HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369D/E/FF-500/600N HELICOPTERS (ISSUED: 1990)

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

bearing cage and fork (bearing turns in

pounds (6.672-22.24 N). If load is not

fork). If failure is noted, remove bearing

within specified limit, replace bearing.

and rebond in fork according to instruc

(8). Reinstall rubber blade stop.

tions in the COM.

(2).

Teeter blades stop-to-stop. Observe

four radial molded ridges on each

bearing as teetering takes place. If

ridges assume continuous curved

shape, bearings are intact. Discontinu

ity in molded ridges indicates bearing

TAIL ROTOR

failure and bearing must be replaced.

(3).

Check bearing for general condition.

Replace bearing if damaged. Evidence

of light swelling, pock marks and

STRING

SPRING SCALE

crumbs are surface conditions and are

2.00 IN.

not indications of bearing failure.

(5.08 CM)

(4).

Elastomeric bearings are suspected of

1.00 IN.

369F/FF

being unserviceable if visual inspection

(2.54 CM)

reveals rubber deterioration or separa

tion, or a vibration is reported. Perform

369D/E

following steps to check blade flapping

SPRING SCALE

resistance measurement to determine if

STRING

suspected elastomeric bearing has

3.00 IN.

failed.

(7.62 CM)

ZERO LOAD POSITION

(5).

To perform measurement, remove

VIEW LOOKING AFT

G64-2003A

rubber blade stop between tail rotor

hub and fork on inboard hub. The

Figure 204. Blade Flapping Resistance

outboard tail rotor assembly can be

Check

checked without any disassembly.

Elastomeric Bearing Care and Cleaning

Do not remove hub-to-drive

CAUTION

Elastomeric bearings are not inherently

fork hinge bolt to remove

resistant to grease, oils or solvents if im

2-bladed tail rotor assembly. This bolt

mersed. They are, however, somewhat resis

should only be removed according to in

tant to occasional splash or spoilage of these

structions in the COM. Damage to strap

materials if exposed on an occasional basis. If

pack may occur if any other procedure is

elastomeric materials do come in contact with

used.

these fluids, the elastomer surface should be

(6). The rubber blade stop must be re

immediately cleaned. If cleaning is accom

moved. Reassemble tail rotor with

plished properly, the effect of greases, oils or

rubber blade stop removed.

solvents on the performance of the elastomeric

material will be minimal. If replacement of

(7). Measure flapping resistance of blades

elastomeric bearing is required, refer to COM.

using spring scale attached within 1.00

inch (2.54 cm) for 369D/E or 2.00 inch

(1). If greases, oils or solvents come in

(5.08 cm) for 369FF inboard of blade tip

contact with the elastomeric material,

(Ref. Figure 204). Block or hold tail

wipe immediately with clean, dry rag.

rotor pedal in neutral position. While

(2). If wiping is not sufficient (oil or grease

pulling 90 degrees from plane of

is too thick), clean the affected area of

rotation, record spring scale value when

the elastomer with a soft bristle brush

blade tip is 3.00 inches (7.62 cm)

and a solution of pure soap and water.

inboard and outboard from no-load

position. Scale must indicate 1.5-5.0

(3). Rinse with tap water.

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CSP-HMI-2

MAINTENANCE MANUAL

ANTI−TORQUE FAN

REMOVAL/INSTALLATION

1. Anti−Torque Fan Assembly

(8). Remove fan from helicopter.

The purpose of the fan is to provide anti-tor

B. Anti−Torque Fan Installation

que control using a variable flow of air, across

variable pitch blades, down the tailboom. The

Consumable Materials

anti-torque fan liner, felt metal seal, provides

(Ref. Section 91−00−00)

a controlled gap between the fan and the felt

Item

Nomenclature

metal seal for optimum efficiency of the fan

CM702

Lockwire CRES

during flight.

NOTE: The NOTARr anti-torque control sys

(1).

Align and install fan assembly on

tem must be re-rigged immediately after re

support shaft.

placement of any component, control rods,

or linkages, and if helicopter operation re

(2).

Install washer on shaft.

veals a rigging deficiency.

(3).

Install locknut and torque nut to 40 -

2. Anti−Torque Fan Replacement

42 foot-pounds (54 - 57 Nm). Install

lock washer.

(Ref. Figure 401 and Figure 402)

(4).

Install pitch bearing housing using six

bolts and washers, Torque bolts to 80 -

Special Tools

100 inch-pounds (9.04 - 11.30 Nm)

(Ref. Section 91−00−00)

and lockwire (CM702).

Item

Nomenclature

ST605

Fan nut socket

(5).

Install fan pitch control tube (Ref. Sec.

67-20-30, Fan Pitch Control Tube

Installation).

A. Anti−Torque Fan Removal

(6).

Install tailboom (Ref. Sec. 53-40-30).

(1).

Remove tailboom (Ref. Sec. 53-40-30).

3. Anti−Torque Fan Blade Replacement

(2).

Remove nut and lock washer from aft

(Ref. Figure 401)

tube assembly.

NOTE: When a blade needs replacement for

(3).

Remove fan pitch control tube (Ref. Sec.

any reason, whether it be service related or

67-20-30, Fan Pitch Control Tube

at overhaul, replace associated bolt, washer,

Removal).

and nut.

(4).

Remove six bolts, washers and pitch

A. Anti−Torque Fan Blade Removal

control housing from fan.

(1). Remove anti-torque fan from helicopter

(5).

Remove lock washer from nut and shaft

(Ref. Anti-Torque Fan Removal).

by releasing the holding tangs from lock

nut and pull locking ring from support

(2). Remove fan blade from strap assembly

shaft knurl.

by removing cotter pin, washer and pin.

(6).

Remove locknut in a counter-clockwise

B. Anti−Torque Fan Blade Installation

direction, using coupling socket (ST605)

and coupling holding fixture tool.

(1). Install fan blade and align retention

hole with upper strap assembly reten

(7).

Remove washer from shaft.

tion hole.

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CSP-HMI-2

MAINTENANCE MANUAL

(2). Install pin, washer and cotter pin.

NOTE: Inspect strap assembly for condition

and expiration date. Pay particular atten

(3). Reinstall anti-torque fan in helicopter

tion to area around the two spools. Inspect

(Ref. Anti-Torque Fan Installation).

for cracks in the polyurethane coating. If

any cuts or breaks are found that exceed

(4). Perform fan balance check (Ref. Sec.

0.020 inch (0.508 mm) in depth or 0.25 inch

18-20-30, Fan Balance Check).

(6.35 mm) in length, replace the strap.

D Tension-torsion straps have a life limit

that starts when their package is opened.

Consumable Materials

If the date the package was opened is un

(Ref. Section 91−00−00)

known, the 5 year calendar life is based

Item

Nomenclature

on the manufacturing cure date.

CM312

Ink stamp, permanent

D Tension-torsion straps can be put back in

their package, and life limit not started, if

not out of the package more than five

4. Fan Blade Strap and Pitch Horn

days.

Replacement

(2). If tension-torsion strap is removed

from package for no more than five

(Ref. Figure 401) Remove and install the pitch

days, do the steps that follow:

horn and strap assembly using the following

procedures.

(a). Replace desiccant in package, use

desiccant (CM826).

NOTE:

NOTE: If you can not seal package; put, ten

sion-torsion strap, package, and desiccant

D The following procedure covers the indi

(CM826) in new plastic bag.

vidual removal of one strap assembly and

pitch horn. If disassembly of all is re

(b). Put tension-torsion strap in package

quired, use the following steps for each

and seal package opening with tape.

one requiring removal.

(c). Put package in box and seal box with

tape.

D When strap is replaced, replace related

bolt, washer, and nut.

(3). If replacement strap is new, remove

from package and write the words

A. Fan Blade Strap and Pitch Horn

EXPIRATION DATE on the strap face

Disassembly

and date five years after the package is

opened. Use permanent ink (CM312).

(1). Remove anti-torque fan from helicopter

(Ref. Anti-Torque Fan Removal).

(4). Make an item component record card

for each tension-torsion strap.

(2). Remove fan blade(s) (Ref. Anti-Torque

NOTE: Install tension-torsion straps so that

Fan Blade Replacement).

the cure date is in view when fan is as

(3). Remove bolt and washer retaining

sembled.

bottom half of strap assembly between

(5). Insert strap assembly thru top of fan

two retention plates.

hub and pitch horn until lower (smaller

diameter) hole is aligned between holes

(4). Remove strap assembly thru top hole of

of two retention plates.

fan hub.

(6). Install blade and align spar before

(5). Remove pitch horn from fan hub.

torquing inboard nut, this ensures

proper alignment of strap with blade.

B. Fan Blade Strap and Pitch Horn

(7). Install new bolt, washers (countersunk

Reassembly

washer against bolt-head), and nut

NOTE: Counterweights on pitch arms are set

thru holes of retention plates and of

by the factory; do not attempt to adjust.

strap assembly.

(1). Install pitch horn in fan assembly.

(8). Install fan blade(s) and torque bolts to

Ensure ball on lower side of pitch horn

100 inch-pounds (11.30 Nm) (Ref.

is inserted in bushing of pitch plate.

Anti-Torque Fan Blade Installation).

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MD Helicopters, Inc.

MAINTENANCE MANUAL

(9). Reinstall anti-torque fan in helicopter

A. Support Shaft Disassembly

(Ref. Anti-Torque Fan Replacement).

(1). Remove anti-torque fan from helicopter

(10). Perform fan balance (Ref. Sec.

(Ref. Anti-Torque Fan Removal).

18-20-30, Fan Balance Check).

(2). Remove fan pitch control tube (Ref. Sec.

67-20-30).

5. Retention Plate and Pitch Plate

Replacement

(3). Remove fan interconnect driveshaft

(Ref. Sec. 63-15-30).

(Ref. Figure 401) Remove and install the

retention strap and pitch plate using the

(4). Remove fan interconnect shaft coupling

following procedures.

from support shaft (Ref. Sec. 63-15-30).

A. Retention Plate and Pitch Plate

(5). Remove support shaft and fan hub

Disassembly

housing from fan support assembly by

removing four cotter pins, nuts,

(1). Remove anti-torque fan from helicopter

washers and bolts.

(Ref. Anti-Torque Fan Removal).

(6). Remove hub spacer from shaft.

(2). Remove fan blades (Ref. Anti-Torque

(7). Remove bearing retainer from support

Fan Blade Replacement).

housing.

(3). Remove strap assemblies and pitch

(8). Press shaft and fan support bearing out

horns.

of support housing.

(4). Remove pitch plate and retention plates

NOTE: Removal of bearing seal at disassembly

from fan hub.

is not required unless seals need replace

ment.

B. Retention Plate and Pitch Plate

Reassembly

(9). Remove bearing seal from support

housing and bearing retainer.

(1). Position retention plates in fan hub.

(10). Press bearing off support shaft using

NOTE: Install tension-torsion straps so that

removal ring.

the cure date is in view when fan is as

sembled.

B. Support Shaft Reassembly

(2). Install pitch horn and strap assemblies

(Ref. Strap and Pitch Horn Reassemb

Consumable Materials

ly).

(Ref. Section 91−00−00)

Item

Nomenclature

(3). Place pitch plate over retention plates

CM111

Grease, aircraft

within fan hub.

CM425

Sealing compound

(4). Install fan blades (Ref. Anti-Torque

Fan Blade Installation).

(1). Install removal ring on support shaft

until firmly seated against shoulder of

(5). Reinstall anti-torque fan in helicopter

support shaft.

(Ref. Anti-Torque Fan Installation).

(2). Install support bearing on support

6. Support Shaft Replacement

shaft.

(Ref. Figure 402) Remove and install the

(3). Install bearing seal in support housing

support shaft using the following procedures.

and bearing retainer using sealant

(CM425).

NOTE: When replacing pitch plate and/or sup

port shaft bearings, do not use 900R bear

(4). Fill seal cavity with 3.3-4.0 CCs of

ings in the 500/600N helicopters.

grease (CM111).

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(5).

Install support bearing and shaft in

(2). Removal with Hand Tool:

support housing.

(a). Insert the applicable size hex wrench

into the pin wrenching cavity and

(6).

Install bearing retainer and align bolt

hold securely to prevent pin rotation.

holes on support housing.

(b). Rotate the collar counterclockwise

(7).

Install hub spacer on shaft.

with pliers or vise grips to remove.

(8).

Install support shaft and housing on

(c). Tap out pin with a nonmetallic-faced

fan support assembly. using four bolts,

mallet.

washers, and nuts. Torque nuts to 40 -

B. Fan Balance Stud Installation

50 inch-pounds (4.52 - 5.65 Nm).

Install cotter keys.

Pins may be reused, provided the finish has

not been marred and the threads and wrench

(9).

Install fan interconnect shaft coupling

ing cavity are in acceptable condition.

on support shaft (Ref. Sec. 63-15-30).

(10).

Install fan interconnect driveshaft (Ref.

Consumable Materials

Sec. 63-15-30).

(Ref. Section 91−00−00)

Item

Nomenclature

(11).

Install fan pitch control tube (Ref. Sec.

CM409

Adhesive, epoxy

67-20-30).

(12).

Install anti-torque fan on helicopter

(1). Apply adhesive (CM409) to pin and

(Ref. Anti-Torque Fan Installation).

insert, while wet, using a nonmetallic-

faced mallet or rivet set into hole.

(13).

Check fan balance (Ref Sec. 18-00-30,

Ensure Pin is seated flush against fan

Fan Balance Check).

hub.

(2). Manually screw the collar onto the pin

7. Fan Balance Stud Replacement

a minimum of two threads.

A. Fan Balance Stud Removal

(3). Installation with Pneumatic Tool:

The following procedure is for removal of the

(a). Insert the hex wrench tip of the

balance studs when the lock collars have

power driver into the wrenching

become loose and allow the stud to rotate.

cavity in the pin

(1). Removal with Pneumatic Tool: Pneu

(b). Press the power driver socket firmly

matic tools may be used only on

against the collar and actuate the

fasteners in interference fit holes and

driver until the collar wrenching

fasteners with aluminum collars.

device is torqued off.

(c). Withdraw the hex wrench tip from

(a). Select the applicable removal tool. Fit

the wrenching cavity and discard the

removal tool to a 0.375 inch (9.525

wrenching collar.

mm) square socket drive that will fit

a reversible screwdriver motor.

(4). Installation with hand tool:

(b). Place the collar removal tool over the

(a). Press socket from hand tool firmly

collar and press firmly.

onto collar.

(b). Insert hex wrench though center of

(c). Rotate the tool counterclockwise by

tool and hold pin to prevent it from

hand until the teeth bite into the

rotating.

collar.

(c). Turn socket clockwise, while holding

(d). Place the motor on the drive socket

hex wrench, until collar is firmly

and unscrew the collar using reverse

seated against fan hub; wrenching

drive.

collar will torque off when proper

(e). Tap out the pin with a nonmetallic-

torque is reached. Discard wrenching

faced mallet.

collar.

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

8. Pitch Horn Counterweight Set Screw

NOTE: Ensure counterweight-to-pitch horn

Replacement

index mark aligns correctly. All counter

weights are indexed the same.

(Ref. Figure 403) If, during fan inspection, a

(7).

Align index mark on counterweight to

counterweight is found to be loose, the set

match with mark on pitch horn and

screw must be replaced.

install into pitch horn.

(8).

Apply grade B locking compound

Consumable Materials

(CM321) to threads of set screw and

(Ref. Section 91−00−00)

install into pitch horn. Tighten set

Item

Nomenclature

screw.

CM216

Loctite remover

CM321

Surface primer locking compound

COUNTERWEIGHT

INDEX MARK

COUNTERWEIGHT

(1). Apply heat to loose counterweight.

(2). Remove and discard set screw.

(3). Remove retaining ring and washer.

(4). Inspect threads in counterweight for

PITCH HORN

condition and cleanliness.

INDEX MARKS

SET SCREW

(5). Clean pitch horn threads with Loctite

PITCH HORN

remover (CM216).

G64-2011

(6). Apply grade T primer (CM321) to

threads of new set screw; allow to dry

Figure 403. Pitch Horn Counterweight Set

for 30 minutes at ambient temperature.

Screw Replacement

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

ANTI−TORQUE FAN

INSPECTION/CHECK

1. Anti−Torque Fan Inspection

(c). Scoring; axial marks from bearing

installation or removal.

Inspect the anti-torque fan for the following

conditions:

(d). Damaged spines; none allowed.

(1). All components for cracks, nicks,

(e). Corrosion and pitting.

corrosion or excessive wear.

(2). Fan support bearing for free movement

of set.

(2). Tension-torsion straps for nicks or cuts

in polyurethane coating. No exposed

(3). Fan support bearing retainer and

kevlar fibers allowed. Spools for cracks.

housing for:

(3). Hub-to-blade bushings for cracks.

(a). Cracks; none allowed.

(4). Pitch horn for excessive wear (out-of-

(b). Wear.

round condition).

(c). Scoring; axial marks from bearing

(5). Counterweights on pitch horn for

installation or removal.

security. If loose, perform Pitch Horn

(4). Bearing seals for condition.

Counterweight Set Screw Replacement.

(5). Hub spacer for cracks and wear.

NOTE: Access the forward counterweights

through the fan inlet. Fan hub fairing must

3. Anti−Torque Fan Liner (Felt Metal Seal)

be removed for access (Ref. Sec. 53-30-30).

Inspection

(6). Pitch plate bushing for excessive wear,

(1). Inspect for cracks and debonding of

grooves or cracking.

liner material.

(7). Blades for cracks, nicks or impact

(2). Inspect for cracks around the radius

damage.

cutouts of fan support.

(8). Inspect gap between fan blade and tip

(3). If cracks are found, stop drill and

seal. Inspect gap between fan blade and

inspect every 50 hours (Ref. Sec.

hub (inboard end of the blade). If gap

05-20-20).

for any blade end exceeds the average

gap of the other blades by more than

NOTE: Cracks protruding into the Felt Metal

0.10 inch (2.54 mm), remove and

Seal are unacceptable, replace seal (Ref.

inspect the tension-torsion strap for

Anti-Torque Fan Liner (Felt Metal Seal)

that blade.

Replacement).

(4). Inspect aft P-seal for tears, deteriora

2. Support Shaft Inspection

tion and debonding.

Inspect the support shaft and its associated

4. Fan Blade Inspection (100−Hour)

components as follows:

NOTE: Ensure proper pitch plate and/or sup

Consumable Materials

port shaft bearings are installed. 900R bear

(Ref. Section 91−00−00)

ings are not to be used in the 500/600N heli

Item

Nomenclature

copters.

CM437

Sealing compound

(1). Support shaft for:

(1). Inspect polypropylene portion of fan

(a). Cracks; none allowed.

blade for nicks, scratches, abrasions

(b). Wear.

and bulges; pay particular attention to

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

leading edge and area around the pin

outboard end of blade are reason for

near the outboard edge of blade.

blade rejection.

(3). Seal cracks up to 0.10 inch (2.54 mm),

(a). Nicks and abrasion pits that are less

coming from area of pin with sealing

than 0.040 inch (1.016 mm) deep and

compound (CM437).

0.25 inch (6.35 mm) in diameter may

be blended out. (No more than two

(4). If any cracks larger than 0.10 inch (2.54

such repairs can be made per blade.)

mm) are found, replace blade.

5. Fan Pitch Slider Inspection

(b). Nicks, scratches and abrasion pits

less than 0.020 inch (0.508 mm) and

(1). Inspect slider for dents, scratches,

1.5 inch (3.81 cm) long may be

nicks, gouges and corrosion, none

blended out. (Total length of all

allowed.

repairs not to exceed 2.0 inch (5.08

(2). Inspect Karon coating on slider for

cm).)

condition.

(2). Any bulges or blisters over 0.10 inch

(3). Measure across slider, minimum

(2.54 mm) long in area of pin near

diameter is 0.805 in. (20.447 mm).

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CSP-HMI-2

MAINTENANCE MANUAL

ANTI−TORQUE FAN

REPAIRS

1. Anti−Torque Fan Liner (Felt Metal Seal)

NOTE: On installation of liner assembly, peel

Replacement

shim laminates equally among the four

shims to provide a tight fit without deform

(Ref. Figure 801)

ing the liner at screw holes and aircraft

structure.

A. Anti−Torque Fan Liner (Felt Metal Seal)

Removal

(2). Install four screws. Torque screws per

standard aircraft practices.

(1). Remove tailboom (Ref Sec. 53-40-30).

Do not install sealant in butt

CAUTION

(2). Disconnect safety wire and remove nut,

splices of liner until after felt

lockwasher, 3 bolts, washers and pitch

metal is turned/cut to correct clearance. Do

bearing retainer plate.

ing so will damage cutting tool and cause in

correct cutting radius to liner seal.

(3). Remove pitch bearing and inner pitch

(3). Install sealant (CM425) in mating bores

bearing retainer; remove pitch slider

(cutouts) and around liner edges.

from pitch bearing housing (Ref. Sec.

67-20-30).

(4). After installing the fan liner and before

installing the fan, trim liner felt metal

(4). Remove fan assembly (Ref. Anti-Torque

seal (Ref. Anti-Torque Fan Liner (Felt

Fan Replacement).

Metal Seal) Machining). Refer to MD

Helicopter Field Service Representative

(5). Remove sealant around liner edges

for additional information.

with plastic scraper.

C. Anti−Torque Fan Liner (Felt Metal Seal)

(6). Remove four screws that secure the

Machining

liner to the aircraft structure.

(Ref. Figure 801 and Figure 802)

NOTE: Mark liner to aircraft structure to en

sure proper clocking upon installation. If

Special Tools

liner is not installed in same position, felt

(Ref. Section 91−00−00)

metal seal machining will be necessary for

Item

Nomenclature

correct fan clearance.

ST603

Tip seal cutting fixture

(7). Carefully slide liner aft through

support structure and fan support

NOTE:

struts.

D Do this procedure only after a new fan lin

B. Anti−Torque Fan Liner (Felt Metal Seal)

er is installed.

Installation

D Felt metal material can cause FOD con

tamination.

Consumable Materials

(1). Apply masking tape and plastic sheet to

(Ref. Section 91−00−00)

fan duct and fan diffuser areas.

Item

Nomenclature

Use only cutter and equipment

CM425

Sealing compound

CAUTION

supplied with (ST603) tip seal

tool.

(1). Install fan liner so that the larger

NOTE: Make sure (ST603) tip seal tool is clean

cutouts fit around the fan support

before you install it.

struts and the smaller cutouts fit

around the rivets that secure the fan

(2). Install pin (5) and spacer (6) in fan

inlet fairing.

support assembly.

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CSP-HMI-2

MAINTENANCE MANUAL

FAN SUPPORT ASSEMBLY (REF)

21 (4 PL)

20 (4 PL)

19 (4 PL)

1 (REF)

15 (REF)

16 (REF)

CUTTING

DIRECTION

CUTTER

ÉÉÉÉÉ

ÉÉÉ

13 (2 PL)

14 (2 PL)

ÉÉÉ

23 (2 PL)

ÉÉÉ

CALIBRATION OF CUTTING TOOL HEIGHT

G64-2008A

1. FAN TIP SEAL TOOL (PART 1)

13. CAP SCREW

2. CALIBRATION ARM

14. WASHER

3. CUTTER

15. POSITION LOCK KNOB

4. MOTOR COLLET

16. ADJUSTMENT KNOB

5. PIN

17. SPEED HANDLE

6. SPACER

18. AIR PRESSURE VALVE

7. THRUST BEARING

19. BOLT

8. SPACER

20. WASHER

9. NYLON WASHER

21. NUT

10. THRUST BEARING RETAINER

22. BALL LOCK PIN

11. THREADED KNOB

23. SPACER

12. FAN TIP SEAL TOOL (PART 2)

Figure 802. Anti−Torque Fan Liner Felt Metal Seal Machining

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MAINTENANCE MANUAL

(3).

Install bolts (19), washers (20), and

Eye protection, a respirator,

WARNING

nuts (21). Torque nuts.

gloves, and protective cloth

ing must be worn during fan liner ma

(4).

Put cutter (3) in motor collet (4). Do not

chining.

tighten collet.

(22).

Loosen position lock knob (15) and turn

(5).

Apply a thin film of oil to inner side of

adjustment knob (16) to position cutter

pin (5) and outer side of tool (1) shaft.

(3) for a cut of not more than one fourth

width of cutter (3). Tighten lock knob.

(6).

Put thrust bearing (7) on tool (1) shaft.

(23).

Connect speed handle (17) to tool (12).

(7).

Put tool (1) in pin (5) and push forward.

(24).

Connect pneumatic pressure source to

(8).

Turn tool (1) by hand and adjust cutter

tool (12).

(3) to highest point on fan liner. Tighten

(25).

Turn valve (18) to adjust cutter (3)

collet (4).

speed.

(9).

Remove tool (1).

(26).

Turn speed handle (17) and turn tool (1)

(10).

Remove thrust bearing (7) from tool (1)

counter-clockwise at a moderate to

shaft.

slow rate. Do not force cut.

(27).

After one full turn, again loosen

(11).

Put calibration arm (2) on tool (1).

position lock knob (15) and turn

(12).

Measure dimension between cutter (3)

adjustment knob (16) to position cutter

and stop on calibration arm (2).

(3) for a cut of not more than one fourth

width of cutter (3). Tighten lock knob.

(13).

Loosen motor collet (4) and move cutter

(3) out 0.040-0.050 in. (1.02-1.27 mm)

(28).

Do step (27). again and again until fan

or until cutter touches stop on calibra

liner is fully machined.

tion arm (2). Tighten collet.

(29).

Disconnect pneumatic pressure source

to tool (12).

(14).

Loosen position lock knob (15) and turn

adjustment knob (16) until cutter (3) is

(30).

Disconnect speed handle (17) from tool

at aft most position. Tighten position

(12).

lock knob.

(31).

Remove cap screws (13), washers (14),

(15).

Put thrust bearing (7) on tool (1) shaft.

and spacers (23).

(16).

Put tool (1) in pin (5) and push forward.

(32).

Remove ball lock pin (22) and tool (12).

(17).

Install spacer (8), thrust bearing (7),

(33).

Remove threaded knob (11), nylon

thrust bearing retainer (10), nylon

washer (9), thrust bearing retainer (10),

washer (9), and threaded knob (11).

thrust bearing (7), and spacer (8).

Tighten knob.

(34).

Remove tool (1).

(18).

Put tool (12) on tool (1) and install ball

lock pin (22).

(35).

Remove thrust bearing (7) from tool (1)

shaft.

(19).

Install cap screws (13), washers (14),

and spacers (23). Torque cap screws.

NOTE: The following clearance may vary be

cause of variations in blade length.

(20).

Make sure there is no radial or axial

movement in tool (1).

(36). Install fan assembly and check for a

0.10 in. (2.54 mm) maximum clearance

(21).

Lubricate tool motor, use pneumatic

between fan blade ends and felt metal

tool oil.

seal.

Page 804

Revision 42

64-25-30

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(37). In step (13). did cutter touch stop on

NOTE: The anti-torque control system must be

calibration arm?

re-rigged immediately after removal or re

placement of control rods, linkages and com

ponents or if helicopter operation reveals a

(a). No, go to step (11).

rigging deficiency.

(41). Install fan assembly (Ref. Anti-Torque

(b). Yes, go to step (38).

Fan Replacement).

(38). Remove nuts (21), washers (20), and

(42). Install interconnect driveshaft (Ref.

bolts (19).

Sec. 63-15-30).

(43). Install fan pitch control rod (Ref. Sec.

(39). Remove pin (5) and spacer (6) from fan

67-20-30).

support assembly.

(44). Install pitch slider and inner pitch

bearing retainer (Ref. Sec. 67-20-30).

(40). Clean fan duct and diffuser areas and

remove masking tape and plastic sheet.

(45). Install tailboom (Ref. Sec. 53-40-30).

Page 805

64-25-30

Revision 42

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

2. Anti−Torque Fan Bearing Regreasing

(2). Carefully remove both seals from

bearings (seals will be reused at

reassembly).

Special Tools

(Ref. Section 91−00−00)

(3). Inspect seals for damage; no damage is

Item

Nomenclature

allowed.

ST614

Fan bearing regreasing tool

(4). Install bearings between regreasing

tools with a 4 inch (10 cm) 10-24

threaded bolt, washers and wing nut.

(Ref. Figure 803 and Figure 804) The following

procedure is for the regreasing of the

NOTE: The following procedure provides 100%

500N5364 and 500N7120 bearings.

grease fill. Normal grease fill is 30 to 50%.

Excess grease will extrude past seals for

several hours of operation until the proper

Consumable Materials

level is met.

(Ref. Section 91−00−00)

Item

Nomenclature

(5). Purge bearing with grease (CM111)

until clean grease protrudes from all

CM111

Grease, aircraft

four holes in back of tool.

(6). Remove regreasing tool.

NOTE:

(7). Hand spin bearing to purge excess

D Ensure proper pitch plate and shaft sup

grease.

port bearings are installed. 900R bear

ings are not to be used in the 500/600N

NOTE: Ensure seals are serviceable. If new

helicopters.

seals are required, seals and bearings must

come from the same vendor.

D Refer to Figure 804 for instructions on

the manufacture of a regreasing tool.

(8). Carefully install seals.

(1). Remove bearings from fan assembly

(9). Reinstall bearings (Ref. Support Shaft

(Ref. Support Shaft Disassembly).

Reassembly).

BOLT

WASHER

FAN BEARING

WASHER

NUT

REGREASE TOOL

PART A

REGREASE TOOL

PART B

GREASE FITTINGS

G64-2010A

Figure 803. Fan Bearing Regreasing Procedure

Page 806

Revision 42

64-25-30

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

0.50 IN.

0.125 IN. (3.175 MM)

(12.7 MM)

0.188 IN. (4.7752 MM)

(NOTE 1)

DIA THRU HOLE

3.00 IN.

0.580 IN.

(7.62 CM)

(14.732 MM)

1.980 IN.

(5.0292 CM)

1.180 IN.

(2.9972 CM)

0.870 IN.

1.640 IN.

(22.098 MM)

(4.1656 CM)

2.280 IN.

(5.7912 CM)

0.040 IN.

0.094 IN. (2.3876 MM) DIA

(1.016 MM)

THRU HOLE (8 PL)

EQUALLY SPACED AND

SECTION A-A

PART A

CENTERED BETWEEN

GREASE FITTING

MACHINED GROOVES

MS15002-1 (2 PL)

0.094 IN. (2.3876 MM) DIA THRU

1/4-28 TAPER

HOLE (2 PL) EQUALLY SPACED

THREADS

AND CENTERED BETWEEN

MACHINED GROOVES (NOTE 2)

SEAL MATERIAL (3PL) (PARTS

A AND B) USE LOCALLY

AVAILABLE MATERIAL FIRM

HARDNESS [ 75

SECTION B-B

PART B

QUANTITY

STOCK SIZE

DESCRIPTION

NOTES:

4 x 4 x .50

PLATE

DIMENSION MAY VARY DEPENDING ON SEAL MATERIAL THICKNESS AVAILABLE.

4 x 4 x .50

PLATE

ALL OTHER DIMENSIONS SAME AS PART A.

AN23-64

BOLT

MATERIALS:

AN960D10L

WASHER

6061-T651 ALUMINUM PER QQ-A-250/11 OR EQUIVALENT.

AN315-3R

NUT

SURFACE FINISH 125 RMS.

MS15002-1

GREASE FITTING

BREAK SHARP EDGES 0.002-0.015 IN. (0.0508-0.381 MM).

M6855/2

RUBBER

CHEMICAL FILM TREAT PER MIL-C-5541.

DIMENSION TOLERANCE ±0.010 IN. (±0.254 MM).

G64-2009B

GROOVE DIAMETERS TO BE CONCENTRIC TO 0 188 IN 4 7752 MM) DIA WITHIN 0 002 IN (0 0508 MM)

Figure 804. Fan Bearing Regreasing Tool (ST614)

Page 807

64-25-30

Revision 42

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

TAIL ROTOR PITCH CONTROL ASSEMBLY

MAINTENANCE PRACTICES

1. Tail Rotor Pitch Control Assembly

On four-bladed tail rotor

WARNING

system, there is strong

(Ref. Figure 203 and Figure 204) The pitch

spring pressure in installed tail rotor

control assembly consists of a swashplate that

linkage. Disconnect the in-line bungee

rotates in a matched set of two bearings

before beginning disassembly. Failure

swaged inside a housing. A self-aligning

to disconnect the bungee can result in

bearing staked in place at the underside of the

personal injury and/or parts damage.

housing provides a pivot for transferring

motion of Sta. 284 bellcrank to the housing.

Clevis ears on end of the swashplate provide

(1). Remove tail rotor hub and fork assem

for connection of pitch control links. Movement

bly (Ref. Sec. 64-20-00).

of Sta. 284 bellcrank shifts the housing axially

on the output shaft of the tail rotor transmis

sion and moves pitch control links inward and

outward to change pitch of tail rotor blades.

NOTE: The manner in which the pitch control

The swashplate is retained in the pitch control

assembly is installed determines rotor-

housing by a washer and locknut.

blade orientation to transmission splined

shaft. Installing rotor blades at 90 degrees

2. Tail Rotor Pitch Control Assembly

to high and low extremes of shaft runout,

Replacement

using reference marks placed on shaft at

time of shaft inspection (Ref. Sec. 63-25-10)

A. Tail Rotor Pitch Control Assembly

reduces chance of high-frequency vibration

Removal

and lessens likelihood of having to reba

(Ref. Figure 203 and Figure 204)

lance tail rotor.

DIRECTION OF PITCH CONTROL

ASSEMBLY WOBBLE ON OUTPUT SHAFT

0.020 IN.

(0.508 MM)

MAX.

BOLT HOLE

PITCH CONTROL

CENTERLINE

ASSEMBLY

0-10 LB (0-50 N)

SPRING SCALE

(NOTE 1)

TWINE

PIVOT

WASHER

(NOTE 2)

NOTES:

FORCE REQUIRED TO SLIDE PITCH CONTROL

ASSEMBLY INWARD OR OUTWARD ON OUTPUT

SHAFT MUST NOT EXCEED THREE POUNDS (13.4 N)

PITCH

WITH PITCH LINKS, BELLCRANK AND RUBBER BOOTS

CONTROL LINK

STA. 284

DETACHED FROM PITCH CONTROL ASSEMBLY.

BELLCRANK

ADD ONE OR TWO AN960KD516 WASHERS AS

G64-3000A

REQUIRED FOR CLEARANCE AT PEDAL FULL STROKE

Figure 201. Pitch Control Assembly − Wobble Check

Page 201

64-30-00

Revision 21

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

0.015 IN. (0.381 MM)

install Sta. 284 bellcrank. Rotate

MIN. CLEARANCE

bellcrank back and forth to align

bellcrank bearing with transmission

arm.

(5). If previously disconnected, reconnect

HOUSING

tail rotor bungee.

SWASHPLATE

3. Tail Rotor Pitch Control Link Replacement

(Ref. Figure 203 and Figure 204)

SWASHPLATE-TO-HOUSING

Consumable Materials

CLEARANCE

G64-3001A

(Ref. Section 91−00−00)

Figure 202. Swashplate−to−Pitch Control

Item

Nomenclature

Housing Clearance

CM318

Primer

(2). Remove Sta. 284 bellcrank from

transmission (Ref. Sec. 67-20-10) so

Prior to removal of pitch control

CAUTION

that pivot pin in bellcrank is disen

links, color-code pitch arm bolt

gaged from self-aligning pivot bearing

and all washers used at each arm. The bolt,

in pitch control housing.

or an identical one, and same combination of

washers must be reassembled at locations

(3). Cut lockwire and pull non-rotating boot

from which removed, or tail rotor balance

from groove in pitch control housing.

can be seriously affected. Do not allow blade

angles to exceed 30 degrees, approximately

(4). Slide pitch control assembly off trans

one inch (2.54 cm), in each direction. Unde

mission output shaft.

tected damage to tension-torsion strap pack

may occur.

B. Tail Rotor Pitch Control Assembly

Installation

(1).

Disconnect ends of pitch control link

(Ref. Figure 203 and Figure 204)

from clevis ear of swashplate and from

blade pitch control arm.

Consumable Materials

(2).

To install, insert either end of pitch

(Ref. Section 91−00−00)

control link between clevis ears of

Item

Nomenclature

swashplate.

CM115

Grease, oscillating bearing

(3).

Install color-coded attaching hardware

CM702

Lockwire CRES

and tighten nut to 30 - 40 inch-

pounds (3.39 - 4.52 Nm); install cotter

pin with wet primer (CM318).

(1). Insert edge of small end of non-rotating

boot into tail rotor transmission

(4).

Pull pitch control assembly inboard or

housing groove. Make certain that

outboard as required to align pitch

drain holes in boot are downward.

control link bearing with pitch control

arm bushing.

(2). Align spline index marks and slide

pitch control assembly on shaft.

(5).

Place special (reduced outside diame

ter) washer and large-diameter spring

(3). Insert non-rotating boot edge into

washer on pitch arm bolt so that

groove of pitch control housing and

concave surface of spring washer is

secure with lockwire (CM702).

against bolt head. With washers in

(4). Apply grease (CM115) to Sta. 284

place on bolt, insert bolt through

bellcrank pivot pin, insert pin into pitch

bearing of pitch control link and

housing self-aligning bearing and

bushing in pitch control arm.

Page 202

Revision 36

64-30-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

PITCH CONTROL

LINK (2) TYPICAL

NUT

PITCH ARM

BOLT (STUD)

SPRING

SPECIAL WASHER

BALANCE WASHER(S)

WASHER

(NOTE 4)

(NOTE 3)

NOTE 1

SPLIT RING

(WIRE SPRING)

TAIL ROTOR

ASSEMBLY

PITCH CONTROL

HINGE

ASSEMBLY (NOTE 5)

BOLT

TRANSMISSION

OUTPUT SHAFT

ROTATING

BOOT

FORK

NOTE 2

FORK BEARING

PITCH ARM

0.255 IN. (6.477 MM)

ORIGINAL THICKNESS

BLADE PITCH ARM

ROOT FITTING

PITCH

0.070 IN. (1.778 MM) MAX. WEAR

CONTROL

ALLOWED 2 PLACES EACH END

LINK

LINK WEAR LIMIT

HUB

0.02 IN. (0.508 MM) MAX.

0.001-0.130 IN.

(0.025-3.302 MM

NOTES:

CENTERLINE TOOTHSPACE MATCHMARK

LINK

SWASHPLATE

MUST ALIGN WITH CENTERLINE TOOTHSPACE

BEARING

HUB-TO-BLADE PITCH

MARK ON FORK WHEN ASSEMBLED ON

ARM-CLEARANCE

OUTPUT SHAFT.

(TYPICAL 2 PLACES)

LINK BEARING AXIAL PLAY

INSTALL WITH WET PRIMER.

QUANTITY (IF ANY) DETERMINED BY BALANCE

REQUIREMENTS.

REDUCE OUTER DIAMETER.

FOR DISASSEMBLY, REFER TO CSP-COM-5.

G64-3002C

Figure 203. Tail Rotor Pitch Control Assembly (Two−Bladed)

Page 203

64-30-00

Revision 21

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

PITCH CONTROL

LINK (2) TYP

COTTER KEY

STATIONARY BOOT

(NOTE 2)

NUT

WASHER

NUT

NOTE 1

WASHER

BOLT

PITCH CONTROL

PITCH

ASSEMBLY (NOTE 5)

CONTROL

PITCH ARM

LINK

ROTATING BOOT

SPLIT RINGS

BLADE PITCH ARM

PITCH CONTROL

LINK (2) TYPICAL

SPECIAL

ROOT FITTING

TAIL ROTOR

WASHER

ASSEMBLY

(NOTE 4)

SPRING

WASHER

PITCH ARM BOLT (STUD)

HUB

BALANCE WASHER(S) (NOTE 3)

NUT

0.001-0.130 IN.

(0.025-3.302 MM

0.02 IN. (0.508 MM) MAX.

HUB-TO-BLADE PITCH

ARM-CLEARANCE

(TYPICAL 2 PLACES)

SWASHPLATE

0.255 IN. (6.477 MM)

ORIGINAL THICKNESS

LINK BEARING AXIAL PLAY

0.070 IN. (1.778 MM) MAX. WEAR

ALLOWED 2 PLACES EACH END

LINK WEAR LIMIT

NOTES:

CENTERLINE TOOTHSPACE MATCHMARK MUST ALIGN WITH CENTERLINE

TOOTHSPACE MARK ON FORK WHEN ASSEMBLED ON OUTPUT SHAFT.

INSTALL WITH WET PRIMER.

QUANTITY (IF ANY) DETERMINED BY BALANCE REQUIREMENTS.

REDUCE OUTER DIAMETER.

G64-3003C

Figure 204. Tail Rotor Pitch Control Assembly (Four−Bladed)

Page 204

Revision 21

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(6). Install washer and nut on end of the

assembly on shaft of tail rotor transmis

bolt that extends through pitch arm.

sion. Note that pitch control links, Sta.

Torque nut to 50 - 60 inch-pounds

284 bellcrank and rubber boots must be

(5.65 - 6.78 Nm); install cotter pin with

detached from the assembly during

wet primer (CM318).

drag check. If drag exceeds three

pounds (13.4 N), remove pitch control

(7). Check for clearance between pitch link

assembly and clean swashplate and

and tail rotor hub pivot bolt.

transmission shaft splines. Use solvent

(CM234) and grade 400 abrasive paper

(8). If removed from pitch arm bolt, install

(CM801) or crocus cloth (CM803). Clean

balance washer(s) of same color code as

again with solvent (CM234) and coat

pitch control arm and secure with nut.

output shaft splines with light film of

grease (CM115).

4. Tail Rotor and Pitch Control Assembly

Repair

(2).

Inspect fork and hub for scratches,

nicks, dents, cracks, corrosion and

(Ref. Figure 203 and Figure 204)

similar surface defects. Check for wear

caused by rubbing of aluminum

Consumable Materials

support. Scratches and nicks that do

(Ref. Section 91−00−00)

not exceed 0.005 inch (0.127 mm)

Item

Nomenclature

depth, 0.120 inch (3.048 mm) depth at

CM801

Abrasive paper, silicon carbide

inside corner of fork, may be repaired

(Ref. COM). Worn areas resulting from

rubbing of aluminum support up to

0.060 inch (1.524 mm) depth may be

Repair allowable surface defects on fork and

repaired (Ref. COM).

hub that may be reworked by using grade 320

abrasive paper (CM801) to round out and

(3).

Check wire-spring split ring halves for

blend defect. Apply exterior surface touchup

damage.

treatment and paint touchup (Ref. Sec.

(4).

If brinelling wear of inner surfaces of

20-30-00). (Repairable damage limits are

swashplate clevis ears is detected, 0.003

defined in the Component Overhaul Manual.)

inch (0.076 mm) depth is allowable

5. Tail Rotor Pitch Control Assembly

without rework or repair. For wear of

Inspection

greater depth, Ref. COM, for limits and

allowable repairs.

(Ref. Figure 203, Figure 204 and Figure 205)

(5).

If there is evidence of swashplate

contact with housing, check that

Consumable Materials

minimum clearance of 0.015 inch (0.381

(Ref. Section 91−00−00)

mm) exists through 360 degrees of

Item

Nomenclature

rotation with axial loading applied. If

CM115

Grease, oscillating bearing

contact is apparent or if axial play can

CM206

Chemical coating

be measured, replace swashplate or

CM234

Solvent, dry-cleaning

bearings (Ref. COM).

CM236

Paint remover

NOTE: Wobble may be accurately measured by

CM721

Tape, aluminum foil

attaching dial indicator support to tail rotor

CM801

Abrasive paper, silicon carbide

drive fork, with indicator probe contacting

CM803

Crocus cloth

swashplate clevis ear. Use care not to allow

pitch control assembly to slide on output

shaft while measuring wobble.

(1). If tail rotor control system drag or

friction is suspected, use spring scale

(6). If pitch control assembly wobbles on

(Ref. Figure 201) to measure drag

transmission output shaft, up to 0.020

(sliding friction) of pitch control

inch (0.508 mm) is allowable. If greater

Page 205

64-30-00

TR12-001

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

amount of wobble is present, replace

from debris and paint remover. Use

swashplate, pitch control housing,

aluminum tape (CM721) that is

bearings (Ref, COM) or the complete

resistant to paint remover.

assembly.

(7). Check that hub-to-blade pitch arm

Extreme care shall be taken to

clearance is 0.001-0.130 inch

CAUTION

prevent debris or paint remover

(0.025-3.302 mm).

contamination in bearing and

bushing areas and tail rotor

(8). Inspect all bolts and nuts for security.

blade bond surfaces and cavit

(9). Inspect boots for installation and

ies.

deterioration.

Failure to comply with the

(c). Remove paint from tail rotor blade

WARNING

following inspection can res

pitch control arm (all four sides and

ult in the pitch control arm separating

the pocket) as shown in Figure 205

from the tail rotor blade. This will lead

with paint remover (CM236). (Ref.

to an unbalanced condition, vibration,

Sec. 20-30-00).

partial loss of tail rotor pitch control

and possible loss of directional control

of the helicopter.

The pitch control arm area is

CAUTION

shot peened and has a protective

(10). For the following tail rotor assemblies

chemical coating. No abrasive

only (Ref Figure 205):

cleaning, sanding or blending is

MDHI P/N 369D21640-501 and -503

allowed.

HTC P/N 500P3100-101

to include “M”, “MT”, “I” and “IT”

MDHI P/N 369D21641-501 and -503

(d).

(Ref. Figure 205 hatched area). Use a

HTC P/N 500P3100-301

bright light and 10X magnifying

to include “M”, “MT”, “I” and “IT”

glass to inspect the tail rotor blade

MDHI P/N 369D21642-501 and -503

pitch control arm (all four sides and

HTC P/N 500P3500-701

the pocket) for corrosion, corrosion

to include “M”, “MT”, “I” and “IT”

pitting or cracks. No corrosion,

MDHI P/N 369D21643-501 and -503

corrosion pitting or cracks are

HTC P/N 500P3300-501

allowed. If corrosion, corrosion

pitting or cracks are present, replace

Inspect pitch horn area for corrosion or

blade assembly before next flight.

evidence of suspect corrosion due to

(Ref. Sec. 64-10-00). Mark the

paint blistering at times specified (Ref.

defective tail rotor blade assembly as

Sec. 05-20-15).

scrap and destroy.

(a). Remove tail rotor blade assembly

(Ref. Sec 64-10-00).

(e).

Make sure the inspection area has a

“dimpled” shot peen surface texture.

Use care when handling pitch

CAUTION

If the inspection area surface is not

bearings. Teflon reinforced lin

shot peened or there is evidence of

ings are easily damaged if mis

blending or material removal that

handled or exposed to contami

affected the shot peened surface,

nants. If lining is damaged or

replace blade assembly before next

contaminated, bearing service

flight. (Ref. Sec. 64-10-00). In

life will be shortened or bearing

addition, check rotorcraft mainten

replacement may be required.

ance records to make sure no rework

(b).

(Ref. Figure 205, Note 2) Carefully

was done in this area. Mark the

tape around bearing, bushing and

defective tail rotor blade assembly as

blade areas to prevent contamination

scrap and destroy.

Page 206

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(f). If no corrosion, corrosion pitting or

(12). Inspect for evidence of rotational

cracks exist and the inspection area

binding by hand-turning tail rotor

has an acceptable shot peen surface

assembly a few turns while listening for

texture, refinish stripped pitch

unusual sounds. If condition is ques

control arm as follows:

tionable, perform applicable inspection.

1). Apply chemical coating (alodine)

(CM206) per instructions con

6. Tail Rotor Blade Stop Inspection

tained in Sec. 20-40-00).

2). Apply primer and paint to match

NOTE: Change of blade pitch angle when tail

original as required (Ref. Sec.

rotor is not rotating can produce audible

20-30-00).

snapping noise. Noise results as lamina

tions of blade strap pack are twisted and

bent without a centrifugal load. Such noise

(g). Install tail rotor blade assembly (Ref

is normal and does not indicate a defect.

Sec. 64-10-00).

(11). Perform following inspections for pitch

(1). Teeter blades back and forth and check

control bearings at times specified (Ref.

for evidence of abnormal binding. Some

Sec. 05-20-00) and when bearing

stiffness is normal, especially when

condition is questionable.

blade stop is newer.

(a).

Remove cotter pin, nut, washers and

bolt securing Sta. 284 bellcrank to

(2). Inspect blade stop for deterioration. Be

transmission. Separate pivot pin on

sure to check for cracking or splitting in

bellcrank from pitch control assem

stem area of stop. Allowable wear for

bly.

rubber stop is to surface of aluminum

support. Stop (and support) may be

(b).

Rotate pitch control housing by hand;

rotated 90 degrees if stop is excessively

check for rough, binding or hard

worn at contact point. Replace rubber

turning. Inspect for grease leakage. If

stop if damaged, or if worn area cannot

any of these conditions exist, remove

be rotated away from contact point.

pitch control assembly and inspect

for further evidence of damage.

NOTE:

If replacement of stop support is re

quired, replace with one-piece stop support

(c).

Check that self-aligning bearing on

and retaining nut.

underside of pitch control housing is

adequately lubricated (packed

approximately 40 percent full) with

(3). Check aluminum support for condition

grease (CM115), is movable and is

and wear. Replace aluminum support if

serviceable.

damaged, or if excessive wear reduces

clearance between tail rotor blade and

(d).

Ensure that pivot pin on Sta. 284

tail boom to less than 0.50 inch (12.70

bellcrank is lubricated with grease

mm) minimum. Measure allowable

(CM115). Position bellcrank to

clearance between tip of tail rotor blade

engage pivot pin with pitch control

and tail boom while holding hub

assembly. Secure bellcrank to trans

against support, and with assistant

mission with bolt, washers, nut and

applying full right tail rotor pedal.

cotter pin.

NOTE: For more detailed information, refer to

NOTE: For any questionable items, refer to

inspection, damage, wear and repair limits,

complete and detailed inspection, damage,

and requirements for pitch control assembly

wear and repair limits, and requirements

(Ref. COM).

for tail rotor assembly in COM.

Page 207

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

7. Tail Rotor Pitch Control Link Inspection

(1). Maximum allowable pitch bearings play

is 0.250 inch (6.350 mm).

Consumable Materials

(Ref. Section 91−00−00)

10. Tail Rotor Swashplate Bearing Regreasing

Item

Nomenclature

CM318

Primer

(Ref. Figure 206)

(1). Maximum axial play for bearing in

pitch control link is 0.020 inch (0.508

Consumable Materials

mm).

(Ref. Section 91−00−00)

Item

Nomenclature

NOTE: Since bearing wear usually occurs only

CM111

Grease, aircraft

at blade pitch control arm from displace

ment during operation, links can be re

CM217

Isopropyl alcohol

versed and continued in service until either

or both bearings exceed wear tolerance.

Special Tools

(2). Replace pitch control link if worn

(Ref. Section 91−00−00)

beyond 0.070 inch (1.778 mm) limit. If

Item

Nomenclature

wear area(s) are within limits, touch-

ST608

Pitch control assembly holding block

up with primer (CM318) and paint (Ref.

Sec. 20-30-00) at inspection.

ST609

Adapter, torque wrench

8. Tail Rotor Conical Bearing Inspection

(1). Remove tail rotor from helicopter (Ref.

(1). Play is not permitted in conical drive

64-20-00, Tail Rotor Hub and Fork

fork bearings (Ref. COM).

Replacement).

9. Tail Rotor Pitch Bearing Inspection

(2). Remove swashplate from helicopter

NOTE: In the following step, physical check for

(Ref. Tail Rotor Pitch Control Assembly

pitch bearing wear that causes root fitting

Replacement).

play on hub can be made by holding one

blade firmly and measuring flapping play at

tip of opposite blade. Measured play indi

(3). Remove pitch control links from

cates combined wear of pitch bearings.

swashplate assembly.

Page 209

64-30-00

TR12-001

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

Tail rotor swashplate bearings

CAUTION

cannot be removed from hous

ing without damage to the bearings. If bear

ings are removed from housing, install new

bearings.

TAIL ROTOR SWASHPLATE

BEARING ASSEMBLY

REGREASE

TOOL

G64-3007

Figure 206. Tail Rotor Swashplate Bearing Regreasing

NOTE: For 4-Bladed tail rotor swashplates,

NOTE: The following procedure provides 100%

holding block (ST608) will need to be modi

grease fill. Normal grease fill is 20 to 40%.

fied. Accomplish modification, or build new

Excess grease will extrude past seals for

block, as per Figure 208.

several hours of operation until the proper

level is met.

(4). Using wrench (ST609) and holding

(8). Purge bearings with grease (CM111).

block (ST608), Remove nut and tang

washer from threaded end of swash

(a). Purge bearings slowly to prevent

plate. Discard tang washer.

damage to outer seal.

(b). Rotate bearings while greasing.

(5). Carefully remove bearing grease seal at

gearbox end of housing (seal will be

(9). Remove plastic wedge (or equivalent

reused at reassembly).

plug) and regreasing tool.

(6). Inspect seal for damage; no damage is

(10). Hand rotate bearing to remove excess

allowed.

grease.

NOTE: Ensure seal is serviceable. If new seal is

(7). Install regreasing tool (Ref. Figure 207)

required, seals and bearings must come

and plug tang washer groove with

from the same vendor.

locally fabricated plastic wedge (or

equivalent plug).

(11). Install serviceable seal.

Page 210

TR12-001

64-30-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

0.75 IN. (19.05 MM)

0.25 IN. (6.35 MM)

1.563-18 UNJS-3B

THREADS PER MIL-S-8879

3.00 IN.

(7.62 CM)

2.25 IN.

(5.715 CM)

MS15002-1 GREASE FITTING

SEAL MATERIAL

1/4-28 TAPER THREADS 0.093 IN.

(2.3622 MM) DIA THRU HOLE

SECTION A-A

0.50 IN.

(12.70 MM)

MATERIAL:

MATERIAL 6061-T651 ALUM PER QQ-A-250/11 OR EQUIVALENT.

SURFACE FINISH 125 RMS.

BREAK SHARP EDGES 0.002-0.015 IN. (0.051-0.381 MM).

CHEMICAL FILM TREAT PER MIL-C-5541.

DIMENSIONAL TOLERANCE ±.030 IN. (±0.762 MM); DIAMETERS TO BE

G64-3006A

Figure 207. Tail Rotor Swashplate Bearing Regreasing Tool

NOTE: Using a 5X to 10X magnifying glass, in

(14). Clean surface of locknut and swash

spect tang washer center tang to ensure it is

plate with a lint-free cloth dampened

acceptable (Ref. Figure 209).

with alcohol (CM217).

(12). Install nut with a new tang washer.

NOTE: Avoid getting torque seal in swashplate

Using wrench (ST609) and holding

splines.

block (ST608), torque nut to 550 - 600

inch-pounds (62.14 - 67.79 Nm).

(15). Apply a 0.125 inch (3.175 mm) wide

torque strip, using torque seal or

(13). Bend one tang of washer into any

equivalent, to surface of swashplate

aligned slot on nut.

assembly and locknut in two places

NOTE: Avoid getting alcohol in bearings.

(Ref. Figure 209).

Page 211

64-30-00

TR12-001

MD Helicopters, Inc.

CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS

Para/Figure/Table

Title

Page

67-00-00 Flight Controls (369D/E/FF - 500/600N)

Fault Isolation

101

1. Main Rotor Flight Control System Troubleshooting

101

2. Anti-Torque Flight Controls

101

3. Anti-Torque and Control System Troubleshooting

101

4. Stability Augmentation System Troubleshooting

101

Table 101. Troubleshooting Main Rotor Controls

102

Table 102. Isolating Main Rotor Control System Troubles

103

Table 103. Isolating Tail Rotor Control System Troubles

104

Table 104. Anti-torque Fan System Troubleshooting

104

Figure 101. YSAS Electrical Diagram (Sheet 1 of 2)

105

Figure 102. YSAS Troubleshooting (Sheet 1 of 4)

107

Figure 103. YSAS Ground Test Box

111

67-10-00 Main Rotor Flight Controls (369D/E/FF - 500/600N)

Description and Operation

Main Rotor Flight Controls

A. Collective Mixer, Lateral and Longitudinal Mixer (Tunnel-Routed)

Control Rods

B. Controls Support Bracket and Bellcranks

C. Collective Controls

D. Pilot's Collective Pitch Stick

E. Copilot's Collective Pitch Stick

F. Collective Pitch Stick Friction

G. Collective Control Interconnecting Torque Tube

H. Collective Bungee

I. Inboard Collective Stick Socket Assembly

J. Cyclic Controls

K. Pilot's Cyclic Control Stick

L. Copilot's Cyclic Control Stick

M. Pilot's Compartment Lateral and Longitudinal Cyclic Control Linkage

N. One-Way Lock Control System

O. Cyclic Trim Actuators

P. Roof-Mounted Control Rods (600N)

Q. Roof-Mounted Bellcranks (600N)

Figure 1. Main Rotor and Control System (369D/E/FF - 500N)

Figure 2. Main Rotor and Control System (600N)

Page i

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MD Helicopters, Inc.

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

Removal/Installation

401

Tunnel-Routed Control Rod Replacement

401

A. Tunnel-Routed Control Rod Removal

401

B. Tunnel-Routed Control Rod Installation

401

Roof-Mounted Control Rod Replacement (600N)

401

A. Roof-Mounted Control Rod Removal (600N)

401

Figure 401. Tunnel-Routed Control Rod Installation

402

Figure 402. Roof-Mounted Controls Installation

403

B. Roof-Mounted Control Rod Installation (600N)

403

Roof-Mounted Bellcrank Replacement (600N)

403

A. Roof-Mounted Bellcrank Removal (600N)

403

B. Roof-Mounted Bellcrank Installation (600N)

404

Link Assembly Replacement (600N)

404

A. Link Assembly Removal (600N)

404

B. Link Assembly Installation (600N)

404

Controls Support Bracket and Bellcrank Replacement

404

A. Controls Support Bracket and Bellcrank Removal

404

Figure 403. Controls Support Bracket, Idler Bellcranks and Cyclic Trim

Actuators Installation

405

B. Controls Support Bracket and Bellcrank Installation

406

Pilot's Collective Pitch Stick Replacement (L/H Command)

406

A. Pilot's Collective Pitch Stick Removal (L/H Command)

406

Figure 404. Dual Collective Controls (L/H Command)

407

B. Pilot's Collective Pitch Stick Installation (L/H Command)

408

Pilot's Collective Pitch Stick Replacement (R/H Command)

408

A. Pilot's Collective Pitch Stick Removal (R/H Command)

408

B. Pilot's Collective Pitch Stick Installation (R/H Command)

408

Figure 405. Dual Collective Controls (R/H Command)

409

Copilot's Collective Pitch Stick Replacement (L/H Command)

410

A. Copilot's Collective Pitch Stick Removal (L/H Command)

410

B. Copilot's Collective Pitch Stick Installation (L/H Command)

410

Figure 406. CoPilot's Collective Stick Assembly Installation (L/H Command)

410

Copilot's Collective Pitch Stick Replacement (R/H Command)

411

A. Copilot's Collective Pitch Stick Removal (R/H Command)

411

B. Copilot's Collective Pitch Stick Installation (R/H Command)

411

Page ii

Revision 42

67 Contents

MD Helicopters, Inc.

CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

10. Collective Control Interconnecting Torque Tube Replacement

411

A. Collective Control Interconnecting Torque Tube Removal

411

B. Collective Control Interconnecting Torque Tube Installation

412

11. Collective Bungee Replacement

412

A. Collective Bungee and Over-Center Fitting - Removal

412

Figure 407. Collective Torque Tube, Gas Producer Torque Tube and

Collective Bungee

413

Figure 408. Inboard Collective Stick Socket Assembly (L/H Command)

414

B. Collective Over-Center Fitting and Bungee - Installation and

Preliminary Adjustment

415

12. Inboard Collective Stick Socket Assembly Replacement

415

A. Inboard Collective Stick Socket Assembly Removal

415

B. Inboard Collective Stick Socket Assembly Installation

415

13. Cyclic Control Stick Replacement (Inboard)

416

A. Cyclic Control Stick Removal (Inboard)

416

B. Cyclic Control Stick Installation (Inboard)

416

Figure 409. Cyclic Stick Assembly Installation (Inboard)

417

14. Cyclic Control Stick Replacement (Outboard)

417

A. Cyclic Control Stick Removal (Outboard)

417

B. Cyclic Control Stick Installation (Outboard)

417

Figure 410. Cyclic Stick Assembly Installation (Outboard)

418

15. Lateral Control Rods and Sta. 67 Lateral Cyclic Bellcrank Replacement

(L/H Command)

418

A. Lateral Control Rods and Sta. 67 Lateral Cyclic Bellcrank Removal

(L/H Command)

418

B. Lateral Control Rods and Sta. 67 Lateral Cyclic Bellcrank Installation

(L/H Command)

418

Figure 411. Cyclic Controls (R/H Command)

419

16. Lateral Control Rods and Sta. 67 Lateral Cyclic Bellcrank Replacement

(R/H Command)

420

A. Lateral Control Rods and Sta. 67 Lateral Cyclic Bellcrank Removal

(R/H Command)

420

B. Lateral Control Rods and Sta. 67 Lateral Cyclic Bellcrank Installation

(R/H Command)

420

17. Cyclic Pitch Interconnecting Torque Tube Replacement (L/H Command)

420

A. Cyclic Pitch Interconnecting Torque Tube Removal (L/H Command)

420

Figure 412. Cyclic Torque Tube and One-Way Lock Installation

421

B. Cyclic Pitch Interconnecting Torque Tube Installation (L/H Command)

422

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Revision 42

CSP−HMI−2

MD Helicopters, Inc.

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

18. Cyclic Pitch Interconnecting Torque Tube Replacement (R/H Command)

422

A. Cyclic Pitch Interconnecting Torque Tube Removal (R/H Command)

422

B. Cyclic Pitch Interconnecting Torque Tube Installation (R/H Command)

422

19. One-Way Lock Replacement

422

A. One-Way Lock Removal

422

B. One-Way Lock Installation

423

20. Cyclic Trim Actuator Replacement

423

A. Cyclic Trim Actuator Removal

423

B. Cyclic Trim Actuator Installation

423

Adjustment/Test

501

Cyclic and Collective Control System Rigging

501

Collective Controls Rigging (L/H Command) (369D/E/FF - 500N)

501

Figure 501. Main Rotor Control System Rigging (369D/E/FF - 500N)

(Sheet 1 of 3)

502

Figure 502. Rigging Main Rotor Control System (600N) (Sheet 1 of 3)

505

Figure 503. Cyclic and Collective Controls Rigging Tools (R/H Command)

508

Collective Controls Rigging (R/H Command) (369D/E/FF - 500N)

509

Collective Control System Rigging (L/H Command) (600N)

509

Collective Controls Rigging (R/H Command) (600N)

510

Cyclic Controls Rigging (L/H Command) (369D/E/FF - 500N)

510

Cyclic Controls Rigging (R/H Command) (369D/E/FF - 500N)

513

Cyclic Controls Rigging (L/H Command) (600N)

513

Cyclic Controls Rigging (R/H Command) (600N)

515

10.

Gas Producer Linkage Adjustment

515

Figure 504. Gas Producer Drive Backlash Adjustment

(Outboard Collective Stick)

516

Figure 505. Gas Producer Drive Backlash Adjustment

(Inboard Collective Stick)

517

11.

Pipe Plug Adjustment

518

12.

Gas Producer Interconnecting Torque Tube Assembly Shimming

(0003D thru 0929D)

518

Figure 506. Gas Producer Interconnecting Torque Tube Shimming Procedure

(0003D thru 0929D) (Sheet 1 of 2)

519

13.

Collective Stick Friction Mechanism Adjustment

521

Figure 507. Collective Stick Friction Adjustment

522

14.

Collective Bungee Adjustment

523

15.

Cyclic Trim Actuator Bench Testing (369D/E/FF - 500N)

524

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Revision 42

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MD Helicopters, Inc.

CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

16. Cyclic Trim Actuator Bench Testing (600N)

525

Figure 508. Cyclic Trim Actuator Assembly

527

Figure 509. Cyclic Trim Wiring Diagram

528

Figure 510. Wiring Diagram and Cable Routing (Collective Stick)

529

Figure 511. Wiring Diagram and Cable Routing (Cyclic Stick)

530

Inspection/Check

601

1. Tunnel-Routed Control Rod Inspection

601

Figure 601. Tunnel-Routed Control Rod Inspection

602

2. Controls Support Bracket and Bellcrank Inspection

603

3. Pilot's Collective Pitch Stick Inspection

603

4. Copilot's Collective Pitch Stick Inspection

603

5. Collective Stick Friction Mechanism Operational Check

603

Figure 602. Outboard Collective Stick Inspection (L/H Command)

604

Figure 603. Outboard Collective Stick Inspection (R/H Command)

605

6. Collective Control Interconnecting Torque Tube Inspection

606

7. Collective Bungee Inspection

606

8. Inboard Collective Stick Socket Assembly Inspection

606

9. Pilot's Cyclic Control Stick Inspection

606

10. Copilot's Cyclic Control Stick Inspection

607

11. One-Way Lock Inspection

607

12. Cyclic Trim Actuator Inspection

607

13. Cyclic Control System Operational Check

607

Figure 604. Cyclic Stick and Friction Inspection

608

14. Main Rotor Flight Control System 600-Hour Inspection

609

Repairs

801

1. Tunnel-Routed Control Rod Repair

801

2. Tunnel-Routed Control Tube Inspection and Sleeve Installation

801

A. Control Tube End Sleeve Installation

801

Figure 801. Sleeve Fabrication and Installation

802

Table 801. Control Tube Re-Identification

803

B. Control Tube Straight Area Sleeve Installation

804

Table 802. Control Tube Straight Area Repair Limits

804

3. Controls Support Bracket and Bellcrank Disassembly

805

4. Controls Support Bracket and Bellcrank Repair

805

5. Controls Support Bracket and Bellcrank Reassembly

805

6. Pilot's Collective Pitch Stick Disassembly (L/H Command)

805

Figure 802. Control Tube Boot Rework

806

Page v

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Revision 42

CSP−HMI−2

MD Helicopters, Inc.

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

Pilot's Collective Pitch Stick Repair (L/H Command)

806

Pilot's Collective Pitch Stick Reassembly (L/H Command)

807

Pilot's Collective Pitch Stick Disassembly (R/H Command)

808

10.

Pilot's Collective Pitch Stick Reassembly (R/H Command)

808

11.

Copilot's Collective Pitch Stick Disassembly (L/H and R/H Command)

809

12.

Copilot's Collective Pitch Stick Repair

809

13.

Copilot's Collective Pitch Stick Reassembly

809

14.

Collective Control Interconnecting Torque Tube Repair

810

15.

Collective Bungee Disassembly

811

16.

Collective Bungee Reassembly

811

17.

Inboard Collective Stick Socket Assembly Disassembly

811

18.

Inboard Collective Stick Socket Assembly Repair

812

19.

Inboard Collective Stick Socket Assembly Reassembly

812

20.

Cyclic Control Stick Repair

813

21.

Cyclic Friction Mechanism Repair

813

22.

Lateral Control Rods and Sta. 67 Bellcrank Repair

813

23.

Cyclic Pitch Interconnecting Torque Tube Repair

814

24.

One-Way Lock Repair

814

25.

Cyclic Trim Actuator Spring Assembly Replacement

814

26.

Cyclic Trim Actuator Housing or Trim Tube Replacement

815

27.

Cyclic Trim Actuator (Motor/Gear Drive Mechanism) Replacement

815

28.

Cyclic Trim Actuator Rework (Calco P/N 8222M6 and 8222M7)

815

67-10-20 Collective and Cyclic Stick Grips (369D/E/FF - 500/600N)

Maintenance Practices

201

1. Collective Pitch Stick Switches

201

2. Collective Pitch Stick Switches Replacement

201

3. Cyclic Stick Grip Switches

201

4. Cyclic Control Stick Grip Replacement

201

A. Cyclic Control Stick Grip Removal

201

B. Cyclic Control Stick Grip Installation

201

Figure 201. Collective Pitch Stick Switch Replacement

202

Figure 202. Cyclic Stick Grips

203

Figure 203. Cyclic Stick Grip Disassembly (Sheet 1 of 2)

204

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Revision 42

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MD Helicopters, Inc.

CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

5. Cyclic Stick Grip Switch Replacement (Standard Grip)

206

6. Cyclic Stick Grip Disassembly (Optional T-Grip, PN 369D297846 Only)

207

7. Cyclic Stick Grip Reassembly and Modification

207

Figure 204. Rework of Cyclic Stick Grip

208

67-20-10 Anti-Torque Flight Controls (Two and Four Blade) (369D/E/FF)

Description and Operation

1. Tail Rotor Control Configuration

2. Upper Fuselage and Tailboom Control Linkage

Figure 101. Tail Rotor and Control System

Removal/Installation

401

Sta. 120 Control Rod or Sta. 142 Bellcrank Replacement

401

A. Sta. 120 Control Rod or Sta. 142 Bellcrank Removal

401

B. Sta. 120 Control Rod or Sta. 142 Bellcrank Installation

401

Figure 401. Upper Fuselage and Boom Tail Rotor Control Linkage

402

Sta. 284 Bellcrank Replacement

403

A. Sta. 284 Bellcrank Removal

403

B. Sta. 284 Bellcrank Installation

403

Tailboom Control Rod Replacement

403

A. Tailboom Control Rod Removal

403

B. Tailboom Control Rod Installation

403

Sta. 95 Bellcrank and Support Replacement

403

A. Sta. 95 Bellcrank and Support Removal

403

Figure 402. Tail Rotor Pedal Installation (Sheet 1 of 2)

404

B. Sta. 95 Bellcrank and Support Installation

405

C. Tail Rotor Pedal Assembly - General

405

D. Co-Pilot's Pedal Installation

406

Tail Rotor Pedal Assembly Replacement

406

A. Tail Rotor Pedal Assembly Removal

406

B. Tail Rotor Pedal Assembly Installation

406

Dual Tail Rotor Pedal Initial Installation

407

Adjustment/Test

501

1. Tail Rotor Controls Rigging

501

Figure 501. Rigging - Tail Rotor Control System

502

2. Tail Rotor Bungee Adjustment

503

Figure 502. Tail Rotor Bungee Adjustment

504

Page vii

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Revision 42

CSP−HMI−2

MD Helicopters, Inc.

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

Inspection/Check

601

1. Upper Fuselage and Tailboom Control Linkage Inspection

601

2. Tail Rotor Pedal Assembly Inspection

601

Table 601. Isolating Control System Troubles

602

Repairs

801

1. Floor- and Tunnel-Routed Control Rods

801

2. Floor-Routed Tail Rotor Control Rod Repair

801

3. Upper Fuselage and Tailboom Control Linkage Repair

801

Figure 801. Rework of Sta. 142 Bellcrank Assembly

803

4. Station 78.50 Tail Rotor (Tunnel-Routed) Control Rod

803

A. Tail Rotor Idler Bellcrank

803

5. Tail Rotor Pedal Disassembly

803

6. Tail Rotor Pedal Repair

803

7. Tail Rotor Pedal Reassembly

804

8. Tail Rotor Bungee Spring Forward Attachment Relocation

804

Figure 802. Relocation of Tail Rotor Bungee Spring Forward Attachment

805

67-20-30 NOTAR) Anti-Torque System Flight Controls (500/600N)

Description and Operation

1. NOTAR Anti-Torque System Control Linkages Configuration and Description . .

2. Stability Augmentation System Description and Operation

500NM7301 YSAS Fin Position Indicator (U.K. Only)

Table 1. 500NM7301 YSAS Fin Position Indicator Components

Removal/installation

401

1. Anti-Torque Flight Controls

401

2. Upper Fuselage Sta. 97.50 (500N) or Sta. 95 (600N) Bellcrank and Support Bracket

Replacement

401

A. Sta. 97.50 (500N) or Sta. 95 (600N) Bellcrank and Support Bracket Removal .

401

B. Sta. 97.50 (500N) or Sta. 95 (600N) Bellcrank and Support Bracket

Installation

401

3. Forward Directional Control Tube Replacement

401

A. Forward Directional Control Tube Removal

401

B. Forward Directional Control Tube Installation

401

Page viii

Revision 42

67 Contents

MD Helicopters, Inc.

CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

Splitter Bungee Spring Replacement (500N)

401

A. Splitter Bungee Spring Removal

402

B. Splitter Bungee Spring Installation

402

Upper Fuselage Station 113.00 Splitter Assembly and Bellcrank Replacement . .

402

A. Station 113.00 Splitter Assembly and Bellcrank Removal

402

B. Station 113.00 Splitter Assembly and Bellcrank Installation

402

Intermediate Control Tube Replacement

402

A. Intermediate Control Tube Removal

402

Figure 401. Anti-Torque Control System

403

B. Intermediate Control Tube Installation

404

Station 137.50 Support Bracket and Bellcrank Replacement

404

A. Station 137.50 Support Bracket and Bellcrank Removal

404

B. Station 137.50 Support Bracket and Bellcrank Installation

404

Fan Pitch Control Tube Replacement

405

A. Fan Pitch Control Tube Removal

405

B. Fan Pitch Control Tube Installation

405

Forward Cable Assembly Replacement

406

A. Forward Cable Assembly Removal

406

Figure 402. Upper Fuselage and Boom Control Linkage (Sheet 1 of 2)

407

B. Forward Cable Assembly Installation

409

10. Center Cable Assembly Replacement

409

A. Center Cable Assembly Removal

409

B. Center Cable Assembly Installation

410

11. Aft Control Rod Assembly Replacement

410

A. Aft Control Rod Assembly Removal

410

B. Aft Control Rod Assembly Installation

410

12. Sector Assembly and Control Cable Replacement

411

A. Sector Assembly and Control Cable Removal

411

B. Sector Assembly and Control Cable Installation

411

13. Drum Assembly and Idler Pulley Replacement

411

A. Drum Assembly and Idler Pulley Removal

411

B. Drum Assembly and Idler Pulley Installation (500N)

412

C. Drum Assembly and Idler Pulley Installation (600N)

412

Page ix

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Revision 42

CSP−HMI−2

MD Helicopters, Inc.

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

14. Anti-Torque Pedal Friction Replacement

412

A. Anti-Torque Pedal Friction Removal

412

B. Anti-Torque Pedal Friction Installation

412

15. Anti-Torque Pedal Assembly Replacement

412

A. Anti-Torque Pedal Assembly Removal

412

Figure 403. Pedal Installation (Sheet 1 of 2)

413

B. Anti-Torque Pedal Assembly Installation

414

16. Stability Augmentation System (S.A.S.) Actuator Replacement

415

A. S.A.S. Actuator Removal

415

B. S.A.S. Actuator Installation

415

17. S.A.S. Rate Gyro and Electronic Control Box (Computer) Replacement

415

A. S.A.S. Rate Gyro and Electronic Control Box (Computer) Removal

416

B. S.A.S. Rate Gyro and Electronic Control Box (Computer) Installation

416

Adjustment/Test

501

1. Directional Controls Rigging

501

2. Fan Pitch Control Rigging

501

Figure 501. Fan Pitch Control Rigging

502

3. Pilot Pedal Rigging

503

Figure 502. Pilot Pedal Rigging

504

4. Anti-Torque Pedal Friction Installation and Adjustment

505

5. Thruster Control Rigging (500N)

505

Figure 503. Thruster Control Rigging (Sheet 1 of 2)

506

6. Thruster Control Rigging (600N)

508

7. Left Vertical Stabilizer Assembly Rigging (500N, and 600N with YSAS)

508

8. Stability Augmentation System Rigging Instructions

(500N, and 600N with YSAS)

509

9. Vertical Stabilizer Assembly Rigging (600N without YSAS System)

509

Figure 504. Left Vertical Stabilizer Rigging (500N, and 600N with YSAS)

510

Figure 505. Stability Augmentation System S.A.S. (Sheet 1 of 2)

511

Figure 506. Vertical Stabilizer Rigging (600N without YSAS)

513

Page x

Revision 42

67 Contents

MD Helicopters, Inc.

CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

10. Vertical Stabilizer Trim Tab Adjustment and Tool Manufacturing

(600N without YSAS)

514

A. Trim Tab Tool Manufacturing

514

B. Trim Tab Adjustment

514

Figure 507. Vertical Stabilizer Trim Tab Bending Tool

515

Table 501. Flight Controls Troubleshooting

516

Inspection/Check

601

1. Upper Fuselage and Tailboom Control Linkage Inspection

601

2. Anti-Torque Pedal Assembly Inspection

601

3. Sta. 97.50 (500N) or Sta. 95 (600N) Bellcrank and Support Bracket Inspection . .

601

4. Forward and Intermediate Directional Control Tube, and Link Inspection

601

5. Splitter Bungee Spring Inspection (500N)

602

6. Sta. 113.00 Splitter Assembly and Bellcrank Inspection

602

7. Forward and Center Cable Assembly Inspection

602

8. YSAS Actuator, Rate Gyro and Electronic Control Box Inspection

602

9. Fan Pitch Control Tube Inspection

602

Table 601. Isolating Control System Troubles

603

Figure 601. Control Cable Coupling Inspection

603

Figure 602. Forward and Center Cable Relief Area Inspection

604

Figure 603. Control Cable Telescopic Swivel End Inspection

605

10. Sector Assembly, Control Cables and Drum Assembly Inspection

606

Repairs

801

1. Anti-Torque Flight Control Repair - General

801

2. Sta. 97.50 (500N) or Sta. 95 (600N) Bellcrank and Support Bracket Repair

801

3. Forward Directional Control Tube Repair

801

4. Upper Fuselage Sta. 113.00 Splitter Assembly Repair

801

5. Intermediate Control Tube Repair

801

6. Sta. 137.50 Support Bracket and Bellcrank Repair

802

7. Fan Pitch Control Tube Repair

802

8. Forward Cable Assembly Repair

802

9. Center Cable Assembly Repair

802

Page xi

67 Contents

Revision 42

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

FLIGHT CONTROLS

FAULT ISOLATION

1. Main Rotor Flight Control System

tube, tunnel-routed control tube, Sta. 120

Troubleshooting

control tube and tail boom control rod trans

mitting input through a series of bellcranks

Ensure that rotor controls are

and idlers.

CAUTION

not struck by any object. Many

of the components are highly stressed and

3. Anti−Torque and Control System

must not be returned to service if surface

Troubleshooting

damage occurs. When maintenance work is

performed near engine air inlet, comply

Troubleshooting information is divided into (1)

with precautions (Ref. Chap. 71) to prevent

investigation of operational vibration problems

entry of foreign objects.

originating with the tail rotor or symptoms

that can be recognized (Ref. Chap. 64) and (2)

Troubleshooting information is divided into: (1)

isolation and localization of an unusual

investigation of main rotor vibrations (Ref.

controls malfunction (Ref. Table 103 or

Chap. 62); (2) investigation of symptoms (Ref.

Table 104).

Table 101); and (3) isolation of troubles (Ref.

Table 102).

4. Stability Augmentation System

Troubleshooting

First determine which major installation is

defective. Isolate each linkage installation

Troubleshooting the Yaw Stability Augmenta

from others until area of malfunction is

tion System (YSAS) shall be performed using

located. Then investigate and determine exact

the wiring diagram (Ref. Figure 101) in

location of malfunction and repair or replace

conjunction with the fault isolation tree (Ref.

defective component(s). Since first indication of

Figure 102) and the ground test box (Ref.

trouble usually is felt at cyclic or collective

Figure 103).

pitch stick, isolation procedures in Table 101

and Table 102 begin with symptoms detected

Troubleshooting the YSAS by field mainte

during operation of these controls.

nance personnel shall be limited to isolating

the trouble to a malfunctioning or defective

Sudden onset of excessive

system unit/component.

WARNING

and/or unusual main rotor

vibrations should be investigated as to

For removal or replacement of YSAS compo

cause, prior to continued flight. Under

nents refer to applicable section.

no circumstance should main rotor

Death or injury can occur if

tracking be attempted to correct the

WARNING

proper safety precautions

problem until a thorough inspection of

are not taken while performing electri

the main rotor blades, hub assembly

cal system checks with electrical pow

and strap pack assembly has been per

er on.

formed.

Maintenance personnel other

2. Anti−Torque Flight Controls

CAUTION

than approved manufacturer's

Anti-Torque flight controls consist of anti-tor

representative shall not attempt to repair

que pedals, torque tube, floor-routed control

any part of the YSAS system.

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MAINTENANCE MANUAL

Table 101. Troubleshooting Main Rotor Controls

Symptom

Probable Trouble

Corrective Action

Cyclic stick pressure in one

Check for continuity between pin S

If continuity exists, replace cyclic trim

direction; hands off condition −

and pins R, U, V, and X of

switch, Cyclic Stick Grip Switch

stick drifts in direction of

connector(s) P109 and/or P130.

Replacement (Standard Grip).

pressure.

Symptom remains.

Isolate wiring to circuit components.

If short exists, repair as necessary. If

Check for short circuit between ground

short does not exist, replace cyclic trim

and suspect trim mode circuit.

actuator.

Cyclic control stick pressures

Trim actuator inoperative.

Replace actuator.

cannot be reduced by

Defective components in trim actuator

Troubleshoot control circuits: replace

operating trim switch.

control circuit.

defective electrical component(s).

Trim change is too slow.

Defective trim actuator.

Replace actuator.

Cyclic control sticks have

Low fluid in one−way lock fluid

Add fluid to one−way lock reservoir.

tendency to move to aft

reservoir.

position.

Inadequate cyclic control

Helicopter loaded out of center of

Check and correct weight and

during flight.

gravity range.

balance.

Incorrect cyclic rigging.

Correct cyclic rigging.

Excessive pressure required

Lateral and/or longitudinal friction

Loosen lateral and/or longitudinal

for lateral and/or longitudinal

device improperly adjusted.

friction device.

movement of cyclic control

Swashplate spherical bearing surface

Replace swashplate bearing assembly

stick on ground and during

damaged.

if torque required to rotate bearing

flight. (Some droop friction is

exceeds 32 inch−pounds (3.61 Nm).

always felt when there is no

rotor rpm.)

Scissors crank bearings or hub lower

Replace defective bearings.

shoe bearings binding or frozen.

Lateral and/or longitudinal

Realign rod end bearing.

interconnecting rod end bearing

binding due to incorrect alignment.

Droop stop plungers sticking.

Clean plungers and mating shoe

bushings with isopropyl alcohol

(CM217).

Droop stop followers, rollers and/or

Apply rust inhibitor and lubricants

stop ring rusty or corroded.

(CM204) to followers, rollers and

droop stop ring.

Droop stop striker plate(s) or cam

Replace striker plate and/or cam roller.

roller(s) damaged.

One−way lock check valve, or push

Replace one−way lock assembly.

rod shaft that unseats the valve, is

galled or seized.

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MAINTENANCE MANUAL

Table 102. Isolating Main Rotor Control System Troubles

Symptom

Isolating Step

Corrective Action

Binding, locking−up and

Disconnect one−way lock.

If symptom gone, replace one−way

erratic action of cyclic control

lock.

stick.

Symptom remains.

Disconnect upper ends of longitudinal

If symptom gone and rod ends are

and lateral control rods.

serviceable, disassemble and inspect

main rotor mixer controls until

defective part is located.

Symptom remains.

Reconnect upper ends of longitudinal

If symptom gone and rod ends are

and lateral control rods, and

serviceable, disassemble and inspect

disconnect lower ends.

pilot compartment controls until

defective part is located.

Trouble corrected (Reconnect all control linkage).

Binding, locking−up and

CAUTION: Before disconnecting collective pitch control rod, install collective

erratic action of collective

bungee installation tool (ST508) to prevent spring reaction on control rod.

control stick.

Disconnect upper end of collective

If symptom gone and rod end is

pitch control rod and operate stick.

serviceable, disassemble and inspect

main rotor mixer controls until

defective part is located.

Symptom remains.

Leave upper end of collective pitch

Trouble is in pilot compartment

control rod disconnected.

collective control linkage.

Symptom remains.

WARNING: Do not disconnect any hardware from pilot‘s collective stick unless

collective bungee installation tool (ST508) is installed. Strong bungee spring

pressure can cause linkage reaction and severe personal injury, or parts

damage.

Disconnect gas producer control rod

If symptom gone, trouble is in engine

from collective stick. Disconnect droop

controls.

control override link from collective

controls torque tube.

Symptom remains.

Leave gas producer control rod and

Disassemble and inspect pilot

droop control override link

compartment collective control linkage

disconnected.

until defective part is located.

Trouble corrected (Reconnect all control linkage)

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MAINTENANCE MANUAL

Table 103. Isolating Tail Rotor Control System Troubles

Symptom

Isolating Step

Corrective Action

Binding, locking up and erratic

Disconnect pitch control links from

If symptom gone, replace tail rotor

action of foot pedals. (Do not

pitch control assembly.

assembly or repair (Ref. COM).

force controls)

Symptom remains.

Disconnect Sta. 284 aft boom

If symptom gone, clean swashplate

bellcrank from pitch control assembly.

bore and output shaft splines.

Lubricate splines. Replace swashplate

if necessary. Check for elongation of

bolt hole in support arm portion of

main housing assembly of tail rotor

gear box, caused by looseness of

bellcrank fulcrum bolt and nut. Repair

(Ref. COM).

Symptom remains.

Disconnect floor−routed tail rotor

If symptom gone, inspect tail rotor

control rod from foot pedal torque tube

control rods and bellcranks until

fitting.

defective part is located.

Symptom remains.

Loosen foot pedal torque tube

If symptom gone, pedal torque tube

brackets mounted on front of floor

misaligned; shim for correct alignment.

structure.

If symptom remains, disassemble and

inspect tail rotor foot pedal installation

until defective part is located (same

section).

Trouble corrected.

Table 104. Anti−torque Fan System Troubleshooting

Symptom

Probable Trouble

Corrective Action

Excessive resistance against Binding in controls linkage.

Isolate damage or obstruction and

pedal movements.

remove.

Restriction against rotating cone.

Isolate restriction or damage and

remove.

Binding, locking up or erratic

Control rod or cable restrictions or

Inspect control rod and control cable

action of pedal movement.

misalignment.

connections, rod end condition and

bearing movement, replace

components as required.

Pedals feel rachety.

Flat spotting on thruster rollers.

Replace rollers (Ref. Sec. 53−40−30).

Degraded movement or

Restriction or malfunction at splitter

Inspect splitter range and freedom of

response of fan control

assembly.

movement.

linkage.

Degraded travel of force limiting

Isolate damage or malfunction and

control rod or diffuser bellcrank

replace components.

connections.

Incorrect rigging.

Correct rigging.

Inadequate anti−torque/direc-

Incorrect rigging.

Correct rigging.

tional movement or response

during flight.

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MAINTENANCE MANUAL

START

VERIFY ALL YSAS SYSTEM ASSOCIATED

ELECTRICAL CONNECTORS ARE MATED WITH

COMPONENTS. VERIFY CIRCUIT BREAKER IS

GO TO SHEET 2

PUSHED IN AND YSAS SYSTEM ON/OFF SWITCH IS

ON. IS YSAS STILL INOPERATIVE?

YES

SHUT OFF ELECTRICAL POWER. CHECK FOR

REPAIR OPEN WIRE(S) BETWEEN PIN B

CONTINUITY TO A/C GROUND AT PINS B, E AND

OF SAS COMPUTER AND GROUND

C OF SAS COMPUTER PLUG (P1 FOR 500N: P512

E40-B OR PIN E AND GROUND E40-A

FOR 600N). DOES CONTINUITY EXIST?

OR PIN C AND GROUND E31-S.

YES

SHUT OFF ELECTRICAL POWER. DISCONNECT

REPAIR OPEN WIRE BETWEEN PIN M

SAS COMPUTER PLUG (P1 FOR 500N: P512 FOR

OF SAS COMPUTER AND CB121.

600N). REAPPLY ELECTRICAL POWER AND

CHECK FOR 28 VDC AT PIN M. IS VOLTAGE

PRESENT?

YES

DISCONNECT ELECTRICAL POWER. CONNECT

SAS TEST BETWEEN SAS COMPUTER AND SAS

WIRE HARNESS. REAPPLY ELECTRICAL POWER

REPLACE FAULTY SAS COMPUTER

AND AT SAS TEST BOX, CHECK FOR +15 VDC

AND -15 VDC COMING FROM COMPUTER

POWER SUPPLY. IS VOLTAGE PRESENT?

YES

REMOVE YAW RATE GYRO ATTACHING HARDWARE

AND CAREFULLY ROTATE GYRO IN A CLOCKWISE

DIRECTION. CHECK RIGHT VERTICAL STABILIZER FOR

GO TO SHEET 3

TRAILING EDGE LEFT (INITIAL MOVEMENT ONLY). DOES

RIGHT VERTICAL STABILIZER MOVE?

YES

REMOVE SAS COMPUTER ATTACHING HARDWARE

AND CAREFULLY TILT COMPUTER, CONNECTOR

SIDE UP, CHECK RIGHT VERTICAL STABILIZER

GO TO SHEET 4

TRAILING EDGE RIGHT MOVEMENT. DOES RIGHT

VERTICAL STABILIZER MOVE?

YES

YAW SAS SYSTEM APPEARS TO OPERATE

CORRECTLY.

G67-2017-1A

Figure 102. YSAS Troubleshooting (Sheet 1 of 4)

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MAINTENANCE MANUAL

FROM SHEET 1

DOES RIGHT VERTICAL STABILIZER MOVE OR

YAW SAS SYSTEM APPEARS TO

OSCILLATE WITH NO SENSOR INPUTS?

OPERATE CORRECTLY.

YES

SHUT OFF ELECTRICAL POWER. CONNECT SAS

SHUT OFF ELECTRICAL POWER. CHECK

REPAIR OPEN WIRES BETWEEN YSAS

TEST BOX BETWEEN SAS COMPUTER AND SAS

FOR OPEN WIRES BETWEEN YSAS

COMPUTER AND RIGHT VERTICAL

WIRE HARNESS. REAPPLY ELECTRICAL

COMPUTER AND RIGHT VERTICAL

STABILIZER ACTUATOR.

POWER. CHECK FOR SERVO COMMAND SIGNAL

STABILIZER WIRE HARNESS. DOES

AT TEST BOX BETWEEN SERVO TEST POINT

CONTINUITY EXIST?

AND TEST BOX GROUND. IS SIGNAL VOLTAGE

YES

CHANGING?

REPLACE VERTICAL STABILIZER

YES

ACTUATOR.

CHECK FOR YAW RATE GYRO SIGNAL AT TEST

BOX BETWEEN YAW RATE TEST POINT AND

REPLACE YSAS COMPUTER.

TEST BOX GROUND. IS SIGNAL PRESENT?

YES

SHUT OFF ELECTRICAL POWER. CHECK FOR

OPEN WIRES BETWEEN YSAS COMPUTER AND

YAW RATE GYRO WIRE HARNESS. VERIFY GOOD

GROUND MODULES AND GROUND TERMINATIONS.

YSAS SYSTEM APPEARS TO OPERATE

CORRECTLY.

VERIFY THERE IS NO SHORTED OR CHAFFED

WIRES. APPLY ELECTRICAL POWER AND CHECK

FOR RATE GYRO SIGNAL TO TEST BOX TEST

POINT. IS SIGNAL PRESENT?

YES

REPLACE FAULTY YAW RATE GYRO.

G67-2017-2

Figure 102. YSAS Troubleshooting (Sheet 2 of 4)

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MAINTENANCE MANUAL

FROM SHEET 1

SHUT OFF ELECTRICAL POWER. CHECK

CHECK YAW RATE GYRO TEST POINT ON THE

FOR OPEN WIRES BETWEEN YSAS

REPAIR OPEN WIRES BETWEEN YSAS

YSAS TEST BOX WHILE ROTATING THE YAW RATE

COMPUTER AND YAW RATE GYRO. DOES

COMPUTER AND YAW RATE GYRO.

GYRO. IS A VOLTAGE CHANGE PRESENT?

CONTINUITY EXIST?

YES

REPLACE YAW RATE GYRO.

CHECK THE SERVO COMMAND TEST POINT ON

THE YSAS TEST BOX WHILE ROTATING THE YAW

REPLACE YSAS COMPUTER.

RATE GYRO. IS A VOLTAGE CHANGE PRESENT?

YES

AT THE YSAS TEST BOX, CHECK THE ACTUATOR

SHUT OFF ELECTRICAL POWER. CHECK

REPAIR OPEN WIRES BETWEEN

POSITION TEST POINT TO TEST BOX GROUND

FOR OPEN WIRES BETWEEN YSAS

YSAS COMPUTER AND RIGHT

WHILE ROTATING THE YAW RATE GYRO. IS A

COMPUTER AND RIGHT VERTICAL

VERTICAL STABILIZER ACTUATOR.

VOLTAGE CHANGE PRESENT?

STABILIZER ACTUATOR. DOES CONTINUITY

EXIST?

YES

DISCONNECT THE RIGHT VERTICAL

STABILIZER ACTUATOR PLUG (P4 FOR 500N:

P515 FOR 600N). REAPPLY ELECTRICAL

POWER AND PLACE THE RIGGING SWITCH

REPLACE YSAS COMPUTER.

ON THE YSAS TEST BOX TO THE EXTEND

POSITION. CHECK THE VOLTAGE AT THE

STABILIZER ACTUATOR PLUG AT

TERMINALS S (H) AND A (L). IS VOLTAGE

GREATER THAN 6 VDC?

YES

REPLACE RIGHT VERTICAL STABILIZER

ACTUATOR.

SHUT OFF ELECTRICAL POWER. CHECK RIGHT

VERTICAL STABILIZER FOR PROPER

INSTALLATION OR DAMAGED CONTROL LINKAGE

REPAIR OR REPLACE CONTROL LINKAGE OR

FROM ACTUATOR TO VERTICAL STABILIZER. IS

VERTICAL STABILIZER AND VALIDATE THE

STABILIZER PROPERLY INSTALLED AND FREE

CONTROL RIGGING AS REQUIRED.

FROM DAMAGE?

YES

REPLACE RIGHT VERTICAL STABILIZER

ACTUATOR.

G67-2017-3A

Figure 102. YSAS Troubleshooting (Sheet 3 of 4)

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MAINTENANCE MANUAL

FROM SHEET 1

CHECK THE ACCELERATION TEST POINT ON THE

YSAS TEST BOX WHILE TILTING THE YSAS

REPLACE THE YSAS COMPUTER.

COMPUTER. IS SIGNAL PRESENT?

YES

CHECK THE SERVO COMMAND TEST POINT ON

THE YSAS TEST BOX WHILE TILTING THE YSAS

REPLACE THE YSAS COMPUTER.

COMPUTER. IS A VOLTAGE CHANGE PRESENT?

YES

AT THE YSAS TEST BOX, CHECK THE ACTUATOR

SHUT OFF ELECTRICAL POWER. CHECK FOR

REPAIR OPEN WIRES BETWEEN

POSITION TEST POINT TO TEST BOX GROUND

OPEN WIRES BETWEEN YSAS COMPUTER AND

WHILE TILTING THE YSAS COMPUTER. IS

YSAS COMPUTER AND RIGHT

RIGHT VERTICAL STABILIZER ACTUATOR. DOES

VERTICAL STABILIZER ACTUATOR.

VOLTAGE CHANGE PRESENT?

CONTINUITY EXIST?

YES

DISCONNECT THE RIGHT VERTICAL STABILIZER

ACTUATOR PLUG (P4 FOR 500N: P515 FOR 600N).

REAPPLY ELECTRICAL POWER AND PLACE THE

RIGGING SWITCH ON THE YSAS TEST BOX TO

REPLACE THE YSAS COMPUTER.

THE EXTEND POSITION. CHECK THE VOLTAGE

AT THE STABILIZER ACTUATOR PLUG AT

TERMINALS S (H) AND A (L). IS VOLTAGE

GREATER THAN 6 VDC?

YES

REPLACE RIGHT VERTICAL STABILIZER

ACTUATOR.

SHUT OFF ELECTRICAL POWER. CHECK RIGHT

VERTICAL STABILIZER FOR PROPER

INSTALLATION OR DAMAGED CONTROL LINKAGE

REPAIR OR REPLACE CONTROL LINKAGE OR

FROM ACTUATOR TO VERTICAL STABILIZER. IS

VERTICAL STABILIZER AND VALIDATE THE

STABILIZER PROPERLY INSTALLED AND FREE

CONTROL RIGGING AS REQUIRED.

FROM DAMAGE?

YES

REPLACE RIGHT VERTICAL STABILIZER

ACTUATOR.

G67-2017-4A

Figure 102. YSAS Troubleshooting (Sheet 4 of 4)

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HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369D/E/FF-500/600N HELICOPTERS (ISSUED: 1990) - page 23