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

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(3). Firmly push bolt inward to free the

Torque nuts to 90 − 110 inch−pounds

bushing stack; then turn the bolt

(10.17 − 12.43 Nm).

approximately 1/4 turn clockwise to

engage the threaded end bushing.

(6). Install bonding jumper.

(4). Remove the bolt and bushing stack as

15. Lower Vertical Stabilizer Inspection

an assembly.

(Ref. Figure 5−3)

(5). On helicopter with dual mounting bolt

installation, remove nuts, washers,

(1).

Inspect the metal skin for holes, cracks,

spacers and bolts.

loose rivets or corrosion. Any crack

must be stop−drilled or patched (CSP−

(6). Slide stabilizer from gearbox mounting

H−5).

frame.

(2).

Inspect attach fittings for cracks, loose

B. Lower Vertical Stabilizer Installation

rivets or corrosion. Check that the

drain holes in stabilizer bottom rib are

(1). Apply a coat of zinc chromate paste (72,

open. If there appears to be excessive

Table 2−4), or lubricant (21), on the

clearance between the stabilizer tube

gearbox mounting frame post.

and attach fitting, a temporary repair

should be made using aluminum

(2). Position stabilizer on mounting frame

laminated shim stock to reduce this

post and align holes in stabilizer and

clearance installation fit.

mounting post.

(3).

Check adjustable bolt or the two

(3). On helicopters using the adjustable

mounting bolts for condition. Oversized

bolt, install the bolt and engage threads

or elongated bolt holes in both the

in nut. (Direction of bolthead is option−

stabilizer and the stabilizer and

al; nut facing aft makes torquing

gearbox mounting frame must be

easier.)

repaired.

Tighten bolt by turning bol−

(4).

Inspect visible portion of tail skid tube

CAUTION

thead; do not turn the nut. After

for cracks, deformation and condition of

torquing, check for proper installation by

plastic sleeve between tube and bottom

measuring the gap between the bolthead

rib.

and fitting and the nut and fitting. A mini−

mum gap of 0.030 inch (0.762 mm) must ex−

(5).

Inspect bonding jumper for security,

ist at either end or in combined total for the

corrosion and fraying.

bolt to be correctly installed. If at least one

full thread is not visible through the nut,

16. Lower Vertical Stabilizer Repair

the wrong bolt is installed, or bolt is in−

stalled incorrectly. Do not try to eliminate

(1). Repair lower vertical stabilizer sheet

gap by over−torquing.

metal or mounting tube according to

applicable instructions in CSP−H−5.

(4). Torque the adjustable bolt to 25 − 40

inch−pounds (2.82 − 4.52 Nm). If no

(2). Repair oversized holes in stabilizer and

torque wrench is available, tighten bolt

gearbox mounting frame having single

until bolt just binds in hole; then

bolt attachment as follows.

tighten nut one more complete turn.

NOTE: An ABC 4677 bolt is originally used in

(5). On helicopters using dual mounting

unbushed holes. Maximum serviceable di−

bolts, install bolts, spacers (curved side

ameter for worn unbushed holes is 0.257

against stabilizer), washers and nuts.

inch (6.5278 mm). Bolt hole wear in excess

Direction of bolthead is optional; upper

of the maximum should be repaired by the

nut facing aft makes torquing easier.

bushing method given in CSP−H−5.

Page 5-9

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(a). If the mounting hole is oversized or

B. Stabilizer Fixed Strut Installation

elongated, but within maximum

NOTE: The use of AN bolts for strut attach−

permissible diameter in either or

ment is not recommended because this bolt

both the gearbox mounting frame

type lacks uniformity in tensile strength.

and stabilizer fitting, rework and

bush the damaged hole(s) according

(1). Position strut between horizontal and

to CSP−H−5 and continue to use an

upper vertical stabilizers. Attach strut

ABC 4677 bolt.

to stabilizers with washers and bolts

(countersunk side of washers to face

(b). If mounting hole(s) are already

bolthead). Do not tighten.

bushed but bushing ID is not within

the permissible wear limit, re−bush

(2). Torque upper vertical stabilizer root

the hole(s) according to CSP−H−5

mounting bolts.

and continue to use an ABC 4677

(3). Torque the attachment bolts to 50 − 70

bolt.

inch−pounds (5.65 − 7.91 Nm).

NOTE: The oversize bolt repair given in step

(4). Position access plates at each end of

(c). below should be used only as an expedi−

strut and attach with screws and

ent repair. Use of the oversize bolt will affect

washers.

interchangeability of other stabilizers on

the gearbox mounting frame. Also, if the

C. Stabilizer Damped Strut Installation

oversize bolt repair is made and any subse−

NOTE: The use of AN bolts is not recommended

quent wear causes hole diameter to exceed

for strut attachment due to the lack of uni−

0.3125 inch (7.9375 mm), the bushing repair

formity in tensile strength of AN type bolts.

is not permissible.

(1). Torque upper vertical stabilizer root

(c). For expedient repair, oversized or

mounting bolts if these were loosened

elongated mounting bolt holes in both

for fixed type strut removal.

stabilizer and mounting frame may

be drilled and reamed to 0.312 inch

(2). Position the damped strut assembly

(7.9248 mm) diameter and an over−

and temporarily install the upper strut

size adjustable ABC 4678 bolt

attachment bolt.

installed. The ABC 4678 bolt is

similar to the ABC 4677 bolt except

(3). Re−adjust the lower end fitting of the

the bolt bushing OD is 0.312 inch

damper assembly so that a bolt will

(7.9248 mm) instead of 0.250 inch

slide into the lower vertical stabilizer

(6.35 mm) and it has a hex head

attachment hole.

instead of a recessed head.

(4). Disengage fitting and turn the fitting

inward one full turn to shorten the

17. Stabilizer Strut Replacement

strut length and establish damper

preload.

(Ref. Figure 5−3)

(5). Install both fitting attachment bolts

A. Stabilizer Strut Removal

and countersunk washers (countersunk

side toward bolthead) and torque to 50

(1). Remove access plates at each end of

−

70 inch−pounds (5.65 − 7.91 Nm).

fixed strut.

(6). Tighten check nut on damper fitting.

(2). Remove attachment bolts and washers

that attach strut to stabilizers.

(a). If installed, bend one tab of tab

washer over a hex flat on the check

(3). At root of upper vertical stabilizer,

nut and another tab over a hex flat

loosen bolts and nuts far enough to

on the damper fitting.

allow the fixed strut to clear the

stabilizer attach fittings.

(b). If check nut and fitting with lockwire

provisions are used, lockwire check

(4). Remove the strut.

nut to fitting.

Page 5-10

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

D. Damped Stabilizer Strut Disassembly

pound (11 − 36 kg) pushing or pulling

load applied to the plunger should

(Ref. Figure 5−4) Disassemble the damped

produce 0.010 inch (0.254 mm) move−

stabilizer strut by removing retaining ring and

ment.

pulling plunger out of damper housing.

Further disassembly, as illustrated, may be

(4). Adjust the nominal length of the

performed if required. Do not remove inboard

damper assembly to the dimension

snubbers unless outboard snubbers are found

shown. If installed, do not bend tab

unserviceable upon inspection. Discard used

washer at this time.

tab washer.

18. Stabilizer Strut Inspection

E. Damped Stabilizer Strut Re-Assembly

(Ref. Figure 5−4)

(1). Inspect the strut for holes, cracks and

corrosion.

Refer to Hughes Notice HN−102.3 for inspec−

tion and/or modification of strut assemblies.

(2). Inspect cushion seals at each end of

fixed strut for deterioration and

(1). Assemble damper as shown. Be sure to

security of bonding.

place the thin snubbers next to the

collar on damper plunger. If a slotted

(3). Inspect outboard snubbers of damped

plunger is used, install a new tab

strut for serviceability as shown. If

washer.

outboard snubbers are not serviceable,

replace all four snubbers.

(2). Push assembled plunger firmly into

damper housing and install retaining

19. Stabilizer Strut Repair

ring. Additional compression of snub−

bers, by pushing on cap assembly, may

No structural repair is currently authorized for

be required in order to completely seat

the stabilizer strut. Replace deteriorated

the retainer in the housing.

cushion seals on fixed strut, using adhesive

(69, Table 2−4) according to container instruc−

(3). Check that plunger will move smoothly

tions. Replace unserviceable snubbers and

with no binding in bearings. A 25 − 80

other parts of the damper on damped struts.

Page 5-11

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

2.83 IN.

INBOARD SNUBBERS

(71.882 MM)

(NOTE 2)

STRUT DAMPER

CAP ASSEMBLY

STRUT

HOUSING

PLUNGER (WITH

TAB SLOT)

OUTBOARD

SNUBBERS

RETAINING

RING

CHECK NUT

TAB WASHER

(NOTE 1)

FITTING

PLUNGER (WITHOUT

FITTING

TAB SLOT)

DAMPER ASSEMBLY

CHECK NUT

LOCKWIRE TO

CHECK NUT

(NOTE 1)

NOTES:

DO NOT BEND TABS OR LOCKWIRE UNTIL

SERVICEABLE SNUBBER

INSTALLED PRELOAD IS ESTABLISHED.

NOMINAL ASSEMBLED DIMENSION.

TACKY OR DETERIORATED

WORN

UNSERVICEABLE SNUBBERS

DAMPER INSPECTION

REMOVE RETAINING RING. PULL PLUNGER AND FITTING

DO NOT REMOVE INBOARD SNUBBER DISCS UNLESS

(WITH TWO OUTBOARD DAMPER SNUBBERS ATTACHED)

OUTBOARD SNUBBERS ARE INSPECTED AND FOUND

OUT OF DAMPER HOUSING. INSPECT FOR CONDITION

UNSERVICIBLE.

AND SERVICEABILITY. IF OUTBOARD SNUBBERS ARE

SERVICIBLE, REINSTALL PLUNGER ASSEMBLY.

30−172C

Figure 5-4. Strut Damper Disassembly and Inspection

Page 5-12

Revision 14

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

TABLE OF CONTENTS

Para/Figure/Table

Title

Page

Section 6 Landing Gear .

6−1

Landing Gear Description and Operation

6−1

Landing Gear Replacement

6−1

A. Landing Gear Removal

6−1

Figure 6−1. Landing Gear

6−2

B. Landing Gear Installation

6−3

Landing Gear Inspection

6−3

Figure 6−2. Repair and Replacement of Landing Gear (Sheet 1 of 2) .

6−4

Landing Gear Strut Inspection

6−6

Figure 6−3. Landing Gear Strut Inspection

6−7

Landing Gear Repair

6−8

Landing Gear Strut Drag Brace Hole Repair

6−8

A. Landing Gear Strut with Bushing Installed

6−8

B. Landing Gear Strut with No Bushing Installed

6−8

Landing Gear Skid Description

6−9

Landing Gear Skid Replacement

6−9

A. Landing Gear Skid Removal

6−9

B. Landing Gear Skid Installation

6−9

Table 6−1. Maximum Damage Limits for Landing Gear Components .

6−10

Heavy−Duty Abrasion Strip Replacement

6−11

10. Landing Gear Skid Inspection

6−11

11. Landing Gear Skid Repair

6−11

A. Repair of Scratches, Nicks, Dents and Punctures

6−11

B. Skid Plug Replacement

6−11

C. Abrasion Strip Replacement

6−11

D. Skid Cap Replacement

6−12

E. Ground Handling Fitting Replacement

6−12

F. Safety Walk Tape Replacement

6−12

G. Skid Tube Nutplate Fitting Replacement

6−12

12. Landing Gear Damper Description and Operation

6−12

13. Landing Gear Damper Replacement

6−13

A. Landing Gear Damper Removal

6−13

B. Landing Gear Damper Installation

6−13

Table 6−2. Damper Assembly Identification

6−14

14. Landing Gear Damper Inspection

6−14

Figure 6−4. Landing Gear Damper Assembly Extension Check .

6−15

Table 6−3. Minimum Damper Extension (Dimension A)

6−15

Page 6−i

Revision 18

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

SECTION 6

LANDING GEAR

1. Landing Gear Description and Operation

(1).

Jack up the helicopter until the landing

gear dampers are fully extended (Ref.

(Ref. Figure 6−1) The landing gear consists of

Section 2). Place support beneath the

two strut−mounted, shock−dampened skids

skid tubes at the strut locations.

aligned longitudinally along the helicopter

fuselage. Both right and left skids pivot as the

damper assemblies extend and retract. Five

(2).

Gain access to the forward brace, strut,

replacement abrasion pads are installed on

and damper at fuselage attachment

each skid to retard skid wear on hard surfaces.

points by opening the compartment

Fairings on each strut reduce aerodynamic

access doors and foot support fairings,

drag during flight. Forged aluminum alloy

respectively.

landing gear braces are attached between the

landing gear strut and fuselage center beam.

The braces prevent shearing of the struts, and

(3).

Gain access to aft landing gear attach−

keep the strut in alignment with the landing

gear. The landing gear struts, made of

ment points by opening the engine

aluminum alloy forgings, attach to the

access doors.

fuselage center beam. At the lower ends of the

struts, feet attach the landing gear skids to the

struts. A cabin entry step is mounted on the

(4).

Disconnect lower end of landing gear

forward struts of all current configuration

dampers. Remove clamp that attaches

helicopters. The step has provisions for

the bonding jumper to strut.

optional side position lights (part of optional

night lighting system). On early configuration

helicopters, the cabin entry step was provided

(5).

Pull fairing fillet downward against

as an optional item and may not be installed

spring tension and secure with tape (14,

on all helicopters. Helicopters not having cabin

Table 2−4).

entry steps are equipped with a forward

fairing cover.

(6).

If optional night lighting system is

NOTE: A skid vibration damper kit may be in−

installed, disconnect wiring by using

stalled on standard or extended landing

appropriate connector insertion/extrac−

gear skids equipped with heavy duty or co−

tion tool (42 or 43, Table 2−2).

balt insert type abrasion strips. The option−

al kit, described in CSP− H− 3, will reduce

any excessive skid vibration by addition of

weight to the aft end of each skid tube.

(7).

Remove cotter pins, nuts, washers and

bolts that attach braces to struts and

2. Landing Gear Replacement

support fittings, and struts to support

fittings, on left side of fuselage. Remove

(Ref. Figure 6−2)

braces.

A. Landing Gear Removal

(8).

Remove supports from beneath left skid

NOTE: The following procedure removes the

entire landing gear, except the landing gear

and carefully remove left struts, skid

damper, as an assembled unit. For removal

and fairings as an assembled unit.

of an individual component, refer to the ap−

plicable paragraph following this procedure.

Two personal are required to accomplish re−

(9).

Repeat the sequence to remove the

moval.

right landing gear.

Page 6-1

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

BRACE

DAMPER

ASSY

FILLET

FAIRING

STRUT

DAMPER

ASSY

STRUT

GROUND HANDLING

BRACE

FILLET

FITTINGS

OLEO SUPPORT

FITTING

SAFETY WALK TAPE

CABIN ENTRY STEP

FAIRING

COTTER PIN

ABRASION STRIP

NOTE 3

(5 PLCS)

BUSHING

OLEO SUPPORT

(NOTE 2)

LANDING GEAR

FITTING

SKID

0.030 IN. (0.762 MM)

MAX. DEFECT

DEPTH

CURRENT

CONFIGURATION

BUSHING

BUSHING (NOTE 2)

BUSHING

(NOTE 5)

DAMPER CAP 0.015 IN.

(0.381 MM) MAX. DEFECT

EARLY

DEPTH

CONFIGURATION

BUSHING

(NOTE 2)

NOTES:

ALL COMPONENTS SHOWN ARE TYPICAL FOR RIGHT GEAR.

EDGE OF BUSHING MUST PROTRUDE A MINIMUM OF 0.010 IN. (0.254 MM) TO A

MAXIMUM OF 0.060 IN. (1.524 MM) ABOVE THE OUTSIDE SURFACE OF PART AFTER

NUT IS TIGHTENED.

LEFT FWD DAMPER ATTACHING BOLT HEAD AFT FOR REMOVAL CLEARANCE.

NOT INSTALLED ON EARLY CONFIGURATION HELICOPTERS.

INSTALL FLUSH WITH INSIDE SURFACE.

30−068C

Figure 6-1. Landing Gear

Page 6-2

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

B. Landing Gear Installation

Do not overtighten brace to

CAUTION

strut hardware. Maximum per−

(1). Gain access to landing gear attachment

missible torque of nut is 5 inch− pounds

points by opening or removing fuselage

(0.56 Nm).

access doors, engine access doors and

(8). Align outboard end of each brace with

foot support fairings.

mating hole in strut and install bolt,

(2). With helicopter supported by jacks,

install two washers and nut.

position left landing gear to align the

(9). Torque nut to 2 − 5 inch−pounds

struts with their openings in the

(0.226 − 0.56 Nm) and install cotter

fuselage structure.

pin.

NOTE: Check that the fairing fillet guide pins

(10). If optional night lighting system is

are engaged with the fairing guide holes be−

installed, connect wiring by using

fore positioning the struts for attachment to

appropriate connector/insertion/extrac−

the structure (Ref. Figure 6−5).

tion tool (42 or 43, Table 2−2).

(3). Lift and carefully position the left

(11). Repeat steps (1). thru (8). to install the

landing gear; then place supports

right landing gear.

beneath the landing gear to hold it in

(12). Remove skid supports, lower helicopter,

place.

and remove jacks.

NOTE: The left forward damper upper bolt

(13). Close engine and underfloor compart−

must be installed with bolt head aft (Ref.

ment access doors; install foot fairings.

Figure 6−2). Bolt direction on right side is

optional.

3. Landing Gear Inspection

(4). Check that slotted bushing is in place.

NOTE: Inspection should be performed with

Align lower bearing of dampers with

helicopter skids clear of the ground.

mating holes in strut and install bolt,

(1). Inspect skids, skid abrasion strips,

two washers, nut and new cotter pin to

struts, feet, braces and fairings for

secure each damper.

dents, cracks, loose components or

rivets, missing cotter pins and loose

(5). Align struts with mating bearings in

nuts.

fuselage support fittings and install

bolt, two washers, nut and new cotter

(2). Inspect the skid−to−foot and foot−to−strut

pin.

attachments for loose bolts and relative

motion between connecting parts. If the

(6). Align inboard end of each brace with

bolts are loose, replace with original

mating bearing in fuselage support

size (if holes are not elongated) or next

fitting and install bolt, two washers,

larger size bolts.

nut and new cotter pin.

NOTE: On other than lock bolt type installa−

(7). Install bonding jumper with clamp and

tions, use of next larger size lock bolt re−

attaching hardware.

quires replacement of nutplate.

Page 6-3

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(12 PLCS)

BONDING JUMPER CENTER BEAM

NUTPLATE FITTING

(NOTE 2)

CLAMP

MLS100M4−4 RIVET

2.00 IN.

(5.08 CM)

FAIRING BRACKET

(8 PLCS)

DAMPER

(NOTES 9, 10)

SKID PLUG

(NOTE 5)

SLOTTED BUSHING

1.00 IN.

(NOTE 1)

(2.54 CM)

MLSP−M4−4 RIVET

CABIN ENTRY STEP

(NOTE 6)

MS20470AD4 RIVET

STRUT

BP−T5−4 LOCKBOLT

(4 PLCS)

BRACE

NON−SKID TAPE

ABRASION

NOTE 7

STRIP

CAP

5 IN.−LB.

GROUND HANDLING FITTING

(0.56 NM) MAX.

FOOT

(NOTE 5)

ABC5244 BOLT 95−115 IN.−LB.

SAFETY WALK TAPE

(10.73−12.99 NM) (4 PLCS) (NOTE 3)

NAS624−6 BOLT

1030−428−8M SCREW

MS20002C4 WASHER

(8 PLCS) (NOTES 3, 4)

80−100 IN.−LB. (9.04−11.30 NM)

CURRENT TYPE

SKID CAP

(8 PLCS) (NOTE 3)

25−35 IN.−LB.

(2.82−3.95 NM)

SKID TUBE

HEAVY DUTY ABRASION STRIP

(EXTRUDED)

(3 PLCS) (NOTE 8)

(NOTE 6)

NOTES:

EDGE OF BUSHING MUST PROTRUDE A MINIMUM OF 0.010 IN. (0.254 MM) TO A MAXIMUM OF 0.060 IN. (1.524 MM)

ABOVE OUTSIDE SURFACE OF PARTS AFTER NUT IS TIGHTENED.

SEAL PARTING EDGE WITH A FILLET OF SEALING COMPOUND (3, TABLE 2−4).

INSTALL ALL RIVETS, AND OTHER HARDWARE WHERE NOTED, WITH WET PRIMER (4, TABLE 2−4).

INSTALL SCREWS ON OUTBOARD SIDE OF INTERCHANGEABLE SKID TUBES.

SEAL MATING SURFACES WITH ZINC CHROMATE PUTTY (71, TABLE 2−4).

NOT INSTALLED ON EARLY TYPE.

LONGER BRACKET WITH THREE MOUNTING HOLES USED ON EARLY TYPE.

MAXIMUM 0.050 IN. (1.27 MM) GAP PERMISSIBLE FORE−AND−AFT CENTERLINE OF ABRASION STRIP AND SKID TUBE.

USE OF PLASTIC COVER IS OPTIONAL ON POPPET TYPE DAMPERS.

10. AT INSTALLATION, POSITION SO THAT TORQUE STRIPES ON CAPS ARE VISIBLE.

30−069−1C

Figure 6-2. Repair and Replacement of Landing Gear (Sheet 1 of 2)

Page 6-4

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

SKID TUBE

STRUT

NAS517−3−4 SCREW

BP−T5−3 LOCKBOLT

MLSP−M4−2 RIVET

(4 PLCS) (NOTE 3)

ABRASION STRIP

NAS1496−5 LOCKBOLT

(NOTES 2, 12)

NAS1080R6 COLLAR

(8 PLCS) (NOTE 3)

BP−T6−3 LOCKBOLT

(8 PLCS) (NOTES 3, 11)

NAS517−3−4 SCREW

MLSP−M4−2 RIVET

NAS1291−3 NUT

MLSP−M4−3 RIVET

(2 PLCS)

AN960PD10L WASHER

(2 PLCS)

ABRASION STRIP

(NOTES 2, 12)

ABRASION STRIP

SKID

SKID PLUG

(NOTE 5)

NAS517−3−5 SCREW

MLSP−M4−4 RIVET

(2 PLCS)

GAP TOLERANCE

NAS517−3−5 SCREW

(NOTES 2, 12)

MLSP−M4−2 RIVET

EARLY CONFIGURATION CHANGES

NOTES: (CONT.)

11. BT−T6−4 LOCKBOLTS MAY BE USED AS ALTERNATE, IF REQUIRED, AS BY TOLERANCE BUILDUP.

12. SMALL GAPS ARE ALLOWED BETWEEN SKID TUBE AND ABRASION STRIPS:

AT FWD STRIP (DETAIL C) − 0.030 IN. (0.762 MM) GAP AT FWD EDGE AND 0.010 IN. (0.254 MM)

GAP AT AFT EDGE; AT ALL OTHER STRIPS − 0.030 IN. (0.762 MM) GAP AT BOTH EDGES.

30−069−2B

Figure 6-2. Repair and Replacement of Landing Gear (Sheet 2 of 2)

Page 6-5

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

4. Landing Gear Strut Inspection

(d). If no cracks are found around drag

brace attach hole in strut and hole is

(Ref. Table 6−1 and Figure 6−3)

not elongated, install new bushing in

hole with wet primer (4, Table 2−4).

(1).

Check landing gear dampers for correct

servicing by observing stance of

(e). If either hole is oversized or cracking

helicopter. Check rear dampers for

is noted, rework strut (Landing Gear

correct extension and signs of leakage.

Strut Drag Brace Hole Repair).

(2).

Remove foot support fairings in passen−

(8). If no bushing is installed in drag brace

ger/cargo compartment and open engine

attach hole in strut, proceed as follows:

access doors.

(3).

Visually inspect strut attachment

(a). Using 10X glass and bright light,

points and pivot bearing for signs of

inspect strut around drag brace

fretting, wear and damage. Fretting

attach holes (top and bottom sur−

will be evident by gray or black materi−

faces) for cracks. If any cracks longer

al around bearing, rivets or seams.

than 0.030 inch (0.762 mm) in length

are noted, strut must be scrapped

(4).

Jack helicopter until landing gear

and serviceable strut installed.

dampers are fully extended.

(b). Check drag brace attach holes in

(5).

Shake landing gear assemblies and

strut for elongation.

note any play or looseness at pivot

bearings, inboard strut assembly

(c). If any cracks, 0.030 inch (0.762 mm)

fittings and drag brace holes.

in length or less, are noted or hole is

elongated, rework strut (Landing

(6).

If any play or looseness is noted,

Gear Strut Drag Brace Hole Repair).

remove landing gear (Ref. Landing

Gear Removal) and inspect drag brace

(9). Reinstall landing gear (Ref. Landing

and strut.

Gear Installation).

(7).

If bushing is installed in drag brace

(10). Inspect strut for cracks or dents.

attach hole in strut, proceed as follows:

(a). Check bushing for looseness. If

(a). If strut is cracked, scrap strut and

bushing is loose, remove it.

replace with serviceable strut.

(b). Using 10X glass and bright light,

(b). If dents in strut exceed 0.060 inch

inspect strut around drag brace

(1.524 mm) depth; or, if scratches and

attach holes (top and bottom sur−

repair area depth would exceed 0.010

faces) for cracks.

inch (0.254 mm) when measured to

surrounding unrepaired surface strut

(c). Check drag brace attach holes in

must be scrapped and serviceable

strut for elongation.

strut installed.

1). Diameter of top hole (DIM. A)

(11). Remove plug button from underside of

should be 0.5313 inch (13.495 mm)

fairing assembly. Using a bright light

maximum in any direction.

and 10X magnifying glass, inspect rivet

2). Diameter of bottom hole (DIM. B)

hole in underside of strut for cracks. If

should be 0.50 inch (12.70 mm)

crack is found, strut must be scrapped

maximum in any direction.

and serviceable strut installed.

Page 6-6

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

5. Landing Gear Repair

(2). Perform fluorescent penetrant inspec−

tion of reworked areas for cracks. If any

(Ref. Figure 6−2)

cracks are noted, replace strut assem−

bly with serviceable strut assembly.

(1). Repair scratches and nicks by smooth−

ing sharp edges.

(3). Perform fluorescent penetrant inspec−

tion of reworked areas for cracks.

(2). Repair elongated, enlarged or worn bolt

holes in strut fittings, either inboard or

(a). If any cracks are noted, rework strut

outboard (Ref. CSP−H−6).

per step (4).

(3). Repair bolt holes at large end of brace

(b). If no cracks are noted, install new

that attaches to strut (Ref. CSP−H−6).

369H6023−1 bushing in hole with

wet primer (4, Table 2−4).

(4). Replace a strut that is cracked or for

(4). Ream out top hole (DIM. A) to

the following damage.

0.5908−0.5913 inch (15.006−15.019

(a). Dents with depth in excess of 0.060

mm) and ream out bottom hole (DIM.

inch (1.524 mm).

B) to 0.5595−0.560 inch (14.211−14.224

mm).

(b). Scratches if repaired area depth

exceeds 0.010 inch (0.254 mm) when

(5). Perform fluorescent penetrant inspec−

measured to surrounding unrepaired

tion of reworked areas for cracks.

surface.

(a). If crack is found, strut must be

scrapped and serviceable strut

(5). Replace defective or badly damaged

installed.

fairing.

(b). If no cracks are noted, install new

(6). Repair fairing fiberglass damage, such

369H6023−3 bushing in hole with

as small tears or punctures that do not

wet primer.

impair the telescoping action of the

fairing (Ref. CSP−H−6).

B. Landing Gear Strut with No Bushing

Installed

(7). Replace cracked, dented or distorted

braces.

(1). Ream out top hole (DIM. A) to

0.5308−0.5313 inch (13.482−13.495

(8). Repair or replace damaged skid tube.

mm) and ream out bottom hole (DIM.

B) to 0.4995−0.50 inch (12.687−12.70

(9). Replace center beam−to−landing gear

mm).

attachment bearings that exceed 0.040

inch (1.016 mm) axial play. Refer to

(2). Perform fluorescent penetrant inspec−

CSP−H−6 for replacement procedure.

tion of reworked areas for cracks.

Landing Gear Strut Drag Brace Hole

(a). If any cracks are noted, rework strut

Repair

per step (3).

(b). If no cracks are noted, install new

(Ref. Figure 6−3) The following procedure is for

369H6002−1 1 bushing in hole with

repair of the bolt hole in the landing gear strut

wet primer (4, Table 2−4).

where the drag brace attaches. This rework is

for either elongated or cracks in the bolt hole

(3). Ream out top hole (DIM. A) to

area (Ref. Landing Gear Strut Inspection).

0.5608−0.5613 inch (12.244−14.257

mm) and ream out bottom hole (DIM.

A. Landing Gear Strut with Bushing

B) to 0.5295−0.530 inch (13.449−13.462

Installed

mm).

(1). Ream out top hole (DIM. A) to

(4). Perform fluorescent penetrant inspec−

0.5608−0.5613 inch (12.244−14.257

tion of reworked areas for cracks.

mm) and ream out bottom hole (DIM.

B) to 0.5295−0.530 inch (13.449−13.462

(a). If any cracks are noted, proceed with

mm).

step (5).

Page 6-8

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(b). If no cracks are found around drag

B. Landing Gear Skid Installation

brace attach hole in strut and hole is

NOTE: Left and right side machine bolt at−

not elongated, install new

tached skids are interchangeable. As re−

369H6023−1 bushing in hole with

quired, eight 1032−428−8M screws are re−

wet primer.

moved from inboard side of skid tube an

(5). Ream out top hole (DIM. A) to

installed on outboard side with primer (4,

0.5908−0.5913 inch (15.006−15.019

Table 2−4) . If machine bolt−attached skids

mm) and ream out bottom hole (DIM.

are to be used with the lockbolt struts, per−

B) to 0.5595−0.560 inch (14.211−14.224

form steps (4). thru (11). below to enlarge

mm).

strut holes. When machine bolt style strut is

to be used with lockbolt style skid, use Huck

(6). Perform fluorescent penetrant inspec−

or Olympic 0.250 inch (6.35 mm) lock−bolts

tion of reworked areas for cracks.

with a washer to protect counterbore sur−

face on strut foot.

(7). If crack is found, strut must be

scrapped and serviceable strut

(1).

Apply a thin coating of primer (4,

installed.

Table 2−4) to strut and skid tube

mating surfaces.

(8). If no cracks are noted, install new

(2).

Align mating parts and install lockbolts

369H6023−3 bushing in hole with wet

with primer, or secure with machine

primer.

bolts and washers.

Landing Gear Skid Description

(3).

Seal edges of landing strut foot with

0.060 inch (1.524 mm) fillet of sealing

(Ref. Figure 6−2) The landing gear skids

compound (3). Seal the two unused

consist of contoured aluminum alloy tubes,

holes on the top of each strut foot (if

bonded skid caps and riveted end plugs,

present) with silicone rubber (17).

ground handling wheel fittings and abrasion

strips having cobalt−barium inserts. Skid tubes

(4).

To enlarge strut foot mounting holes for

(excepting the early configuration) are

machine bolt−attached skids, place the

extruded and have a 0.095 inch (2.413 mm)

left (−1 detail) landing gear foot drill jig

wall thickness along underside and around

(40, Table 2−2) on the left strut forward

entire perimeter of tube at both strut foot

foot. Use the small diameter alignment

attachment locations. Table 6−1 lists maxi−

pin to locate the existing lockbolt hole.

mum damage limits.

(5).

Clamp the tool to strut with C−clamps

8. Landing Gear Skid Replacement

in three places.

(Ref. Figure 6−2)

(6).

Insert the drill bushing in the jig and

drill a 0.250 inch (6.35 mm) hole in the

A. Landing Gear Skid Removal

strut by a flat end (bottom) drill (size

F). Install the large diameter alignment

(1). Jack up the helicopter until the landing

pin in the drilled hole. Use the bushing

gear dampers are fully extended. Place

and drill the remaining holes.

supports beneath the skid tubes at the

strut locations.

(7).

Remove special tool from strut. Deburr

drilled holes.

(2). Remove the lower fairing from the

(8).

Enlarge counterbore of mounting holes

two−piece fairing assembly.

on face of strut to 0.687 inch (17.4498

(3). As applicable, remove the machine

mm) diameter, flush with, or 0.020 inch

bolts or lockbolts that attach the skid

(0.508 mm) above original depth (0.090

tube assembly to feet on forward and

inch (2.286 mm) minimum thickness

aft struts.

remaining). Maintain the 0.030−0.060

inch (0.762−1.524 mm) lower corner

(4). Remove skid from landing gear.

radius.

Page 6-9

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(9). Apply chemical film protection (8,

(11). Perform steps (4). thru (10). above,

Table 2−4) on exposed aluminum

using the right (−2 detail) drill jig (41,

surfaces.

Table 2−2) for the right struts as

necessary.

(10). Repeat steps (4). thru (9). above for left

(12). Install lower fairing of two−piece fairing

aft strut foot.

assembly.

Table 6-1. Maximum Damage Limits for Landing Gear Components

Dents

Nicks

Scratches

Cracks

Holes

Component

in. / mm

Skid tube (1)

0.200 / 5.08

0.010 / 0.254 from aft side of aft Same as (2)

No cracks

0.250 / 6.35

(2)

strut to 10 / 254 forward of the

for nicks

allowed

(2)(3)

strut, with cleanup not

exceeding 0.015 / 0.381 if

forward of that point to start of

curved section, with cleanup not

exceeding 0.020 / 0.508 (1)

Foot

0.060 / 1.524

0.010 / 0.254

No cracks

No holes

allowed

Strut

0.060 / 1.524

(2)

No cracks

No Holes

allowed

Brace

0.040 / 1.016

0.010 / 0.254

0.005 / 0.127

No cracks

No holes

allowed

Damper

0.060 / 1.524

0.010 / 0.254

No cracks

No holes

Assembly

allowed

Fitting

0.010 / 0.254

No cracks

No holes

allowed

Plug

0.200 / 5.08

0.250 / 6.35

0.010 / 0.254

0.250 / 6.35

NOTES:

(1) Repair of minor skid tube damage aft of the rear strut and on the forward (curved) section is not required

but surface finish must be restored.

(2) Refer to CSP-H-6 for other repair data.

(3) Hole must be plugged with correct size blind rivet.

Page 6-10

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

9. Heavy-Duty Abrasion Strip Replacement

(6.35 mm) and a depth of 0.020 inch

(0.508 mm) when repaired.

(Ref. Figure 6−2)

(8). Inspect ground handling fittings for

(1). Remove bolts and washers attaching

cracks, loose rivets and corrosion.

heavy−duty abrasion strips to landing

gear skid tube.

(9). Install the lower fairing.

(2). Completely remove any residual zinc

11. Landing Gear Skid Repair

chromate putty or sealing compound

(Ref. Figure 6−2)

from attachment and mating areas of

the skid tube.

A. Repair of Scratches, Nicks, Dents and

Punctures

(3). Attach and secure replacement heavy−

duty abrasion strip to nutplate fittings

(1). Repair scratches and nicks by smooth−

on skid tube with four bolts and

ing sharp edges (Ref. Table 6−1).

washers. Comply with the following.

(2). Drill (0.250 inch (6.35 mm) maximum)

(a). Use washer under each bolt head.

out dents, nicks and scratches to the

nearest blind rivet size when such

(b). Apply a 0.060 inch (1.524 mm) bead

damage exceeds the depth limits

of sealing compound (3, Table 2−4) to

specified in Landing Gear Skid Inspec−

all mating part edges.

tion. Clean out puncture holes in the

same manner.

(c). Install with minimum gap between

abrasion strip and skid tube. Gap

(3). Apply zinc chromate putty (72,

limit is 0.030 inch (0.762 mm)

Table 2−4) to edges of drilled repair

maximum along fore−and−aft center−

holes and install the appropriate size

line of abrasion strip.

rivet to close the hole.

(d). Torque bolts to 25 − 35 inch−pounds

(4). Repair the skid tube assembly when

(2.82 − 3.95 Nm).

puncture hole, or drilled out dents,

nicks or scratches will exceed 0.250

10. Landing Gear Skid Inspection

inch (6.35 mm) diameter, or when

fluorescent penetrant inspection reveals

(1).

Jack the helicopter until the landing

damage adjacent to punctures. Perform

gear dampers are fully extended.

repair of the skid tube according to

(2).

Remove the lower fairing from a

CSP−H−6.

two−piece fairing assembly.

B. Skid Plug Replacement

(3).

Inspect for dents and depressions in

(1). Drill out rivets or remove screws

excess of 0.20 inch (0.508 mm) in depth.

attaching skid plug. Remove unservice−

able plug by drilling a hole in the center

(4).

Inspect for punctures.

of the plug and using a suitable puller.

(5).

Perform fluorescent penetrant inspec−

(2). Apply a thin layer of zinc chromate

tion of areas adjacent to punctures.

putty (72, Table 2−4) to the mating

(6).

Inspect from the aft end of the tube to a

surfaces of the new plug and skid tube

point 10 inches (25.4 cm) forward of the

to ensure a watertight fit.

aft strut for scratches and nicks which

(3). Rivet new skid plug through aft

will exceed a length of 0.250 inch (6.35

abrasion strip to tube.

mm) and a depth of 0.015 inch (0.381

mm) when repaired.

C. Abrasion Strip Replacement

(7).

Inspect from the forward end of the

(1). Remove screws or drill out rivets, as

tube to 10 inches (25.4 cm) forward of

applicable. Drill out rivets attaching

the aft strut for scratches and nicks

abrasion strip and remove unservice−

which will exceed a length of 0.250 inch

able strip.

Page 6-11

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(2). Completely remove any residue zinc

G. Skid Tube Nutplate Fitting Replacement

chromate putty. Apply primer (4) to any

(1). Drill out rivets attaching nutplate

bare metal.

fitting to skid tube and remove fitting.

(3). Secure new skid plug to tube with

(2). Completely remove any residual zinc

screws, or rivets, as applicable, through

chromate putty or sealing compound

the aft abrasion strip.

from nutplate mounting area on skid

tube.

(4). Coat new screws or rivets with primer.

As applicable screw or rivet the replace−

(3). When installing replacement nutplate

ment abrasion strip to tube while

fitting on skid tube, use sealing com−

primer is still wet.

pound (3). Rivet nutplate fitting in

place. Apply a 0.060 inch (1.524 mm)

NOTE: To allow use of common abrasion strips

bead of sealing compound around

on the curved portion of the skid, a maxi−

mating part edges.

mum gap of 0.10 inch (2.54 mm) between

center underside of skid and aft end of the

12. Landing Gear Damper Description and

abrasion strip is permissible. Permissible

Operation

gap at forward end is 0.030 inch (0.762 mm).

Each landing gear assembly is equipped with a

(5). After installation, seal all of the parting

front and rear damper assembly.

edge of the abrasion strip next to the

skid tube. Apply an approximate 0.060

The landing gear dampers absorb vertical

inch (1.524 mm) bead (fillet) of sealing

shock to the landing gear struts during

compound (3) to ensure a watertight

helicopter landings. The front damper assem−

assembly.

blies are attached to the oleo attachment

fittings located on the outboard side of the

D. Skid Cap Replacement

pilot’s compartment seat structure. The aft

damper assemblies are attached to oleo

(1). Remove skid cap.

support fittings in the engine compartment.

The damper assemblies are 12.21 inches

(2). Using isopropyl alcohol (71, Table 2−4)

(31.0134 cm) long when extended and 8.96

clean bonding area.

inches (22.7584 cm) long when compressed.

There are two basic types of landing gear

(3). Bond new cap to skid tube with sealing

dampers which can be installed on the

compound (3).

helicopter:

E. Ground Handling Fitting Replacement

(1) A bladder−type damper assembly consisting

of a barrel, upper and lower mounting cap, and

(1). Replace an unserviceable ground

internal rubber bladder, and a piston.

handing fitting using the same proce−

dures as Abrasion Strip Replacement

(2) A poppet−type damper assembly consisting

except gaps are not allowable and seal

of a barrel, upper and lower mounting cap,

mating surfaces with zinc chromate

main poppet, rebound poppet and a piston.

putty (72, Table 2−4) instead of primer.

The poppet−type damper is one−way inter−

changeable (in sets of four only) with the

F. Safety Walk Tape Replacement

bladder−type damper. Use of poppet−type

(1). Carefully pull or scrape away damaged

dampers requires larger bushings and 5/16

tape. Remove all residual adhesive from

inch diameter hardware for both upper and

skid tube by wiping with a clean cloth

lower attachment. A damper must be replaced

wetted by naphtha (59, Table 2−4).

if damaged, or if loss of pneumatic pressure

(nitrogen gas) or hydraulic oil occurs. Replace−

(2). Carefully align new tape (73) with

ment of a single damper must be with the

mounting surface and press firmly into

same type and configuration as the one

place. Expel air bubbles while pressing

removed. Refer to Table 6−2 for damper

down the tape.

application.

Page 6-12

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

13. Landing Gear Damper Replacement

Protective glasses and

WARNING

heavy gloves must be worn

(Ref. Figure 6−1 and Figure 6−2)

when drilling the pressure relief hole

in the damaged damper. The spray of

A. Landing Gear Damper Removal

hydraulic oil under pressure can result

in injury to personnel.

Be sure the helicopter is jacked

CAUTION

up evenly and in a level area;

(c). Drill a 0.0625 inch(1.5875 mm) hole

otherwise, jacks might slip and damage the

in lower end of the damper body.

helicopter structure.

Keep the drill bit in the hole until the

hydraulic fluid stops flowing.

(1). Jack up the helicopter until the landing

gear skids just clear the ground.

NOTE: Note damper part number and color

(2). For forward damper removal, remove

code to be sure that correct dampers are re−

foot support fairings located in the

installed.

passenger compartment.

(4). Remove hardware, except bushings,

attaching the damper assemblies to the

WARNING

fuselage fitting and to landing gear

D Check that all electrical power is

struts; remove damper assemblies.

OFF. This precaution will prevent

personal injury or helicopter dam−

B. Landing Gear Damper Installation

age which could result from body or

tool contact with electrical termi−

nals.

NOTE: Ensure the replacement damper is cor−

rect for the helicopter (Ref. CSP−H−7 and

D Use extreme care during damper re−

Table 6−2). Also check that the cap torque

moval if a green or white bladder−

stripes will be visible for inspection after in−

type damper is extended beyond

stallation.

11.38 inches (28.9052 cm) as mea−

sured between flat surface of both

(1). Install replacement damper in upper

end caps. This condition indicates an

internal failure of the damper that

and lower mounting position with

will result in a sudden release of in−

attaching hardware. Ensure bushings

ternal pressure and explosion of the

are in place.

bladder if the damper is released

from the fuselage fittings before ac−

NOTE: Left forward damper upper bolt must be

complishing step (3). below.

installed with bolt head aft. Bolt direction

on right side is optional.

(3). Bladder−type dampers that show

evidence of, or are suspected of, inter−

(2). For aircraft 0001 thru 0100, torque

nal failure must have the pressure

nuts to 25 − 30 inch−pounds (2.82 −

relieved, steps (a). thru (c). below,

3.39 Nm) and install cotter pin.

before performing removal.

(a). Removal any avionics equipment in

(3). For aircraft 0101 & subs, torque nuts to

the immediate area of the damaged

48 − 55 inch−pounds (5.42 − 6.21 Nm)

damper. Cover all electrical connec−

and cotter pin.

tors with plastic material.

(4). Check installation for proper alignment

(b). Wrap the damaged damper with 1

of torque stripes.

inch (2.54 cm) thick polyfoam (or

material equivalent absorption

property) to minimize spraying of

(5). Install foot support fairings and close

hydraulic oil.

engine access doors.

Page 6-13

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

Table 6-2. Damper Assembly Identification

Factory Charge

Landing Gear

Part No.

Configuration

Color

Type

psi / kPa

Application

369A6300

Basic

Light Green

Bladder

560 ±10 / 3861 ±69

Early standard (4)

369A6300

-501

Light Green

Bladder

560 ±10 / 3861 ±69

Early standard (4)

369A6300

-503

Light Green

Bladder

560 ±10 / 3861 ±69

Current standard (4)

369A6300

-601

White

Bladder

560 ±10 / 3861 ±69

Early standard (4)

369H6340

Basic

Blue

Poppet

520 ±2 / 3585 ±14

Current standard (4)

* * *

Extended option (2 fwd)

369H92131

Basic

Orange

Poppet

850 ±3 / 5861 ±21

Extended option (2 aft)

* * *

369H92800 *

Basic

Medium Green Poppet

705 ±2 / 4861 ±14

Winterized standard

option (4)

Winterized extended

option (2 fwd)

369H92801 * *

Basic

Yellow

Poppet

1075 ±3 / 7412 ±21

Winterized extended

option (2 aft)

NOTES:

* Not available for replacement purposes; replaced by winterized version of 369H6340. May be modified to

369H6340 at overhaul; refer to CSP−H−5.

* * Not available for replacement purposes; replaced by winterized version of 369H92131. May be modified

to 369H92131 at overhaul; refer to CSP−H−5.

* * * Requires a higher charge and adjustment of oil level for winterized service; refer to CSP−H−5 for

charging data.

14. Landing Gear Damper Inspection

discarded, or replaced if spare is

available.

NOTE: It is normal for a thin hydraulic oil film

(3). Inspect landing gear dampers for

to remain on damper as a result of wiping

condition by observing stance of

contact with piston seal. Newly installed

helicopter (normal stance is slightly

dampers may also have slight oil seepage

nose up). If stance indicates excessive

from oil trapped in end cap threads during

nose up/nose down attitude, perform

damper assembly. Neither of these should

damper extension check.

be considered damper leakage or cause for

damper replacement.

(a). Inspect landing gear damper assem−

blies for proper extension, with

(1). With helicopter on jacks, inspect

helicopter in empty weight configura−

damper assemblies for evidence of

tion (no passengers or cargo) but with

bearing looseness in upper and lower

full fuel tanks. This configuration

caps, worn bearings (excessive radial

should weight between 1675−1825

play) loose or cracked caps and oil

pounds (760−583 kg) exclusive of skid

leakage. Any misalignment of torque

mounted float gear. Place helicopter

stripes on caps, piston and barrel

on smooth concrete or equivalent

indicates loosening of caps. Replace

surface (not asphalt).

immediately and repair damper

according to CSP−H−5.

(b). Check dampers which have been

modified (winterized) for cold weath−

(2). Inspect damper for security of attaching

er operation are to be checked at not

hardware and condition of plastic cover.

more than 30°F (−1°C) above the

Plastic cover is no longer required or

coldest temperature at which the

installed in production; it may be

helicopter is operated.

Page 6-14

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(i). Determine average extension from all

six readings for each damper assem−

bly. Remove and overhaul any damper

END CAP

assembly not meeting dimensions shown

(FLAT)

in Table 6−3.

NOTE: If two damper assemblies fail to meet

the minimum extension shown in Table 6−3,

replace the damper having the greater

amount of deflection with a known service−

DIMENSION A

able damper and repeat steps (c). thru (i). If

the original damper again fails to meet

PISTON

minimum extension requirements, replace

it with serviceable damper, reinstall the

first damper, and repeat steps (c). thru (i).

This will determine whether one or both

dampers require overhaul. Dampers which

have been modified (winterized) for cold

BARREL

weather operation are to be soaked at −3° to

+3°F (−19 to −16°C) for 24 hours minimum

prior to conducting the bench check.

(4). Inspect for damper internal failure by

checking for clearance between the

bottom of the landing gear strut and

30−226

measuring the length of the damper. If

the gear strut is touching the fuselage

Figure 6-4. Landing Gear Damper Assembly

or the length of the damper measured

Extension Check

between the end cap flat surfaces is

11.38 inches (28.9052 cm) or more, it

(c).

Raise and lower tailboom above and

must be replaced.

below the normal at−rest position

three times. On the last cycle, allow

Table 6-3. Minimum Damper Extension

the tailboom to slowly settle to the

(Dimension A)

at−rest position.

Standard Landing Gear

Extended Landing Gear

(d).

Measure and record dimension from

upper end cap to upper end of barrel

in. / cm

on all four damper assemblies (Ref.

Aft

2.55 / 6.477

Aft

2.60 / 6.604

Dimension A, Figure 6−4).

Fwd

3.00 / 7.62

Fwd

2.90 / 7.366

(e).

Repeat steps (c). and (d). two more

times.

15. Landing Gear Damper Repair

(f).

Lower and raise tailboom below and

Exterior damage limits for the landing gear

above the normal at−rest position

damper are provided in Table 6−1. Refer to

three times. On the last cycle, allow

CSP−H−5 for available repair and overhaul

the tailboom to slowly rise to the

information. Remove scratches and nicks in

at−rest position.

damper fittings as follows:

(1). Use grade 400 (or finer) wet or dry

(g).

Measure and record dimension from

abrasive paper (9, Table 2−4) to remove

upper end cap to upper end of barrel

any raised or sharp edges and to blend

on all four damper assemblies (See

the defect smoothly with the surround−

dimension A, Figure 6−4).

ing surfaces.

(h).

Repeat steps (f). and (g). two more

(2). Use crocus cloth (23) to remove any

times.

surface scratches left by the coarser

Page 6-15

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

abrasive and to polish the repaired area

17. Landing Gear Fairing Replacement

to match the surrounding surfaces.

(Ref. Figure 6−5)

(3). Apply corrosion protection treatment

A. Landing Gear Fairing Assembly Removal

(Ref. Section 2).

The following removal instructions are typical

NOTE: If dust cover is not installed, there is no

for all four fairing assemblies.

requirement for the felt spacer, rubber re−

(1). Remove 6 screws, 12 washers and 6

taining sleeve and the tie strap (or plastic

nuts that secure trailing edge of

tape) for securing cover. When replacing or

lower fairing and 6 screws and

discarding a plastic cover, only the upper

washers that secure lower fairing to

end of the damper must be detached.

the two strut brackets.

(4). To replace a damper assembly plastic

(a). Carefully spread trailing edge of

cover (installed only at aft locations on

lower fairing and remove in a for−

early damper configurations), remove

ward direction.

plastic tape or rubber sleeve and tie

strap used to compress cover tangs and

NOTE: Be sure that doublers between lamina−

carefully but firmly pull cover toward

tions at trailing edge are retained for reuse.

top end to disengage tangs from bearing

(2). Remove the fillet from the upper part of

cap groove. Install replacement by

the fairing assembly as follows.

reversing the procedure. Secure the

cover tangs in place with rubber sleeve

(a).

Remove the four rivets from the

and tie strap or by wrapping several

trailing edge of the fillet.

turns of tape (74) around tanged end of

(b).

Drill out one of the six rivets securing

cover

the fillet to the upper guide. Replace

the rivet with a sheet metal hole

16. Landing Gear Fairing Assembly

fastener (Cleco, or equivalent).

Description

Repeat this step on the other five

rivets.

The landing gear fairing consists of a stream−

lined fiberglass fairing surrounding each

(c).

Open underfloor compartment or

landing gear strut, extending from the

engine compartment doors to gain

fuselage to the landing gear skid. Each fairing

access to the strut cutout in the

assembly is constructed of either two or three

fuselage skin. Have an assistant

main parts; a fillet and an upper and lower

push down on the upper guide with a

(two−piece) fairing are used on all but early

suitable tool (wood dowel or equiva−

configurations which have a one−piece fairing.

lent) to relieve the spring tension.

The fillet is spring−loaded to remain in firm

(d).

With spring tension off the guide,

contact with a fiberglass rubbing plate that is

take out the six fasteners. Slowly

bonded and riveted to the fuselage. The upper

relax the dowel pressure on the guide

part of the two−piece fairing is bonded and

until the springs reach maximum

riveted to a strut bracket that is riveted to the

travel.

strut. The lower part of the two−piece fairing

is attached to the upper fairing and strut

(e).

Carefully spread fillet at trailing

brackets with screws for ease of removal

edge and remove in a forward

and/or replacement of the strut feet and skid

direction.

tubes. The fairing telescopes inside the fillet to

allow movement of the strut as the landing

(3). Remove the upper part of the fairing, or

gear dampers compress or extend. A seal on

the one−piece fairing as follows.

the bottom edge of the fairing forms a fillet

(a). As applicable, remove one or two (or

between the fairing and the skid tube. The

eight or nine) rivets that secure

forward fairing may have a fairing cover

trailing edge of fairing.

installed. When a cabin entry step is installed,

the fairing assembly has an opening with a

(b). Remove two (or eight) rivets that

rubber seal.

secure fairing to strut bracket(s).

Page 6-16

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(c). Use a putty knife or similar thin−

(e).

Back up the fairing with a fiber block

bladed tool to carefully pry apart the

at the transfer punch location. Using

bonding and separate the upper 5

a plastic hammer, hit the opposite

inches (12.7 cm) of the trailing edge;

side of the fairing hard enough to

then separate the fairing from the

transfer the hole centers.

flange of the lower guide.

(f).

Remove fairing and check that all the

transfer marks appear within the

(d). Carefully spread trailing edge of

outline of the small laminated

fairing and remove in a forward

doublers. Drill out the located holes.

direction.

(g).

Carefully bond the fairing to the

B. Landing Gear Fairing Assembly

lower guide. Use adhesive (19)

Installation

according to container instructions.

The following installation instructions are

(h).

As applicable, install two (or eight)

typical for all four fairing assemblies. Where

rivets to secure the fairing to the

riveting is required, use rivets of the type

strut bracket(s).

shown.

(i).

As applicable, install one or two (or

(1). Install the upper part of the fairing, or

eight or nine) rivets to secure the

the one−piece fairing as follows.

trailing edge of the fairing.

(a). Assemble upper guide, pin assembly,

(j).

Using a soft lead pencil, draw a

inner guide half, outer guide half,

continuous line along the horizontal

springs and lower guide on the

center of the upper guide flange.

landing gear strut. Install two rivets

(2). Install the fillet as follows.

with wet primer (4, Table 2−4) to

secure lower guide to strut.

(a).

Drill a 0.0980 inch(2.4892 mm) hole

in the center of each 0.375 inch

(b). Push guide pins into the matching

(9.525 mm) square doubler in the

holes of the lower guide. Wedge a

fillet. (There are six doublers.)

temporary holding device between

the upper guide and the strut to keep

(b).

Carefully spread trailing edge of fillet

the pins engaged.

and position about upper guide.

Clamp the lower end of the fillet

NOTE: Use two small wood blocks or any simi−

trailing edge to the upper end of the

lar suitable means to keep the springs in

fairing trailing edge. Clamping will

compression. The device used must be small

prevent fillet movement when the

enough to be removed through the strut cut−

fillet rivets are installed.

out in the skin after the fillet is assembled.

(c).

Have an assistant remove the

(c). Install blind hole transfer punches

temporary holding device and push

(two or four places, as applicable) or

down on the upper guide with a

fabricate suitable tools as shown in

suitable tool (wood dowel, etc). Have

Figure 6−5. Install tool(s) between

the guide pushed down to a point

opposing holes in strut bracket(s).

where the pencil line drawn on the

guide flange is visible through one of

(d). Carefully spread trailing edge of

the 0.0980 inch(2.4892 mm) holes in

fairing and position the fairing on the

the fillet. Match−drill the guide and

strut bracket(s) and the lower guide.

secure the fillet and guide with a hole

Have an assistant hold the fairing in

fastener (Cleco, or equivalent).

this position.

Repeat the procedure for all six rivet

locations. Remove the pushing tool

NOTE: On the one−piece fairing, there should

from the strut opening.

be 0.020−0.080 inch (0.508−2.032 mm) com−

pression of the fairing seal against the skid

(d).

Remove one fastener at a time,

tube when the fairing is correctly posi−

enlarge the hole to rivet diameter

tioned.

and install a blind rivet.

Page 6-17

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

UPPER

CHAFING PAD

FAIRING

TEFLON STRIP

0.35 IN. (8.89 MM)

FILLET (NOTE 3)

0.80 IN. (20.32 MM)

MS20470A RIVETS

LOWER

MS20600AD OR CKL−P RIVETS

0.35 IN. (8.89 MM)

FAIRING

0.375 IN. (9.525 MM) DOUBLER

NOTE 5

NOTE 4

RETAINING BLOCKS AND CLAMPS

TEFLON PAD (INSIDE GUIDES)

5 IN. (12.7 CM) (NOTE 1)

FAIRING−TO−LOWER GUIDE (NOTE 1)

UPPER GUIDE PIN ASSY,

INNER GUIDE HALF AND SPRING

UPPER FAIRING (NOTE 3)

MS20470A RIVET

OUTSIDE GUIDE HALF

(FWD FAIRING − 1 RIVET)

MS20600AD OR CKL−P RIVETS (NOTE 2)

(AFT FAIRING − 2 RIVETS)

1.4375 IN. (3.65125 CM) DOUBLER

LOWER GUIDE (NOTE 1)

LOWER FAIRING (NOTE 3)

MS20470A RIVET (2 PLCS)

SCREW, WASHER (2 PLCS)

SCREW, WASHERS, NUT (6 PLCS)

SEAL

(NOTE 7)

NAS1398D4−4 RIVETS

0.750 IN. (19.05 MM) DOUBLER

CABIN ENTRY STEP

(UPPER BRACKET)

(NOTE 7)

S3L10−DT4−3 HUCKBOLTS

SCREW, WASHER (4 PLCS)

(LOWER BRACKET (NOTES 2, 8)

NOTE 7

CKL−P RIVETS

0.50 X 0.750 IN. (12.7 X 19.05 MM)

(NOTES 2, 9)

DOUBLER

SEAL

SKID

STRUT

NOTES:

BONDED AREA: USE EPOXY ADHESIVE (19, TABLE 2−4).

INSTALL NEW RIVETS WITH WET PRIMER (4, TABLE 2−4)

REFER TO CSP−H−6 FOR FIBERGLASS REPAIR.

CLAMP FILLET AND FAIRING TRAILING EDGES DURING INSTALLATION OF

FAIRING

FILLET RIVETS.

BRACKET

PENCIL CENTERLINE ALONG FLANGE.

3/16 IN. (4.7625 MM) WELDING ROD OR OTHER SUITABLE DEVICE (4 PLCS).

FWD FAIRING ONLY.

HUCKBOLT HEAD COUNTERSUNK INSIDE STRUT; NO PORTION OF HEAD TO

PROTRUDE INSIDE STRUT.

AFT FAIRING BRACKETS AND LWR FWD FAIRING BRACKET ON ONE−PIECE

FAIRING ONLY.

30−070−1C

Figure 6-5. Repair and Replacement of Fairing (Sheet 1 of 2)

Page 6-18

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

UPPER FWD

FAIRING COVER

0.40 IN. (10.16 MM)

UPPER FWD FAIRING

BRACKET

0.64 IN. (16.256 MM)

DOUBLER

NOTE 6

STRUT

FWD

0.32 IN.

FAIRING

(8.128 MM)

CKL−P RIVETS

(4 PLCS) (NOTE 2)

FAIRING

(NOTE 3)

SCREW (10 PLCS)

UPPER FWD FAIRING

MS20470A RIVETS

BRACKET

(FWD FAIRING − 9 RIVETS)

(AFT FAIRING − 8 RIVETS)

TO FWD FAIRING

DOUBLER

UPPER EDGE

LOWER GUIDE

(NOTE 1)

MS20600AD OR CKL−P

RIVETS (NOTE 2) OR

SCREW AND WASHER

7.87 IN. (19.9898 CM)

(NOTES 11, 12)

0.50 X 0.750 IN.

(12.7 X 19.05 MM)

FWD FAIRING

DOUBLER

COVER

12.13 IN. (30.8102 CM)

(NOTE 7)

SEAL

(NOTE 11)

NOTE 10

12.96 IN. (32.918 CM)

(NOTES 11, 12)

SKID

DOUBLER

4.32 IN. (10.973 CM)

(NOTE 2)

0.020 IN.

(0.508 MM)

SKID C

NOTES: (CONT.)

LWR FAIRING

FAIRING

10. UPPER AFT FAIRING BRACKET ON ONE−PIECE FAIRING

SHOWN IN DETAIL B.

11. DIMENSIONS FOR BRACKET AND GUIDE LOCATIONS ON

NEW STRUTS.

12. MEASURED TO LWR EDGE OF UPPER FAIRING BRACKET

SHOWN IN DETAIL B ON TWO−PIECE FAIRING.

30−070−2B

Figure 6-5. Repair and Replacement of Fairing (Sheet 2 of 2)

Page 6-19

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

(e). Install four rivets to secure the fillet

(2). Inspect fairing support brackets for

trailing edge together.

security of attachment to strut, cracks

and deformation.

(f). Check for smooth telescoping action

of fairing into fillet by manually

(3). Inspect fairing−to−skid seal for deterio−

sliding the fillet up and down several

ration.

times.

(4). Inspect the fuselage rubbing plate for

(g). Close access doors.

security of bond and excessive wear.

(3). Install the lower part of the two−piece

(5). Inspect fairing cover for damage.

fairing as follows.

(6). Inspect fairing step seal for deteriora−

(a).

Carefully spread the trailing edge of

tion.

fairing and position the fairing on the

upper fairing and lower strut brack−

et; at the correct position there

19. Landing Gear Fairing Assembly Repair

should be 0.020−0.080 inch

(Ref. Figure 6−5) If the two−piece upper fairing

(0.508−2.032 mm) compression of the

or one−piece fairing fiberglass is damaged

fairing seal against the skid tube.

beyond repair limits (Ref. CSP−H−6), the fillet

Have an assistant hold the fairing in

as well as the fairing must be removed.

this position.

(b).

Back up the fairing with a fiber block

(1).

Replace an excessively damaged lower

at the transfer punch location. Using

fairing or step fairing cover.

a plastic hammer, hit the opposite

(2).

Replace a damaged fairing bracket or

side of the fairing hard enough to

lower guide. Remove the rivets, locate

transfer the hole centers.

the new part, and install blind rivets.

(c).

Remove fairing and check that all

Use next larger size rivets if mating

transfer marks appear within the

holes in strut are enlarged.

outline of the small laminated

(3).

Replace a damaged guide/pin assembly

doublers. Drill out the located holes.

or guide half if guide is cracked, pins

(d).

Reinstall the fairing in mounting

are bent or badly worn, or Teflon pad is

position and secure to upper strut

loose or badly worn.

bracket with two screws and washers

and lower strut bracket with four

(4).

Replace springs that are badly worn,

screws and washers.

rusty, or if free length is less than 8.72

inches (22.1488 cm).

(e).

Secure fairing trailing edge with 6

screws, 12 washers and 6 nuts.

(5).

Replace fillet if the Teflon strip is loose

or badly worn.

NOTE: Ensure doublers are installed between

laminations at trailing edge.

(6).

Replace a damaged strut bracket.

Remove the rivets, locate the new part,

18. Landing Gear Fairing Assembly

and install blind rivets. Use next larger

Inspection

size rivets if mating holes in strut are

(Ref. Figure 6−5)

enlarged.

(1). Refer to Landing Gear Inspection for

(7).

Replace unserviceable rubber seals. Use

inspection of installed fairing assem−

adhesive (69, Table 2−4) according to

blies.

container instructions.

Page 6-20

Revision 15

MD Helicopters, Inc.

CSP−H−2

500 Series − Basic HMI

20. Cabin Entry Step Description

are elongated use next size larger

lockbolts.

(Ref. Figure 6−2) The landing gear step is

formed of aluminum alloy tubing, covered with

(5). If applicable, install and connect the

non−skid tape and attached to the forward

optional side position light in the step.

landing gear strut with lockbolts. The step also

(6). Install the lower fairing on the strut.

has mounting provisions for a position light

when this type of optional night lighting

22. Cabin Entry Step Inspection and Repair

system is installed.

(Ref. Figure 6−2)

21. Cabin Entry Step Replacement

(1). Remove landing gear fairing assembly.

(Ref. Figure 6−2)

(2). Inspect step to strut attachment for

(1). Remove the landing gear fairing.

loose lockbolts by checking for relative

motion between mating parts. Replace

(2). If installed, disconnect and remove the

loose lockbolts with lockbolts same size

optional side position light.

as original if holes are not elongated;

otherwise, use next size larger lock−

(3). Remove four lockbolts and step from

bolts.

front of forward landing gear strut.

(3). Inspect safety walk tape for condition

(4). Install replacement step on forward

and security. Replace unserviceable

landing gear strut, using four lockbolts

tape.

(BP−T5−4) with wet primer (4,

Table 2−4). The four holes in the step

(4). Inspect fairing step cover and seal for

collar must be drilled out to

condition.

0.164−0.167 inch (4.1656−4.2418 mm)

for installation of the lockbolts. If holes

(5). Install landing gear fairing assembly.

Page 6-21/(6-22 blank)

Revision 15

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS

Para/Figure/Table

Title

Page

Section 7 Main Rotor and Control System .

7−1

Main Rotor and Control System

7−1

Main Rotor and Control System Troubleshooting

7−1

Figure 7−1. Main Rotor Control System

7−2

Table 7−1. Troubleshooting Main Rotor Vibrations

7−3

Table 7−2. Troubleshooting Controls

7−4

Table 7−3. Isolating Control System Troubles

7−5

Cyclic, Collective and Main Rotor Control Rigging

7−6

A. Collective Control Rigging

7−6

B. Cyclic Control Rigging

7−6

Figure 7−2. Rigging Main Rotor Control System (Sheet 1 of 2) .

7−8

Main Rotor Blades

7−10

Main Rotor Blade Tracking

7−10

Main Rotor Tracking Equipment Installation

7−1 1

Figure 7−3. Main Rotor Blade Assembly

7−12

Figure 7−4. Installation of Main Rotor Blade Tracking Strobe .

7−13

Table 7−4. Summary Procedure for Blade Tracking

7−14

Main Rotor Blade Track Adjustment

7−14

A. Pitch Control Rod Adjustment

7−15

B. Blade Tab Adjustment

7−15

Figure 7−5. Main Rotor Blade Tab Adjustment

7−16

Figure 7−6. Typical Tracking Conditions and Adjustments .

7−17

C. Main Rotor Blade Ground Tracking

7−17

D. Hover Track Verification

7−18

E. Forward Flight Tracking

7−18

F. Autorotation RPM Check

7−18

G. Autorotation Rpm Adjustment

7−19

Table 7−5. Autorotation RPM Chart

7−20

Main Rotor Balancing

7−20

A. Balancing Equipment and Balance Spare Kit

7−20

B. Procedural Instruction

7−20

C. Balance Equipment Installation

7−20

Figure 7−7. Main Rotor Hub − Cross Section

7−21

D. Balancing Procedure

7−22

Table 7−6. Main Rotor Balancing Hardware

7−22

Main Rotor Blade Replacement

7−22

A. Main Rotor Blade Removal

7−22

Page

7-i

Revision 17

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

B. Main Rotor Blade Installation

7−22

10. Main Rotor Blade Inspection

7−22

Figure 7−8. Main Rotor Blade Damage and Repair Limits for Nicks,

Scratches, Gouges and Cracks

7−25

Figure 7−9. Main Rotor Blade Damage and Repair Limits for Dents

and Depressions

7−26

11. Main Rotor Blade Repair

7−27

A. Nicks, Scratches and Wear Spots

7−27

B. Dents, Depressions and Erosion

7−28

C. Forward Tip Cap Insert

7−28

D. Loose Balance Weights

7−28

E. Loose or Missing Rivets or Aft Tip Cap

7−28

F. Vibration Absorber

7−29

12. Leading Edge Erosion Protection

7−29

13. Bearing Replacement − Damper Attach, Blade Fitting

7−29

Figure 7−10. Bearing Replacement − Main Rotor Blade Attach Fitting

Repair

7−30

14. Repair of Trim Tab and Trailing Edge (369A1100 Series) .

7−30

Figure 7−1 1. Repair and Removal of Trim Tab, Main Rotor Blade .

7−31

15. Main Rotor Blade and Damper Attach Pin Inspection and Corrosion Protection .

7−31

16. Main Rotor Blade and Damper Attach Pin Disassembly and Special Inspection .

7−32

Figure 7−12. Main Rotor Blade and Damper Attach Pin . .

7−32

17. Main Rotor Blade and Damper Attach Pin Adjustment

7−32

18. Main Rotor Blade Forward Tip Cap Inspection and Corrosion Prevention .

7−33

19. Main Rotor Blade Upper and Lower Root Fitting Attach Lug and Lead−Lag Link

Inspection (25 Hour)

7−33

20. Main Rotor Blade Upper and Lower Root Fitting, Attach Lug and Lead−Lag Link

Inspection (100 Hour)

7−33

21. Main Rotor Blade Leading Edge Abrasion Strip Check

7−35

22. Main Rotor Blade Torque Event Inspection

7−35

23. Vibration Absorber

7−35

A. Vibration Absorber Removal

7−35

B. Vibration Absorber Installation

7−36

Figure 7−13. Main Rotor Blade Root Fitting Attach Lugs and Lead−Lag Link

Assembly Inspection

7−36A

Figure 7−14. Application of Slippage Mark to Main Rotor Blade Bushings and

Root Fittings

7−37

C. Vibration Absorber Inspection

7−38

D. Vibration Absorber Disassembly

7−38

Page 7-ii

Revision 17

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

E. Vibration Absorber Repair

7−38

Figure 7−15. Vibration Absorber

7−38

F. Vibration Absorber Reassembly

7−38

G. Vibration Absorber Weighing

7−39

24. Main Rotor Hub Assembly

7−39

25. Main Rotor Hub Assembly Replacement

7−39

A. Main Rotor Hub Assembly Removal

7−39

B. Main Rotor Hub Assembly Installation

7−39

Figure 7−16. Main Rotor Hub Installation

7−41

Figure 7−17. Main Rotor Mast Locknut Installation

7−42

Figure 7−18. Pulling Hub Assembly

7−43

26. Main Rotor Hub Assembly Inspection

7−44

Figure 7−19. Repair of Main Rotor Hub Components (Sheet 1 of 3)

7−45

27. Main Rotor Strap Pack Lamination Inspection

7−48

Table 7−7. Strap Pack Inspection

7−50

Figure 7−20. Strap Pack Lamination Inspection (Sheet 1 of 2) .

7−51

28. Main Rotor Strap Pack Repair

7−53

29. Pitch Housing Assembly Repair

7−53

30. Pitch Housing Parts Repair or Replacement

7−54

A. Pitch Control Bearing Housing Assembly, Spacer or Striker Strip

Replacement

7−54

B. Replacing Pitch Control Bearing

7−55

C. Lead−Lag Link Blade Stop Replacement

7−55

D. Corrosion Control − Lead−Lag Bolt

7−56

E. Taping Broken Strap Ends of Strap Pack

7−56

31. Pitch Control Bearing Pivot Pin Repair or Replacement .

7−56

32. Droop Stop Restrainer and Roller Repair or Replacement . .

7−57

33. Droop Stop Ring Repair

7−57

34. Droop Stop Ring Replacement

7−57

Figure 7−21. Main Rotor Hub Assembly Repair

7−58

35. Droop Stop Plunger Inspection and Replacement

7−59

36. Main Rotor Hub Tapered Bearing Replacement

7−60

Figure 7−22. Main Rotor Hub Tapered Bearing Tools

7−62

37. Main Rotor Hub Assembly Droop Angle Check

7−63

38. Main Rotor Hub Assembly Droop Angle Adjustment

7−63

39. Main Rotor Damper (Friction Type, P/N 369A1400)

7−63

A. Main Rotor Damper Removal (Friction Type, P/N 369A1400) .

7−64

Page 7-iii

Revision 17

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

B. Main Rotor Damper Installation (Friction Type, P/N 369A1400) .

7−64

C. Main Rotor Damper Inspection (Friction Type, P/N 369A1400) .

7−64

D. Main Rotor Damper Torque Check (Friction Type, P/N 369A1400) .

7−65

Table 7−8. Temperature vs Damper Torque

7−66

E. Installed Main Rotor Damper Phasing Check (Friction Dampers Only,

P/N 369A1400)

7−66

40. Main Rotor Damper (Elastomeric Type, P/N 369D21400−503) .

7−66

A. Main Rotor Damper Removal (Elastomeric Type, P/N 369D21400−503) .

7−67

B. Main Rotor Damper Installation (Elastomeric Type, P/N 369D21400−503) .

7−67

C. Main Rotor Damper and Attachments Inspection (Elastomeric Type, P/N

369D21400−503)

7−67

D. Main Rotor Damper Weight Loading and Extension Check (Elastomeric

Dampers Only, P/N 369D21400−503)

7−68

E. Blade Phasing Procedure (Elastomeric Type, P/N 369D21400−503) .

7−68

Figure 7−23. Periodic Check of Main Rotor Elastomeric Damper Assembly .

7−69

41. Main Rotor Controls

7−70

42. Pitch Control Rods

7−70

A. Pitch Control Rod Removal

7−70

B. Pitch Control Rod Installation

7−70

43. Scissors Assembly

7−71

A. Scissors Assembly Removal

7−71

B. Scissors Assembly Installation

7−71

C. Scissors Disassembly

7−71

Figure 7−24. Pitch Control Rods and Swashplate Scissors Assembly

Installation

7−72

D. Scissors Inspection

7−73

E. Scissors Reassembly

7−73

44. Main Rotor Swashplate

7−73

A. Swashplate Assembly Removal

7−73

Figure 7−25. Main Rotor Swashplate Assembly

7−74

B. Swashplate Assembly Installation

7−74

C. Swashplate Disassembly

7−75

D. Swashplate Assembly Inspection

7−75

E. Swashplate Reassembly

7−75

45. Mixer Controls

7−76

A. Mixer Controls Removal

7−76

B. Mixer Controls Installation

7−76

Figure 7−26. Mixer Controls Assembly

7−77

Page 7-iv

Revision 17

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

C. Mixer Controls Inspection

7−78

D. Mixer Control Repair

7−78

46. Tunnel−Routed Control Tubes

7−79

A. Tunnel−Routed Control Tube Removal

7−79

B. Tunnel−Routed Control Tube Installation

7−79

C. Tunnel−Routed Control Tube Inspection

7−79

D. Tunnel−Routed Control Tube Repair

7−80

Figure 7−27. Tunnel−Routed Control Tubes

7−81

47. Tunnel−Routed Control Tube Inspection and Sleeve Installation .

7−82

A. Control Tube Tapered Area Sleeve Installation

7−82

Figure 7−28. Sleeve Fabrication and Installation

7−83

Table 7−9. Control Tube Re−Identification

7−84

B. Control Tube Straight Area Sleeve Installation

7−84

Table 7−10. Control Tube Straight Area Repair Limits

7−84

Figure 7−29. Control Tube Boot Rework

7−85

48. Controls Support Bracket and Bellcranks

7−85

A. Controls Support Bracket and Bellcrank Removal

7−85

Figure 7−30. Installation of Controls Support Bracket, Idler Bellcranks and

Cyclic Trim Actuators

7−86

B. Controls Support Bracket and Bellcrank Disassembly .

7−87

C. Controls Support Bracket and Bellcrank Inspection

7−87

D. Control Support Bracket and Bellcrank Repair

7−87

E. Controls Support Bracket and Bellcrank Reassembly

7−87

F. Controls Support Bracket and Bellcrank Installation

7−87

49. Collective Controls

7−88

50. Pilot’s Collective Pitch Control Stick (Left Position)

7−88

A. Pilot’s Collective Pitch Stick Removal (Left Position)

7−88

Figure 7−31. Pilot’s Compartment Collective Controls

7−89

B. Pilot’s Collective Pitch Stick Installation (Left Position) .

7−90

Figure 7−32. Assembly of Pilot’s Collective Pitch Stick (L/H Command) .

7−91

Figure 7−33. Copilot’s Collective Pitch Stick (R/H Command) .

7−92

C. Pilot’s Collective Pitch Stick Disassembly (Left Position) .

7−93

D. Pilot’s Collective Pitch Stick Inspection (Left Position) .

7−93

E. Pilot’s Collective Pitch Stick Repair (Left Position)

7−93

F. Pilot’s Collective Pitch Stick Reassembly (Left Position) .

7−94

51. Gas Producer Linkage Adjustment

7−95

Figure 7−34. Gas Producer Drive Mounting Distance and Backlash Adjustment

(Pilot’s Collective Pitch Stick)

7−96

Page 7-v

Revision 17

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

52. Gas Producer Interconnect Torque Tube Shimming

7−97

53. Pipe Plug Adjustment for Zero Backlash

7−97

Figure 7−35. Collective Pitch Stick Friction Adjustment .

7−98

Figure 7−36. Shimming of Gas Producer Interconnecting Torque Tube

Assembly

7−99

54. Collective Pitch Stick Friction

7−100

A. Collective Stick Friction Mechanism Operational Check .

7−100

B. Collective Stick Friction Mechanism Adjustment

7−101

Figure 7−37. Collective Torque Tube, Gas Producer Torque Tube, Collective

Bungee (Sheet 1 of 2)

7−102

55. Collective Control Interconnect Torque Tube

7−104

A. Collective Control Interconnect Torque Tube Inspection .

7−104

B. Collective Control Interconnect Torque Tube Removal .

7−104

C. Collective Control Interconnect Torque Tube Repair

7−104

D. Collective Control Interconnect Torque Tube Installation .

7−104

56. Collective Bungee

7−105

A. Collective Bungee Removal

7−105

B. Collective Bungee Installation

7−106

C. Collective Bungee Disassembly

7−106

D. Collective Bungee Inspection

7−106

E. Collective Bungee Reassembly

7−106

F. Collective Bungee Adjustment

7−107

57. Inboard Collective Stick Socket Assembly

7−108

A. Inboard Collective Stick Socket Assembly Removal

7−108

B. Inboard Collective Stick Socket Assembly − Disassembly .

7−108

C. Inboard Collective Stick Socket Assembly Inspection

7−108

Figure 7−38. Inboard Collective Stick Socket Assembly

7−109

D. Inboard Collective Stick Socket Assembly Repair

7−1 10

E. Inboard Collective Stick Socket Assembly − Reassembly .

7−1 10

F. Inboard Collective Stick Socket Assembly Installation .

7−1 10

58. Cyclic Controls

7−1 11

Figure 7−39. Adjustment of Gas Producer Drive Backlash (Inboard Collective

Stick Socket Assembly)

7−1 12

59. Pilot’s Cyclic Control Stick (Left Position)

7−1 13

A. Pilot’s Cyclic Control Stick Removal (Left Position)

7−1 13

B. Pilot’s Cyclic Control Stick Installation (Left Position) .

7−1 13

C. Pilot’s Cyclic Control Stick Grip Removal

7−1 13

D. Pilot’s Cyclic Control Stick Grip Installation

7−1 13

Page 7-vi

Revision 17

MD Helicopters, Inc.

CSP-H-2

500 Series - Basic HMI

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

Figure 7−40. Pilot’s Cyclic Stick, Control Linkage and Friction Controls .

7−1 14

E. Pilot’s Cyclic control Stick Inspection (Left Position)

7−1 15

F. Pilot’s Cyclic Control Stick Repair (Left Position)

7−1 15

G. Pilot’s Friction Mechanism Replacement

7−1 15

60. Cyclic Stick Guard

7−1 15

A. Cyclic Stick Guard Replacement

7−1 15

61. Pilot’s Compartment Lateral and Longitudinal Cyclic Control Linkage .

7−1 15

A. Lateral Control Rods and Station 67 Bellcrank Removal .

7−1 15

Figure 7−41. Pilot’s Compartment Cyclic Control and Guard Installation .

7−1 16

B. Lateral Control Rods and Station 67 Bellcrank Installation .

7−1 16

C. Lateral Control Rods and Station 67 Bellcrank Repair .

7−1 17

D. Cyclic Pitch Interconnect Torque Tube Removal

7−1 17

E. Cyclic Pitch Interconnect Torque Tube Repair

7−1 17

F. Cyclic Pitch Interconnect Torque Tube Installation

7−1 18

62. One−W ay Lock Control System

7−1 18

A. One−W ay Lock Removal

7−1 19

B. One−W ay Lock Inspection

7−1 19

C. One−W ay Lock Repair

7−1 19

Figure 7−42. Cyclic Torque Tube and One−Way Lock Control System .

7−120

D. One−W ay Lock Installation

7−121

63. Installation of Fuselage Access Panels for Cyclic Trim Actuator Assemblies .

7−121

Figure 7−43. Removal of Stiffeners and Doublers

7−122

Figure 7−44. Installation of Trim Actuator Assembly Access Panels .

7−123

64. Cyclic Trim Actuators

7−125

A. Cyclic Trim Actuator Removal

7−125

B. Cyclic Trim Actuator Installation

7−125

C. Cyclic Trim Actuator Inspection

7−126

D. Cyclic Trim Actuator Bench Testing

7−126

Figure 7−45. Cyclic Trim Actuator

7−127

65. Cyclic Trim Actuator Repairs

7−128

A. Cyclic Trim Actuator Drive Gear Retention Nut Field Repair .

7−128

B. Cyclic Trim Actuator Spring Assembly Replacement

7−129

C. Cyclic Trim Actuator Housing or Trim Tube Replacement .

7−129

D. Cyclic Trim Actuator (Motor/ Gear Drive Mechanism) Replacement .

7−129

Page 7-vii/(7-viii blank)

Revision 17

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

SECTION 7

MAIN ROTOR AND CONTROL SYSTEM

1. Main Rotor and Control System

(1). Troubleshooting information is divided

into:

(Ref. Figure 7−1) The main rotor is located at

the approximate center of the CG range and

provides lateral control, longitudinal control,

(a). Investigation of operational vibration

and the lifting force of the helicopter.

problems originating with the main

rotor assembly (Ref. Table 7−1).

The main rotor is fully articulated with offset

flapping hinges and consists primarily of four

removable rotor blades attached to rotor hub

(b). Investigation of symptoms that can

pitch housings and a central hub with cross−

be recognized (Ref. Table 7−2).

connected retention straps, and associated

pitch change mechanism.

(c). Isolation of an unusual controls

The main rotor is controlled by the collective

malfunction (Ref. Table 7−3).

pitch control system that governs the rate of

ascent or decent and the cyclic pitch control

system that controls horizontal movement.

(2). First determine which of the four major

installations is defective.

The four major installations are the main rotor

installation, the upper (exterior) main rotor

controls, the pilot’s compartment cyclic

(3). Isolate each linkage installation from

controls, and the pilot’s compartment collective

the others until the area in which the

controls.

malfunction is occurring has been

located.

2. Main Rotor and Control System

Troubleshooting

(4). Then investigate and locate the mal−

Sudden onset, excessive

function and repair or replace the

WARNING

and/or unusual main rotor

defective component.

vibrations should be investigated as to

cause, prior to continued flight. Under

no circumstance should main rotor

NOTE: Since the first indication of trouble will

tracking be attempted to correct the

appear at the cyclic control stick or the col−

problem until a thorough inspection of

lective pitch stick, the isolation procedures

the main rotor blades, hub assembly

in Table

7−2 nd Table

7−3 egin with

and strap assembly has been per−

symptoms detected during operation of

formed.

these controls.

Page 7-1

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

30−030A

1. MAIN ROTOR DRIVE SHAFT (REF. SEC. 9)

14. COLLECTIVE CONTROL TORQUE TUBE

2. DAMPER

15. PILOT’S COLLECTIVE PITCH STICK

3. DAMPER ARM (LINK)

16. DROOP CONTROL OVERRIDE LINK (REF. SEC. 1)

4. BLADE ATTACH PIN (TYP)

17. PILOT’S CYCLIC STICK

5. MAIN ROTOR BLADE

18. LATERAL CYCLIC FRICTION KNOB

6. DAMPER LINK ATTACH PIN

19. CYCLIC LATERAL CONTROL ROD

7. MAIN ROTOR MAST BASE

20. LATERAL CYCLIC TRIM ACTUATOR

8. ROTATING SWASHPLATE

21. LONGITUDINAL CYCLIC TRIM ACTUATOR

9. MAIN ROTOR CONTROLS (MIXER, IDLER

22. LONGITUDINAL CYCLIC FRICTION KNOB

BELLCRANKS AND LINKS)

10. LATERAL MIXER CONTROL ROD (CYCLIC)

23. ONE-W AY LOCK (LONGITUDINAL CYCLIC CONTROL)

11. LONGITUDINAL MIXER CONTROL ROD (CYCLIC)

24. CYCLIC CONTROL TORQUE TUBE

12. COLLECTIVE MIXER CONTROL ROD

25. GAS PRODUCER CONTROL ROD (REF SEC 1)

13. STATIONARY SWASHPLATE

26. COLLECTIVE BUNGEE

Figure 7-1. Main Rotor Control System

Page 7-2

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 7-1. Troubleshooting Main Rotor Vibrations

Symptom

Probable Trouble

Corrective Action

Unusual and/or excessive

Damage to main rotor blades.

Inspect blades.

vibration: Vertical or lateral.

Damage to main rotor hub

Inspect main rotor hub and strap

components.

pack assemblies(Ref. Figure 7-20).

One per revolution lateral beat first

Damper torque is not at required

Check damper torque. Replace

encountered at high power

value.

damper if torque not within limits.

settings, in autorotation, and in

turns. This beat may also occur on

the ground during warmup or

shutdown.

Lateral beat occurs at low (idle)

Damper torque is not at require

Check damper torque. Replace

rotor rpm. When operating at

value.

damper if torque not within limits.

normal (flight) rotor rpm, lateral

beat becomes a vertical beat.

Four per revolution or medium

Main rotor dampers sticking, or low

Check damper torque. Replace

frequency beat.

range torque is not at required

damper if torque not within limits.

value.

Vibration absorber defective.

Replace vibration absorber.

Worn feathering bearings.

Replace feathering bearings.

One per revolution vertical beat.

Main rotor blades not tracked

Track main rotor blades.

Beat may appear throughout entire

correctly.

flight regime, becoming more

pronounced at higher airspeeds.

Lateral feedback (beat) in cyclic

Rotor blades out of track.

Track main rotor blades.

control stick (no longitudinal

feedback detected).

One per revolution lateral beat,

Main rotor blade tip weights not

Check tip weights for security, repair

continuous.

secure.

as necessary.

Torque setting on main rotor blade

Set torque of all four dampers to the

damper(s) too high for proper

allowable minimum torque value.

operation at low ambient

temperature.

High frequency vibrations.

Loose or defective component in

Ref. Sec. 5, 8, 9 and 10.

another system.

Page 7-3

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 7-2. Troubleshooting Controls

Symptom

Probable Trouble

Corrective Action

Cyclic control stick pressures

Improperly set cyclic trim.

Re-trim cyclic control stick.

cannot be reduced by operating

trim switch.

Trim change is too slow.

Trim actuator inoperative.

Troubleshoot cyclic trim electrical

circuit; replace defective component.

Cyclic control sticks have tendency

Low fluid in one-way lock fluid

Add fluid to one-way lock reservoir

to move to aft position.

reservoir.

as required (Ref. Sec. 2).

Inadequate cyclic control during

Helicopter loaded out of center of

Check and correct weight and

flight.

gravity range.

balance.

Excessive pressure required for

Lateral friction device improperly

Loosen lateral friction device.

lateral or longitudinal movement of

adjusted.

cyclic control stick

s on the groun

Swashplate spherical bearing

Replace swashplate bearing

and during flight. Some droop stop

surface damaged.

assembly if torque required to rotate

friction will always be felt when

bearing exceeds 120 inch-pounds

there is no rotor rpm.

(13.56 Nm).

Scissors crank bearings or hub

Replace defective bearings.

lower shoe bearings binding or

frozen.

Lateral interconnecting rod end

Realign rod end bearing.

bearing binding due to incorrect

alignment.

Droop stop plunger sticking.

Clean plungers and mating brushes

with isopropyl alcohol (71,

Table 2-4).

Droop stop striker plate(s) or cam

Replace striker plate and/or cam

roller(s) damaged.

roller.

Longitudinal friction devise

Loosen longitudinal friction devise.

improperly adjusted.

Binding rod end bearings in

Realign rod end bearings.

longitudinal push rods.

One-way lock check valve or push

Replace one-way lock assembly.

rod shaft that unseats the valve

galled or seized.

Swashplate spherical bearing

Replace swashplate bearing

surface damaged.

assembly if torque required to rotate

bearing exceeds 120 inch-pounds

(13.56 Nm).

Page 7-4

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 7-3. Isolating Control System Troubles

Symptom

Isolating Step

Corrective Action

Binding, locking−up and erratic

Disconnect one−way lock.

If symptom gone, replace one−way

action of cyclic control stick.

lock.

Symptom remains

Disconnect upper ends of

If symptom gone and rod ends are

longitudinal and lateral control

good, disassemble and inspect main

rods (10 and 11, Figure 7−1).

rotor mixer controls until defective

part is located.

Symptom remains.

Reconnect upper ends of

If symptom gone and rod ends are

longitudinal and lateral control

good, disassemble and inspect pilot

rods, and disconnect lower ends. compartment controls until

defective part is located.

Trouble corrected

(Reconnect all control linkage)

WARNING: Do not disconnect any hardware from the pilot’s collective stick unless collective bungee

installation tool 369A9936 is installed. Strong bungee spring pressure can cause linkage reaction and

severe personal injury, or parts damage.

Binding, locking−up, and erratic

Disconnect upper ends of

If symptom gone and rod ends are

action of collective control stick.

collective pitch control rod (12,

good, disassemble and inspect main

Figure 7−1) and operate stick.

rotor mixer controls until defective

part is located.

Symptom remains

Leave upper end of collective

Trouble is in pilot’s compartment

pitch control rod disconnected.

collective control linkage.

Symptom remains

Disconnect gas producer control

If symptom gone, trouble is in

rod (25, Figure 7−1) from

engine controls (Ref. Sec. 11).

collective stick. Disconnect droop

control override link (16) from

collective control torque tube.

Symptom remains

Leave gas producer control rod

Disassemble and inspect pilot’s

and droop control override link

compartment collective control

disconnected.

linkage until defective part is

located.

Trouble corrected

(Reconnect all control linkage)

Page 7-5

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

3. Cyclic, Collective and Main Rotor Control

(Detail C), to the surface of mixer

Rigging

rigging plate; it should be the same as

the dimension recorded in step (6).

(Ref. Figure 7−2) Rigging of the main rotor

above.

control system must be accomplished immedi−

ately after replacement of linkage that can not

(a). If not, loosen checknut, disconnect

be accurately measured (by trammeling) before

upper end of collective control rod,

it is installed in the main rotor control system,

and adjust rod end of collective

or if helicopter operation reveals a rigging

control rod, and adjust rod end until

deficiency.

dimensions are the same.

(8).

Reconnect the control rod, remove the

NOTE: The cyclic and collective controls must

collective stick rigging fixture and

be rigged, in sequence, starting with the col−

check mixer travel.

lective. Control rod end bearing adjust−

ments are to be made to the nearest half

(9).

With stick at the down stop, the

turn that will produce correct rigging. When

centerline of the collective pitch mixer

tightening the jam nut at the adjustable end

bellcrank bolt (Detail C) should move

of control rods, always hold the rod end with

down so that the dimensions recorded

a wrench to prevent jamming of the bearing.

in step (6). above is decreased by not

less than 0.074 inches (1.8796 mm).

A. Collective Control Rigging

(10).

With stick at the up stop, the centerline

(1). Remove main rotor blades, or manually

of the collective pitch mixer bellcrank

raise the blades off their droop stops by

bolt should move up so that the dimen−

simultaneously lifting the blade tips.

sion recorded in step (6). above is

increased by not less than 0.74 inch

NOTE: All four blades must be off the stops

(1.8796 mm).

during rigging. Padded supports should be

used, if available.

(11).

Adjust rod end of collective pitch control

rod if necessary to meet the limits

(2).

Release the friction and raise pilot’s

specified in steps (8). and (10). above.

collective stick.

When adjustment is complete, tighten

checknut and make certain that length

(3).

Position collective rigging fixture (9,

of control rod is not changed.

Table 2−2) in outboard lower end of slot

in collective friction guide link (Ref.

When tightening rod end check−

Detail A).

CAUTION

nuts, ensure that rod end bear−

ings at both ends of rod are aligned between

(4).

Lower collective stick on rigging fixture

the bellcrank ears.

and tighten friction grip (drive gear).

(12). Reconnect collective pitch control rod

(5).

Position mixer rigging plate (11) on

and secure with a new cotter pin.

mast support fitting and secure firmly

by use of the two toggle clamps.

(13). Reinstall collective rigging fixture. All

mixer rigging is done with collective in

(6).

Measure the distance from horizontal

mid−position.

centerline of the mast support bracket

hingeline bolt (attaching the longitudi−

B. Cyclic Control Rigging

nal idler bellcrank and collective pitch

When timing the longitudinal

mixer bellcrank to the mast support

CAUTION

trim motor for full travel in the

bracket) to the surface of mixer rigging

following step, do not continue to hold the

plate and record actual distance (Detail

trim switch after the actuator has reached

B).

the travel limit.

(7).

Measure the distance from the horizon−

(1). Loosen longitudinal friction knob.

tal centerline the bolt that attaches the

collective pitch mixer bellcrank to the

(2). Actuate longitudinal cyclic trim for no

longitudinal pitch mixer bellcrank

load by accurately timing trim motor

Page 7-6

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

from full aft to full forward trim.

NOTE: Make adjustment carefully as there is

Return trim to full aft; then trim

only 1/2 turn tolerance. When adjustment is

forward for one−third the travel time.

complete, tighten checknut and make cer−

tain that length of control rod does not

(3). Position cyclic stick so that longitudinal

change.

rigging fixture (12, Table 2−2) will fit in

outboard side of slot in longitudinal

(11). Reconnect control rod to longitudinal

friction guide link.

pitch idler and secure with a new cotter

pin.

(a). Bushing end of fixture butts against

forward end of the slot, and friction

(12). Reinstall longitudinal rigging fixture,

knob stud fits in fixture detent

reposition and secure mixer rigging

(Detail D).

plate, and continue with lateral rigging.

(4). Secure fixture hook in aft end of slot,

tighten knurled thumbnut to seat

(13). Loosen friction knob and actuate lateral

bushing at forward end, and tighten

cyclic trim for no load.

friction knob.

(14). Position cyclic stick so that lateral

(5). Measure the distance from the horizon−

rigging fixture (14) will fit in forward

tal centerline of bolt at aft end of

side of slot in lateral friction guide link.

longitudinal pitch mixer bellcrank

(Detail E) to the surface of mixer

(a). Bushing end of fixture butts against

rigging plate;

outboard end of slot, and friction

knob stud fits in fixture detent

(a). It should be the same as the dimen−

(Detail F).

sion recorded in step A.(6).

(15). Secure fixture hook in inboard end of

(b). If not, loosen checknut, disconnect

slot, tighten knurled thumbnut to seat

longitudinal pitch control rod, and

bushing at outboard end, and tighten

adjust rod end until dimensions are

friction knob.

the same.

(6).

Reconnect the control rod, remove the

(16). Measure the distance from the horizon−

longitudinal stick rigging fixture and

tal centerline of bolt connecting lateral

check mixer travel.

bellcrank to stationary swashplate

mixer link (Detail G) to the surface of

(7).

With stick at the forward stop, the

mixer rigging plate;

centerline of the longitudinal pitch

mixer bellcrank bolt (Detail E) should

(a). It should be the same as the dimen−

move up so that the dimension recorded

sion recorded in step A.(6).

in step A.(6). is increased by not less

than 1.12 inches (28.448 mm).

(b). If not, loosen checknut, disconnect

lateral pitch control rod, and adjust

(8).

Reposition the mixer rigging plate to

rod end until dimensions are the

clear the longitudinal pitch mixer

same.

bellcrank.

(17). Reconnect the control rod, remove the

(9).

With the stick at the aft stop, the

lateral stick rigging fixture and check

centerline of the longitudinal pitch

mixer travel.

mixer bellcrank bolt (Detail E) should

move down so that the dimension

(a). With stick at the left stop, the

recorded in step A.(6). is decreased by

centerline of the lateral bellcrank

not less than 0.60 inch (15.24 mm).

bolt (Detail G) should move down so

(10).

Adjust rod end of longitudinal pitch

that the dimension recorded in step

control rod if necessary to meet the

A.(6). is decreased by not less than

limits specified in steps A.(6). and A.(7).

0.50 inch 12.7 mm).

Page 7-7

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(18). With stick at the right stop, the center−

A vibration absorber is installed on the lower

line of the lateral bellcrank bolt should

inboard end, and two balance weights are

move up so that the dimension recorded

installed in the tip end of each blade.

in step A.(6). is increased by not less

A removable forward tip cap, attached to the

than 0.43 inch (10.922 mm).

outboard end of the blade, is replaced with a

tracking cap when tracking procedures are

(19). Adjust rod end of lateral pitch control

performed.

rod, if necessary, to meet the limits

specified in steps (17). and (18). above.

The blade trailing edge tab may be bent up or

down to compensate for the differences in

(20). When adjustment is complete, tighten

diving or climbing characteristics between

checknut, and make certain that length

individual blades during forward flight.

of control rod is not changed.

5. Main Rotor Blade Tracking

(21). Reconnect control rod to lateral bell−

(Ref. Figure 7−4 thru Figure 7−5)Track of the

crank and secure with a new cotter pin.

main rotor blades is observed by means of

(22). Loosen friction control, friction knobs,

tracking tip caps temporarily attached to the

knurled thumbnuts and hooks of

tip of each blade, and a high−intensity strobe

rigging fixture and remove all three

light that flashes in synchronization with the

fixtures.

rotating blades.

The strobe light operates from electrical power

NOTE: The following step establishes initial

obtained from the helicopter electrical system.

adjustment of the main rotor pitch control

rods.

By observing the image pattern formed by the

four reflectors attached to the blade tips, it is

(23). Set each pitch control rod (Detail H)

possible to view the track of the rotating

(centerline to centerline of rod bearings)

blades.

to the applicable strap pack pitch link

Sudden onset, excessive

length specified on the tower tracking

WARNING

and/or unusual main rotor

data decal of the mating blade.

vibrations should be investigated as to

(a). Set pitch control rods to 6.60 inches

cause, prior to continued flight. Under

(16.764 cm) (between rod end bearing

no circumstances should main rotor

centerlines) for the two blades

tracking be attempted to correct the

attached to the hub upper strap pack

problem until a thorough inspection of

the main rotor blades, hub assembly

(b). Set pitch control rods to 6.35 inches

and the strap pack assembly has been

(16.129 cm) (between rod end bearing

performed.

centerlines) for the two blades

NOTE: Before attempting to track the rotor

attached to the lower strap pack.

blades, it is important to read and thorough−

(c). Install the pitch control rod.

ly understand the tracking sequence and in−

terrelationship of the various adjustments.

(24). Install main rotor blades or remove

A review of the following should prove help−

supports and simultaneously lower all

ful.

four blades to normal position.

(1). Install the tracking strobe light, blade

tip cap reflectors and related equipment

(25). Track main rotor blades and adjust

(Ref. Main Rotor Tracking Equipment

autorotation rpm.

Installation).

4. Main Rotor Blades

(2). Refer to Table 7−4 for a condensed

summary of the proper sequence for

(Ref. Figure 7−3) Each of the four main rotor

blade tracking.

blades is a balanced airfoil that consists of a

wrap−around, aluminum alloy skin bonded to

(3). Ground tracking basically involves

an extruded aluminum alloy spar, and upper

track−observation and adjustment at

and lower root fitting.

idle rpm and at flight rpm.

Page 7-10

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(a). Track at idle rpm is adjusted by the

manual apply (instead of any conflicting

pitch control rods connecting the

instructions in the manual).

rotating swashplate and the blades.

Install equipment as follows:

(b). Ground track at flat pitch and flight

NOTE: The helicopter is originally equipped

rpm is corrected by blade tab adjust−

with four tracking interrupters

ment.

(369A9946−23, −25, −27 and −29) installed on

NOTE: No track adjustments are made on the

the rotating swashplate, and a support

basis of track observations during hovering.

bracket (369A9943) for the magnetic pickup

installed on the stationary swashplate.

(4).

Hover track verification is essentially

(Spare swashplate assemblies are also pro−

an observation to check for track

vided with these tracking devices.) The du−

variation that might occur between

plicate set of interrupters and pickup brack−

high rpm (flat pitch) ground track check

et included in the strobe light installation

and hovering. However, track varia−

kit will not have to be used unless existing

tions should be noted and recorded for

parts are unserviceable. See Figure 7−4

reference use during the check of track

when replacement is necessary.

in forward flight.

(1). Install strobe light (369A9925) contain−

(5).

Forward flight tracking requires track

er on cargo floor, using four adjustable

observation during the following

straps for tiedown.

airspeeds and maneuvers.

(a). Straps should extend diagonally

(6).

Flight track is corrected by making

outward from container to tiedown

blade tab adjustments ONLY.

fittings attached to cargo floor.

* Flight at 0−100 knots.

(2). Remove strobe light from container and

* Forty−five degree banked turns at

pass light through opening in forward

80−100 knots.

bulkhead to observer’s seat location.

* Flight at 100−130 knots.

(3). Route all three electrical cables from

(7).

Obtaining correct autorotation rpm

container through cutout opening in

consists of checking the main rotor rpm

container and close cover.

during stabilized autorotation flight

and adjusting rpm to specified limits as

(4). Attach 24 Vdc power cord connector to

necessary.

utility power receptacle at lower left

corner of forward canted bulkhead.

(8).

The autorotation rpm check must be

accomplished to ensure that track

When maintenance work is be−

adjustments have not altered the rotor

CAUTION

ing performed near the engine

performance necessary for safe power−

air inlet, use care to prevent entry of foreign

off landings.

objects. Tape covers of cardboard or other

suitable material in place over the engine

Main Rotor Tracking Equipment

inlet screen and oil cooler air inlets. Do not

Installation

remove covers until work is completed and

debris is thoroughly cleaned out of the area.

(Ref. Figure 7−4) Prepare for main rotor blade

After removing covers, verify that area

tracking by installing strobe light components

around base of mast, inlet−to−plenum, and

furnished either with the strobe light installa−

entire plenum chamber is clean.

tion kit (16, Table 2−2) or tracking analyzer

instrument kit (59).

(5). Route triggering cable through either

vent in right−side cargo door, continuing

If the tracking analyzer instrument kit is used,

up around engine air inlet.

instructions for equipment installation are

part of the Balancer and Strobex Blade

(a). Use strips of pressure−sensitive tape

Tracker Manual supplied with the kit. Any of

(32, Table 2−4) to attach cable to

the following instructions that differ with the

fuselage and air intake.

Page 7-11

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

BOLT (NAS1305−14D)

WASHER

COTTER PIN

BOLT ATTACHED

LINK

NUT 30−60 IN. LB

(3.39−6.78 NM)

BLADE ATTACHING PINS

DAMPER

UPPER ROOT FITTING

ARM LINK

LOWER ROOT

FITTING

VIBRATION ABSORBER

SPAR AND WEIGHT

ASSY RIVETS

AFT TIP CAP

FWD BALANCE WEIGHT

BLADE TIP

THREAD INSERT

DAMPER ARM

ATTACHING PIN

0.130−0.160 IN.

SCREW

DRAIN HOLES

(3.302−4.060 MM)

15−20 IN. LB

PIN ATTACHED LINK

(NOTE 2)

(1.69−2.26 NM)

2.62 IN.

MS20604AD3C2

(66.548 MM)

BUSHING

TIP CAP RIVET

(TYP)

FWD TIP CAP

(NOTE 1)

AFT BALANCE WEIGHT

VIBRATION ABSORBER

RADIUS BLOCK

INSTALLATION

NUT 50−60 IN. LB

NOTES:

(5.65−6.78 NM)

BLIND RIVET TO BE INSTALLED THRU

RUBBER PAD

EACH SIDE, ALL BLADES, IF ONE TIP

DAMPER ARM

CAP REPLACED OR REPAIRED.

BEARING

ASSEMBLY BALANCE NOT AFFECTED.

FITTING

BLADE MAY HAVE EITHER TWO OR

THREE DRAIN HOLES.

SHIM WASHER(S)

RADIUS BLOCK

(AN960PD10

AND/OR 10L

NUT 50−60 IN. LB

BRACKET

(5.65−6.78 NM)

5−PER−REV

3−PER−REV

PENDULUM

30−032D

Figure

7-3. Main Rotor Blade Assembly

Page 7-12

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

TRACKING TIP CAP

TAPE

INSTALLATION

(16, TABLE 2−4)

TIP CAP

369A9942−( * )

(NOTES 1, 2)

SCREW 15−20 IN. LB

(1.69−2.26 NM)

NOTE 7

0.020−0.030 IN.

(0.508−0.762 MM)

NOTE 7

INTERRUPTER−TO−

TAPE

PICKUP GAP

(16, TABLE 2−4)

ROTATION

OF HUB

NOTES:

MUST ALWAYS BE REMOVED AFT

BOLT NAS464P4−41

TRACKING.

(NOTES 5, 6)

INSTALL IN NUMERICAL SEQUENCE

BOLT NAS464P3A7

IN DIRECTION OF HUB ROTATION.

NUT 15−20 IN. LB

(2 PLCS) (TYP)

( * INDICATES −7, −9, −11 AND −13

(1.69−2.26 NM)

OR −17, −19, −21 AND −23.)

INTERRUPTER

(2 PLCS) (TYP)

AS REQUIRED BETWEEN BRACKET

369A9946−27

AND SWASHPLATE TO FILL GAP.

INTERRUPTER

COLOR CODE TO MATCH BLADES

ROTATING

369A9946−23 OR−25

AND MAINTAIN SEQUENCE.

SWASHPLATE

(NOTE 4)

NUT 30−60 IN. LB

(3.39−6.78 NM)

SCISSORS LINK

ADJUSTMENT NUT

15−20 IN. LB

LONGITUDINAL

(1.69−2.26 NM)

LINK

30−60 IN. LB

(3.39−6.78 NM)

BOLT NAS464P4−26

INTERRUPTER

(NOTE 5)

369A9946−25 OR−23

INTERRUPTER

BRACKET

(NOTE 4)

369A9946−29

369A9943

STATIONARY

SWASHPLATE

NUT 30−60 IN. LB

(3.39−6.78 NM)

SHIM WASHERS

BOLT NAS464P4−20

NUT

(NOTE 3)

(NOTE 5)

MAGNETIC PICKUP

369A9944 (NOTE 1)

NOTES: (CONT)

REPLACES BOLT ON HUB WITHOUT PERMANENTLY

STROBE LIGHT CABLE

PICKUP

INSTALLED INTERRUPTERS.

(NOTE 1)

INSTALLATION

COAT WITH GREASE (26, TABLE 2−4).

ADJUST AS NECESSARY FOR GAP INDICATED; THEN

TORQUE UPPER NUT (DETAIL C).

30−033D

Figure

7-4. Installation of Main Rotor Blade Tracking Strobe

Page 7-13

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 7-4. Summary Procedure for Blade Tracking

NOTE: The 0.50 inch (12.7 mm) diameter tracking tip cap reflector size should be used as a guide for estimating

track accuracy. For example: a reflector image displaced a half diameter upward or downward indicates that

the corresponding blade tip is approximately 0.250 inch (6.35 mm) out of track; one full reflector diameter

indicates 0.50 inch (12.7 mm) out of track.

Observed ground track

Adjust pitch control rods and/or blade tabs as required

Satisfactory

Unsatisfactory

and repeat track observation.

Perform hover verification

Record track verification and proceed with forward flight

Satisfactory

Unsatisfactory

tracking.

Perform forward flight tracking

Satisfactory

Unsatisfactory

Adjust blade tabs and repeat forward flight tracking.

Perform autorotational rpm check

Satisfactory

Unsatisfactory

Adjust autorotation rpm and repeat rpm check.

Remove tracking equipment and return helicopter to service.

(6). Install magnetic pickup (369A9944) in

369A9926−5). Torque attaching screws

bracket on stationary swashplate.

to 15 − 20 inch−pounds (1.69 − 2.26

Nm). Do not to over−tighten screws.

NOTE: Do not tighten top nut securing pickup

at this time.

(10). To operate strobe, turn ON the UTIL−

ITY switch/circuit breaker. Refer to

strobe manufacturer’s instructions for

(7). Plug triggering cable into pickup and

strobe operation and other additional

secure cable so that it will not interfere

information on the strobe equipment.

with extreme control movements.

Rotor must be turning to trigger the

lamp.

(8). Adjust gap between interrupters and

pickup to 0.020−0.030 inch (0.508−0.762

NOTE: Strobe light operation can be checked

mm) and torque top nut securing

with no signal input (rotor not turning) by

pickup to 15 − 20 inch−pounds (1.69 −

actuating the lamp trigger several times.

2.26 Nm).

This action will flash the light. Do not de−

press lamp trigger for prolonged periods

Gap must not be less than 0.020

when rotor is not turning; to do so may dam−

CAUTION

inch (0.508 mm). Swashplate

age lamp circuitry. The tracking strobe light

must be rotated to check the clearance be−

unit is a Model 135M (or 135M−( )) Point

tween each interrupter and the pickup. Do

Source Strobex Rotor Blade Tracker man−

not use over 20 inch−pounds (2.26 Nm)

ufactured by Chadwick−Helmuth Co., Inc.

torque in tightening nut on pickup.

7. Main Rotor Blade Track Adjustment

(9). Remove existing forward tip caps from

tips of rotor blades and install reflector−

equipped tip caps starting with cap

(Ref. Figure 7−6 and Figure 7−5) Although

369A9942−17, followed by caps −19, −21

adjustment of pitch control rods will affect

and −23 in dash number order and in

blade track at all rotor speeds, they should be

direction of hub rotation. (Early type

adjusted only when necessary to establish

caps 369A9942−7, −9, −11 and −13,

acceptable track at ground idle speed; the

without retainers over reflectors, are

blade tabs are used for all other track correc−

furnished with tracking equipment

tions.

Page 7-14

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

NOTE:

(2). Different zones of the tabs are used to

D If pitch control rods are badly out of ad−

adjust blade track at different air−

justment, or if the rod end bearings have

speeds.

been replaced, set the length of the af−

(a). Tab Zone A is used for high−rpm, flat

fected pitch control rod(s) (as measured

pitch ground tracking (103% N₂).

between the rod end bearing centerline)

to the applicable strap pack pitch link

(b). Zones C, D, and E are used for

length specified on the tower tracking

tracking at the higher airspeeds.

data decal of the mating blade. Observe

the ground track before adjusting control

(c). Zone B is used to supplement Zone A

rods.

track correction when maximum tab

D Blade tab and/or track can make the col−

(5 degrees) has been applied to Zone

lective heavy or light.

A; Zone B may also be used, if

A. Pitch Control Rod Adjustment

necessary, for correction in the 0 to

100 knot airspeed range.

Repeat this adjustment procedure as necessary

to establish ground idle track.

Restrict bending to very small

CAUTION

increments so that the bonded

(1). Remove lockwire from both ends of

trailing edge joint between the upper and

pitch control rod and loosen the rod end

lower skins will not be damaged. All tabs

jam nuts.

must never be displaced more than 5 de−

NOTE: The upper jam nut and rod end have

grees above or below the normal position

left−hand threads.

(parallel to the chordline).

(a). To lower a blade tip, shorten the

NOTE: Tab zones on same blade can require

pitch control rod assembly by turning

bending in opposite directions. For example,

the rod in a counterclockwise direc−

after bending tab zone C downward to get

tion as viewed from below.

good tracking at 60 to 90 knots, it might be−

come necessary to bend tab zone E upward

(b). To raise a blade tip, lengthen the

to correct track at redline airspeed. In any

pitch control rod assembly by turning

case, do not use larger tab corrections than

in a clockwise direction.

are actually necessary.

(c). One−sixth of a turn of the rod (one

(3). To lower the blade tip that tends to

flat) will raise or lower the blade tip

climb during ground tracking at high

approximately 0.250 inch (6.35 mm).

rpm or during forward flight, bend the

appropriate tab section slightly down−

After adjusting pitch control

ward.

CAUTION

rods, check that the rod end

threads are engaged far enough to block the

(4). To raise the tip of a blade that tends to

rod body inspection (witness) hole. Center

descend, bend the tab slightly upward.

each rod end or fitting wear will result.

(5). If only slight track correction is neces−

Make sure there is no binding in the full up

sary, limit tab bending to the width of

travel position.

the bending tool.

(2). After adjusting the pitch control rod

(6). If more correction is necessary, bend a

length, center each rod end in its fitting

slightly wider section of the tab.

and hold while tightening the jam nuts.

Safety with lockwire.

NOTE: Avoid excessive re−bending of tabs by

B. Blade Tab Adjustment

using small adjustments until the necessary

(Ref. Figure 7−5)

result is obtained.

(1). Once ground idle track is obtained, all

(7). Each time blade tabs are adjusted,

remaining tracking correction is

recheck ground idle track and readjust

accomplished by VERY SLIGHT

if necessary.

bending of the various blade tab zones

with tab bending tool (17 or 18,

(8). After completion of forward flight

Table 2−2).

tracking, and check autorotation rpm.

Page 7-15

Revision 19

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

TIP PATH PLANE

(1). Before tracking blades that are NOT

new, check that normally straight (not

to be used) tab areas (Ref. Figure 7−5)

are in neutral position (centered on

IMAGE A: ALL BLADES IN TRACK

chordline) and straight.

NOTE: On NEW (untracked) blades, check that

all tab areas are straight and in neutral po−

sition (centered on chordline 0° ±5°).

IMAGE B: ONE BLADE APPROX. 0.50 IN. (12.7 MM) HIGH

(2). Load helicopter to a gross weight of

approximately 1900−2250 pounds

(862−1021 kg).

(3). With collective pitch stick full down,

operate engine for a brief period at

IMAGE C: ONE BLADE APPROX. 0.50 IN. (12.7 MM) HIGH;

ONE BLADE APPROX. 1 IN. (25.4 MM) LOW

103% N₂ and then reduce rpm to the

ground−idle (approximately 62% N₁);

CORRECTIVE ACTION

this will ensure that the blade dampers

HIGH RPM AND

CONDITION

GROUND IDLE RPM

FWD FLIGHT

are correctly positioned.

IMAGE A NONE REQUIRED

NONE REQUIRED

(4). Observe tracking tip cap reflector image

IMAGE B SHORTEN PITCH CONTROL MOVE TAB DOWNWARD

by directing strobe light beam toward

ROD (2^ND BLADE)

(2^ND BLADE)

blade tip path and sweeping beam

slowly back and forth until reflector

IMAGE C SHORTEN PITCH CONTROL MOVE TAB DOWNWARD

images are clearly seen.

ROD (2^ND BLADE);

(2^ND BLADE); MOVE

LENGTH CONTROL

TAB UPWARD (3^RD

(a). The tracking image should appear

ROD (3^RD BLADE)

BLADE)

directly in front of helicopter or

30−034A

slightly off helicopter centerline.

Figure 7-6. Typical Tracking Conditions and

(5). If blades are in track, tip cap reflector

Adjustments

image pattern should resemble image

A, (Ref. Figure 7−6) (none of the blade

C. Main Rotor Blade Ground Tracking

tip more than 1/4 of one tracking

(Ref. Figure 7−6 and Figure 7−5) For best

reflector diameter, 0.125 inch(3.175

results, tracking should be performed under

mm) above or below adjacent reflec−

calm air conditions. Wind velocity should not

tors).

exceed 6 knots during preliminary adjust−

(a). If blades are in track, proceed with

ments or 3 knots for final adjustment.

step (6). below.

Accurate adjustment of initial ground track is

(b). If blades are out of track, adjust pitch

very important. In most instances, forward

control rods and repeat step (3).

flight tracking problems can be avoided or

above.

greatly reduced by setting initial track as

(6). With collective pitch stick full down,

nearly perfect as possible.

increase engine speed to 103% N₂ and

observe tip cap reflector image to see if

Tolerances specified in following instructions

blade track is changed from ground idle

should be considered maximum permissible

track.

deviation rather than desired goal.

(a). When all four blades are in track

NOTE: If a replacement main rotor hub has

within 1/4 of one reflector diameter,

been installed, or if a replacement pitch con−

0.125 inch(3.175 mm), ground track

trol rod assembly or rod end bearing has

is good; proceed with hover verifica−

been installed, set the length of each pitch

tion.

control rod assembly to the applicable strap

pack pitch link length specified on the tower

(b). When a blade is out of track, adjust

tracking data decal of the mating blade be−

blade tab zone A until high rpm

fore proceeding with ground tracking

ground track is within tolerance.

Page 7-17

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

D. Hover Track Verification

(3). Check autorotation rpm; rpm must not

be less than 450.

(Ref. Figure 7−6 and Figure 7−5) Hover track

Do not attempt to adjust chord−

verification must be performed after ground

CAUTION

wise balance of a blade found to

tracking and before forward flight tracking.

be faulty when performing banked turns

Verification is only a CHECK of hover track.

((4). below). Chordwise balance corrections

DO NOT adjust pitch control rods or blade

must be accomplished by manufacturer

tabs because of track images observed during

(MDHI).

hovering.

(4). Perform a series of 45 degree banked

Tab adjustments often cause variation between

turns 80−100 knots and observe track

ground track and hovering track.

change from level flight. If any blade

climbs or dives more than one inch out

A large track variation may indicate that one

of track with others, chordwise balance

or more blades is beyond its chordwise balance

(center of gravity) of that blade is

tolerance, but this can only be determined

beyond its tolerance and blade must be

during forward flight tracking.

replaced. (Hover track variations of this

type that do not repeat during banked−

NOTE: Collective pitch stick may be ‘‘heavy" af−

turn maneuver may be disregarded.)

ter tracking reflectors are mounted on blade

tips. This condition is not unusual and may

(5). Perform flight tracking at 100−130

be disregarded.

knots at 103% N₂. If necessary, adjust

tab zone D (five degrees maximum) to

(1). Verify helicopter gross weight,

limit track variation to 0.50 inch (12.7

1900−2200 pounds (862−998 kg).

mm) or less and to minimize excessive

vertical (one−per revolution) vibration.

(2). With collective pitch stick full down,

If variation is excessive, bend tab zone

increase N₂ to 103 percent.

E (five degrees maximum).

(3). Observe tracking reflector images to

NOTE: When determining whether blade track

verify that ground track is within

is acceptable, overall vibration level of heli−

limits.

copter should be determining factor. Some

combinations of rotor blades might produce

(4). With helicopter in a stable hover,

higher four− per− revolution vibration as

observe reflector images.

blade tips are brought into close track; in

such cases, lowest vibration level is pre−

(a). If one or more blades are out of track,

ferred, even though observed blade track

record condition(s) for reference

may be beyond specified tolerances.

during forward flight tracking.

(6). After flight tracking is completed,

(5). Proceed with forward flight tracking.

perform a autorotation rpm check.

E. Forward Flight Tracking

F. Autorotation RPM Check

(Ref. Figure 7−6 and Figure 7−5) Forward

(Ref. Table 7−5) An autorotation rpm check is

flight tracking should be performed whenever

required after each blade tracking operation

vertical flight vibrations indicate that blades

and whenever rpm is outside limits. Check

may be out of track.

rotor rpm and make adjustments as follows:

Main rotor blade (targets− cap/

(1). Verify helicopter gross weight,

CAUTION

plates) reduce blade to tailboom

1900−2200 pounds (862−998 kg).

clearance. Performing autorotations to−

(2). Perform flight tracking from hover up

the−ground could result in tailboom strikes.

to 100 knots at 103% N₂. If flight track

(1). Load helicopter to a gross weight of

varies from hover track more than 0.50

1900−2200 pounds (862−998 kg).

inch (12.7 mm), bend tab zone C (five

degrees maximum) to limit variation to

(2). Perform a practice autorotative descent

tab zone B (five degrees maximum).

according to the Owner’s Manual,

Page 7-18

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

taking care not to allow rpm to exceed

control interference as described in

the rotor speed limitations.

steps (4). and (5). below.

(3). During autorotative descent, take

careful note of the stabilized autorota−

(4). Check for interference between the

tive rpm at one of the gross weight/

lateral bellcrank and longitudinal pitch

density altitude combinations given.

idler (Ref. Figure 7−2, Details B and G)

of the mixer control by positioning the

(4). After landing, compare observed rpm

collective stick full up and the cyclic

with the values given in Table 7−5.

stick at the aft stop.

(a). If observed rpm is within the limits

(a). If interference exists, lengthen the

given in the table, rpm setting is

collective pitch mixer control rod

correct.

enough to eliminate the interference;

then lengthen the four blade pitch

(b). If limits were exceeded, make correc−

link control rods (Detail H) equally

tions adjustments until rpm falls

the same amount.

within limits.

NOTE: When the rotor track autorotation rpm

(5). Check for interference between the

adjustment have been satisfactorily accom−

rotating swashplate and longitudinal

plished, remove tracking equipment before

pitch idler of the mixer controls by

returning helicopter to service. Take care to

positioning the collective stick on the

properly tighten and safety all bolts after

downstop and the cyclic stick full

they have reinstalled.

forward and full left.

G. Autorotation Rpm Adjustment

(a). If less than 0.150 inch (3.81 mm)

(Ref. Table 7−5)

clearance exists, shorten the collec−

tive pitch mixer control rod enough to

NOTE: RPM adjustments in excess of 25 RPM

establish clearance, 0.250 inch (6.35

should be accomplished by adjusting the

mm) preferred; then shorten the four

four pitch control links.

blade pitch link control rods equally

by the same amount.

(1). Hold the lower end of the collective

mixer control rod with a wrench to

restrain it against rotation and loosen

(6). After accomplishing checks and

the upper rod end jam nut.

adjustments in steps (4). and (5). above,

install nut, washer and new cotter pin.

(2). Remove bolt that attaches upper control

Tighten the rod assembly jam nut while

rod end to bellcrank and shorten rod by

holding rod end centered in the bell−

turning rod end clockwise (as viewed

crank fitting.

from above) to decrease rotor rpm or

counter clockwise to increase rotor rpm.

Each 1/2 turn of rod end will change

(7). If more adjustment is needed, change

rotor speed by approximately 6 rpm.

the length of all four pitch link control

rods as necessary to obtain additional

After adjusting collective pitch

autorotation rpm.

CAUTION

control rod, check to make sure

that all threads of the rod are engaged far

enough to block the rod body inspection (wit−

NOTE: Lengthen or shorten all four rods exact−

ness) hole.

ly the same or blade track will be changed.

One flat (1/6 turn) of the control rod body

(3). After adjusting collective mixer control

will cause approximately 8 rpm change in

rod length, install bolt and check for

autorotation rpm.

Page 7-19

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

Table 7-5. Autorotation RPM Chart

Stabilized Autorotation RPM at Density Chart

Gross Wt

1000 Ft

2000 Ft

3000 Ft

4000 Ft

5000 Ft

lb / kg

Sea Level

(305 M)

(610 M)

(915 M)

(1220 M)

(1525 M)

1900 / 862

447-457

454-464

461-471

468-478

475-486

482-492

2000 / 907

459-469

466-476

473-483

480-490

487-497

494-504

2100 / 953

471-481

478-488

485-495

492-502

499-509

---

2200 / 998

483-493

490-500

497-507

504-514

---

NOTE:

(1) Chart values based upon 15°C (59°F) OAT. At sea level, 8°C (14°F) temperature change is equal to

1000 ft.. (305 M) of change in density altitude.

(2) Perform autorotation rpm checks at gross weight/density altitude combinations for which rpm values are

given. Blank spaces indicate that application of collective pitch may be necessary to avoid rotor

overspeed.

8. Main Rotor Balancing

The maximum allowable bal−

CAUTION

ance weight per pitch case hous−

ing on the main rotor hub assembly is 150

(Ref. Figure 7−7) Analysis of main rotor

grams.

balance is accomplished using instrumentation

that measures and localizes vibrations due to

B. Procedural Instruction

main rotor imbalance.

The Tracking and Balancing Manual for

Data provided by the instrumentation is

Helicopter Main Rotor and Tail Rotor Track

plotted on a chart designed to indicate how

and Balance is a part of the balancing equip−

much weight shall be added to or subtracted

ment (59, Table 2−2) and shall be used for

from thin bolts installed through the hollow

equipment installation and balancing proce−

lead−lag bolts.

dure, except that any following instructions

that differ apply (instead of any conflicting

instruction in the Tracking and Balancing

No other means of balancing is to be used.

Manual).

Do not attempt the balancing procedure

C. Balance Equipment Installation

without first tracking the blades.

Complying with instructions in the Chadwick−

Never add weight to, sub−

Helmuth Balancer and Strobex Blade Tracker

WARNING

tract weight from, nor redis−

Manual to install that portion of the balancing

tribute weight on the main rotor

kit (59, Table 2−2) needed to balance the main

blades.

rotor.

When working near engine air

A. Balancing Equipment and Balance Spare

CAUTION

inlet, comply with precautions

Kit

to prevent entry of foreign material. During

main rotor balancing the helicopter is air−

The balancing equipment (59, Table 2−2)

borne. Carefully observe precautions in the

contains all equipment needed to analyze main

Tracking and Balancing Manual relating to

rotor balance. The balance spare kit (60)

the placement and security of equipment

contains quantities of the balancing hardware

(especially cables) fastened to the exterior of

listed in Table 7−6.

the helicopter.

Page 7-20

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

D. Balancing Procedure

etc). Detach damper arm link from

blade by removing cotter pin, nut, two

Balance the main rotor according to instruc−

washers and bolt. Or, if damper link

tions in the Tracking and Balancing Manual.

attaching pin is used, unlock and

remove pin. Remove the two blade

Since vibration reduction by weight adjust−

fitting attaching pins.

ment depends on mechanical condition and

functioning of the main rotor and the main

(3). Using masking tape and/or grease

rotor drive system, the troubleshooting

pencil, mark each blade and its respec−

information (Ref. Main Rotor and Control

tive pitch housing links so that blades

System Troubleshooting and Troubleshooting

can be reinstalled in same relative

the Power Train System) should be used in

positions.

conjunction with balancing kit instructions.

B. Main Rotor Blade Installation

Acceptance criteria for balance and vibration

(1). Position main rotor blade in its

are contained in the balancing kit (59,

(marked) pitch housing links. Install

Table 2−2) and on each balancing chart. The

blade attaching pins.

charts are components of the balancing

equipment.

NOTE:

D If new blade is to be installed, or if blades

Figure 7−7 shows how balancing hardware is

are not reinstalled in same positions from

installed and sealed at the lead−lag bolts.

which removed or are installed on new ro−

tor hub, blade attach pins must be ad−

Table 7−6 lists approved balancing hardware

justed. It is also necessary to track blades.

and gives the weight of each item.

D Check that cutout (scalloped) area on in−

The balancing charts indicate an option of

board end of damper arm link is installed

adding or subtracting weight. Keep overall

towards the damper (Ref. Figure 7−16). If

weight at a minimum always removing when

incorrectly installed interference between

possible.

the arm and damper can occur.

Table 7-6. Main Rotor Balancing Hardware

(2). Align damper arm link with fitting on

main rotor blade; install damper attach

Hardware

Unit Weight (Grams)

pin or bolt to attach link to blade.

NAS603-56 Screw

11.10

NOTE: Standard hardware may be used to re−

NAS603-64 Screw

12.25

place damper attach pins. If used, install at

all four locations, torque nuts to 30 − 60

MS21042-3 Nut

1.90

inch−pounds (3.39 − 6.78 Nm) and safety

AN960C10 Washer

0.63

with cotter pin.

AN960C10L Washer

0.32

(3). Lock all attaching pins.

AN970-3 Washer

4.33

(4). Remove blade−to−pitch housing link

HS1554 Washer

1.00

match−markings.

HS1555 Washer

2.80

10. Main Rotor Blade Inspection

9. Main Rotor Blade Replacement

(Ref. Figure 7−8 and Figure 7−9)

NOTE: MDHI Notice HN−8 requires additional

(Ref. Figure 7−3)

inspections of a limited number of main ro−

A. Main Rotor Blade Removal

tor blades with specific serial numbers.

These blades must be inspected for the pos−

(1). Relieve load on blade attachment points

sibility of unsatisfactory bonding of root fit−

by supporting main rotor blade from

ting doublers which can impose a reduction

below.

in service life.

(2). Identify blade attaching hardware and

(1). Inspect skin for evidence of cracks and

pins for location (grease pencil, tape,

holes.

Page 7-22

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(a). Cracks or holes in blade skin surface,

mm) removal of skin surface are

regardless of location, are cause for

permissible.

rejection of the blade. Scratches,

AREA 4: Scratches to 0.003 inch (0.076

dents, nicks and other surface defects

mm) deep if oriented 0 to 30 degrees

in the blade skin are limited accord−

and to 0.003 inch (0.076 mm) deep if

ing to steps (2). and (3). below.

oriented between 30 and 90 degrees

(b). Use a suitable dial indicator to check

from span−line must be removed. No

depth of blade dents and scratches.

sharp nicks or gouges requiring more

than 0.003 inch (0.076 mm) removal of

The repairable limit dimensions

skin surface are permissible.

CAUTION

presented in the following pro−

AREA 5: Scratches exceeding a depth of

cedure apply to surfaces that have not been

0.001 inch (0.025 mm) are cause for

repaired before. Be sure that material has

rejection. Remove scratches to a depth

not been removed from damaged areas be−

of 0.001 inch (0.025 mm). The area

fore determining that the damage depth has

inside of the outboard two root fitting

not been exceeded. Refer all questionable

bolt holes (includes both upper and

surface damage, not covered by the follow−

lower surfaces) and including the skin

ing information, to MDHI as outlined in Sec−

surface adjacent to these bolt holes

tion 2.

within a radius of l.00 inch (25.4 mm)

(2).

Limitations for surface scratches, nicks,

from each hole must be free of

gouges and erosion in seven areas of

scratches, nicks, or gouges as would be

the blade skin are described below.

detected under 5X magnification

Scratches that do not penetrate the clad

(minimum).

surface are acceptable without rework

AREA 6: Scratches to 0.005 inch deep

in all areas except areas 5 and 8.

and oriented 0 to 15 degrees from

AREA l: Minor scratches, nicks and

spanline are acceptable without repair.

gouges without skin penetrations are

Scratches to 0.005 inch (0.127 mm)

acceptable without repair. Skin defor−

deep and oriented from 15 to 30 degrees

mation with holes is cause for replace−

from spanline must be removed.

ment. Blade leading edge erosion may

Scratches 0.003 inch (0.076 mm) deep

be repaired (Ref. Main Rotor Blade

and oriented from 15 to 30 degrees from

Repair) if the skin is not eroded

spanwise are acceptable without repair.

through. If the leading edge skin is

Scratches to 0.003 inch (0.076 mm)

eroded through, no matter how slightly,

deep and oriented from 30 to 90 degrees

the blade must be immediately re−

from spanline must be repaired. Nicks

placed.

and gouges not exceeding 0.005 inch

(0.127 mm) depth must be repaired. All

AREA 2: Scratches to 0.005 inch (0.127

gouges, nicks, scratches and cracks on

mm) deep if oriented 0 to 30 degrees

trailing edge not exceeding 0.030 inch

from spanline and to 0.003 inch (0.076

(7.62 mm) depth must be smoothed and

mm) deep if oriented between 30 and 90

radiused out over 0.120 inch (3.048

degrees from spanline are acceptable

mm) area on each side of damage.

without repair. Nicks and gouges not

Defects beyond 0.030 inch (7.62 mm)

exceeding 0.003 inch (0.076 mm) in

depth are cause for rejection.

depth are acceptable without repair and

AREA 7: Scratches, nicks, or gouges up

to 0.005 inch (0.127 mm) with repair.

to 0.005 inch (0.127 mm) deep and

AREA 3: Scratches to 0.005 inch (0.127

detectable with 5X magnification are

mm) deep if oriented 0 to 30 degrees

not acceptable without repair. Defects

from spanline and to 0.003 inch (0.076

beyond 0.005 inch (0.127 mm) depth are

mm) deep if oriented between 30 and 40

cause for rejection. Gouges, nicks,

degrees from spanline must be re−

scratches and cracks not exceeding

moved. No sharp nicks or gouges

0.250 inch (6.35 mm) depth on trailing

requiring more than 0.005 inch (0.127

edge, except for AREA 8, must be

Page 7-23

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

smoothed and radiused out to 0.250

AREA G: No repairs permitted.

inch (6.35 mm) area on each side of

damage center. Defects beyond 0.250

AREA H: Dents and depressions

inch (6.35 mm) depth are cause for

exceeding 0.010 inch (0.254 mm)

rejection.

without sharp change in section to

maximum of 0.040 inch (1.016 mm)

AREA 8: Check for gouges, nicks,

must be repaired.

scratches and cracks detected by using

AREA J: Dents and depressions

a bright light and 5X magnification at

exceeding 0.010 inch (0.254 mm)

trailing edge corners where blade and

without sharp changes in section to a

tabs join. View area from different

maximum of 0.040 inch (1.016 mm)

angles during inspection. Damage at

must be repaired. Dents and depres−

this point not exceeding 0.030 inch

sions exceeding these limitations

(7.62 mm) depth must be smoothed and

require blade replacement.

radiused out over a 0.120 inch (3.048

mm) area on each side of damage.

NOTE: MDHI Notice HN− 211 contains infor−

Defects beyond 0.030 inch (7.62 mm)

mation relative to inspection of main rotor

depth are cause for rejection.

fittings and lead−lag link assemblies.

(3).

Depth limitations for surface dents or

(4). Inspect surface areas of upper− and

depressions in eight areas of blade skin

lower−root fittings (other than Area 5)

are described below. A dent or depres−

for evidence of nicks, scratches, and

sion is defined as a smooth depression

wear spots.

or discontinuity with no sharp changes

in section.

(a). Nicks, scratches, and wear spots

deeper than 0.010 inch (0.254 mm) in

AREA A: Dents and depressions

attachment lug area, and bolt hole

exceeding 0.015 inch (0.381 mm)

area are not repairable.

without sharp changes in section to a

maximum of 0.062 inch (1.5748 mm)

(b). Damage 0.010 inch (0.254 mm) deep

must be repaired.

or less must be repaired.

AREA B: Dents and depressions to a

(5). Inspect four attachment lug bushings

maximum of 0.010 inch (0.254 mm) are

in root fittings for security, and evi−

acceptable without repair. No repairs

dence of cracks or severe scoring.

are permitted in this area.

(6). Inspect trailing edge bearing for

binding, evidence of galling or scoring

AREA C: No repairs permitted.

in bore and wear.

AREA D: Dents and depressions

(a). No radial play is permissible.

exceeding 0.005 inch (0.127 mm)

without sharp change in section to a

(b). Maximum axial play is 0.015 inch

maximum of 0.030 inch (0.762 mm)

(0.381 mm).

must be repaired.

(7). Inspect all bonded areas for evidence of

AREA E: Dents and depressions

separation.

exceeding 0.010 inch (0.254 mm)

without sharp change in section to a

(a). If there appears to be separation of

maximum of 0.040 inch (1.016 mm)

trailing edge bond, lightly probe joint

must be repaired.

with a 0.001−0.002 inch (0.025−0.051

mm) plastic inspection tool.

AREA F: Dents and depressions

exceeding 0.010 inch (0.254 mm)

(b). If plastic inspection tool can be

without sharp change in section to

inserted to a depth of 0.50 inch (12.7

maximum of 0.040 inch (1.016 mm)

mm) or more, either above or below V

must be repaired.

insert, separation is evident.

Page 7-24

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

DAMAGE 0.010 IN. (0.254 MM) IN DEPTH OR LESS

IS REPAIRABLE IN THESE AREAS (NOTE 1)

CHORD LINE

1.00 IN. (25.4 MM) RADIUS AROUND LAST

2 BOLT HOLES 0.001 IN. (0.025 MM)

SPAN LINE

MAXIMUM DEPTH

0.38 IN. (9.652 MM)

90°

3.00 IN.

120°

1.25 IN.

(76.2 MM)

(31.75 MM)

30°

120°

30°

120°

30°

15°

30°

DAMAGE LESS THAN

0.030 IN. (0.762 MM)

DEPTH REPAIRABLE IN

THIS AREA (NOTE 1)

30°

15°

1.00 IN.

(25.4 MM)

23.00 IN.

(58.42 CM)

GOUGES, NICKS AND CRACKS

SCRATCHES

GOUGES AND NICKS

TRAILING EDGE ONLY

ORIENTATION

MAX. DEPTH

AREA

FROM SPANLINE

WITHOUT REPAIR

WITH REPAIR

WITHOUT REPAIR

WITH REPAIR

WITHOUT REPAIR

WITH REPAIR

MINOR WITHOUT

0°−90°

SKIN PENETRATION

0.005 IN. (0.127 MM)

0.003 IN. (0.076 MM)

0.005 IN. (0.127 MM)

0°−30°

0.003 IN. (0.076 MM)

0.005 IN. (0.127 MM)

30°−90°

ÉÉÉ

NONE

0°−30°

NONE

0.005 IN. (0.127 MM)

N/A

30°−90°

NONE

0.003 IN. (0.076 MM)

NONE

0.005 IN. (0.127 MM)

ÉÉÉ

0.003 IN. (0.076 MM)

NONE

0°−30°

NONE

0.003 IN. (0.076 MM)

NONE

0.002 IN. (0.051 MM)

NONE

30°−90°

0.003 IN. (0.076 MM)

0.001 IN. (0.025 MM)

0°−90°

NONE

(NOTE 3)

NOTE 2

0°−15°

0.005 IN. (0.127 MM)

NONE

0.005 IN. (0.127 MM)

15°−30°

0.003 IN. (0.076 MM)

NONE

0.005 IN. (0.127 MM)

NONE

0.030 IN. (0.762 MM)

30°−90°

NONE

0.005 IN. (0.127 MM)

(NOTES 3, 5)

0.005

0.250 IN. (6.35 MM)

0°−90°

NONE

0.005 IN. (0.127 MM)

NONE

(NOTE 3)

(NOTES 3, 6)

(NOTES 3, 4, 6)

0.030 IN. (0.762 MM)

NOT APPLICABLE

NONE

(NOTES 3, 5, 6)

TAB END

NOTES:

AREAS NOTED: 0.25 SMOTHERED AND RADIUSED

DAMAGE LIMITS APPLY TO BOTH UPPER AND LOWER ROOT

CLEANOUT ALLOWED.

FITTING SURFACES.

SMOOTHED AND RADIUSED CLEANOUT OVER 0.12 IN. (3.048 MM)

INSPECTION UNDER 5X MAGNIFICATION (MIN.) REQUIRED.

AREA ON EACH SIDE OF DAMAGE.

REFER TO TRIM TAB DAMAGE REPAIR.

G62−1001A

Figure 7-8. Main Rotor Blade Damage and Repair Limits for Nicks,

Scratches, Gouges and Cracks

Page 7-25

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

0.38 IN.

2.12 IN.

(9.652 MM)

(5.3848 CM)

1.58 IN.

(4.0132 CM)

2.00 IN.

(5.08 CM)

0.58 IN.

(14.732 MM)

2.17 IN.

(5.5118 CM)

23.00 IN.

0.96 IN.

(58.42 CM)

(24.384 MM)

DENTS AND DEPRESSIONS (NOTE)

MAXIMUM

MINIMUM DISTANCE

AREA

DEPTH

ALLOWED

NUMBER

BETWEEN DEFECT

WITHOUT REPAIR

WITH REPAIR

AREA

OF DEFECTS

CENTERS

0.015 IN.

0.062 IN.

1.5 X 1.5 IN.

N/A

(0.381 MM)

(1.5748 MM)

(3.81 X 3.81 CM)

0.010 IN.

0.25 X 0.25 IN.

18 IN.

0.000

(0.254 MM)

(6.35 X 6.35 MM)

(45.72 CM)

NONE

0.000

N/A

ALLOWED

0.005 IN.

0.030 IN.

1.5 X 1.5 IN.

18 IN.

(0.127 MM)

(0.762 MM)

(3.81 X 3.81 CM)

(45.72 CM)

0.010 IN.

0.040 IN.

1.5 X 1.5 IN.

18 IN.

(0.254 MM)

(1.016 MM)

(3.81 X 3.81 CM)

(45.72 CM)

0.010 IN.

0.040 IN.

1.5 X 1.5 IN.

18 IN.

(0.254 MM)

(1.016 MM)

(3.81 X 3.81 CM)

(45.72 CM)

NONE

0.000

N/A

ALLOWED

0.010 IN.

0.040 IN.

1.5 X 1.5 IN.

N/A

(0.254 MM)

(1.016 MM)

(3.81 X 3.81 CM)

0.35 IN.

0.010 IN.

1.5 X 1.5 IN.

N/A

(8.89 MM)

(0.254 MM)

(3.81 X 3.81 CM)

(NOTE 3)

NOTES:

N/A − NOT APPLICABLE.

REFER TO TRIM TAB DAMAGE REPAIR.

H07−0001A

Figure 7-9. Main Rotor Blade Damage and Repair Limits for Dents

and Depressions

Page 7-26

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

NOTE: Trailing edge structural bond line to V

(c). If a torque wrench is not available,

insert starts 0.250 inch (6.35 mm) in (chord−

check weight security by fitting a

wise) from trailing edge joint: therefore the

small coin in the slots and applying

above tolerance allows 0.250 inch (6.35 mm)

the maximum force that can be

separation. Be sure measurement is taken

exerted by ONLY the index finger

from the trailing edge joint, not the tab trail−

and thumb.

ing edge. Maximum trailing edge joint gap

allowed during fabrication is 0.080 inch

(13). Inspect vibration absorber pad on

(2.032 mm).

underside of blade for security.

(14). Inspect vibration absorber for security

(8). Inspect doubler shown in area G for

of installation on blade.

bonding voids between doubler and

blade skin top and bottom.

(15). Ensure both pendulums swing freely

and no more than 0.015 inch (0.381

(a). Use a heavy coin and lightly tap

mm) radial play exists between the

doubler surface.

pendulums and the hinge pins.

(b). A void will appear as a distinct

(a). Maximum allowable axial play

change in sound.

between pendulums and bracket is

0.085 inch (2.159 mm).

NOTE: Tapping sound will differ slightly due to

blade structure in leading and trailing edge,

(16). Inspect all parts of the vibration

internal channel and doubler areas.

absorber for cracks and breaks.

(17). Inspect pad on bracket below pivot end

(9). Ensure that vent holes are open.

of largest pendulum for security.

NOTE: Two or three vent holes are located in

(18). Inspect thrust washers bonded to the

the lower blade skin 5.50 inches (13.97 cm)

bracket, to the 5−per−revolution

aft of the leading edge with the first hole

pendulum, and to the 3−per−revolution

7.50 inches (19.05 cm) inboard from the tip.

pendulum for evidence of damaged

Teflon surfaces, wear and failure of

(10). Inspect the fasteners that secure upper

bond.

and lower root fittings, and the six

rivets that secure skin to spar near tip,

11. Main Rotor Blade Repair

for security.

A. Nicks, Scratches and Wear Spots

(11). Inspect forward tip cap screw insert for

security and thread damage.

(Ref. Figure 7−8)

(1). Using abrasive paper (9, Table 2−4), no

(12). When continuous one−per−revolution

coarser than grade 320, remove nicks,

lateral vibration occurs, inspect forward

scratches and wear spots from upper

and aft balance weights for security

and lower root fittings, and from blade

(Ref. Figure 7−3).

skin.

(a). Weights are normally recessed 0.050

(2). Use finer grade of paper, as necessary

inch (1.270 mm) below the end

to restore surface roughness to original

surface of the weight assembly tip.

finish.

(b). Security of the weights may be

(3). Remove material in such a manner that

checked by using a torque wrench

no abrupt changes occur in surface

with a screwdriver socket in the slot

contours.

of the weight to detect if the weight

can be rotated by less than 20

(4). Apply chemical film surface treatment

inch−pounds (2.26 Nm).

to repaired surface (Ref. Sec. 2).

Page 7-27

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

B. Dents, Depressions and Erosion

(1). Unscrew loose weight until it projects

approximately one−half inch and

(Ref. Figure 7−9)

remove old accumulation of powdered

compound.

Repair only those damaged

CAUTION

areas that are within repairable

(2). Apply grade A locking compound (29)

limits.

and screw the weight back into the

blade until slotted end of the weight is

(1). Use paint remover (11, Table 2−4) to

recessed 0.050 inch (1.27 mm) below

remove paint from surface area to be

the surface of the weight assembly tip.

repaired.

Wipe off excess compound.

(2). Wipe away all residue with clean cloth

Allow to cure for a minimum of

CAUTION

dampened by solvent (1). Allow to dry

12 hours. If faster cure is de−

for minimum of 15 minutes.

sired, complete cure can be obtained by al−

lowing part to set for 30 minutes at room

(3). Mask edges of repair areas with one

temperature and then heating for 30 min−

layer of tape (93).

utes at approximately 212°F (100°C).

Do not cut tape after it is

(3). If locking compound is not available,

CAUTION

applied to blade.

screw weight into normal position and

centerpunch the end of the weight into

(4). Mix filler (94), three parts ‘‘A’’ and two

the mating threads at three evenly

parts ‘‘B’’ by weight. Mix thoroughly

spaced points to prevent rotation.

until mixture is dark red in color. An

alternate filler (95) may be used if

E. Loose or Missing Rivets or Aft Tip Cap

equal parts ‘‘A’’ and ‘‘B’’ by weight are

Replace all loose or missing rivets. Reinstall or

mixed.

replace loose or missing aft tip cap as follows:

(5). Allow filler to cure for minimum of 24

NOTE: Spare tip caps are supplied with the

hours at room temperature.

bonding surface pretreated (coated) with a

nylon primer to facilitate installation.

(6). Smooth filler area with grade 400

abrasive paper (9). Limit smoothing to

(1).

Lightly abrade primed surfaces of the

masked area.

tip cap with grade 180 abrasive paper

(9, Table 2−4).

(7). Remove the tape and inspect alclad

coating of area around repair. Penetra−

(2).

Wipe away residue with cloth damp−

tion of coating is cause for blade

ened in solvent (1) and allow tip cap to

replacement.

dry at room temperature for 30 min−

utes.

(8). Clean repaired area with a cloth

dampened by solvent (58).

(3).

Mix two−part bonding adhesive (19) in

equal proportions by weight.

(9). Apply chemical film treatment to

repaired surface.

(4).

Apply bonding adhesive previously

prepared tip cap and mating surfaces at

C. Forward Tip Cap Insert

rotor blade tip. To extent possible, be

sure that there are no adhesive voids.

Replace a loose or stripped insert. Use

self−locking insert NAS1394 of correct size for

(5).

Install tip cap in blade tip, apply

replacement and install with wet primer (4,

uniform clamping pressure to the joint,

Table 2−4) (Comply with replacement require−

and wipe away excess adhesive. Allow

ments of applicable NAS standard).

adhesive to cure for 8 hours at room

temperature or 2 hours at 150°F (66°C).

D. Loose Balance Weights

(6).

Install two MS20604AD3C2 blind

Reinstall loose forward and aft balance

rivets, one through each side of the

weights as follows:

blade tip and tip cap (Ref. Figure 7−3).

Page 7-28

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

(7). Check other blades of rotor for tip cap

13. Bearing Replacement - Damper Attach,

security. Rebond if necessary and add

Blade Fitting

rivets to the other tip caps in the same

manner.

(Ref. Figure 7−10)

NOTE: Main rotor balance will not be affected.

(1). Use fly or circle cutter with 5/16 inch

(0.3125 mm) pilot to remove staked lip

F. Vibration Absorber

from one side of bearing without

(Ref. Vibration Absorber Repair)

removing any material from fitting.

12. Leading Edge Erosion Protection

If fitting is damaged by cutter,

CAUTION

blade must be replaced.

Blades subjected to operation in a highly

abrasive environment should have the outer

(2).

Use an arbor press to press bearing

12−36 inches (30−91 cm) of each blade leading

from fitting.

edge covered equally by protective tape so that

blade life will not be reduced by excessive

(3).

Clean primer residue from fitting bore

erosion.

with MEK (22, Table 2−4). Remove

locking compound residue (if any) with

NOTE: Cement and tape must be applied to a

locking compound remover (33).

thoroughly clean surface with no rough

paint edges. Work out trapped air bubbles

(4).

Using 10 power magnifying glass,

during application and allow 2 hours for

inspect fitting bore for cracks. No

tape to set.

cracks are permitted.

(1).

Thoroughly wash the blade leading

edge with clean cloths dampened with

(5).

Measure fitting bore diameter. Accept−

MEK (22, Table 2−4). Allow to air dry at

able limits are 0.7488−0.7493 inch

least 15 minutes.

(19.0195−19.0322 mm).

(2).

Mask around the outside of the area to

(6).

Apply thin coat of primer (4) to fitting

be taped leaving a 0.250 inch (6.35 mm)

bore.

gap.

(7).

Press bearing into fitting with arbor

(3).

Apply a uniform brush coat of cement

press and fixture (61, Table 2−2). Wipe

(120). Allow to air dry for 5 to 10

away excess primer.

minutes.

(4).

Remove backing from 3 inch (7.62 cm)

(8).

Stake bearing at both sides of fitting

width by 0.014 inch (0.3556 mm) thick

with staking tool (62) in hydraulic press

tape (42), and apply along the leading

with 6000 − 8000 pounds (26689 −

edge so that tape overlap over bottom

35586 N) of force.

and top of leading edge is equal.

(a). When staked, outer race of bearing

(5).

Roll out any air trapped under the tape

shall be flush to not more than 0.010

with a cylindrical object.

inch (0.254 mm) above fitting surface

(both sides).

(6).

Remove masking tape; then carefully

remove cement residue using MEK.

(b). Gap between staked lip of bearing

(7).

Replace the tape when it becomes

race and chamfered surface of fitting

abraded. Operation in rain reduces tape

bore shall not exceed 0.005 inch

life and more frequent replacement will

(0.127 mm) as checked with feeler

be necessary.

gage.

NOTE: The use of abrasion tape will not affect

(c). Staking operation shall produce no

flight characteristics or vibration levels;

cracks in fitting or bearing.

however, with 36 inches (91 cm) of tape

applied there is a 3 to 4 hp loss in rotor pow−

(9). Fill staking gap (if any) with primer (4,

er.

Table 2−4).

Page 7-29

Revision 16

MD Helicopters, Inc.

CSP−H−2

500 Series - Basic HMI

0.005 IN. (0.127 MM)

MAX.

EDGE OF STAKING TOOL

FLUSH TO

+0.010 IN.

ARM

(+0.254 MM)

BEARING WITH STAKING

GROOVE IN OUTER RACE

PRESSING BEARING

STAKING BEARING

IN ARM

30−215A

Figure 7-10. Bearing Replacement - Main Rotor Blade Attach Fitting Repair

14. Repair of Trim Tab and Trailing Edge

(3). Wipe away dirt on and around trim tab

(369A1100 Series)

area with clean cloth dampened with

dry cleaning solvent.

(Ref. Figure 7−11) The following procedures

provide broad cleanup of a damaged trim area,

(4). Mask edges of blade area around trim

which distributes stresses over a larger area to

tab area with tape; DO NOT cut tape

after it has been applied to blade.

preclude cracking and permit continued use of

the rotor blade.

(5). Remove damaged area of trimtab by

making V−type cut with 45° sides

No minimum length of trim tab is required.

joined by a 0.250 inch (6.35 mm) radius

The entire trim tab or portion of the trim tab

at the bottom of the V. Blend into

may be removed.

trailing edge of the blade with a 0.250

inch (6.35 mm) radius as shown.

Main rotor blades with and without trim tabs

are 100% interchangeable, individually and in

NOTE: Maximum V cut depth is 0.350 inch

ship sets.

(8.89 mm); do NOT cut past trim tab area

into portion of blade.

(1). Inspect trim tab area of main rotor

blade and repair tab area, as required.

(6). If damage occurs within 1 inch (25.4

mm) of either or both ends of trim tab,

NOTE: If damage to trim tab area exceeds limi−

remove tab end(s) and restore contour

tations (Ref. Figure

7−9, perform the fol−

as shown.

lowing:

(7). If excessive damage requires full or

(2). As applicable, remove main rotor blade.

partial removal of trim tab from blade,

perform the following (no minimum

Provide protective surface and/

length of trim tab is required):

CAUTION

or covering to prevent scratch−

ing, nicking or other damage to blade during

(a). Position blade on workbench so that

rework. Position blade on work bench or

a firm straight edge is provided for

equivalent.

cutting or filing off trim tab.

Page 7-30

Revision 16

CSP-H-2 BASIC HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369H HELICOPTERS - page 4