part to be

Feather primer coating onto sur−

stripped.

rounding color coat.

(d). Allow primer to air−dry for 30

minutes.

(5).

When possible, use a high pressure

water spray to rinse off paint remover

(e). Apply lacquer color coats (6), to

and paint particles and to neutralize

match original finish color, as appli−

the paint remover.

cable.

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Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(2). Touchup − Flaking or Dried Paint or

(b). Mix equal parts (1:1) of primer resin

Primer:

(109) and thinner (110). Apply one

coat to surface and allow to air−dry

(a). Using 320−grit or finer sandpaper

minimum of three hours.

(9), and wet or dry sanding method,

sand the nonadherent surface to a

(c). Apply epoxy primer and color finish

smooth feather edge with the sur−

according to step (1). above.

rounding area. Do not sand beyond

point where chemical film protection

(6). Touchup − ABS Thermoplastic Parts:

begins to show through primer.

(a). Clean surface with mild soap and

(b). Touchup sanded area according to

water. Dry thoroughly.

step (1). above.

(b). Apply one coat of lacquer according to

(3). Touchup − Primer Not Adhering to

step (1).(e).

Metal Finish:

12. Main Rotor Blade Paint

(a). Use 320−grit or finer sandpaper and

wet or dry sanding method to sand

The following procedures is to be used whenev−

through chemical film to bare metal.

er the main rotor blades require either

Feather edge the surrounding surface

repainting or paint touch−up.

with the bare surface.

NOTE:

(b). Touchup re−treated surface according

to step (1). above.

D Repaint main rotor blades only in sets to

maintain rotor balance. Never completely

(4). Touchup − Glass Fiber Laminate Parts:

repaint only one main rotor blade

installed on helicopter.

(a). Use 100−grit or coarser sandpaper to

D New main rotor blades have the inboard

abrade area requiring finish. Remove

24 inches (610 mm) painted gloss white.

all gloss until there is a uniform dull

This aids in inspection of the blade.

condition.

D At owner−operators convenience, in−ser−

(b). Wipe surface clean with 1:1 mixture

vice main rotor blades may have the in−

of MEK (22) and isopropyl alcohol

board 24 inches (610 mm) painted gloss

(71).

white.

(c). Squeeze one coat of Poly−EP (107),

A. Main Rotor Blade Paint Removal

thinned as required with thinner

(108), into fiberglass pores until

(1). Position main rotor blade on a bench of

surface of fibers is smooth.

sufficient length to provide support.

(d). Lightly sand surface with 320−grit

(2). Inspect main rotor blade (Ref. Sec. 7,

sandpaper. Normal grain appearance

Main Rotor Blade Inspection).

does not require further filling or

sanding.

When removing paint from

CAUTION

main rotor blade, do not use any

(e). Apply epoxy primer according to step

paint remover. Bonding agents used in

(1). above.

manufacture of the blade may be damaged

by the chemicals causing the blade to be un−

(5). Touchup − Polycarbonate Plastic Parts:

serviceable.

(a). Wipe surface clean with a 1:1 mix−

(3). Apply tape (14, Table 2−4) to all

ture of naphtha (59) and isopropyl

bushings, bearing, data plates and the

alcohol (71).

abrasion strip.

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(6). Apply primer to sanded areas, feather

CAUTION

into surrounding color coat.

D When sanding paint from the main rotor

(7). Allow to air−dry for one hour minimum.

blade, take care to not damage rivet heads

and sealant.

NOTE: Mix paint (148) according to manufac−

turer’s recommendations.

D Do not sand through the paint and primer

into the base metal.

(8). Allow mixed paint (148) to stand for 20

minutes minimum prior to use.

(4). Using 320 grit, or finer, abrasive paper

(9) and wet or dry sanding method,

NOTE:

sand areas that require painting.

D Working life of mixed paint is four hours

maximum.

(5). Using a soft cloth, dampened in

isopropyl alcohol (71), thoroughly clean

D Addition of freshly mixed primer to re−

main rotor blade.

plenish an older mixture is not permitted.

(6). Inspect sanded areas for damage.

(9). Apply paint to primed areas. Feather−

edge paint while applying.

B. Main Rotor Blade Paint Application

(10). Allow to air−dry for eight hours

NOTE: If inboard 24 inches (610 mm) of main

minimum.

rotor blade is to be painted white, paint is to

(11). Remove protective tape from main rotor

be applied to the entire circumference of the

blade.

blade. There is to be no ridges in the paint

when completed.

NOTE: Main rotor assembly may need to be re−

balanced after painting.

(1). Inspect main rotor blade (Ref. Sec. 7,

Main Rotor Blade Inspection).

13. Metal Tail Rotor Blade Paint

(2). Ensure all bushings, bearing, data

The following procedures is to be used whenev−

plates and the abrasion strip are

er the metal tail rotor blades require either

protected from paint with tape (14).

repainting or paint touch−up.

(3). Using a soft cloth, dampened in

NOTE: Repaint tail rotor blades only in sets to

isopropyl alcohol (71), thoroughly clean

maintain rotor balance. Never completely

main rotor blade.

repaint only one tail rotor blade installed on

helicopter.

(4). Treat any bare metal areas of main

rotor blade with chemical coating (8).

A. Metal Tail Rotor Blade Paint Removal

NOTE: Mix primer (4) according to manufac−

(1). Inspect tail rotor blade (Ref. Sec. 8,

turer’s recommendations.

Metal Blade Inspection).

(5). Allow mixed primer (4) to stand for 15

When removing paint from tail

CAUTION

rotor blade, do not use any paint

to 30 minutes prior to use.

remover. Bonding agents used in manufac−

NOTE:

ture of the blade may be damaged by the

chemicals causing the blade to be unservice−

D Working life of mixed primer is four hours

able.

maximum.

(2). Apply tape (14, Table 2−4) to all

D Primer allowed to stand for more than

bushings, data plates and the abrasion

two hours must be stirred or shaken be−

strip.

fore use.

D Addition of freshly mixed primer to re−

(3). Plug root end of tail rotor blade to

plenish an older mixture is not permitted.

ensure no paint enters.

Page 2-54

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MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

NOTE: Mix paint (148) according to manufac−

CAUTION

turer’s recommendations.

D When sanding paint from the tail rotor

(9). Allow mixed paint (148) to stand for 20

blade, take care to not damage rivet heads

minutes minimum prior to use.

and sealant.

D Do not sand through the paint and primer

NOTE:

into the base metal.

D Working life of mixed paint is four hours

maximum.

(4). Using 320 grit, or finer, abrasive paper

(9) and wet or dry sanding method,

D Addition of freshly mixed primer to re−

sand areas that require painting.

plenish an older mixture is not permitted.

(5). Using a soft cloth, dampened in

(10). Apply paint to primed areas. Feather−

isopropyl alcohol (71), thoroughly clean

edge paint while applying.

tail rotor blade.

(11). Allow to air−dry for eight hours

(6). Inspect sanded areas for damage.

minimum.

B. Metal Tail Rotor Blade Paint Application

(12). Remove protective tape from tail rotor

blade.

(1). Inspect tail rotor blade (Ref. Sec. 8,

Metal Blade Inspection).

NOTE: Tail rotor assembly may need to be re−

(2). Ensure all bushings, data plates and

balanced after painting.

the abrasion strip are protected from

paint with tape (14).

14. Fluid Leak Analysis

(3). Ensure root end of tail rotor blade is

A. Main Rotor or Tail Rotor Transmission Oil

plugged to prevent entry of paint.

Leaks

(4). Using a soft cloth, dampened in

Oil leakage, seepage or capillary wetting at oil

isopropyl alcohol (71), thoroughly clean

seals assembly joint lines of main or tail rotor

tail rotor blade.

transmission are permissible if leakage rate

does not exceed 2 cc per hour (one drop per

(5). Treat any bare metal areas of tail rotor

minute). An acceptable alternate rate of

blade with chemical coating (8).

leakage from either transmission is, if oil loss

is not more than from full to the add mark on

NOTE: Mix primer (4) according to manufac−

sight gage within 25 flight hours. Repair leaks

turer’s recommendations.

according to instructions in CSP−H−5.

(6). Allow mixed primer (4) to stand for 15

NOTE: On transmission input and output pin−

to 30 minutes prior to use.

ion gear oil seals with less than 2 hours of

NOTE:

operation, some seepage or wetting of adja−

cent surfaces is normal until seal is wetted

D Working life of mixed primer is four hours

and worn−in (seated). If seepage continues

maximum.

at rate of one drop per minute or less, seal

D Primer allowed to stand for more than

may be continued in service. Check trans−

two hours must be stirred or shaken be−

mission oil level and observe seepage rate

fore use.

after every 2 hours of operation. Shorter in−

spection periods may be required if seal

D Addition of freshly mixed primer to re−

leakage appears to be increasing.

plenish an older mixture is not permitted.

(7). Apply primer to sanded areas, feather

NOTE: If excessive tail rotor gearbox oil seep−

into surrounding color coat.

age occurs, check breather filler for sticky

piston (Ref. CSP− H− 5 for cleaning proce−

(8). Allow to air−dry for one hour minimum.

dures).

Page 2-54A

Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

B. Engine Oil Leaks

damper is not replaced when leakage is

noticed, continuation of damper in service can

Refer to the appropriate Allison Operation and

cause internal damage that might otherwise

Maintenance Manual for definition of permis−

not occur.

sible engine oil leakage.

NOTE: It is normal for a thin hydraulic oil film

C. Landing Gear Damper Hydraulic Fluid

to remain on the damper piston as a result

Leaks

of wiping contact with the piston seal. New−

Hydraulic fluid leakage from any of landing

ly installed dampers may also exhibit slight

gear dampers is not permissible. When

oil seepage caused by oil trapped in the end

leakage is observed, the damper assembly

cap threads during damper assembly. Nei−

should be overhauled as required and service−

ther of these should be construed as damper

able unit installed. If leaking landing gear

leakage or cause for damper replacement.

IF REQUIRED, REDUCE WIDTH OF

6.0 IN. (15 CM) MACHINIST SCALE

TO LESS THAN 0.50 IN (12.70 MM).

CLUTCH CL

CLUTCH OUTPUT SHAFT

CLUTCH

0.875 IN (22.23 MM)

(13 CC; NOTE 2)

ENGINE

FULL OIL LEVEL

2.875 IN (7.30 CM)

4−7/8 IN.

(12.38 CM)

COUPLING BOLT

COUPLING

(TYP) 50−70 IN. LB.

O−RING

(5.65−7.91 NM)

DRAIN HOLES

COUPLING BOLT;

WASHER

50−70 IN. LB.

WASHER

(5.65−7.91 NM) (TYP)

NOTES:

MAIN TRANSMISSION

DRAG TORQUE FOR BOLTS (SELF−LOCKING)

DRIVE SHAFT

SERVICEABILITY IS 25 IN. LB. (2.82 NM) MIN,

200 IN. LB. (22.60 NM) MAX.

COUPLING BOLT;

MINIMUM ALLOWABLE OIL QUANTITY

250−300 IN. LB. (28.25−33.90 NM)

PERMITTING REFILL WITHOUT REPAIR.

PLUS DRAG TORQUE (NOTES 1, 3)

IF OIL QUATITY IS LESS, CLUTCH MUST

BE REPAIRED AS REQUIRED BY HMI APPX C.

COAT COUPLING BOLT THREADS WITH

ANTI−SEIZE COMPOUND (36, TABLE 2−4)

BEFORE REASSEMBLY.

30−010K

Figure 2-9. Checking Overrunning Clutch Oil Level

Page 2-54B

Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

D. Overrunning Clutch Oil Leak Analysis

(a). Full oil level will read 2−7/8 inches

and Servicing

(7.30 cm) on LOWER edge of 6 inch

(15.24 cm) scale. Recheck reading a

(Ref. Figure 2−9) When oil leakage or seepage

minimum of three times.

is noticed at the oil seals or assembly joint

(b). Minimum allowable oil quantity (13

lines of the overrunning clutch, the clutch

cc of trapped oil) will read 7/8 inch

requires further inspection and investigation

(2.22 cm) on bottom edge of scale.

as follows.

Recheck reading a minimum of three

times.

CAUTION

NOTE: If oil quantity is less than 13 cc, the

D Mixing of oils within an oil series, not in

clutch must be removed for repair according

the same group, is not recommended. If

to instructions in CSP−H−5.

oils of different groups are mixed, flush

(7). Service clutch with lubricating oil

and re−service overrunning clutch.

(Table 2−3) if oil level readings indicate

D Checking clutch oil level requires removal

less than the full level. Do not overfill.

of the main transmission drive shaft. Do

Recheck oil level.

not stress the drive shaft diaphragms

(8). If coupling was removed, shim coupling

during shaft removal and installation. Di−

so that there is 0.035−0.055 inch

aphragm deflection is limited because of

(0.889−1.397 mm) O−ring gap from end

material hardness.

of clutch shaft to face of coupling recess

(surface that bolt head contacts).

(1).

Remove, in order, the sound insulation,

Measure gap with feeler gage.

gearbox access cover, and transmission

drain assembly.

When installing the clutch cou−

CAUTION

pling bolt in the installation

(2).

Remove four bolts and washers from

torque on the bolt must not be less than

each end of main transmission drive

250 − 300 inch pounds (28.25 − 33.90

shaft. Carefully slide shaft from drive

Nm). Torquing to a lower value will reduce

couplings; do not strike shaft against

clutch bearing clamp−up and possibly lead

any object.

to bearing race spinning.

(3).

Remove bolt and O−ring packing from

(9). Coat bolt threads with anti−seize

end of clutch.

compound (36). Install coupling bolt

and O−ring packing. Check drag

(4).

On helicopters with clutch housing

torque for bolt self locking service−

drain holes, check that the three drain

ability is 25 inch−pounds (2.82 Nm)

holes are clean and free of obstruction.

minimum, 200 inch−pounds (22.60

Oil leakage may indicate engine power

Nm) maximum. Torque bolt to 250 −

output seal leakage if clutch oil level is

300 inch−pounds (28.25 − 33.90 Nm)

checked and found within limits.

plus drag torque.

(5).

Using a CLEAN, 6 inch (15.24 cm)

(10). Position main transmission drive shaft

machinists scale, 1/2 inch (12.7 mm)

between drive couplings and install.

width, slowly insert the scale into

(11). Reinstall, in order, the transmission

center of clutch output shaft until scale

drain assembly, gearbox access cover,

bottoms. Scale must be inserted 4−7/8

and the sound insulation.

inches (12.38 cm).

E. One-W ay Lock (Uniloc) Fluid Leak

NOTE: Reduce 1/2 inch (12.7 mm) scale width

as required to allow scale to bottom in

Hydraulic fluid leakage from any part of the

clutch.

one−way lock is not permissible. When leakage

is observed the assembly should be overhauled

(6). Read scale to determine oil level and

as required and a serviceable unit installed. If

servicing required.

a leaking one−way lock is not replaced when

Page 2-55

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

leakage is noticed, continuation in service may

(g). Install a static ground.

result in mechanical malfunction that could be

(3). Return to Service:

hazardous to safety of flight.

(a). Remove covers and equipment used

15. Preservation and Storage

to park and moor the helicopter.

Helicopters to be put in storage or non−opera−

(b). Perform a preflight inspection.

tional status must get adequate inspection,

maintenance and preservation to avoid

B. Storage up to 45 Days

unnecessary deterioration of the airframe,

(1). Inspection During Storage:

components or equipment during the storage

or non−operational interval. The extent of

(a).

Where local average humidity

preventive maintenance that should be

exceeds 40 percent carefully inspect

performed will depend on the anticipated time

the helicopter every 15 days for

in storage. The following paragraphs establish

corrosion. Apply corrosion control as

what should be performed on a helicopter: for

necessary. In conducting an inspec−

flyable storage; for up to 45 days in storage;

tion for corrosion, pay particular

and for up to 6 months in storage.

attention to those area where mois−

ture deposits will not evaporate

A. Flyable Storage (No Time Limit)

rapidly.

(1). Inspection Before Storage:

(b).

Where local average humidity is 40

(a). Perform a preflight inspection.

percent or less, inspect for corrosion

every 30 days.

(b). Ensure that fuel cells are full (topped

off), and that the engine oil tank and

(c).

If interior temperature of fuselage

rotor transmissions are at the FULL

exceeds 160°F (71°C), ventilate

level.

helicopter by opening all doors and

vents. If necessary, promote air

(2). Storage: To maintain a flyable storage

circulation by use of fans or other

condition, perform daily inspection. A

forced air equipment.

ground runup must also be performed

at least once every 5 days.

(d).

Ensure that fuel cells are full (topped

off) and that the rotor transmissions

(a). Perform a preflight inspection.

are at the FULL level.

(b). Start the engine (Ref. PFM). After

(e).

Drain fuel cell sump daily. (Replenish

idle has stabilized, accelerate the

fuel as necessary.)

engine to 100 percent N₂ collective

full down. Operate until the oil

(f).

Check fuel and oil systems periodical−

temperature is in normal operating

ly for leakage. Repair as necessary.

range and ammeter indicates battery

(2). Storage:

is fully charged.

(a). Perform engine preservation accord−

(c). Drain fuel cell sump (Ref.

ing to the engine operation and

Figure 2−5). (Replenish fuel as

maintenance manual and current

necessary.)

engine service letters.

(d). Ensure that fuel shutoff valve is

(b). Remove battery and store it in a cool,

closed.

dry area.

(e). Open movable air vents in each door

(c). Clean the battery compartment, if

of the cargo compartment. Position

necessary.

opening in each air vent downward.

Close all other vents.

(d). Ensure that the fuel shutoff valve is

closed.

(f). Install covers and equipment used to

park and moor helicopter.

(e). Clean entire helicopter.

Page 2-56

Revision 20

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(f). Inspect all drain holes (blades,

(b).

Drain the engine oil system and fill

fuselage, etc) for obstructions and

the engine oil tank with corrosion

clear them where necessary.

preventive (13, Table 2−4).

(g). Open movable air vents in each door

(c).

Remove battery and store it in a cool,

of cargo compartment. Position

dry area.

opening in each air vent downward.

(d).

Clean the battery compartment, if

Close all other air vents.

necessary.

(h). Install main rotor blade covers, if on

(e).

Ensure that the fuel shutoff valve is

hand. Park and moor the helicopter.

closed.

(i). Install a static ground.

(f).

Seal static source openings in the

engine inlet fairing with tape (14)

(j). Remove from the area any objects

and cover pitot tube with pitot cover

that are likely to strike the helicopter

(4, Table 2−2).

during high wind conditions.

(g).

Clean entire helicopter.

(3). Return to Service:

(h).

Inspect all drain holes (blades,

(a). Check that the battery area is clean;

fuselage, etc) for obstructions and

then install and connect battery.

clear them where necessary.

(b). Check that fuel cells are full.

(i).

Spray or brush on the canopy and all

windows a 0.008 inch (0.2032 mm)

(c). Remove covers and equipment used

thickness of protective coating (15,

to park and moor the helicopter.

Table 2−2). Cover and overlap all

edges.

(d). Inspect areas around mooring

attachments for damage. Repair

(j).

Inspect all external access doors for

damage as necessary.

close fit. If doors are likely to admit

moisture, seal edges with tape.

(e). Clean the helicopter, as necessary.

(k).

Install main rotor blade covers, if on

(f). Check that all drain holes in helicop−

hand. Park and moor helicopter.

ter are free of obstructions.

(l).

Install a static ground.

(g). Perform a preflight inspection.

(m).

Remove from the area any objects

that are likely to strike the helicopter

C. Storage up to 6 Months

during high wind conditions.

(1). Inspection During Storage:

(3). Return to Service:

(a). Perform same inspection as for 45

(a). Carefully lift protective coating along

days of storage.

the edges and peel it from the canopy

and windows.

(b). Check rotor blades for damage every

15 days.

(b). Remove masking tape from all

external access doors.

(c). Check areas around mooring attach−

ments for damage every 15 days.

Do not use steam or unautho−

CAUTION

rized cleaning compounds to

(2). Storage:

clean the helicopter as damage to equip−

ment may result.

(a). Perform engine preservation accord−

ing to the engine operation and

(c). Drain corrosion preventive from the

maintenance manual and current

oil tank and replenish with correct oil

engine service letters.

(Table 2−3).

Page 2-57

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(d). Perform same procedures as for

(d).

The turning (drag) torque required to

return to service after 45 days of

install self−locking nut or bolt up to

storage.

point of final tightening must always

be added to the final torque value or

NOTE: Depreservation of the engine fuel sys−

the maintenance instruction, as

tem can usually be accomplished by making

applicable.

a normal start. (Refer to the engine opera−

tion and maintenance manual, and current

(e).

Torques specified in handbook

engine service letters for engine depreserva−

maintenance instructions are special

tion procedures.)

torque that take precedence over

those listed in Table 2−5 thru

16. Torque Data

Table 2−8.

A. Torque Wrenches

(f).

If adapters are used such that the

Torque wrenches should be of good quality and

adapter and the torque wrench are

must be calibrated at least every 90 days to

not at right angles (90°) to each

other, wrench or indicator reading

verify accuracy. Torque wrench accuracy at

must be corrected.

room temperature, 70°F (21°C) must be within

the following limits.

(g).

Any reuse of self−locking nuts over

(1). From zero thru 19 percent of the torque

3/8 inch will be governed by the

wrench range, the error may not exceed

values in Table 2−8.

±7 percent of the load applied.

(h).

The bolt must not be rotated during

(2). From 20 thru 79 percent of the torque

installation or torquing of the mating

wrench range, the error may not exceed

nut.

±4 percent of the load applied.

(3). From 80 thru 100 percent of the torque

NOTE: All special (non−standard) torque val−

wrench range, the error may not exceed

ues appearing in Table 2−9

±5 percent of the load applied.

(2).

Installation of Castellated Nuts on

17. Torque Wrench Load Application

Non−rotating (Static) Parts: Finger−

tighten the nut on installation. Turn

Recommended tightening torque values and

the nut a minimum of 60 degrees and a

minimum drag torque values for fine and

maximum of 110 degrees (or the next

coarse thread nuts, and minimum breakaway

slot after 60 degrees of rotation) past

torque for used self−locking bolts or screws are

finger−tight and insert and secure

shown in Table 2−5 thru Table 2−8.

cotter pin for final installation. Maxi−

mum applied torque must not exceed

(1). Requirements Governing Application of

the applicable values in Table 2−5 and

Torque Loads:

Table 2−6.

(a). The values apply to cadmium− plated

(3).

Installation of Castellated Nuts on

bolts, cadmium−plated nuts and nuts

Rotating (Dynamic) Parts: When

coated with molybdenum disulfide

tightening castellated nuts and bolts, it

(MoS2).

is possible that the cotter pin holes will

(b). Manufacturer−applied lubricant

not line up with the slots in the nuts for

must not be removed nor additional

the range of recommended installation

lubricant added.

torques. In such a case, the nut may be

overtighten just enough to line up the

(c). The bolts, nuts and surfaces they

nearest slot with the cotter pin hole,

bear on must be clean, dry and free of

but the maximum applied torque must

lubricant (except as stated in step (b).

not exceed the applicable values in

above).

Table 2−5 and Table 2−6.

Page 2-58

Revision 20

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(4). Installation of Self−Locking Tension−

which are all metal and non−metallic

and Shear−Type Nuts:

which have non−metallic locking

inserts. Non−metallic self−locking

NOTE: Non−metallic self−locking nuts should

nuts should not be subject to temper−

not be subjected to temperatures in excess of

atures in excess of 250°F (121°C).

250°F (121°C).

(b). Self−locking bolts come in three

(a). Use torques in Table 2−5 for tension−

general types: a round pellet, a hex

type cadmium−plated steel nuts.

pellet or a strip type insert is placed

in the threaded area to provide the

(b). Use torques in Table 2−6 for shear−

self−locking feature. In addition to

type cadmium−plated steel nuts.

checking for breakaway torque

(5). Installation of Bolts − General:

values listed in Table 2−8, the bolts

should be checked for loose or miss−

(a). If bolt can be inserted through the

ing inserts.

material and started into the nut by

fingers, use the applicable torque in

NOTE: Burrs on cotter pin holes tend to tear

Table 2−5 and Table 2−6.

the non−metallic inserts.

(b). If installing the bolt in a close

(c).

Bolts, nuts or screws of 5/16 inch

tolerance hole, or under other

(7.94 mm) diameter and over with

conditions that increase the tighten−

cotter pin holes may be used with

ing resistance, torque to the high

self−locking nuts provided the cotter

limit of the applicable recommended

pin holes are free from burrs.

torque in Table 2−5 and Table 2−6.

(d).

Bolts and screws of 1/4 inch (6.35

mm) diameter and under with cotter

(6). Installation of Bolts Into Threaded

Parts:

pin holes may be used with self−lock−

ing nuts only in an emergency for one

(a). When installing the bolt into a

time flight. They will be replaced

threaded part, use the applicable

before the next flight with the

torque in Table 2−5 if the mating

specified type.

thread length is equal to or greater

(e).

Self−locking nuts will not be used at

than one diameter of the bolt.

joints in control systems of the

(b). Use Table 2−6 if the mating thread

helicopter when movement of the

length is less than one diameter of

joint may result in motion of the nut

the bolt.

relative to the surface against which

it is bearing.

NOTE: The requirements in steps (5). and (6).

above also apply to thread inserts.

(f).

Self−locking nuts may be used with

anti−friction bearings and control

(7). Installation of Used Self−Locking Bolts

pulleys provided the inner race of the

or Screws: New self−locking nuts or

bearing is clamped to the supporting

bolts provide tight connections which

surfaces by the nut and bolt.

will not loosen under vibration. Self−

locking nuts or bolts approved for use

(g).

The nuts which are attached to the

on helicopters meet critical specifica−

structure must be attached in a

tions as to strength, corrosion−resis−

positive manner to eliminate the

tance and temperatures. Reuse of

possibility of their rotating or misal−

self−locking nuts or bolts are limited to

igning when the tightening is to be

those nuts and bolts that meet the

accomplished by rotating the bolts or

minimum requirements established in

screws.

Table 2−7 and Table 2−8 for drag or

(h).

The manner of attachment must

breakaway torque values.

permit removal without injury to the

(a). Self−locking nuts come in two

structure and the replacement of the

general types: metallic lock type

nuts.

Page 2-59

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(i). Round or chamfered−end bolts must

ing units of one system into different but

extend at least the full round or

related units of other systems.

chamfer through the nut.

20. Related Publications

(j). Flat end bolts must extend at least

1/32 inch (0.794 mm) through the

Table 2−15 provides a listing of publications

nut.

and directives that form part of the available

information file for maintenance of helicopter

18. Installation, Staking or Swaging Force

components.

Needed for Bearings

21. Maintenance Information Requests

The following procedure explains how to

convert from a given ‘‘Force’’ which is required

Questions that may arise during maintenance

to perform a given task to a proper hydraulic

of the helicopter or it’s components should,

pressure reading.

when possible, be referred to the company’s

(1). Determine the diameter of the ram on

Field Service Representative assigned to the

the hydraulic press to be used.

geographic area in which the helicopter is

being operated. Should there be no factory

NOTE: The hydraulic press to be used must

representative in the area, contact Customer

have a pressure gauge.

Service, MDHI, Mesa, Arizona or the manufac−

turer of the component as appropriate.

(2). Divide the ram diameter by two to get

Table 2−15 lists manufacturers of major

the radius.

components, and addresses.

(3). Multiply 3.14159 (pi, π) times the

22. Inspection Practices and Technical

Radius squared (R²). This will give the

Definitions

area of the ram.

(4). Divide the force required for the task by

Inspection procedures and serviceability

the area of the ram. This gives the

(wear) tolerances for maintenance of the

actual PSI reading for the hydraulic

helicopter are provided either as part of the

press pressure gauge needed to perform

instructions for reassembly and installation of

the task.

components or in inspection and repair

paragraphs. Any damage or wear of a part that

EXAMPLE:

exceeds the given tolerance or that affects the

function and/or integrity of the part is cause

(a). Ram Diameter = 2.65 inch

for replacement with a new or serviceable unit.

Definitions of technical terms normally

(b). Ram Radius (R) = 1.325 inch

associated with the inspection and repair of

the helicopter and its components are shown in

(c). Radius squared (R2 ) = 1.756

Figure 2−10 and listed in Table 2−16.

(d). R2 x 3.14159 = 5.517 (Area of ram)

23. Service and Operations Report Form 853

(e). Force required = 7500−8500 pounds

(variable)

MDHI Service and Operations Report Form

853 may be used to report to MDHI in detail

(f).

7500−8500 = 1359−1540 PSI

any service difficulties encountered with any

MDHI helicopter. Use of the form is encour−

(g). PSI Required = 1359 PSI Minimum

aged and recommended to enable MDHI to

1540 PSI Maximum

provide Owner’s and Operator’s improved

FORCE NEEDED

= Pressure Gauge Reading

service,support and product improvements.

(R2 ) x 3.14159

The form also serves a convenient detailed

record for Owner’s and Operator’s. Copies of

19. Useful Conversion Data

the form may be procured by contacting the

Table 2−10 thru Table 2−14 provide useful

Customer Service Department − Commercial

information for converting common engineer−

Service Publications.

Page 2-60

Revision 20

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-5. Recommended Standard Torques for Tension-T ype Nut:

Min. and Max. Torque Values; AN310, AN365, MS20365, MS21042, NAS1021, NAS1291, NAS679

Recommended

Maximum

Recommended

Maximum

Thread

Torque

Allowable

Torque

Allowable

Size

in. lb (Nm)

12 - 15

8 - 36

8 - 32

(1.13

- 1.36)

(2.26)

(1.36

- 1.69)

(2.26)

20 - 25

10 - 32

10 - 24

(2.26

- 2.82)

(4.52)

(2.26

- 2.82)

(3.95)

50 - 70

100

40 - 50

1/4 - 28

1/4 - 20

(5.65

- 7.91)

(11.30)

(4.52

- 5.65)

(8.47)

100 - 140

225

80 - 90

160

5/16 - 24

5/16 - 18

(11.30

- 15.82)

(25.42)

(9.04

- 10.17)

(18.08)

160 - 190

390

160 - 185

275

3/8 - 24

3/8 - 16

(18.08

- 21.47)

(44.06)

(18.08

- 20.90)

(31.07)

450 - 500

840

235 - 255

475

7/16 - 20

7/16 - 14

(50.84

- 56.49)

(94.91)

(26.55

- 28.81)

(53.67)

480 - 690

1100

400 - 480

880

1/2 - 20

1/2 - 13

(54.23

- 77.96)

(124.3)

(45.19

- 54.23)

(90.39)

800 - 1000

1600

500 - 700

1100

9/16 - 18

9/16 - 12

(90.39

- 112.98)

(180.8)

(56.49

- 79.09)

(124.3)

1100 - 1300

2400

700 - 900

1500

5/8 - 18

5/8 - 11

(124.3

- 146.9)

(271.2)

(79.09

- 101.69)

(169.5)

2300 - 2500

5000

1150 - 1600

2500

3/4 - 16

3/4 - 10

(259.9

- 282.5)

(565.0)

(129.95

- 180.8)

(282.5)

2500 - 3000

7000

2200 - 3000

4600

7/8 - 14

7/8 - 9

(282.5

- 339.0)

(791.0)

(248.6

- 339.0)

(542.4)

3700 - 5500

10000

3700 - 5000

7600

1 - 14

1 - 8

(418.1

- 621.5)

(1130.0)

(418.1

- 565.0)

(858.8)

5000 - 7000

15000

5500 - 6500

12000

1-1/8 - 12

1-1/8 - 8

(565.0

- 791.0)

(1695.0)

(621.5

- 734.5)

(1356.0)

9000 - 11000

25000

6500 - 8000

16000

1-1/4 - 12

1-1/4 - 8

(1017.0

- 1243.0)

(2825.0)

(734.5

- 904.0)

(1469.0)

Page 2-61

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-6. Recommended Standard Torques for Shear-Type Nut:

Min. and Max. Torque Values; AN320, AN364, MS20364, NAS1022, MS21083

Recommended

Maximum

Recommended

Maximum

Thread

Torque

Allowable

Torque

Allowable

Size

in. lb (Nm)

7 - 9

8 - 36

8 - 32

(0.79

- 1.02)

(1.36)

(0.79

- 1.02)

(1.36)

12 - 15

10 - 32

10 - 24

(1.36

- 1.69)

(2.82)

(1.36

- 1.69)

(2.37)

30 - 40

25 - 30

1/4 - 28

1/4 - 20

(3.39

- 4.52)

(6.78)

(2.82

- 3.39)

(5.08)

60 - 85

140

48 - 55

100

5/16 - 24

5/16 - 18

(6.78

- 9.60)

(15.82)

(5.42

- 6.21)

(11.30)

95 - 110

240

95 - 110

170

3/8 - 24

3/8 - 16

(10.73

- 12.43)

(27.12)

(10.73

- 12.43)

(19.21)

270 - 300

500

140 - 155

280

7/16 - 20

7/16 - 14

(30.51

- 33.90)

(56.49)

(15.82

- 17.51)

(31.64)

290 - 410

660

240 - 290

520

1/2 - 20

1/2 - 13

(32.77

- 46.32)

74.57)

(27.12

- 32.77)

(58.75)

480 - 600

960

300 - 420

650

9/16 - 18

9/16 - 12

(54.23

- 67.79)

(108.47)

(33.90

- 47.45)

(73.44)

660 - 780

1400

420 - 540

900

5/8 - 18

5/8 - 11

(74.57

- 88.13)

(158.2)

(47.45

- 61.01)

(101.69)

1300 - 1500

3000

700 - 950

1500

3/4 - 16

3/4 - 10

(146.9

- 169.5)

(339.0)

(79.09

- 107.34)

(169.5)

1500 - 1800

4200

1300 - 1800

2700

7/8 - 14

7/8 - 9

(169.5

- 203.4)

(474.6)

(146.9

- 203.4)

(305.1)

2200 - 3300

6000

2200 - 3000

4500

1 - 14

1 - 8

(248.6

- 372.9)

(678.0)

(248.6

- 339.0)

(508.5)

3000 - 4200

9000

3300 - 4000

7200

1-1/8 - 12

1-1/8 - 8

(339.0

- 474.6)

(1017.0)

(372.9

- 452.0)

(813.6)

5400 - 6600

15000

4000 - 5000

10000

1-1/4 - 12

1-1/4 - 8

(610.2

- 745.8)

(1695.0)

(452.0

- 565.0)

(1130.0)

Page 2-62

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-7. Self-Locking Nut Minimum Run-On Torque Values

Fine Thread Series

Minimum Drag

Thread Size

in. lb (Nm)

7/16 - 20

8 (0.90)

7/16 - 14

8 (0.90)

1/2 - 20

10 (1.13)

1/2 - 13

10 (1.13)

9/16 - 18

13 (1.47)

9/16 - 12

14 (1.58)

5/8 - 18

18 (2.03)

5/8 - 11

20 (2.26)

3/4 - 16

27 (3.05)

3/4 - 10

27 (3.05)

7/8 - 14

40 (4.52)

7/8 - 9

40 (4.52)

1 - 12

55 (6.21)

1 - 8

51 (5.76)

1-1/8 - 12

73 (8.25)

1-1/8 - 7

68 (7.68)

1-1/4 - 12

94 (10.62)

1-1/4 - 7

88 (9.94)

Table 2-8. Minimum Breakaway Torque For Used Self-locking Bolts or Screws

Fine Thread Series (UNF)

Coarse Thread Series (UNC)

Minimum Drag

Thread Size

in. lb (Nm)

4 - 40

0.5

(0.06)

6 - 32

1.0

(0.11)

8 - 32

1.5

(0.17)

10 - 32

2.0

(0.23)

10 - 24

2.0

(0.23)

1/4 - 28

3.5

(0.40)

1/4 - 20

4.5

(0.51)

5/16 - 24

6.5

(0.73)

5/16 - 18

7.5

(0.85)

3/8 - 24

9.5

(1.07)

3/8 - 16

12.0

(1.36)

7/16 - 20

14.0

(1.58)

7/16 - 14

16.5

(1.86)

1/2 - 20

18.0

(2.03)

1/2 - 13

24.0

(2.71)

9/16 - 18

24.0

(2.71)

9/16 - 12

30.0

(3.39)

5/8 - 18

32.0

(3.62)

5/8 - 11

40.0

(4.52)

3/4 - 16

50.0

5.65)

3/4 - 10

60.0

(6.78)

7/8 - 14

70.0

(7.91)

7/8 - 9

82.0

(9.27)

1 - 12

90.0

(10.17)

1 - 8

110.0

(12.43)

1-1/8 - 12

117.0

(13.22)

1-1/4 - 12

143.0

(16.16)

Page 2-63

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

If any size self−locking nut un−

NOTE:

CAUTION

der 3/8 inch (9.525 mm) can be

D The final torque value for self− locking

run down with the fingers after the locking

nuts must be determined by adding the

feature engages the bolt or stud, indicating

free running torque (torque wrench read−

the locking friction does not exist, the nut or

ing) to the specified torque value. The free

friction device must be replaced. These val−

running torque (drag torque) is the torque

ues for self−locking nuts over 3/8 inch (9.525

required to overcome the friction of the

mm) are to be used only for determining con−

nut running down the bolt threads prior

tinued serviceability. The values apply only

to tightening.

when the nut is being run down on the mat−

D Minimum breakaway torque will be the

ing threads prior to reaching the clamp−up

minimum torque required to start remov−

point. Standard torque values for final

al (turning) of the bolt or screw from the

tightening are shown in Table

2−5 hru

installed position. The installed position

Table 2−8.

is after the self−locking device of the bolt

or screw has been completely engaged

plus two or three turns of engagement.

Table 2-9. Special Torques

Torque

Location

in. lb.

(Nm)

ft. lb.

(Nm)

Transmission and Drive System

Main transmission mounting nuts

60-80

(6.78-9.04)

Main transmission lubrication pump attach nuts

50-70

(5.65-7.91)

Oil pressure sender

30-40

(3.39-4.52)

Oil temperature sender

12-25

(1.36-2.82)

Main transmission oil level sight plug

80-90

(9.04-10.17)

Main rotor drive shaft head hoisting eyebolts nuts

120-140

(13.56-15.82)

Main rotor drive shaft head attach nuts

120-140

(13.56-15.82)

Main transmission output pinion/tail rotor drive shaft coupling

250-300

(28.25-33.90)

bolts

Main transmission input pinion coupling bolt

250-300

(28.25-33.90)

Overrunning clutch coupling bolt

250-300

(28.25-33.90)

Main transmission drive shaft coupling flange attach bolts

50-70

(5.65-7.91)

Oil cooler blower scroll to transmission attach bolts

5-10

(0.56-1.13)

Oil cooler blower driven pulley

160-190

(18.08-21.47)

Oil cooler blower impeller shaft fiber locknut

250-300

(28.25-33.90)

Tail rotor transmission output cover attach bolts

65-70

(7.34-7.91)

Tail rotor transmission chip detector valve:

body

50-60

(5.65-6.78)

detector

40-50

(4.52-5.65)

Tail rotor transmission breather-filler

45-55

(5.08-6.21)

Tail rotor transmission liquid level plug

50-60

(5.65-6.78)

Tail rotor gearbox coupling bolt

250-300

(28.25-33.90)

Tail rotor drive shaft coupling flange attach bolts

80-100

(9.04-11.30)

Deleted

Main Rotor and Controls System

Rotor tracking magnetic pickup nut

15 - 20

(20-26)

Forward tip cap and tracking tip cap attaching screws

15-20

(1.69-2.26)

Blade vibration absorber attach bolts:

long

50-60

(5.65-6.78)

short

15-20

(1.69-2.26)

Main rotor pitch control bearing attach nuts

50-70

(5.65-7.91)

Page 2-64

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-9. Special Torques (Cont.)

Torque

Location

in. lb.

(Nm)

ft. lb.

(Nm)

Main rotor mast nut

200 - 250

(271-339)

Main rotor damper attach nuts

50-70

(5.65-7.91)

Main rotor damper arm to damper attach nut

30-60

(3.39-6.78)

Pitch control rod upper attach nut

60-140

(6.78-15.82)

Pitch control rod lower attach nut

30-60

(3.39-6.78)

Scissors link to crank attach nut

30-40

(3.39-4.52)

Scissors link to swashplate attach nut

30-60

(3.39-6.78)

Scissors crank to hub nut

30-60

(3.39-6.78)

Swashplate bearing retainer nuts

50-70

(5.65-7.91)

Swashplate bearing flange to stationary swashplate nuts

30-40

(3.39-4.52)

Tracking interrupter (369A9946 -23 & -25) attach nuts

15-20

(1.69-2.26)

Tracking interrupter (369A9946 -27 & -29) attach nuts

30-60

(3.39-6.78)

Mixer support bracket to mast base attach nuts

80-100

(9.04-11.30)

Torque tube bungee adjusting bolt

30-40

(3.39-4.52)

Fuselage

Main rotor mast holddown bolts

700-820

(79.09-92.65)

58 - 68

(79-92)

Main rotor mast studs

160-190

(18.08-21.47)

Tail Rotor and Control System

Spar to strap assembly bolts and nuts, tail rotor blade

600-650

(67.79-73.44)

50 - 54

(68-73)

Pitch control link to swashplate bolt

50-80

(5.65-9.04)

Pitch control link to pitch control arm

50-80

(5.65-9.04)

Tail rotor retaining nut (Ref. Sec. 8 for torquing method)

400-450

(45.19-50.84)

Left pedal bushing bolt

50-80

(5.65-9.04)

Bellcrank support to mast structure attach nuts

80-100

(9.04-11.30)

Hub threaded bushing

60-65

(6.78-7.34)

Hub to fork hinge bolt and nut

170-210

(19.21-23.73)

Servicing and General Maintenance

Engine accessory gearbox chip detector

50-60

(5.65-6.78)

Tail rotor transmission breather/filler

50-60

(5.65-6.78)

Main transmission self-closing valves

50-60

(5.65-6.78)

Main transmission lubrication pump oil filter housing

70-100

(5.65-11.30)

Main transmission chip detectors (without knurled detector

40-50

(4.52-5.65)

knob)

Tail rotor transmission chip detector

40-50

(4.52-5.65)

Main transmission drain assembly nut

10 (1.13) max.

Overrunning clutch coupling bolt

250-300

(28.25-33.90)

Main transmission drive shaft coupling flange attach bolts

50-70

(5.65-7.91)

Tailboom and Tail Surfaces

Tailboom attach nuts

200-240

(22.60-27.12)

Upper vertical stabilizer forward attach bolts

50-70

(5.65-7.91)

Upper vertical stabilizer attach nuts

170-200

(19.21-22.60)

Horizontal to vertical stabilizer strut bolts

50-70

(5.65-7.91)

Horizontal stabilizer forward mounting bolt

50-70

(5.65-7.91)

Horizontal stabilizer attach nuts

380-410

(42.93-46.32)

Page

2-65

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-9. Special Torques (Cont.)

Torque

Location

in. lb.

(Nm)

ft. lb.

(Nm)

Lower vertical stabilizer adjustable bolt

25-40

(2.82-4.52)

Engine Installation and Cooling System

Engine mount fitting-to-engine bolt

140-160

(15.82-18.08)

Compressor bleed air tube nuts

150-250

(16.95-28.25)

Engine hoist fitting:

3/8 inch dia. bolts

160-190

(18.08-21.47)

5/16 inch dia. bolts

140-160

(15.82-18.08)

Fuel pressure switch

40-50

(4.52-5.65)

Engine mount-to-engine fitting bolts

100-140

(9.04-11.30)

Engine oil vent line nut

120-140

(13.56-15.82)

Accessories drive overboard vent tube nut

150-250

(16.95-28.25)

Cabin air outlet tube to firewall fitting tube nuts

150-250

(16.95-28.25)

Engine fuel pump seal drain line nut

20-30

(2.26-3.39)

Fuel inlet line to fuel pump line nut

120-140

(13.56-15.82)

Anti-icing lever cable wire adapter nut

10 (1.13) max.

Engine Fuel System

Power plant fuel supply tube nuts

150-250

(16.95-28.25)

Left fuel cell cover (and cell support brackets) attach bolts

50-70

(5.65-7.91)

Right fuel cell cover attach bolts

50-70

(5.65-7.91)

Forward fuel vent crossover fitting bolts

20-25

(2.26-2.82)

Aft vent tube nuts

80-100

(9.04-11.30)

Fuel inlet mounting pad bolts

20-25

(2.26-2.82)

Fuel shutoff valve inlet hose nut

150-250

(16.95-28.25)

Fuel supply tube nuts

250-300

(28.25-33.90)

Engine fuel pump supply hose nut (drain valve end)

270-420

(30.51-47.45)

Engine fuel hose coupling halves

120-140

(15.82-18.08)

Fuel inlet hose to start pump

270-325

(30.51-36.72)

Pump-to-mounting pad attach bolt

20-25

(2.26-2.82)

Sta. 124 bulkhead fitting nut

270-420

(30.51-47.45)

Engine Oil System

Oil tank liquid level plug

80-90

(9.04-10.17)

Oil supply 1/4 inch tube nuts

80-100

(9.04-11.30)

Oil supply 5/16 inch tube nuts

150-200

(16.95-22.60)

Engine Exhaust System

Engine-to-tailpipe clamp nuts

15-18

(1.69-2.03)

Support fitting bolt

12-15

(1.36-2.82)

Instrument Panel and Indicating System

Engine oil temperature sender

100-150

(11.30-16.95)

Fuel quantity tank unit attach bolts

50-70

(5.65-7.91)

Fuel pressure switch

40-50

(4.52-5.65)

Electrical System

Battery cell bus bar attach screw

(Gulton)

20-25

(2.26-2.82)

(Marathon/Sonotone)

26-30

(2.94-3.39)

Page 2-66

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-10. Temperature Convervision

Numbers in the center column (between those

temperature in left−hand column marked C; in

marked C and F) refer to temperature, either

like manner, find equivalent temperature in

Centigrade or Fahrenheit, which it is desired

right−hand column when converting from

to convert into the other scale. To convert from

Centigrade to Fahrenheit. Example: 50F is

Fahrenheit to Centigrade, find equivalent

10C; 50C is 122F.

-40.0

-40

-40.0

-6.7

68.0

15.6

140.0

37.8

100

212.0

82.2

180

356.0

137.8

280

536.0

-38.9

-38

-36.4

-6.1

69.8

16.1

141.8

38.9

102

215.6

83.3

182

359.6

140.6

285

545.0

-37.8

-36

-32.8

-5.6

71.6

16.7

143.6

40.0

104

219.2

84.4

154

363.2

143.3

290

554.0

-36.7

-34

-29.2

-5.0

73.4

17.2

145.4

41.1

106

222.8

85.6

186

366.8

146.1

295

563.0

-35.6

-32

-25.6

-4.4

75.2

17.8

147.2

42.2

108

226.4

86.7

188

370.4

148.9

300

572.0

-34.4

-30

-22.0

-3.9

77.0

18.3

149.0

43.3

110

230.0

87.8

190

374.0

151.7

305

581.0

-33.3

-28

-18.4

-3.3

78.8

18.9

150.8

44.4

112

233.6

88.9

192

377.6

154.4

310

590.0

-32.2

-26

-14.8

-2.8

80.6

19.4

152.6

45.6

114

237.2

90.0

104

381.2

157.2

315

599.0

-31.1

-24

-11.2

-2.2

82.4

20.0

154.4

46.7

116

240.8

91.1

196

384.8

160.0

320

608.0

-30.0

-22

-7.6

-1.7

84.2

20.6

156.2

47.8

118

144.4

92.1

198

388.4

162.8

325

617.0

-28.9

-20

-4.0

-1.1

86.0

21.1

158.0

48.9

120

248.0

93.3

200

392.0

165.5

330

626.0

-27.9

-18

-0.4

-0.6

87.8

21.7

159.8

50.0

122

251.6

94.4

202

395.6

168.3

335

635.0

-26.7

-16

+3.2

0.0

89.6

22.2

161.6

51.1

124

255.2

95.6

204

399.2

171.1

340

644.0

-25.6

-14

6.8

+0.6

91.4

22.8

163.4

52.2

126

258.8

96.7

206

402.8

173.9

345

653.0

-24.4

-12

10.4

1.1

93.2

23.3

165.2

53.3

128

262.4

97.8

208

406.4

176.7

350

662.0

-23.3

-10

14.0

1.7

95.0

23.9

167.0

54.4

130

266.0

98.9

210

410.0

179.4

355

671.0

-22.2

-8

17.6

2.2

96.8

24.4

168.8

55.6

132

269.6

100.0

212

413.6

182.2

360

680.0

-21.1

-6

21.2

2.8

98.6

25.0

170.6

56.7

134

273.2

101.1

214

417.2

185.0

365

689.9

-20.0

-4

24.8

3.3

100.4

25.6

172.4

57.8

136

276.8

102.2

216

420.8

188.2

370

698.0

-18.9

-2

28.4

3.9

102.2

26.1

174.2

58.9

138

280.4

103.3

218

424.4

190.6

375

707.0

-17.8

32.0

4.4

104.0

26.7

176.0

60.0

140

284.0

104.4

220

428.0

193.3

380

716.0

-17.2

33.8

5.0

105.8

27.2

177.8

61.1

142

287.6

105.6

222

431.6

196.1

385

725.0

-16.7

35.6

5.6

107.6

27.8

179.6

62.2

144

291.2

106.7

224

435.2

198.9

390

734.0

-16.1

37.4

6.1

109.4

28.3

181.4

63.3

146

294.8

107.8

226

438.8

201.7

395

743.0

-15.6

39.2

6.7

111.2

28.9

183.2

64.4

148

298.4

108.9

228

442.4

204.4

400

752.0

-15.0

41.0

7.2

113.0

29.4

185.0

65.6

150

302.0

110.0

230

446.0

210.0

410

770.0

-14.4

42.8

7.8

114.8

30.0

186.8

66.7

152

305.6

111.1

232

449.6

215.6

420

788.0

-13.9

44.6

8.3

116.6

30.6

188.6

67.8

154

309.2

112.2

234

453.2

221.1

430

806.0

-13.3

45.4

9.9

118.4

31.1

190.4

68.9

156

312.8

113.3

236

456.8

226.7

440

824.0

-12.8

48.2

9.4

120.2

31.7

192.2

70.0

158

316.4

114.4

238

460.4

232.2

450

842.0

-12.2

50.0

10.0

122.0

32.2

194.0

71.1

160

320.0

115.6

240

464.0

237.8

460

860.0

-11.7

51.8

10.6

123.8

32.8

195.8

72.2

162

323.6

116.7

242

467.6

243.3

470

878.8

-11.1

53.6

11.1

125.6

33.3

197.6

73.3

164

327.2

117.8

244

471.2

248.9

480

896.0

-10.6

55.4

11.7

127.4

33.9

199.4

74.4

166

330.8

118.3

245

473.0

254.4

490

914.0

-10.0

57.2

12.2

129.2

34.4

201.2

75.6

168

334.4

121.1

250

482.0

260.0

500

932.0

-9.4

59.0

12.8

131.0

35.0

203.0

76.7

170

338.0

123.9

255

491.0

265.6

510

950.0

-8.9

60.8

13.3

132.8

35.6

204.8

77.8

172

341.6

126.7

260

500.0

271.1

520

968.0

-8.3

62.6

13.9

134.6

36.1

206.6

78.9

174

345.2

129.4

265

509.0

276.7

530

986.0

-7.8

64.4

14.4

136.4

36.7

208.4

80.0

176

348.8

132.2

270

518.0

282.3

540

1004.0

-7.2

66.2

15.0

138.2

37.2

210.2

81.1

178

352.4

135.0

275

527.0

287.8

550

1022.0

Page 2-67

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-11. Conversion of Inches to

Table

2-12. Conversion of Millimeter to

Millimeter

Inches

Milli-

Inches

meters

0.001

0.025

0.290

7.37

0.660

16.76

0.01

0.0004

0.35

0.0138

0.68

0.0268

0.002

0.051

0.300

7.62

0.670

17.02

0.02

0.0008

0.36

0.0142

0.69

0.0272

0.003

0.076

0.310

7.87

0.680

17.27

0.03

0.0012

0.37

0.0146

0.70

0.0276

0.004

0.102

0.320

8.13

0.690

17.53

0.04

0.0016

0.38

0.0150

0.71

0.0280

0.005

0.127

0.330

8.38

0.700

17.78

0.05

0.0020

0.39

0.0154

0.72

0.0283

0.006

0.152

0.340

8.64

0.710

18.03

0.06

0.0024

0.40

0.0157

0.73

0.0287

0.007

0.178

0.350

8.89

0.720

18.29

0.07

0.0028

0.41

0.0161

0.74

0.0291

0.008

0.203

0.360

9.14

0.730

18.54

0.08

0.0031

0.42

0.0165

0.75

0.0295

0.009

0.229

0.370

9.40

0.740

18.80

0.09

0.0035

0.43

0.0169

0.76

0.0299

0.010

0.254

0.380

9.65

0.750

19.05

0.10

0.0039

0.44

0.0173

0.77

0.0303

0.020

0.508

0.390

9.91

0.760

19.30

0.11

0.0043

0.45

0.0177

0.78

0.0307

0.030

0.762

0.400

10.16

0.770

19.56

0.12

0.0047

0.46

0.0181

0.79

0.0311

0.040

1.016

0.410

10.41

0.780

19.81

0.13

0.0051

0.47

0.0185

0.80

0.0315

0.050

1.270

0.420

10.67

0.790

20.07

0.14

0.0055

0.48

0.0189

0.81

0.0319

0.060

1.524

0.430

10.29

0.800

20.32

0.15

0.0059

0.49

0.0193

0.82

0.0323

0.070

1.778

0.440

11.18

0.810

20.57

0.16

0.0063

0.50

0.0197

0.83

0.0327

0.080

2.032

0.450

11.43

0.820

20.83

0.17

0.0067

0.51

0.0201

0.84

0.0331

0.090

2.286

0.460

11.68

0.830

21.08

0.18

0.0071

0.52

0.0205

0.85

0.0335

0.100

2.540

0.470

11.94

0.840

21.34

0.19

0.0075

0.53

0.0209

0.86

0.0339

0.110

2.794

0.480

12.19

0.850

21.59

0.20

0.0079

0.54

0.0213

0.87

0.0343

0.120

3.048

0.490

12.45

0.860

21.84

0.21

0.0083

0.55

0.0217

0.88

0.0346

0.130

3.302

0.500

12.70

0.870

22.10

0.22

0.0087

0.56

0.0220

0.89

0.0350

0.140

3.56

0.510

12.95

0.880

22.35

0.23

0.0091

0.57

0.0224

0.90

0.0354

0.150

3.81

0.520

13.21

0.890

22.61

0.24

0.0094

0.58

0.0228

0.91

0.0358

0.160

4.06

0.530

13.46

0.900

22.86

0.25

0.0098

0.59

0.0232

0.92

0.0362

0.170

4.32

0.540

13.72

0.910

23.11

0.26

0.0102

0.60

0.0236

0.93

0.0366

0.180

4.57

0.550

13.97

0.920

23.37

0.27

0.0106

0.61

0.0240

0.94

0.0370

0.190

4.83

0.560

14.22

0.930

23.62

0.28

0.0110

0.62

0.0244

0.95

0.0374

0.200

5.08

0.570

14.48

0.940

23.88

0.29

0.0114

0.63

0.0248

0.96

0.0378

0.210

5.33

0.580

14.73

0.950

24.13

0.30

0.0118

0.64

0.0252

0.97

0.0382

0.220

5.59

0.590

14.99

0.960

24.38

0.31

0.0122

0.65

0.0256

0.98

0.0386

0.230

5.84

0.600

15.24

0.970

24.64

0.32

0.0126

0.66

0.0260

0.99

0.0390

0.240

6.10

0.610

15.49

0.980

24.89

0.33

0.0130

0.67

0.0264

1.00

0.0394

0.250

6.35

0.620

15.75

0.990

25.15

0.34

0.0134

0.260

6.60

0.630

16.00

1.000

25.40

0.270

6.86

0.640

16.26

0.280

7.11

0.650

16.51

Page 2-68

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-13. Conversion of Fractional Inches to Decimals and Millimeter

Inches

Decimal Inch

Millimeter

Inches

Decimal Inch

Millimeter

1/64

0.015625

0.396785

33/64

0.515625

13.096875

1/32

0.03125

0.79375

17/32

0.53125

13.49375

3/64

0.046875

1.190625

35/64

0.546875

13.890625

1/16

0.0625

1.5875

9/16

0.5625

14.2875

5/64

0.078125

1.984375

37/64

0.578125

14.684375

3/32

0.093125

2.38125

19/32

0.59375

15.08125

7/64

0.109375

2.778125

39/64

0.609375

15.478125

1/8

0.125

3.175

5/8

0.625

15.875

9/64

0.140625

3.571875

41/64

0.640625

16.271875

5/32

0.15625

3.96875

21/32

0.65625

16.66875

11/64

0.171875

4.365625

43/64

0.671875

17.065625

3/16

0.1875

4.7625

11/16

0.6875

17.4625

13/64

0.203125

5.159375

45/64

0.703125

17.859375

7/32

0.21875

5.55625

23/32

0.71875

18.25625

15/64

0.234375

5.953125

47/64

0.734375

18.653125

1/4

0.25

6.35001

3/4

0.75

19.05

17/64

0.265625

6.746875

49/64

0.765625

19.446875

9/32

0.28125

7.14375

25/32

0.78125

19.84375

19/64

0.296875

7.540625

51/64

0.796875

20.240625

5/16

0.3125

7.9375

13/16

0.8125

20.6375

21/64

0.328125

8.334375

53/64

0.828125

21.034375

11/32

0.34375

8.73125

27/32

0.84375

21.43125

23/64

0.359375

9.128125

55/64

0.859375

21.828125

3/8

0.375

9.525

7/8

0.875

22.225

25/64

0.390625

9.921875

57/64

0.890625

22.621875

13/32

0.40625

10.31875

29/32

0.90625

23.01875

27/64

0.421875

10.715625

59/64

0.921875

23.415625

7/16

0.4375

11.1125

15/16

0.9375

23.8125

29/64

0.453125

11.509375

61/64

0.953125

24.209375

15/32

0.46875

11.90625

31/32

0.96875

24.60625

31/64

0.484375

12.303125

63/64

0.984375

25.003125

1/2

0.50

12.7

1.00000

25.4

Table 2-14. Conversion of U.S. Measure used in Servicing and Maintenance

Multiply

To Obtain

Pints

0.437

Liters

Quarts

0.946

Liters

1000

Cubic Centimeters (CC)

Ounces

29.57

Gallons

3.785

Liters

Gallons

0.833

Imperial Gallon

Pounds / sq in.

703.1

Kgs. / sq Meter

Inch−pounds

1152

Gram − Centimeters

Foot−pounds

0.1383

Kilogram − Meters

Page 2-69

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-15. Related Publications and Directives

NOTE: Publication numbers marked with an asterisk should be maintained and treated as part of the primary

information file for the helicopter.

Component and

Publication or

Publication Title

Manufacture, or Source

Directive

General Information

Superintendent of Documents

Acceptable Methods, Techniques, and

FAA

U.S. Government Printing Office

Practices-Aircraft Inspection and Repair (GPO

AC No. 43.13-1A*

Division of Public Documents

Catalog No. TD 4-28/2:972)

AC No. 43-13-2B*

Washington D.C. 20402

Advisory Circular - Corrosion Control for

FAA AC No. 43-4*

Aircraft

Aerospace Industries Association of

National Aerospace Standard

NAS No. as applicable

America, Inc.

(Title as applicable)

1725 De Sales Street, N.W.

Washington 6, D.C.

MDHI Publications

MD Helicopters, Inc.

Illustrated Parts Catalog, MDHI Helicopter,

369H Series IPC*

Commercial Technical Publications

Model 369HS, 369HM, 369HE

4555 E. McDow ell Rd

Corrosion Control Manual

CSP-A-3*

Mesa, Arizona 85215-9734

Battery

Marathon Battery Company

Marathon Battery Instruction Manual

BA-89 (Rev. 2-71)

Cold Spring, New York 10516

Phone: (817) 776-0650

(formerly Sonotone)

Gulton Industries Inc.

Gulton Instructions for Use and Care of

ABD1100

Metuchen, N.J. 08840

Sintered Plate Nickel Cadmium Storage

Batteries

Engine

Allison Engine Company, Inc.

Operation and Maintenance Manual,

5W2*

Parts Distribution Center

Turboshaft Engine Models 250-C18, -C18A,

7100 Riverport Drive

-C18B, C18C

Louisville, KY 40258

Overhaul Manual, Turboshaft Engine Models

5W3*

USA

250-C18,-C18A, -C18B, C18C

Illustrated Parts Catalog, Turboshaft Engine

5W4*

Models 250-C18,-C18A, -C18B, C18C

Operation and Maintenance Manual,

10W2*

Turboshaft Engine Model 250-C20

Overhaul Manual, Turboshaft Engine Model

10W3*

250-C20

Illustrated Parts Catalog, Turboshaft Engine

10W4*

Model 250-C20

Page 2-70

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-15. Related Publications and Directives (Cont.)

Component and

Publication or

Publication Title

Manufacture, or Source

Directive

Starter-Generator

Aircraft Parts Corporation

Brush Seating - APC Brushes in High Speed

SB150SG105

160 Finn Court

Starter/Generators: MDHI Part No. 369A4550

Farmingdale, NY 11735

Phone: (516) 249-3053

Datafax: (516) 249-2577

Lucas Aerospace

Overhaul Instructions with Parts Breakdown,

File No. 23206

(formerly Lear Siegler, Inc.)

Models 23032-010, 23032-011, 23032-020,

17600 Broadway Ave.

23032-022

Maple Heights, Ohio 44137

Phone: (216) 662-1000

Datafax: (216) 663-5336

Avionics Equipment

Vhf COMM Receiver-Transmitter

Maintenance Manual, CNS-220 VHF

RT-221

Bendix Avionics Division

Comm-Nav System, RT-221

Fort Lauderdale, Florida

Receiver-T ransmitter

VHF Navigation Receiver

Maintenance Manual, CNS-220 VHF

RN-222

Bendix Avionics Division

Comm-Nav System, RN-222 Receiver

VOR/LOC Converter

Maintenance Manual, CNS-220 VHF

IN-225

Bendix Avionics Division

Comm-Nav System, IN-225 VOR/LOC

Converter

Distance Measuring Equipment

Maintenance Manual for CN-142A Narco DME

UDI-4

National Aeronautical Corp.,

Model UDI-4 Interrogator Distance Measuring

Fort Washington, Pennsylvania

Equipment

Automatic Directional Finder

Type ADF-73 Automatic Direction Finder

TM34-53-0

Bendix Radio Division,

System Maintenance Manual

IB1073-1

Avionics Products,

Automatic Direction Finder System Type

TM34-53-1

Baltimore, MD 21204

DFA-73A-1 ADF Receiver Overhaul Manual

IB1073A-1

Automatic Direction Finder System ADF 73

TM34-53-3

System Access Overhaul Manual

IB1073C-1

ATC Transponder System

Maintenance Manual, TPR-640 ATC

Manual Number

Bendix Avionics Division

Transponder System

I,.B. 2640A

Installation Manual, TPR-610 ATC

I.B. 2610A

Transponder System

Vhf COMM Transceiver

AVC-1 10 VHF Communication Transceiver

IB8029004

RCA Aviation Eqpt. Dept.

Instruction Manual

11819 W. Olympic Blvd.

Los Angeles, CA 90064

Vhf NAV Receiver

AVN-210 Series Integrated Navigation

IB96460

RCA Aviation Equipment Dept.

Systems

Page 2-71

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-15. Related Publications and Directives (Cont.)

Component and

Publication or

Publication Title

Manufacture, or Source

Directive

University Sound of LTV

Operators Manual, SA-250 & SA-500 High

Ling Altec, Inc.

Power Sound and Siren

Oklahoma City, Okla.

Operators Manual, Model 500 Super High

Power Solid-State Amplifier and Model

RMC-1 Remote Control

Automatic Direction Finder

KR 85 Automatic Direction Finder Installation

KPN 006-0043-00

King Radio Corp.

Manual

400 North Rogers Road

KR 85 Automatic Direction Finder Maintenance

Olathe, Kansas

Manual

Automatic Direction Finder

Maintenance Manual for King KR80 Automatic

KR80

King Radio Corp

Direction Finder

Nav/Comm Transceiver and

Maintenance/Overhaul Manual KX 170A/KX

006-5053-00

Communications Transceiver

175 Nav/Comm Transceiver, KY 195

King Radio Corp.

Communications Transceiver

Transponder King Radio Corp.

Installation Manual, KT 76/78 Transponder

006-0067-1

Maintenance/Overhaul Manual, KT 76/78

006-5085-02

Transponder

Sunair Electronics, Inc.

Maintenance Manual SSB Communications

99655

3101 S. W. Third Avenue

Equipment ASB-125, ASB-60

Fort Lauderdale, Fla. 33315

Spilsbury & Tindall, Ltd.

Instruction Manual ”Stringer” Model AC-31

65-018

120 E. Cordova Street

Mobile Antenna System

Vancouver 4, B. C. Canada

Hoist Equipment

Hoist Winch Assembly

BL-16600 Series 300 Lb Capacity Hoist

HB-136

Breeze Corporations, Inc.,

Operating Instructions - Use and Maintenance

700 Liberty Avenue

of Aircraft Hoist Cable

Union, New Jersey 07083

Maintenance and Test Equipment

Tail Rotor Balancer

Operation and Maintenance Manual for Model

Chadwick-Helmuth Co., Inc.

170 Tail Rotor Balancer

111 E. Railroad Avenue

Monrovia, Ca. 91016

Rotor Blade Tracker Chadwick-Hel-

Operation and Maintenance Manual for Point

muth Co., Inc.

Source Strobex Rotor Blade Tracker Model

135M- ( )

Model 177MÄ6 Balancer and Model

Chadwick-Helmuth Operation and Service

135MÄlOB Strobex Blade Tracker

Instruction Handbook for Helicopter Main and

Chadwick-Helmuth Co., Inc.

Tail Rotor Track and Balance

Landing Gear Equipment

Helicopter Float Assemblies

Overhaul Manual With Illustrated Parts List

Garrett-Air Cruiser Company

Helicopter Float Assemblies Utility Floats,

P. O. Box 180

21D24368-1/-2 Emergency Floats,

Belmar, New Jersey

D24484-5/-6

Page 2-72

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Determination of Excessive Wear or Damage

NOTE: Wear tolerances are provided in this manual whenever practical. In addition, excessive wear or damage

can usually be determined by visual inspection as shown in the following table.

QUESTIONABLE WEAR / DAMAGE CONDITIONS

* YES /

NO /

Is the condition dangerous for flight

Is the condition on a highly stressed part of the helicopter

Could the condition contribute to failure of another part

Will the condition continue to worsen at the same rate (or faster)

Does the condition affect the quality of performance, function or apperance

*Any check mark ( √ ) in the YES column indicates that the part is worn or damaged excessively and should be

replaced with a new or serviceable unit.

WORN

SWOLLEN

SCORED

SCRATCHED

GALLED

DISTORTED

PITTED

BACKLASH

BENT

BOWED

ELONGATED

COLLAPSED

STRIPPED

GOUGED

RUPTURED

DENTED

BROKEN

SHEARED

TWISTED

STRETCHED

BRINNELLED

CRACKED

SPALLED

GROOVED

30−170

Figure 2-10. Technical Definitions

Page 2-73

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-16. Technical Definitions

Example No.

Technical Terms

Definition

(Figure 2-10)

Abrasion

An area of roughened scratches or marks; usually caused by

foreign matter between moving parts or surfaces.

Arced

Visible effects (burn spots, fused metal) of an undesired electrical

discharge between two electrical connections.

Axial play

The back and forth movement of a part along the line (shaft, tube or

bolt) about which it rotates; usually a bearing.

Backlash

The lost motion between two mating gear teeth; the amount the first

has to move owing to distance between tooth contact surfaces.

Bent

Sharp deviation from original line or plane; usually caused by lateral

force.

Binding

Restricted movement such as tightened or sticking condition

resulting from misalignment or jamming.

Blend

To form or smooth metal or fiberglass so there is no sharp change

or line from one area to another.

Blister

An enclosed raised spot or bulge, usually with a void underneath.

Bowed

Curved or gradual deviation from original line of plane; usually

caused by lateral force.

Brinnelled

Circular surface indentions on bearing races; usually caused by

repeated shock loading of the bearing: i. e., ball or roller indention.

Broken

Separated by force into two or more pieces.

Burning

Surface damage due to excessive heat; usually caused by improper

fit, defective lubrication, overtemperature operation.

Burrs

A sharp projection or rough edge remaining after machining or

rework.

Chafed

Frictional wear damage; usually caused by two rubbing together

with limited motion.

Checked

Surface cracks.

Chipped

A breaking away of the edge, corner or surface of material; usually

caused by heavy impact (not flaking).

Chord

An imaginary straight line joining the leading and trailing edges of

an airfoil: i. e., main and tail rotor blades, stabilize.

Circuit - grounded

Undesired current path to ground (common).

Circuit - open

Incomplete electrical circuit due to separation at or between

electrical connection points.

Circuit - shorted

Undesired current path between leads or circuits that normally are

at a different potential.

Clogging

Blockage of fluid or air passage or line; usually by foreign material.

Collapsed

Inward deformation of the original contour of a part; usually due to

high pressure differential.

Concentricity

Perfect roundness about a common center. The appearance of a

part and its readiness to function.

Condition

The appearance of a part and its readiness to function.

Page 2-74

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-16. Technical Definitions (Cont.)

Example No.

Technical Terms

Definition

(Figure 2-10)

Contamination

The introduction of undesirable elements, usually into a fluid.

Corrosion

Pitting, or a surface breakdown of a material due to chemical or

electro-chemical attack by atmosphere, moisture or other agents.

(Sometimes called rust on steel surfaces.)

Cracked

Visible (not requiring special fluorescent or magnetic penetrants)

partial separation of material which may progress to a complete

break.

Crossed

Damage to parts (crossed threads) or parts made inoperative

(crossed wires) from improper assembly.

Crushed

Destruction of a part or structure by a squeezing force. Changes

original shape.

Defect

Imperfection; anything that will not allow a part to function as

intended or that might cause failure.

Deflection

The turning away from original shape or direction by an undesired

force.

Delamination

Separation into layers; usually fiberglass.

Dented

A surface indention with rounded bottom usually caused by impact

of a foreign object. Material is displaced, seldom separated.

Depression

See dent.

Deterioration

To grow worse; quality less than new or original.

Dimension

Under blueprint dimension or other dimensions published in an

authoritative publication (not caused by wear).

Discoloration

A color that is not normal to a part; usually caused by heat.

Distorted

Extensive deformation of the original shape of apart; usually due to

structural stresses, excessive localized heating or any combination

of these.

Dye-penetrant

A portable method of detecting small cracks in metal too small to be

inspection

seen with the naked eye. The questionable area is thoroughly

cleaned and dye is then applied to the area. After penetration time

the excess dye is removed and developer is applied. After a drying

period, a mark will appear in the developer if a crack is present.

Eccentric

Part(s) wherein the intended common center is displaced

significantly.

Elongated

A hole (bolt or rivet) that is not round; usually due to loose fastener

or improper drilling.

Erosion

Carry away of material by flow of fluids or gases, accelerated by

heat or grit.

Excessive

Greater than the usual or specified amount; more than normal.

Faulty

See defect.

Ferrous

Metal having a high iron content such as steel.

Finite life

A definite time limit for part serviceability; established by the

manufacturer and usually in accumulated hours of operation.

Page 2-75

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-16. Technical Definitions (Cont.)

Example No.

Technical Terms

Definition

(Figure 2-10)

Fluctuation

Moving or swinging back-and-forth: often seen as an unstable

instrument indication.

Fluorescent-penetrant

Method of inspecting components used for detecting cracks, flaws,

inspection

or defects in nonferrous metal which are too small or in such a

position that they cannot be detected with the naked eye. This

method uses the principle of submerging the component in a

penetrating dye and placing it under ultra-violet light.

Foreign particle

A piece of material not normally found in or around a part or

location.

Fouling

Clogging or choking with a foreign substance; usually found in oil.

Frayed

Worn into shreds by rubbing action.

Freedom of motion

Operating as intended without binding or excessive friction.

Friction

Rubbing together of two parts, resisting motion; usually causes

excessive wear.

Fused

Joining together of two materials; usually caused by heat, friction or

current flow.

Galled

A transfer of metal from one surface to another in an advanced

case of fretting corrosion or pitting.

Gap

An opening, break, space or separation.

Gouged

Scooping out of material; usually caused by a foreign object.

Grooved

Smooth, rounded furrow or furrows of wear; usually wider than

scoring, with rounded corners and smooth on the groove bottom.

Hot-Spot

Subjected to excessive temperature; usually evidenced by change

in color and appearance of part.

Impact

The forceful striking or contact of one thing against another.

Imperfection

See defect.

Inclusion

A particle of foreign matter in the metal; usually associated with

magnetic particle inspection.

Indications

Cracks, inclusions, fractures, etc., not visible without fluorescent or

magnetic penetrant.

Inoperative

Not functioning.

Intermittent

A coming and going at various times, not all the time.

Internal

Inside, within the surface or structure.

Kink

A short tight twist or curl caused by doubling or winding of

something upon itself.

Leakage

Escaping fluid or air; usually caused by a crack, hole or worn seal.

Longitudinal

The length or lengthwise dimension; usually the longest area.

Page 2-76

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-16. Technical Definitions (Cont.)

Example No.

Technical Terms

Definition

(Figure 2-10)

Magnetic-particle

The method used to detect cracks, flaws or defects in ferrous metal

inspection

which are too small or in such a position that they cannot be seen

with the naked eye. Two distinct magnetic fields are established

around a flaw in ferrous metal. By submerging the specimen into a

solution containing iron filings and exposing it to a magnetic field,

the iron filings, attached to the ferrous specimen, form a pattern

about the flaw.

Malfunction

Not operating as intended.

Misalignment

Not in correct relative position.

Mismatched

Improper association of two or more parts.

Mis-positioned

Improper installation of a part resulting in damage to the installed

part or to associated parts.

Moisture

Condensed liquid; usually a small quantity of water.

Nicked

A sharp surface indentation caused by impact of a foreign object.

Material is displaced, seldom separated.

Obstruction

A condition of being clogged or blocked; in the way of something.

Out-of-round

penetra-

Diameters of part not constant.

tion

Penetration

The amount that an object has entered a material by overcoming

resistance.

Peripheral

The outer surface or edge of a body.

Pitted

Small irregular shaped hollows in the surface; usually caused by

corrosion, chipping or heavy electrical discharge.

Play

Movement of one part in relation to another: free motion. (Limited

play between parts is often required.)

Plugged

Pipe, hoses, tubing, channeling, internal passage, etc., which are

totally or partially blocked.

Preload

The exact clamping force applied to bearing races or mating parts

to eliminate the possibility of play during operation; usually

established in bearings by shimming and measuring rotational drag

torque.

Propagation

To grow, spread out; usually referring to cracks.

Puncture

A hole through material; usually caused by complete penetration of

a foreign object.

Radial play

The perpendicular movement of a part outward (at right angles)

from the line (shaft, tube or bolt) about which it rotates; usually a

bearing.

Radius

The distance from the center of a circle to the outside edge. Often

used to discuss a curve in material.

Resistance - high

High electrical resistance in an electrical circuit, causing improper

component or circuit operation.

Resistance - low

Low electrical resistance in an electrical circuit, causing improper

component or circuit operation.

Page 2-77

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 2-16. Technical Definitions (Cont.)

Example No.

Technical Terms

Definition

(Figure 2-10)

Restricted

Blocked or limited; usually refers to limited flow in hoses or tubing.

Rough

Usually applies to operation as opposed to surface finish; i. e., a

condition of bearings where during the spin test the rotation is

rough.

Rubbed

To move with pressure or friction against another part.

Ruptured

Extensive breaking apart of material; usually caused by high

stresses, differential pressure, locally applied force or any

combination of these.

Rust

See Corrosion.

Scored

Deep scratch or scratches made during part operation by sharp

edges of foreign particles.

Scratched

Light narrow, shallow mark or marks caused by movement of a

sharp object or particle across a surface.

Security

Correctly installed or fastened so as not to loosen.

Seized

Parts bound together because of expansion or contraction due to

high or low temperature; foreign object jammed in mechanism.

Separation

A space or gap caused by two parts moving away from each other.

Sheared

Dividing a body by cutting action; i.e., division of a body so as to

cause its parts to slide relative to each other in a direction parallel to

their plane of contact.

Spalled

Sharply roughened area characterized by progressive

chipping-away of surface material (Not to be confused with flaking).

Usual causes are surface cracks, inclusions or any similar surface

injury causing a progressive breaking away of the surface under

load.

Snug

A close fit between two parts.

Spanline

The maximum distance from tip to root, as of main rotor blade.

Springback

The partial return motion of a control handle or lever back from its

end stop after release; usually ensures complete actuation of unit

being controlled. Sometimes called cushion.

Stress

Force running through an object or material, caused externally;

usually tension or shearing.

Stretched

Elongation of a part as a result of exposure to operating conditions

(tension type stress) or overtorquing.

Stripped

A condition usually associated with threads or insulation. Involves

removal of material (threads) by force.

Swollen

A bulge; usually found in hoses and plastic tubing. A puffed-up or

expanded area caused by internal pressure.

TIR

Total indicator reading. The result of checking (usually with a dial

indicator) for an out-of-round condition; usually of a shaft surface

and/or shaft rotational axis.

Torn

Separation by pulling apart.

Page 2-78

Revision 14

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS

Para/Figure/Table

Title

Page

Section 3 Fuselage .

3−1

Fuselage Assembly

3−1

Fuselage Sheet Metal Repair

3−1

A. Stressed Sheet Metal Panels

3−1

B. Non−Stressed Sheet Metal Panels

3−1

Figure 3−1. Major Sections of Fuselage

3−2

Mast Support Structure

3−3

A. Mast Support Structure Inspection

3−3

Main Rotor Mast

3−3

A. Main Rotor Mast Removal

3−3

Figure 3−2. Main Rotor Mast and Support Structure

3−4

Figure 3−3. Main Rotor Mast Inspection and Repair Criteria .

3−5

B. Main Rotor Mast Installation

3−6

C. Main Rotor Mast Inspection and Repair

3−6

Fuselage Structure

3−7

A. Center Beam

3−7

B. Sta. 78.50 Canted Frame

3−7

C. Sta. 124.00 Canted Frame and Lower Section Frame

3−7

D. Pilot’s Compartment Floor

3−7

E. Instrument Panel Support Structure

3−7

F. Pilot’s Seat Support Structure

3−7

G. Cargo Compartment Floor

3−7

H. Cargo Floor Fittings

3−8

Fuel Tank Support Skins

3−8

J. Fuel Tank Support Skin Inspection

3−8

K. Fuel Tank Support Skin Repair

3−8

Firewalls

3−8

A. Firewall Inspection

3−8

B. Upper Firewall Replacement

3−8

Figure 3−4. Major Bulkheads and Structural Members

3−8A

C. Upper Firewall Patch Silver Brazing

3−9

Figure 3−5. Firewall Installation

3−10

Fuselage Fittings

3−11

A. Fuselage Fitting Repair

3−11

Aft Section Strut

3−11

A. Aft Section Strut Repair

3−11

Landing Gear Fitting Swivel Bearing Replacement

3−11

Page 3-i

Revision 19

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

10. Optional Equipment Structural Hard Points

3−11

11. Engine Air Inlet Fairing

3−11

12. Engine Air Inlet (Plenum Chamber)

3−12

A. Plenum Chamber Inspection

3−12

B. Plenum Chamber Hole Sealing

3−12

13. Aft Fuselage Skin Cracks Inspection/Repair (Sta. 146.62) .

3−12

14. Underfloor Compartments

3−13

A. Underfloor Compartment Inspection

3−13

15. Firewall and Sta. 124.00 Insulation

3−13

A. Insulator Padding and Insulation Tape Inspection

3−13

B. Insulator Padding Replacement

3−13

C. Oil Cooler/Tank Insulation Tape Replacement

3−13

Figure 3−6. Insulation Padding

3−14

Figure 3−7. Oil Cooler/Tank Compartment Sealing

3−15

16. Engine Access Doors

3−16

A. Engine Access Door Removal

3−16

B. Engine Access Door Inspection

3−16

C. Engine Access Door Repair

3−16

Figure 3−8. Engine Access Doors (Sheet 1 of 2)

3−17

D. Engine Access Door Fit Adjustment

3−19

17. Aft Section Windows

3−19

A. Aft Section Window Repair

3−19

18. Canopy and Windshield

3−19

A. Canopy Panel Inspection

3−19

Figure 3−9. Canopy and Window Installation

3−20

B. Canopy Panel Repair

3−20

C. Canopy Frame Replacement

3−20

19. Pilot and Cargo Doors

3−20

A. Pilot and Cargo Door Removal

3−21

B. Pilot and Cargo Door Auto−Latching Operational Check .

3−21

C. Pilot and Cargo Door Manual−Latching Operational Check .

3−21

D. Pilot and Cargo Door Hinge Repair

3−21

E. Pilot and Cargo Door Window Repair

3−22

Figure 3−10. Pilot’s Door, Auto−Latching (Sheet 1 of 2)

3−23

Figure 3−11. Pilot’s Door, Manual Latching

3−25

Figure 3−12. Cargo Door, Auto−Latching (Sheet 1 of 2)

3−26

Figure 3−13. Cargo Door, Manual Latching (Sheet 1 of 2) .

3−28

Page 3-ii

Revision 19

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

F. Geon Strip Repair

3−30

G. Window Snapvent Replacement

3−30

20. Door Latching Mechanism

3−30

A. Door Latching Mechanism Inspection and Repair

3−31

B. Pilot and Cargo Door Automatic Latch Replacement

3−31

C. Pilot and Cargo Door Automatic Latch Adjustment

3−32

Figure 3−14. Latch Engagement for Auto−Latching Door Handle Positions .

3−33

D. Pilot and Cargo Door Manual Latch Adjustment

3−34

E. Pilot and Cargo Door Auto−Latching Handle Replacement .

3−35

21.

369H90085 Litter Door Installation Inspection

3−36

22. Pilot and Cargo Door Seal Compression Check

3−36

A. Pilot and Cargo Door Seal Replacement

3−36

Figure 3−15. Door Seal Installation, Current Type

3−37

B. Partially Separated Pilot and Cargo Door Seal Repair .

3−38

C. Pilot and Cargo Door Frame Anti−Chafing Tape Repair .

3−38

23. Improved Door Seal Installation

3−38

Figure 3−16. Improved Door Seal Installation

3−39

Page 3-iii

Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

SECTION 3

FUSELAGE

1. Fuselage Assembly

are those that form the cylindrically tapered

boom assembly.

(1).

Forward Section

(1). Negligible Damage

The fuselage forward section includes

upper−, center−, and lower−canopy

No damage can be considered negligi−

windshield assemblies, door frames,

ble. All repairable damage shall be

and a canopy panel containing an air

repaired upon detection. Cracks, tears

intake duct and provisions for a

or punctures in stressed sheet metal

landing/hovering light.

panels that do not exceed 0.20 inch

(5.08 mm) diameter and can be re−

(2).

Lower Section

moved by drilling out with a 1/4 inch

(6.35 mm) or smaller diameter drill do

The fuselage lower section includes the

not require structural doublers.

pilot’s compartment floor, cargo

compartment floor, underfloor stowage

(2). Repair or Replacement

compartment and battery area, floor

and seat support bulkheads and seat

Cracks, tears or punctures in stressed

support bulkheads and associated

sheet metal panels exceeding 0.20 inch

structure, the center beam assembly,

(5.08 mm) diameter are to be repaired.

landing gear fittings, and the fuel tank

support structure.

B. Non-Stressed Sheet Metal Panels

Non−stressed sheet metal members consist

(3).

Aft Section

primarily of hinged covers and doors except

The fuselage aft section includes the

the fuel cell access and controls access doors

main rotor mast support structure,

which are stressed (Ref. Stressed Sheet Metal

cargo door frames, engine compart−

Panels).

ment, engine air inlet (plenum cham−

ber) installation, engine inlet aft

(1). Negligible Damage

fairing, firewall installation, and the

Small dents, scratches, nicks, and light

boom fairing.

corrosion deposits are considered

negligible damage. Cracks that do not

2. Fuselage Sheet Metal Repair

exceed 0.250 inch (6.35 mm) in length,

Perform repair of the structure according to

are less than one−fourth the width of

applicable instructions in CSP−H−6. Refer to

the damaged component, and are

the following paragraphs for classification and

removed at least one−inch from the end

definition of the types of negligible damage,

of the damaged component or an

and for guidelines defining the extent of

attachment point, may also be conĊ

damage requiring repair or replacement.

sidered negligible damage.

A. Stressed Sheet Metal Panels

(2). Repair or Replacement

Stressed sheet metal panels consist primarily

Repair or replacement of non−stressed

of the helicopter fuselage skins and bulkhead

panels shall be at the discretion of the

webs. The most highly stressed skin sections

owner. Refer to CSP−H−6.

Page 3-1

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

3. Mast Support Structure

(a). Inspect the side channels and

forward and aft webs of the controls

tunnel, from the mast support fitting

(Ref. Figure 3−2) The mast support structure

down to the top of the pilot’s seat−

consists of two mast support fittings, stiffener

back (canted bulkhead waterline

angles, a panel riveted to the upper−rear

45.36).

surface of the mast support fittings, a pan, a

doubler riveted to the lower forward surfaces

(b). Inspect visible areas of mast support

of the mast support fittings, and two channels.

fitting, mast base and mast tube,

Two bolt holes in each mast support fitting

with particular attention to base

provide the four attach points for mounting

attachment areas and shaded areas.

the main rotor mast support base. Three

(c). Inspect both side of channels on aft

additional holes through the forward end of

canted bulkhead from mast support

the left−hand mast support fitting provide

fitting down to waterline 34.00 with

attach points for mounting the tail rotor

particular attention to points of

control rod bellcrank support bracket. The

attachment.

forward end of the mast support fittings are

riveted to the upper ends of two channels on

(d). Clean and inspect any suspected

the rear surface of Sta. 78.50 canted bulkhead.

area; use dye−penetrant to determine

The aft ends of the mast support fittings are

if a crack does exist. If a crack is

riveted to the upper ends of two channels on

found, part must be replaced.

the forward surface of Sta. 124.00 canted

bulkhead.

(5). Inspect mast support structure for

corrosion, loose bolts and rivets and

general condition of finish.

A. Mast Support Structure Inspection

(6). Check that the two 1/4 inch (6.35 mm)

drain holes located in the pan are not

Any time work is being per−

CAUTION

plugged.

formed near the engine air inlet,

use care to prevent entry of foreign objects.

(7). Reinstall controls tunnel cover.

Tape covers of cardboard or other suitable

material in place over the engine inlet

(8). Reinstall left and right forward sections

screen and oil cooler air inlets. Do not re−

of air inlet fairing.

move covers until work is completed and de−

(9). Reinstall main transmission access

bris is thoroughly cleaned out of the area.

cover and main gearbox access cover.

After removing covers, verify that the area

around base of mast, air inlet, and entire

4. Main Rotor Mast

plenum chamber are free of foreign materi−

al.

(Ref. Figure 3−3) The main rotor mast consists

of a steel tube and a forged base assembly. The

mast encloses the main rotor drive shaft and

(1). Remove left and right forward sections

supports the main rotor hub assembly.

of air inlet forward fairing.

A. Main Rotor Mast Removal

(2). Remove main transmission cover and

Main rotor mast is highly

CAUTION

main gearbox access cover.

stressed. Do not allow tools to

strike mast or mast to strike any object. Any

impact damage may require replacement of

(3). Detach controls tunnel cover from

mast.

structure. Slide cover up on control rods

and secure it out of the way. and slide

(1). Remove main rotor hub.

out of way.

(2). Remove main rotor controls.

(4). Using a bright light and a 5−power

(3). Remove main transmission. Transmis−

magnifying glass, carefully inspect the

sion removal is required for access to

following areas for evidence of cracks.

the mounting studs.

Page 3-3

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

MAXIMUM

REPAIRABLE

AREA

REMOVAL OF

REPAIR

DAMAGE

MATERIAL (DEPTH)

PROCEDURE

POLISH AREA SMOOTH WITH ABRA−

CORROSION

SIVE CLOTH (20 AND 23, TABLE 2−4)

0.010 IN.

AND

(0.254 MM)

IF CADMIUM PLATING HAS BEEN

SCRATCHES

PENETRATED. TREAT REWORKED

AREA WITH PRIMER (4).

THICKNESS OF

0.063 IN.

POLISH AREA SMOOTH WITH ABRA−

CHIPPING

NICKEL PLAT−

(1.6002 MM)

SIVE CLOTH (20 AND 23, TABLE 2−4).

OF NICKEL

ING 0.0035 IN.

THREAT REWORKED AREA WITH

PLATING

(0.0889 MM)

PRIMER (4).

MAXIMUM

LONGITUDINAL

SCRATCHES THAT

DO NOT PENE−

TRATE THROUGH

MUST NOT PER−

THE NICKEL PLATE.

NETRATE NICKEL

POLISH AREA WITH ABRASIVE CLOTH

SCRATCHES MUST

PLATING 0.0035

(20 AND 23, TABLE 2−4) TO REMOVE

BE A MINIMUM OF

IN.

BURRS AND SHARP EDGES ONLY.

0.25 IN. (6.35 MM)

(0.0889 MM) MAX−

APART. RADIAL

IMUM

SCRATCHES ARE

NOT PERMITTED.

CORROSION

0.020IN.

POLISH AREA SMOOTH WITH ABRASIVE

AND

(0.508 MM)

CLOTH (20 AND 23, TABLE 2−4)

SCRATCHES

POLISH AREA SMOOTH WITH ABRA−

CORROSION

SIVE CLOTH (20 AND 23, TABLE 2−4).

0.010 IN.

AND

TREAT REWORKED AREA WITH PRIM−

(0.254 MM)

SCRATCHES

ER (7) AND A TOP COAT OF LACQUER

(6).

REMOVE DAMAGED OR DETERI−

AREA

ORATED TAPE. POLISH CORROSION

ENCLOSED

CORROSION AND

SPOTS WITH ABRASIVE CLOTH (20

0.010 IN.

REPLACEMENT OF

MAST BASE

(0.254 MM)

AND 23, TABLE 2−4). TREAT RE−

TAPE

WORKED AREA WITH PRIMER (7) AND

A TOP COAT OF LACQUER (6). RE−

MAST TUBE TO BE PERPENDICULAR TO

PLACE TAPE (32).

MAST BASE WITHIN 0.010 IN. (0.254 MM)

IN 10 INCHES (25.4 CM)

NOTE: FOR MAGNETIC PARTICLE INSPECTION, REMOVE

PAINT FROM APPLICABLE SURFACES.

30−160B

Figure 3-3. Main Rotor Mast Inspection and Repair Criteria

Page 3-5

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(4). Remove four studs, washers and nuts

C. Main Rotor Mast Inspection and Repair

(Ref. Figure 3−3). Nuts securing studs

Inspect all areas of main rotor mast for cracks,

have left−hand threads.

nicks, scratches and evidence of impact

damage. Refer to Figure 3−3 for inspection and

(5). Remove shaft support hold−down nuts,

repair criteria. Inspect bearing surfaces for

washers and bolts.

scoring and galling. Inspect threads and

(6). Lift main rotor mast from helicopter.

serrations for damage. Inspect four rivets that

secure base to mast tube for security. Check

B. Main Rotor Mast Installation

that tape on forward edge of mast tube is

secure and undamaged.

(1).

Apply silicone sealant (17, Table 2−4)

NOTE: To inhibit corrosion of mast when oper−

on bottom surface of mast tube and

ating in salt water environment, check tape

base at drive shaft opening to seal base

at frequent intervals. Also, apply thin

to mast support structure at installa−

grease film (18, Table 2−4) to bearing jour−

tion. Sealing will contain any oil

nals.

leakage coming from top of transmis−

sion.

(1). Inspect all areas of main rotor mast for

cracks, nicks, scratches and evidence of

(2).

Position main rotor mast so that holes

impact damage.

in base align with holes in mast

support structure.

(2). Inspect bearing surfaces for scoring and

galling.

(3).

Install four holddown bolts, eight

(3). Inspect threads for damage.

washers and four nuts; torque nuts to

700 − 820 inch−pounds (79.09 − 92.65

(4). Inspect rivets that secure base to mast

Nm).

tube for security.

(4).

Check underside of mast support

(5). Check that tape (Ref. Figure 3−2) on

structure at left aft stud hole location.

forward edge of mast tube is secure and

Stud−to−pan doubler surface must be

undamaged; replace if defective.

clean to bare metal for electrical

(a). Peel defective tape from mast.

bonding (Ref. Figure 3−2). Install main

transmission mounting four studs,

(b). As required, polish area to remove

plate spacers and nuts. Torque studs to

burrs and sharp areas with abrasive

160 − 190 inch−pounds (18.08 − 21.47

cloth (20, Table 2−4) or crocus cloth

Nm).

(23).

(c). Clean mast thoroughly with cleaner

(5).

Using 0.001−0.0015 inch

(183) and allow to dry.

(0.0254−0.0381 mm) feeler gage, check

for gap between self−locking nuts and

(d). Apply primer (4) and paint (6) to

plate spacers. No gap is allowed.

affected area.

(6).

If gap is observed, remove nut and

(e). Apply pressure sensitive tape (123) to

replace with new self−locking nut.

mast.

Torque studs into replacement nuts to

NOTE: To inhibit corrosion of mast when oper−

160 − 190 inch−pounds (18.08 − 21.47

ating in salt water environment, check tape

Nm) and repeat step (5). above.

at frequent intervals. Also, apply thin

Continue until each nut is flush against

grease film (18, Table 2−4) to bearing jour−

its spacer. Seal bare bond area with

nals.

clear lacquer (47).

(6). Inspect internal bore for paint chipping,

(7).

Install main transmission.

orange peeling or flaking, none allowed.

(8).

Install main rotor controls.

NOTE: Chipping, orange peeling or flaking

paint will normally be at the base of the

(9).

Install main rotor hub.

static mast tube.

Page

3-6

Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(7). Re−apply finish to mast internal bore

the helicopter. Three cutouts, at cargo floor

as follows:

level, provide access to the landing gear

dampers, other underseat components and the

(a).

Remove main rotor hub (Ref. Sec.

four flight control push rods that are routed

62−20−00 or 62−20−60, Main Rotor

upward through the canted tunnel.

Hub Replacement).

C. Sta. 124.00 Canted Frame and Lower

(b).

Remove main transmission (Ref. Sec.

Section Frame

63−20−00 or 63−20−25, Main Trans−

mission Replacement).

The Sta. 124.00 upper and lower section

frames are primary structural members of the

(c).

Remove static mast (Ref. Main Rotor

helicopter. The upper canted frame is formed

Static Mast Replacement).

of channel and sheet aluminum. Passenger

seat, shoulder harness and engine mount

(d).

Thoroughly clean interior tube with

support fittings are bolted to the chanted

Solvent (1).

frame. The lower section frame is formed of

(e).

Inspect for any corrosion, none

titanium sheet and aluminum channel

allowed.

members.

(f).

Remove paint from bad areas and

D. Pilot’s Compartment Floor

lightly feather paint edge with crocus

cloth (23), remove any residue from

The pilot’s compartment floor is a structure of

feathering.

aluminum alloy formed channels, intercostals,

clips, gussets and skin. The pilot’s seat support

(g).

Apply primer (131) to repair areas.

structure attaches to the aft end of the floor.

Tail rotor control support fittings are at the

(h).

Allow to cure per manufacturer’s

forward end of the floor and there are openings

instructions.

on each side for access to the underfloor

compartments.

(i).

Reinstall static mast.

E. Instrument Panel Support Structure

(j).

Reinstall main transmission.

The instrument panel support assembly is

(k).

Reinstall main rotor hub.

aluminum alloy sheeting, stiffeners, webs and

Fuselage Structure

channels riveted together to form a pedestal

assembly.

Center Beam

F. Pilot’s Seat Support Structure

(Ref. Figure 3−4) The lower section center

beam is a primary structural member of the

The pilot’s seat support structure is formed of

helicopter. The beam is a riveted and bolted

aluminum alloy ribs and sheet. The seat

assembly of aluminum alloy webbing, stiffen−

structure incorporates forged or cast and

ers and doublers. Landing gear fittings of

machined aluminum alloy and/or magnesium

machined aluminum forgings are mounted at

fittings for seat belt attachment, landing gear

the forward and aft ends of the center beam.

damper attachment, and flight and engine

Each fitting contains four swivel bearings for

control components. Refer to Section 2 for

attachment of the landing gear braces and

corrosion control and identification of magne−

struts. The forward fittings have two addition−

sium and aluminum alloy.

al bearing attachment points for the longitudi−

G. Cargo Compartment Floor

nal and lateral cyclic trim actuators.

The cargo compartment provides a multi−use

B. Sta. 78.50 Canted Frame

area for accommodation of cargo and/or

The Sta. 78.50 canted frame establishes the

passengers. If floor is bent or punctured,

forward portion of the cross−sectional form of

remove appropriate fuel cell access cover and

the helicopter. The canted frame, constructed

inspect fuel cell. If water accumulation is

of formed sheet metal webs, stiffeners and

noted, refer to CSP−H−6 for drain hole

doublers, is a primary structural member of

addition instructions.

Page 3-7

Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

H. Cargo Floor Fittings

upper firewall is thin, 0.0015 inch (0.0381 mm)

thick sheet, rigidized CRES sheet, covered

The cargo floor incorporates 8 cargo tiedowns,

with a double thickness of nonflammable

4 seat belt attachment fittings and on the

ceramic fiber blanket. Flanges at the forward

underside of the floor, 12 tiedown eyelets that

and lower edges of the upper firewall are

support the fuel cell and lacing.

covered with heat−resistant tape. Pronged

fasteners attach the upper firewall to three

I. Fuel Tank Support Skins

vertical fuselage rings and to a horizontal rib.

The fuel tank support skins located under the

The semicircular forward firewall is an

cargo compartment floor are made of fiberglass

assembly of CRES sheets that contain circular

sheets riveted to the tank support ribs.

cutouts for passage of the engine drive shaft

and engine oil cooler lines, and a reinforced

J. Fuel Tank Support Skin Inspection

rectangular opening for the engine oil cooler.

The forward firewall is riveted to the fuselage

When the cells are removed, check security of

structure.

fiberglass skin attachment to support angles

and brackets, and inspect the anti−abrasion

A. Firewall Inspection

tape for security of adhesion over rivet heads,

all sharp edges and lap joints.

Inspect the aft upper firewall for security,

punctures, and corrosion. Inspect the forward

K. Fuel Tank Support Skin Repair

firewall for punctures, corrosion, and for a

(1). Cover exposed rivet heads with 10−mil

complete seal around the openings for the

by one inch (2.54 cm) tape (16,

overrunning clutch, engine compressor air

Table 2−4) to prevent chafing fuel cell

inlet, and the oil cooler. No un−repaired

fabric.

damage is permissible. Refer to CSP−H−6 for

forward firewall repair.

(2). Perform repair of the fuel tank support

skins according to applicable instruc−

B. Upper Firewall Replacement

tion in CSP−H−6.

Be careful when working on or

CAUTION

6. Firewalls

around the firewall shell. It is

extremely light gage, 0.0015 inch (0.0381

(Ref. Figure 3−5) The shell like aft section

mm) thick sheet.

upper firewall surrounds the upper portion of

the engine combustion chamber and exhaust

(1). Remove tailpipes.

pipe assembly and is designed to contain

engine heat as well as any fire that might

(2). Remove tape covering fasteners and

develop within the engine compartment. The

firewall edges.

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Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(3).

Detach the compressor cooling air duct

ness range of 0.0015−0.0018 inch

support bracket. Remove firewall shell

(0.0381−0.04572 mm).

by pulling out the button head fasten−

ers attaching it to surrounding fuse−

(7).

Contour the patch to match the contour

lage.

of the firewall shell repair area.

(4).

Replace damaged or corroded fasteners.

(8).

Use a stiff bristle brush with the

cleaning solution prepared in step (5).

(5).

Replace aft firewall shell if damaged

to clean the inner and outer surfaces of

beyond practical repair. Trim replace−

the stainless steel patch and firewall.

ment shell to fit installation. Allow

sufficient trim excess for folding back

(9).

Rinse the patch and firewall shell

the edge to provide double thickness at

thoroughly with clean water and allow

the attach points.

to air dry.

(6).

Pierce fastener holes in new firewall

(10).

Coat the surfaces to be joined with a

shell to align holes in surrounding

thin even coating of silver alloy brazing

fuselage rings and waterline 34.96 rib.

flux (66).

(7).

Place firewall shell in position and

secure in place by pressing fasteners

(11).

Use a clamp or other suitable device to

into holes. Attach the compressor

hold the patch in place during the

cooling air duct support bracket to hoist

brazing operation.

fitting.

(12).

Braze the patch in place with Class 8

(8).

Using solvent (1, Table 2−4) clean the

silver brazing alloy (67) using a

forward flanges, lower flanges, and

suitable torch to heat the patch area to

surface where tape routing will cover

a temperature moderately above the

the fasteners; then apply tape (62).

flow point, 1295°F, (707°C) of the

brazing alloy.

(9).

Install tailpipes.

Use extreme care not to over−

CAUTION

C. Upper Firewall Patch Silver Brazing

heat and burn through the fire−

wall shell.

(1). Remove the aft section upper firewall.

(13). Allow joint to cool for at least 60

(2). Remove tape and ceramic fiber blan−

seconds before removing clamping

kets from the firewall shell.

device.

(3). Clean the firewall with a stiff bristle

(14). Remove flux by immersing repaired

brush moistened with solvent (1,

area in water at 160−212°F (71−100°C)

Table 2−4) and wipe dry with a clean,

for 40 minutes.

dry cloth.

(15). Follow by a thorough rinse in clear,

(4). Smooth out the rigidized pattern in the

running water and air−dry, or wipe dry

area on which the patch will be brazed.

with a clean, dry cloth.

(5). Prepare a cleaning solution as follows:

(16). Install ceramic blanket on outer surface

1 − 30 percent hydrofluoric acid (64)

of firewall shell.

and 18 − 30 percent nitric acid (65) by

volume at 75 − 140°F (24 − 60°C)

maximum temperature.

(17). Install aft section upper firewall shell.

(6). Cut a suitable repair patch from Type

(18). Install tape (62) on flanges of firewall

321 stainless steel sheet in the thick−

shell.

Page 3-9

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

7. Fuselage Fittings

9. Landing Gear Fitting Swivel Bearing

Replacement

The mast support structure fittings and the

Replace landing gear swivel bearings accord−

fuselage boom fairing frame fitting are critical

ing to applicable instructions in CSP−H−6.

fatigue−loaded parts. Any damage in excess of

negligible limits requires replacement of the

10. Optional Equipment Structural Hard

damaged part. Any crack, regardless of length,

Points

requires replacement of the part. Refer to

CSP−H−6 for location and identification of

Structural hard points for attachment of

fuselage fitting

optional equipment are installed on certain

helicopters. The associated structure is

A. Fuselage Fitting Repair

strengthened for installation of options such as

a hoist, cargo hook or litter. On early configu−

Repair of cast and forged fittings should be

ration helicopters, hard points may not be

performed only when replacement components

provided. However, equivalent mounting

are not immediately available. Replacement of

brackets and other provisions are available by

bushings, bearings or inserts that become part

modification of the helicopter or by installation

of the fitting assembly are considered insertion

of alternate equipment. If external provisions

repairs. Insertion repairs are described in

for the optional hoist installation are not in

CSP−H−6.

use, the mounting holes are filled with nylon

screws. The holes are located near and above

(1). Negligible Damage

the cargo door opening in the fuselage and

must be filled with the screws to prevent entry

Longitudinal scratches, nicks or dents

of moisture when the hoist is not installed.

shall not exceed 0.010 inch (0.254 mm)

Current configuration hard points are located

depth or 15 percent of the length of the

as follows.

fitting. Transverse scratches, nicks or

(1). Three hoist attachment points are

dents shall not exceed 0.010 inch (0.254

located on the exterior fuselage above

mm) depth or 10 percent of the thick−

both cargo doors.

ness of the fitting. The preceding

damage limits apply after polishing,or

(2). Eight litter bracket attachment points

repair is accomplished.

are located on the passenger/cargo

compartment side of the Sta. 78.50

(2). Replacement

bulkhead.

(3). A cargo hook attachment fitting is

Replace fittings according to applicable

riveted to the helicopter lower center

instructions CSP−H−6.

beam structure for attachment of an

external cargo hook.

8. Aft Section Strut

11. Engine Air Inlet Fairing

(Ref. Figure 3−4) The aft section strut is

The engine air inlet fairing on top of the

approximately 28 inches (71 cm) long, is

fuselage structure directs ambient outside air

diagonally attached by lock−bolts to the aft

to the engine air inlet, oil cooler blower, and

end of the left mast support structure fitting at

main transmission. The fairing installation

the canted firewall, and to a longeron and

consists of a forward fairing section and an aft

angle in the upper right corner of the boom

fairing section. The removable right and left

fairing ring.

halves of the forward fairing encircle the mast

support structure above the cargo compart−

A. Aft Section Strut Repair

ment. The aft fairing is riveted to the fuselage

structure and directs airflow down into the

Repair of the strut is limited to smoothing out

plenum chamber of the engine air inlet. A

minor dents, scratches or nicks. Replace the

uhf/vhf antenna, consisting of a triangular−

strut if it is badly damaged, according to

shaped aluminum sheet and and antenna

applicable instructions in CSP−H−6.

cable connection bracket, is bonded to the aft

Page 3-11

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

vertical face and is part of the aft fairing.

B. Plenum Chamber Hole Sealing

Refer to Section 2 for maintenance information

All tape must be applied to out−

on the forward fairing section.

CAUTION

side of inlet surfaces, so that

any subsequently loosened tape cannot en−

12. Engine Air Inlet (Plenum Chamber)

ter plenum chamber. The engine can be

badly damaged by entry of foreign materi−

The engine air inlet plenum chamber is just

als.

below the engine air inlet aft fairing. The basic

air chamber is formed by a forward panel, two

(1). Using 10−mil by l inch (2.54 cm)

pressure−sensitive tape (32, Table 2−4),

side panels, and a pan that extends between

tape all small holes 0.130 inch (3.302

the lower edges of the side panels. The pan

mm) diameter or larger.

contains an opening for entry of the engine

compressor bell mouth into the air chamber.

(2). Using sealant (60), seal all holes less

The boom fairing ring at Sta. 137.50 forms the

than 0.130 inch (3.302 mm) diameter.

rear wall of the plenum chamber. A diagonal

strut passes through a cutout in the upper left

(3). Rebond loose rubber seals with adhe−

side of the forward panel (Ref. Figure 3−4).

sive (69) according to container instruc−

The strut braces the structure opening from in

tions.

back of the left mast support fitting to the

boom fairing ring. The tail rotor drive shaft

13. Aft Fuselage Skin Cracks

fairing passes through the chamber. Five angle

Inspection/Repair (Sta. 146.62)

clips, each with a nutplate, provide attach

(1).

Remove tail rotor control bellcrank

points for the engine air shield screen.

access door from left side of fuselage

boom fairing.

A. Plenum Chamber Inspection

(2).

Use light source and mirror and

visually inspect fuselage skin adjacent

(1).

Open two access doors on right side of

to doublers for evidence of cracks. If no

engine air inlet fairing and open the

cracking is found, replace boom fairing

engine compartment access doors.

access door.

(3).

Commence repair procedure when

(2).

Inspect all panels for evidence of

cracking is found by removing engine

corrosion, for rivet security and for

from helicopter.

punctures.

(4).

Remove tail rotor control bellcrank

(3).

Inspect the engine air shield mounting

access door from left side of fuselage

clips for secure attachment.

boom fairing when not previously

removed.

(4).

Inspect the aft section strut for rivet

(5).

Gain access through boom fairing

corrosion and for edge clearance where

access door and use angled drill motor

it passes through the cutout in the

and appropriate bit to drill out man−

forward panel.

ufactured head of four rivets each

which secure 369A3000−67 and −68

(5).

On belt−driven blower installation,

doublers.

check that removable forward panels

(6).

Drill out four rivets each to left and

are secure. Inspect rubber seals for

right of helicopter centerline securing

security and partial compression.

aircraft skin to Sta. 146.62 ringer

former flange.

(6).

Inspect the tail rotor drive shaft tube

(7).

Stop−drill all cracks.

fairing for dents, buckled or wrinkled

areas and signs of corrosion.

(8).

Slide 88−369H3000−3 doubler between

Sta. 146.62 ring former flange and

(7).

Close the engine compartment access

fuselage skin (equally distant) on either

doors and two air inlet access doors.

side of center line.

Page

3-12

Revision 14

CSP-H-2 BASIC HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369H HELICOPTERS - page 2