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

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

MISCELLANEOUS ACCESS DOORS

MAINTENANCE PRACTICES

1. Access and Inspection Provisions

(3). Inspect doors for corrosion, distortion,

breaks and cracks.

Any time maintenance work is

CAUTION

to be performed near engine air

3. Pilot Compartment Floor Access Doors

and engine cooling air inlets, use care to pre

vent entry of foreign objects that might later

Each of the two pilot's compartment floor

be sucked into compressor or cooling air

access doors are formed by two hinged panels,

blower. Tape covers of cardboard or other

hinged at the forward edge to the pilot's

suitable material in place over engine cool

compartment floor.

ing air screens. Covers should not be re

moved until work is completed and debris is

A latch at the rear, secures each door in place.

thoroughly cleaned out of the area.

Two stainless steel heel strips are hinged and

held in place over each door by a spring.

Removable access doors and covers are

provided in the helicopter for servicing,

NOTE: Remove heel strips for better access.

inspection, removal, installation and adjust

Detach springs from clips on underside of

ment of components.

strips. Remove hinge pins attaching forward

ends of strips to natatorium pedal mounting

Locations of access and inspections provisions

bracket.

are shown in Figure 201 for 369D/E/FF,

Figure 202 for 500N and Figure 203 for 600N

4. Pilot Compartment Floor Access Door

helicopters.

Replacement

Areas, components and items accessible

A. Pilot Compartment Floor Access Door

through locations shown in the figures are in

Removal

Table 201. Screws are used to secure access

doors in stress areas.

(1). Remove floor access doors by releasing

latch at rear of door.

Liquid level sight gages allow inspection of

lubricant levels for main transmission, engine

(2). Raise and hold up rear of heel strips for

oil tank and tail rotor transmission (369

access to hinge pins at forward end of

D/E/FF) or fan transmission (500/600N).

door.

Methods for removal and installation are

(3). Remove hinge pin securing forward

obvious for most doors and covers.

edge of door to pilot's compartment floor

and remove door.

For information on access doors and covers

that are also used for interior trim, Refer to

B. Pilot Compartment Floor Access Door

Sections 25-30-00 and 25-40-00.

Installation

2. General Access Doors Inspection

(1). Position door and secure forward edge

(1). Check door hinges, door-attaching

to floor using hinge pin.

hardware and latches for looseness,

(2). If removed, heel strips are reinstalled

cracks and damage.

by inserting hinge pins through

(2). Check outside edge of door for security

brackets on forward end of strip and

of bonding between outer and inner

anti-torque pedal mounting bracket

skin. Any separation requires repair,

and connecting springs to clips on

refer to Structural Repair Manual.

underside of heel strips.

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MD Helicopters, Inc.

MAINTENANCE MANUAL

Table 201. Access and Inspection Provisions Information

Door, Cover or Access Provision

Provides Access To

Air inlet forward fairings

Main rotor mixer controls, main rotor mast base and supporting

structure.

Collective stick cover

Aft end of collective stick and associated electrical wiring.

Wiring cover

Electrical wiring at seat structure and auxiliary power receptacle.

Pilot’s seat cover or inboard collective

Underseat controls for engine and flight control systems.

pitch stick cover

Plenum chamber access door (air inlet

Interior of engine air inlet aft fairing.

bypass door)

Tail rotor drive shaft access door

Tail rotor drive shaft and interior of air inlet forward fairing.

Pilot’s compartment floor access door

Left door − battery.

Right door − optional avionics equipment and controls linkage.

Aft bulkhead access covers

Right side − oil tank, oil cooler and oil system drain valve.

Left side − components of optional cabin heating installation and main

transmission oil cooler.

Footwell fairing

Forward landing gear struts and dampers, controls of engine and flight

control systems and electrical wiring. Outboard windows allow

inspections of forward landing gear dampers.

Control access door (1)

Lower end of tunnel−routed flight control rods and other control

components in underseat area.

Fuel vent cover

Fuel cells vent system crossover fitting.

Tail rotor control bellcrank access

Bellcrank connecting tail rotor control rod to tailboom control rod.

fitting

Boom bolts access covers

Bolts that secure tailboom to fuselage aft section, tail rotor drive shaft,

tailboom control rod, and damper for tail rotor drive shaft.

Engine access doors

Engine, transmission oil cooler, and components in engine

compartment.

Fuel cell access covers (1)

Left door − fuel quantity transmitter, fuel shutoff valve, fuel cell cover

(for access to engine starting pump), and left fuel cell.

Right door − right fuel cell.

Tail rotor drive access hole (below

Forward end of tail rotor drive shaft and limited access to aft end of

engine cooling air inlet screen)

main transmission.

Instrument panel lower section front

Electrical and avionics wiring at lower forward area of instrument panel.

panel

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CSP-HMI-2

MAINTENANCE MANUAL

Table 201. Access and Inspection Provisions Information

Door, Cover or Access Provision

Provides Access To

Instrument panel lower section side

Wiring, tubing, fuel shutoff control cable, and anti−torque control torque

panels

tube.

Right side cover is mounting surface for landing light relay.

Left side cover mounting running time meter.

Cargo hook access cover

Mount fitting and electrical connectors for optional cargo hook

installation.

Convenience trim panel and main

Sight gage to check main transmission oil level. Chip detectors and

transmission trim panel (Ref. Sec.

main transmission drain valve.

25−00)

Blower access door

Main transmission, air cooler blower, and engine−to transmission drive

shaft.

Instrument panel fairings

Avionics, gages and electrical wiring.

Engine oil filter access panel

Gain access for replacement of engine oil filter. (369FF − 600N)

Access Provisions Unique to 500/600N

Air inlet forward fairings

Main rotor mixer controls, main rotor mast base and supporting

structure.

Anti−torque splitter assembly, forward, intermediate and aft control

tube.

Engine plenum access fairing

Inner area of air inlet aft fairing.

Fan inlet screen

Fan blades and fan/gearbox access cover.

Fan gearbox access cover

Fan gearbox and forward driveshaft.

Driveshaft door

Forward driveshaft rear coupling.

Pressure relief screens

Fan gearbox oil level sight gauge (L/H side).

Tailboom fairing (1)

Tailboom attach bolts.

Anti−torque control cable quick disconnect and electrical connectors.

Horizontal stabilizer end plates (1)

Vertical stabilator controls and YSAS actuator (R/H side).

Horizontal stabilizer access panel (1)

Vertical stabilator controls.

Thruster fairing

Rotating thruster attachment.

Access Provisions Unique to 600N

Forward floor access covers

Fuel cell components.

Engine air bypass door

Interior of engine.

NOTE:

(1) Items are stressed and must be installed prior to helicopter flight.

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MAINTENANCE MANUAL

# $ TAILBOOM MOUNTING

PLENUM ACCESS

BOLTS ACCESS DOORS

COVER

# AIR INLET FOR

WARD FAIRING

# TAIL ROTOR CONTROL BELL

CRANK ACCESS COVER

# * ENGINE OIL FILTER

CONTROLS TUNNEL

ACCESS DOOR

COVER

# $ TAIL ROTOR DRIVE ACCESS

HOLE (UNDER ENGINE COOLING

AIR INLET SCREEN)

# $ BLOWER ACCESS DOOR

# COLLECTIVE STICK COVER

INSTRUMENT PANEL

FAIRING-LEFT SIDE

# TRIM MOTOR AC

# WIRING COVER

CESS PANELS

# INSTRUMENT PANEL LOWER

SECTION SIDE PANEL

PILOT'S SEAT COVER

CAUTION:

ITEMS PREFIXED WITH AN ASTERISK ( * ) ARE STRESSED AND MUST BE

INSTALLED PRIOR TO HELICOPTER FLIGHT.

NOTES:

# ITEMS TO BE REMOVED FOR 100-HOUR OR ANNUAL INSPECTIONS.

$ ITEMS TO BE REMOVED FOR 300-HOUR INSPECTIONS.

G52 5000 1B

Figure 201. Access and Inspection Provisions and Locations (369D/E/FF) (Sheet 1 of 3)

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CSP-HMI-2

MAINTENANCE MANUAL

# FOOTWELL

# $ * CONTROLS

FAIRING

ACCESS DOOR

INSTRUMENT PANEL

TAIL ROTOR DRIVE

FAIRING-RIGHT SIDE

SHAFT ACCESS DOOR

PLENUM CHAMBER AC

CESS DOOR

# TAIL ROTOR CONTROL

BELLCRANK ACCESS COVER

# INSTRUMENT PANEL

LOWER SECTION SIDE

PANEL

# INSTRUMENT PANEL LOWER

SECTION FRONT PANEL

PILOT'S COMPARTMENNT

FOOR ACCESS DOOR

ENGINE ACCESS

DOORS

# * FUEL CELL AC

CESS DOOR

# FOOTWELL FAIRING

# AFT BULKHEAD AC

# FUEL VENT COVER

CESS COVER

# * FUEL CELL AC

CARGO HOOK COVER (FUSE

CESS DOOR

LAGE UNDERSIDE)

INSTRUMENT PAN

EL FAIRING

# INSTRUMENT PANEL LOWER

SECTION SIDE PANEL

# INSTRUMENT PANEL LOWER SEC

TION FRONT PANEL

G52-5000-2A

Figure 201. Access and Inspection Provisions and Locations (369D/E/FF) (Sheet 2 of 3)

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CSP-HMI-2

MAINTENANCE MANUAL

# $ HORIZONTAL STABILIZER

ACCESS PANEL

# $ FAN INLET

SCREEN

# ENGINE PLENUM

ACCESS FAIRING

# $ HORIZONTAL STABILIZER

END PLATE (2 PLACES)

# AIR INLET FOR

WARD FAIRINGS

# $ TAILBOOM FAIRING

PRESSURE RELIEF

SCREEN (2 PLACES)

# CONTROL

# $ BLOWER ACCESS COVER

ACCESS

COVER

# COLLECTIVE STICK COVER

# WIRING COVER

INSTRUMENT PANEL

# TRIM MOTOR

FAIRING - LEFT SIDE

ACCESS PANEL

# INSTRUMENT PANEL LOWER

SECTION SIDE PANEL

CAUTION:

ITEMS PREFIXED WITH AN ASTERISK ( * ) ARE STRESSED AND MUST BE

INSTALLED PRIOR TO HELICOPTER FLIGHT.

NOTES:

# ITEMS TO BE REMOVED FOR 100-HOUR OR ANNUAL INSPECTIONS.

$ ITEMS TO BE REMOVED FOR 300-HOUR INSPECTIONS.

G52 5001 1B

Figure 202. Access and Inspection Provisions and Locations (500N) (Sheet 1 of 2)

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MD Helicopters, Inc.

MAINTENANCE MANUAL

# FOOTWELL

# $ CONTROLS

FAIRING

ACCESS DOOR

INLET ACCESS PANEL

INSTRUMENT PANEL

FAIRING - RIGHT SIDE

ENGINE PLENUM

BYPASS DOOR

# FAN GEARBOX

ACCESS COVER

# INSTRUMENT PANEL L

PRESSURE RE

SECTION SIDE PANEL

LIEF SCREEN

# INSTRUMENT PANEL LOW

SECTION FRONT PANEL

# $ TAILBOOM

PILOT'S COMPARTMENT

FAIRING

FLOOR ACCESS DOOR

ENGINE ACCESS

DOORS

# * FUEL CELL

ACCESS COVER

# FOOTWELL FAIRING

# AFT BULKHEAD

ACCESS COVER

# * FUEL CELL

# FUEL VENT COVER

# AFT BULKHEAD

ACCESS COVER

CARGO HOOK COVER (FU

SELAGE UNDERSIDE)

Figure 202. Access and Inspection Provisions and Locations (500N) (Sheet 2 of 2)

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CSP-HMI-2

MAINTENANCE MANUAL

# CONTROL AC

CESS COVER

# COLLECTIVE

STICK COVER

# WIRING COVER

# $ HORIZONTAL STABILIZER

ACCESS PANEL

INSTRUMENT PANEL

FAIRING-LEFT SIDE

# INSTRUMENT PAN

EL LOWER SECTION

# $ TRIM MOTOR

# $ FAN INLET SCREEN

SIDE PANEL

ACCESS PANEL

# ENGINE PLENUM

ACCESS FAIRING

# $ HORIZONTAL STABILIZER

BYPASS DOOR ASSY

END PLATE (2 PL)

# $ TAILBOOM FAIRING

PRESSURE RELIEF

# $ CONTROLS FAIRING

SCREEN (2 PL)

# * ENGINE OIL FILTER

ACCESS DOOR

# $ BLOWER ACCESS COVER

* FUEL CELL AC

CESS COVER

INSTRUMENT PANEL

FAIRING-RIGHT SIDE

# $ CONTROLS

# FOOTWELL

ACCESS DOOR

PILOT'S COMPARTMENT

FAIRING

FLOOR ACCESS DOOR

# FAN GEARBOX

ACCESS COVER

# FOOTWELL

FAIRING

# FUEL VENT

CAUTION:

COVER

ITEMS PREFIXED WITH AN ASTERISK ( * ) ARE STRESSED AND MUST BE

INSTALLED PRIOR TO HELICOPTER FLIGHT.

# AFT BULKHEAD

NOTES:

ACCESS COVER

# ITEMS TO BE REMOVED FOR 100-HOUR OR ANNUAL INSPECTIONS.

$ ITEMS TO BE REMOVED FOR 300-HOUR INSPECTIONS.

6G52-096

Figure 203. Access and Inspection Provisions and Locations (600N)

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CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS

Para/Figure/Table

Title

Page

53-00-00 Fuselage

Maintenance Practices

201

1. Fuselage - General

201

2. Stressed Sheet Metal Panels

201

3. Stressed Sheet Metal Panel Inspection

201

4. Non-Stressed Sheet Metal Panels

201

5. Negligible Damage Inspection

201

Table 201. Negligible Damage Inspection - Fuselage

202

Figure 201. Fuselage - Major Sections

203

Figure 202. Fuselage - Model 600N

204

53-10-00 Windshields and Aft Section Windows

Maintenance Practices

201

1. Windshields

201

2. Aft Section Windows

201

3. Aft Section Windows Replacement

201

A. Aft Section Windows Removal

201

B. Aft Section Windows Installation

201

4. Windshield Frame Replacement

201

A. New-Style Windshield Installation

201

5. Windshield Inspection

201

6. Windshield Repair

201

7. Water Leak Prevention

202

8. Geon Strips Repair

202

Table 201. Negligible Damage of Canopy/Windshield

202

Figure 201. (Round Nose) Windshields and Aft Section Windows

203

Figure 202. (Extended Nose) Windshield and Aft Section Windows

204

Figure 203. Windshield Installation (New Style)

205

Figure 204. (Extended Nose) Windshields and Aft Section Windows

(New Style)

206

53-20-00 Lower Center Fuselage

Maintenance Practices

201

1. Lower Center Fuselage - General

201

2. Lower Center Fuselage Inspection

201

3. Fuel Tank Support Skin Inspection (Fuel Cells Removed)

201

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MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

4. Fuel Tank Support Skins Repair (Fuel Cells Removed)

201

Figure 201. Lower Center Fuselage (369D/E/FF - 500N)

202

Figure 202. Lower Center Fuselage (Model 600N)

203

53-30-00 Upper Aft Section Fuselage (369D/E/FF)

Maintenance Practices

201

Upper Firewall Replacement

201

Firewall and Plenum Chamber Panels Replacement

201

Figure 201. Soundproofing Insulation - Firewall and Plenum Chamber

(Sheet 1 of 2)

202

A. Mast Support Structure

204

Mast Support Structure Inspection

204

A. Firewalls

204

Firewalls Inspection

204

Figure 202. Firewall and Aft Section

205

A. Firewall, Station 124.00 Insulation and Soundproofing

205

Firewall and Plenum Chamber Soundproofing Panel Inspection

205

A. Engine Air Inlet Fairing

205

Engine Air Inlet (Plenum Chamber) Inspection

206

A. Upper Aft Section General Repair

206

B. Aft Fuselage Fittings

206

C. Aft Fuselage Fittings General Repair

206

Aft Section Strut Repair

206

Silver Brazing Procedure - Upper Firewall Shell Patch

206

Figure 203. Major Bulkheads and Structural Members - Aft Fuselage

207

Plenum Chamber Hole Sealing

208

10. Forward Fuselage Section Structure Rework

208

11. Transmission Compartment Air Baffle, Seal and Cover Initial Installation

209

Table 201. Weight and Balance Data

210

Figure 204. Forward Fuselage Section Structure Rework

211

Figure 205. Installation of Air Baffle, Seal and Cover Assemblies

(Sheet 1 of 2)

212

53-30-30 Upper Aft Section Fuselage (500/600N)

Maintenance Practices

201

1. Engine/Anti-Torque Air Inlet Fan Fairings

201

2. Engine Air and Fan Inlet (Plenum Chamber Area) Inspection

201

Figure 201. Upper Aft Section (500N)

202

Figure 202. Upper Aft Section Fuselage (600N)

203

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MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

A. Upper Aft Section General Repair

204

Upper Fuselage Controls Fairing (600N)

204

Upper Fuselage Controls Fairing Replacement (600N)

204

A. Upper Fuselage Controls Fairing Removal

204

B. Upper Fuselage Controls Fairing Installation

204

Engine Inlet Fairings Replacement

204

A. Engine Inlet Fairing Removal

204

B. Engine Inlet Fairing Installation

204

Anti-Torque Fan Air Inlet Screen Replacement

204

A. Fan Air Inlet Screen Removal

204

B. Fan Air Inlet Screen Installation

204

Fan Hub and Transmission Cover Fairing Replacement

204

A. Fan Hub and Transmission Cover Removal

204

B. Fan Hub and Transmission Cover Installation

205

Engine Plenum Access Cover Replacement

205

A. Engine Plenum Access Cover Removal

205

B. Engine Plenum Access Cover Installation

205

Tailboom Attach Fitting Inspection

205

Figure 203. Tailboom Attach Fitting Inspection

206

10. Lower Longeron Inspection (L158, R158)

207

11. Forward Upper Longeron Inspection (L137, R137)

207

Figure 204. Inspection Hole Locations

208

12. Control Tunnel (FS 78.50) Beam Inspection

208

Figure 205. Control Tunnel (FS 78.50) Beam Inspection

209

53-40-00 Tailboom (369D/E/FF)

Maintenance Practices

201

1. Tailboom - General

201

2. Tailboom Replacement

201

A. Tailboom Removal

201

B. Tailboom Installation

201

Figure 201. Tailboom Assembly and Tailboom Extension

202

3. Tailboom Extension Replacement (369FF)

202

4. Tailboom Inspection

203

5. Tailboom Repair

203

Figure 202. Tailboom Installation and Removal

204

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MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

53-40-30 Tailboom (500/600N)

Maintenance Practices

201

Tailboom Description

201

Tailboom Replacement

201

A. Tailboom Removal

201

Figure 201. Tailboom Assembly (Sheet 1 of 3)

202

B. Tailboom Installation

205

Tailboom Inspection

205

Figure 202. Tailboom Flap Inspection

206

Tailboom Repair

207

Stator Replacement

207

A. Stator Removal

207

B. Stator Installation

207

Stator Blade Replacement

207

Rotating Thruster Cone Replacement

207

A. Rotating Thruster Cone Removal

207

B. Rotating Thruster Cone Installation

207

Rotating Thruster Cone Inspection

207

Stationary Thruster Cone Replacement

208

A. Stationary Thruster Cone Removal

208

B. Stationary Thruster Cone Installation

208

10. Stationary Thruster Cone Inspection

208

11. Conduit and Support Strap Rebonding

208

Figure 203. Conduit and Support Strap Rebonding

209

12. Horizontal Stabilizer Mount Fitting Replacement

210

13. 500N3500-5 Cover Installation

211

Figure 204. 500N3500-5 Cover Installation

212

14. Tail Skid Replacement

212

A. Tail Skid Removal

212

B. Tail Skid Installation

212

Figure 205. Tail Skid Installation

213

Repairs

801

1. Rotating Thruster Cone Strap Repair

801

A. Rotating Thruster Cone Strap Removal

801

Figure 801. Rotating Thruster Cone

801

B. Rotating Thruster Cone Strap Installation

802

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CSP−HMI−2

MAINTENANCE MANUAL

TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

53-50-10 Stabilizer (T-Tail) (369D/E/FF)

Maintenance Practices

201

1. Stabilizer - General

201

A. Stabilizer Troubleshooting

201

2. Horizontal Stabilizer and Tip Plate Replacement

201

A. Horizontal Stabilizer and Tip Plate Removal

201

B. Horizontal Stabilizer and Tip Plate Installation

201

3. Vertical Stabilizer Replacement

202

A. Vertical Stabilizer Removal

202

B. Vertical Stabilizer Installation

202

4. Horizontal Stabilizer and Tip Plate Inspection

202

5. Vertical Stabilizer Inspection

202

Figure 201. Stabilizer T-Tail Removal and Installation

203

6. Horizontal Stabilizer and Tip Plate Repair

204

7. Vertical Stabilizer Repair

204

8. Angle of Incidence Measurement

204

Table 201. Horizontal Stabilizer Angle of Incidence

204

9. Angle of Incidence Adjustment

205

10. Horizontal Stabilizer Tab Weight Installation

205

Table 202. Troubleshooting Tailboom and Tail Surfaces

205

Figure 202. Horizontal Stabilizer Incidence Angle Measuring Tool

206

Figure 203. Establishing Horizontal Stabilizer Angle of Incidence

206

Figure 204. Sealing - Vertical Stabilizer (0003D - 0286D)

207

53-50-30 Stabilizer (500/600N)

Maintenance Practices

201

1. Stabilizers Description

201

A. Horizontal Stabilizer Description

201

B. Vertical Stabilizers Description

201

2. Vertical Stabilizer Replacement

201

A. Vertical Upper and Lower Stabilizer Removal

201

B. Vertical Upper and Lower Stabilizer Installation

201

3. Horizontal Stabilizer Replacement

202

A. Horizontal Stabilizer Removal

202

B. Horizontal Stabilizer Installation

202

Figure 201. Stabilizer Installation with YSAS (Sheet 1 of 2)

203

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TABLE OF CONTENTS (Cont.)

Para/Figure/Table

Title

Page

4. Horizontal Stabilizer Eye Bolt Replacement

205

A. Horizontal Stabilizer Eye Bolt Removal

205

B. Horizontal Stabilizer Eye Bolt Installation

205

5. Horizontal/Vertical Stabilizer Control Tube and Bellcrank Replacement

205

A. Horizontal/Vertical Stabilizer Control Tube and Bellcrank Removal

205

B. Horizontal/Vertical Stabilizer Control Tube and Bellcrank Installation

205

6. Vertical Stabilizer Inspection

205

7. Vertical Stabilizer Repair

205

8. Horizontal Stabilizer Inspection

205

9. Vertical Stabilizer Torque Tube Replacement

206

A. Vertical Stabilizer Torque Tube Removal

206

B. Vertical Stabilizer Torque Tube Installation

206

Figure 202. Stabilizer Installation without YSAS

207

Figure 203. Vertical Stabilizer Installation with Expandable Bolts

208

10. Horizontal Stabilizer Repair

209

11. Vertical Stabilizer Torque Tube and/or Bushing Replacement

(Non-Bonded Bushings)

209

12. Vertical Stabilizer Torque Tube and/or Bushing Replacement

(Bonded Bushings)

209

13. Vertical Stabilizer Torque Tube Bushing Rework

(Non-Bonded Bushings to Bonded Bushings)

210

14. Vertical Stabilizer Torque Tube Bearing Race Replacement

211

15. Stabilizer Troubleshooting

212

Table 201. Troubleshooting Tailboom and Tail Surfaces

212

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CSP-HMI-2

MAINTENANCE MANUAL

FUSELAGE

MAINTENANCE PRACTICES

1. Fuselage − General

webs. The most-highly-stressed skin sections

are those that form the cylindrically-tapered

(Ref. Figure 201) The helicopter fuselage

tailboom assembly (Ref. Sec. 53-40).

consists of three major structural sections; the

forward, lower and aft fuselage sections. For

NOTE: No damage can be considered negligi

classification and definition of types of

ble. All damage shall be repaired upon de

negligible damage, and for guidelines defining

tection.

extent of damage requiring repair or replace

3. Stressed Sheet Metal Panel Inspection

ment, (Ref. Stressed Sheet Metal Panels,

Non-Stressed Sheet Metal Panels and

Cracks, tears or punctures in stressed sheet

Table 201).

metal panels that do not exceed 0.20 inch (5.08

mm) diameter and can be removed by drilling

(Ref. Figure 202) The fuselage of the 600N

out with 1/4 inch (6.35 mm) or smaller

helicopter is a stretched version of the 500N

diameter drill do not require structural

Series helicopter with numerous upgrades and

doublers. If cracks, tears or punctures exceed

improvements. (shaded areas indicate new

0.20 inch (5.08 mm) diameter, they are to be

sections to fuselage) The longer cabin area of

repaired or the panel must be replaced per

the 600N greatly increases passenger and/or

instructions in FAA AC 43.13-1B and FAA AC

cargo carrying capacity. Upper deck area

43.13-2B Inspection and Repair for Standard

fairings and covers were added or modified to

Sheet Metal Repair and Alterations and

accommodate control surfaces or air inlet

Structural Repair Manual.

passages.

4. Non−Stressed Sheet Metal Panels

The tailboom on the 600N helicopter is

essentially the same as the 500N Series, only

Non-stressed sheet metal members consist

longer. The vertical stabilizers or endplates are

primarily of hinged covers and doors, except

longer than on the 500N model, providing an

fuel cell access and controls access doors,

increased control surface area.

which are stressed (Ref. Stressed Sheet Metal

Panels).

An extended passenger step alongside the

passenger/cargo compartment allows for easy

5. Negligible Damage Inspection

entrance and exit through either mid or aft

cabin doors.

(Ref. Table 201) Panels damaged in excess of

negligible damage limits (Ref. Table 201)

2. Stressed Sheet Metal Panels

should be repaired, or damaged panel should

be replaced per instructions in FAA AC

Stressed sheet metal panels consist primarily

43.13-1A & 2A and CSP-SRM-6 (Structural

of helicopter fuselage skins and bulkhead

Repair Manual).

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MD Helicopters, Inc.

MAINTENANCE MANUAL

Table 201. Negligible Damage Inspection − Fuselage

Maximum

Maximum Length

Area

*Damage

Depth

or Surface

Remarks

Stressed sheet

No unrepaired damage

metal panels.

allowed.

(For tailboom, Ref. Sec.

53−40).

Non−stressed sheet

Dents.

Small dents allowed.**

metal panels.

Scratches/nicks.

Minor scratches/nicks

allowed.**

Cracks.

Smaller of 0.250

Must be one inch or more

inch (6.35 mm) or

from any attachment fitting

one−fourth panel

and/or panel edge.

width.

Main rotor mast.

No unrepaired damage

allowed (Ref. Figure 201)

Firewalls.

No unrepaired damage

allowed.

Fuselage fittings.

Longitudinal

0.010 inch

15% of fitting

After polishing or repair.

scratches, dents, and

(0.254 mm)

length.

nicks.

Transverse scratches,

0.010 inch

10% of fitting

After polishing or repair.

dents, and nicks.

(0.254 mm)

thickness.

NOTES:

* All damage to fuselage exceeding limits given requires repair or replacement of effected panel or

component.

** Dents, scratches and nicks that penetrate aluminum protective coating (4% of panel thickness with paint or

other surface finishes removed) will allow corrosion of aluminum panel, and should be repaired.

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MAINTENANCE MANUAL

WINDSHIELDS AND AFT SECTION WINDOWS

MAINTENANCE PRACTICES

1. Windshields

(2). Using a blunt plastic spatula or probe,

gradually work edge of window under

Center and lower windshield panels are

flap surface of window seal.

clearest acrylic (Ref. Figure 201 and

(3). Maintain pressure on window until

Figure 202). Upper windshield panels are

entire perimeter of window is under

smoke-grey-tinted cast acrylic. The center

seal.

windshield panels are approximately 0.100

inch (2.540 mm) thick.

(4). Apply an even amount of sealing

compound (CM425) to form a water

2. Aft Section Windows

tight seal around window seal to

fuselage and from window seal to

For repair of plastics, Ref. FAA AC 43.13-1B.

window.

Replace aft section window if it is damaged

beyond practical repair, according to applicable

4. Windshield Frame Replacement

instructions in Structural Repair Manual.

Consumable Materials

(Ref. Figure 204) On the 600N helicopter the

(Ref. Section 91−00−00)

”Aft Section Windows” refer to the upper mid

Item

Nomenclature

section windows located above the mid

passenger/cargo doors. On the 500 Series

CM305

Lacquer, acrylic

helicopters this area was referred to as the

CM425

Sealing compound

”Aft Section”.

For older model helicopters with riveted-in

3. Aft Section Windows Replacement

windshields, remove or replace windshield

according to applicable instructions in the

(Ref. Figure 204)

Structural Repair Manual.

A. Aft Section Windows Removal

A. New−Style Windshield Installation

(1). Remove old sealing compound from

(1). Install windshields in place and install

around edge of window and window

hardware (Ref. Figure 203 and

seal.

Figure 204).

(2). After normal installation of windshield,

(2). Using a blunt plastic spatula or probe,

grind two screws flush with nuts (Ref.

pull back flap of window seal and

Figure 203).

gradually work window out from under

flap of seal.

(3). Touch-up with lacquer (CM305).

(3). Remove seal and clean for re-installa

(4). Seal all windshield seams with sealing

tion of window.

compound (CM425).

5. Windshield Inspection

Consumable Materials

Minor defects or imperfections that do not

(Ref. Section 91−00−00)

impair pilot's critical visibility, or that obvious

Item

Nomenclature

ly are not signs of impending structural failure

CM425

Sealing compound

may be considered as negligible. (For allowable

damage limits, Refer to Table 201.)

B. Aft Section Windows Installation

6. Windshield Repair

(1). Install window seal around periphery of

For repair of plastics, Ref. FAA AC 43.13-1B.

window opening in fuselage.

Replace windshields if damage beyond

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MD Helicopters, Inc.

MAINTENANCE MANUAL

practical repair, according to applicable

having less than 0.125 inch (3.175 mm)

instructions in Structural Repair Manual.

insertion. Replace parts with debonding

areas over 8 inches (20.32 cm) in

7. Water Leak Prevention

length.

(2). Mask the geon weatherstrip and

Consumable Materials

windshield on both sides with tape

(Ref. Section 91−00−00)

(CM722).

Item

Nomenclature

CM425

Sealing compound

(3). Wipe all faying surfaces with aliphatic

naphtha (CM220) and dry for a mini

mum of 15 minutes.

If water leakage through geon strips of the

forward canopy occurs, remove any existing

(4). For small voids:

sealant using a plastic or other non-metallic

scraper which will not scratch the canopy

(a). Apply adhesive (CM414) to all faying

glass. Apply 0.060 inch (1.524 mm) bead of

surfaces using syringe if necessary.

sealant (CM425) along gaps between geon

strips. Apply sealant as directed by sealant

(b). Use light pressure to hold the joint

manufacturer.

closed for a minimum of 2 minutes.

8. Geon Strips Repair

(5). For large voids:

(a). Apply accelerator to the acrylic

Consumable Materials

transparency and air dry for a

(Ref. Section 91−00−00)

minimum of 2 minutes.

Item

Nomenclature

CM220

Naphtha aliphatic

(b). Apply adhesive to the geon weather

CM414

Adhesive, cyanoacrylic / Accelerator

strip only.

CM722

Tape, polyethylene

(c). Apply local pressure to insure

complete contact between adherents

Fill voids between geon strips and transparen

and maintain pressure for a mini

cies as follows:

mum of 30 seconds.

(1). Measure the insertion depth of acrylic

(d). Remove tape and remove excess

windshield into geon slot, reject parts

residue with aliphatic naphtha.

Table 201. Negligible Damage of Canopy/Windshield

Maximum

Length or

Area

Damage

Depth

Surface Area

Remarks

Canopy and Windshield.

Nicks

0.010 inch

0.250 inch

One per square foot

(0.254 mm)

(6.35 mm)

only.

Scratches

0.010 inch

5.000 inch

(0.254 mm)

(12.7 cm)

Spots or stains

If removable by light

polishing.

Panels (not windshields or Punctures

0.200 inch

windows).

(5.08 mm) dia

Windshield.

Polarization faults

Small area near edges.

(distortion)

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CSP-HMI-2

MAINTENANCE MANUAL

Table 201. Negligible Damage of Canopy/Windshield (Cont.)

Maximum

Length or

Area

Damage

Depth

Surface Area

Remarks

Doublers or stiffeners.

Delamination

No more than one area

within each square foot

of windshield.

Grazing around

0.010 inch

delamination

(0.254 mm)

UPPER CANOPY WINDSHIELD

(TWO SECTIONS)

OUTSIDE AIR TEMPERATURE

INDICATOR

CENTER CANOPY WINDSHIELD

(TWO SECTIONS)

FUSELAGE AFT SECTION

WINDOWS (BOTH SIDES)

(NOTE)

CABIN VENTILATION PANEL

(FIBERGLASS)

LOWER CANOPY WINDSHIELD

(TWO SECTIONS)

NOTE:

FUSELAGE AFT SECTION WINDOWS ARE UNIQUE TO

G53-1000

ROUND-NOSE HELICOPTERS ONLY.

Figure 201. (Round Nose) Windshields and Aft Section Windows

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CSP-HMI-2

MAINTENANCE MANUAL

LOWER CENTER FUSELAGE

MAINTENANCE PRACTICES

1. Lower Center Fuselage − General

(4). Perform repair (Ref. Fuel Tank Support

Skins Repair (Fuel Cells Removed)).

(Ref. Figure 201) Lower center fuselage is

those areas below fuselage floor level (WL

3. Fuel Tank Support Skin Inspection (Fuel

13.10) on both sides of the center beam and

Cells Removed)

between Sta. 78.50 and Sta. 124.00.

(1). Check security of fiberglass skin

attachment to support angles and

(Ref. Figure 202) The Lower Center Fuselage

brackets.

for the Model 600N helicopter is similar to that

of the 500 Series helicopters except for the

(2). Inspect anti-abrasion tape for security

additional stretched or extended fuselage

of adhesion over rivet heads, all sharp

IplugI station. The extended lower center

edges and lap joints.

fuselage section is located at Sta. 78.50

(designated P. Sta. 0.00 thru 30.00) (Ref.

(3). Negligible damage (Ref. Table 201,

Section 06-00-00). Additional floor access

53-00-00).

covers for the fuel cell are also contained

within this section of fuselage.

4. Fuel Tank Support Skins Repair (Fuel

Cells Removed)

2. Lower Center Fuselage Inspection

Consumable Materials

(1). Ref. FAA AC 43.13-1B Aircraft Inspec

(Ref. Section 91−00−00)

tion and Repair for Standard Sheet

Item

Nomenclature

Metal Repair and Structural Repair

CM711

Tape, pressure sensitive

Manual for standard sheet metal

repair.

(1). Repair fuel tank support skins accord

(2). Inspect electrical harnesses and wiring

ing to applicable instructions in FAA

for frayed insulation and grounding

AC 43.13-1A & 2A or Structural Repair

terminals for corrosion.

Manual.

(3). If cargo floor is bent or punctured,

(2). Cover exposed rivet heads with 10 mil

remove appropriate fuel cell access

by 1 inch (2.54 cm) tape (CM711) to

cover and inspect fuel cell.

prevent chafing fuel cell fabric.

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MD Helicopters, Inc.

MAINTENANCE MANUAL

FLOOR WEB

CENTER BEAM

(0.016 IN. (0.4064 MM)

2024-T3 AL ALY)

STIFFENER

(0.020 IN. (0.508 MM)

STIFFENERS

7075-T6 AL ALY)

(0.032 IN. (0.8128 MM)

WEB

(TYPICAL 8 PLCS)

7075-T6 AL ALY)

(0.016 IN. (0.4064 MM)

(TYPICAL 7 PLCS)

7075-T6 AL ALY)

DOUBLER

STIFFENER

(0.032 IN. (0.8128 MM)

7075-T6 AL ALY)

STA 119.67 RIB

(0.025 IN. (0.635 MM)

7075-T6 AL ALY)

WL 13.10

124.00 LOWER FRAME

(0.020 IN. (0.508 MM)

15-7 CRES)

STA 113.85 RIB

STIFFENERS

(0.025 IN. (0.635 MM)

(0.020 IN. (0.508 MM)

7075-T6 AL ALY)

2024-T3 AL ALY)

STA 108.04 RIB

DOUBLER

(0.025 IN. (0.635 MM)

7075-T6 AL ALY)

2024-T3 AL ALY)

STA 102.23 RIB

WEB

(0.025 IN. (0.635 MM)

(0.016 IN. (0.4064 MM)

STA 90.61 RIB

7075-T6 AL ALY)

2024-T3 AL ALY)

(0.040 IN. (1.016 MM)

7075-T6 AL ALY)

JACK FITTING

DOUBLER

(PART OF STA 96.42 RIB)

(0.050 IN. (1.270 MM)

7075-T6 AL ALY)

STA 96.42 RIB ASSY

DOUBLER

CARGO HOOK FITTING

STIFFENER

(0.050 IN. (1.270 MM)

(IF APPLICABLE)

(0.032 IN. (0.8128 MM)

7075-T6 AL ALY)

STA 84.70 RIB

(0.032 IN. (0.8128 MM)

7075-T6 AL ALY)

CANT STA 78.50

LOWER FRAME

G53-2002A

(0 040 IN (1 016 MM)

Figure 201. Lower Center Fuselage (369D/E/FF − 500N)

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CSP-HMI-2

MAINTENANCE MANUAL

UPPER AFT SECTION FUSELAGE (369D/E/FF)

MAINTENANCE PRACTICES

1. Upper Firewall Replacement

(9). Using solvent (CM234), clean forward

flanges, lower flanges and surface

where tape routing covers fasteners;

Consumable Materials

then apply tape (CM721).

(Ref. Section 91−00−00)

Item

Nomenclature

(10). Install compressor cooling air duct

support bracket.

CM234

Solvent, dry-cleaning

CM721

Tape, aluminum foil

(11). Install tailpipes.

2. Firewall and Plenum Chamber Panels

Use care when working on or

Replacement

CAUTION

around firewall shell because of

its light-weight construction.

Consumable Materials

(Ref. Section 91−00−00)

(1).

Remove tailpipes (Ref. Chap. 78,

Item

Nomenclature

Exhaust System Replacement).

CM234

Solvent, dry-cleaning

(2).

Remove tape covering fasteners and

CM419

Sealer

firewall edges.

(3).

Detach compressor cooling air duct

Replace all defective, torn or fraying sound

support bracket (Ref. Chap. 71, Engine

proofing panels. Loose panels may be pressed

Cooling System Repair and Replace

back in place. (For part number identification

ment). Remove firewall shell by pulling

of individual panels, refer to the IPC.)

out button head fasteners (Ref.

(1). Open engine compartment access doors.

Figure 202).

(2). Remove individual panels (Ref.

(4).

If burn marks are detected on firewall

Figure 201, Sheet 1 of 2) by pulling

shell or button head fasteners, inspect

away from structure.

airframe above burn marks for damage.

(3).

(If applicable) Remove individual

(5).

Replace damaged or corroded fasteners.

panels (Ref. Figure 201, Sheet 2 of 2) by

removing fasteners.

(6).

Replace aft firewall shell if damaged

beyond practical repair. Trim replace

NOTE: Panels have pressure-sensitive tape

ment shell to fit installation. Allow

backing.

sufficient trim excess for folding back to

(4). Prior to installing replacement panel,

provide double thickness at attach

clean surfaces with solvent (1, Table

points.

201, 91-00).

(7).

Pierce fastener holes in new firewall

(5). Install replacement panel in place and

shell to align holes in surrounding

trim edges as necessary. Press panel in

fuselage rings and waterline 34.96 rib.

place to secure.

(8).

Place firewall shell in position and

(6). Seal edges of replacement panel with

secure in place by pressing fasteners

sealer (130).

into holes. Attach compressor cooling

air duct support bracket to hoist fitting

(7). Reinstall trim (Ref. Sec. 25-30, Interior

(Ref. Chap. 75, Engine Cooling System

Trim Replacement) and close engine

Repair and Replacement).

access doors.

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MAINTENANCE MANUAL

-3 PANEL

-5 PANEL

-7 PANEL

-39 PANEL

SOUNDPROOFING PANELS

(FIREWALL AND PLENUM

AFT SECTION AND CANTED

CHAMBER)

FORWARD FIREWALL

-37

-29

-11

-45

-35

-33

-31

-9

-43

-15

-17

-18

-16

-21

-23

-22

SOUNDPROOFING PANELS

(ON AFT SIDE OF ACCESS

-13

-19

-14

DOORS) (NOTE 1)

-20

-27

-25

-28

NOTES:

RIGHT PANEL SHOWN. OPPOSITE

SIDE LEFT PANEL (-41) IS SAME;

SOUNDPROOFING PANELS

EXCEPT MIRROR IMAGE AND A

(ENGINE COMPARTMENT

SOLID PANEL.

SIDE OF FIREWALL)

ALL DASH NUMBERS SHOWN

APPLY TO BASIC PART NO.

369H2008. (EXAMPLE: -25

G53-3003-1

Figure 201. Soundproofing Insulation − Firewall and Plenum Chamber (Sheet 1 of 2)

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MD Helicopters, Inc.

MAINTENANCE MANUAL

A. Mast Support Structure

(7). Clean and inspect any suspected area;

use dye-penetrant to determine if a

The mast support structure is part of the

crack does exist. If a crack is found,

fuselage structure and is composed of two

part must be replaced.

longitudinal forged fittings, a lower pan and

an aft pan. The mast support structure

(8). Inspect mast support structure for

supports and mounts the main rotor mast.

corrosion, loose bolts and rivets and

general condition of finish.

NOTE: The main rotor static mast has been re

moved, in it's entirety, from this section be

(9). Check that mast support structure pan

cause of duplicate information in Section

drain hole is open.

63-30-00. Refer to Section 63-30-00 for all

information concerning the main rotor stat

(10). Reinstall controls tunnel cover.

ic mast.

(11). Reinstall left and right forward sections

of air inlet fairing (Ref. Engine Inlet

3. Mast Support Structure Inspection

Fairing Replacement).

Accomplish the following inspection at

(12). Reinstall main gearbox access cover

specified intervals (Ref. Chap. 05).

and trim.

When working near or around

CAUTION

A. Firewalls

engine air and cooling inlets,

use care to prevent entry of foreign objects

(Ref. Figure 202) A shell-like aft section upper

(Ref. Sec. 71).

firewall surrounds the upper portion of engine

combustion chamber and exhaust pipe

(1). Remove left and right sections of air

assembly. The design contains engine heat as

inlet forward fairing (Ref. Engine Inlet

well as any fire that might develop within the

Fairing Replacement).

engine compartment. Upper firewall is thin,

(2). Remove interior trim (Ref. Sec. 25-30,

0.0015 inch (0.0381 mm) thick sheet, rigidized

Interior Trim Replacement) and main

CRES sheet covered with double thickness of

gearbox access cover (same section).

nonflammable ceramic fiber blanket.

(3). Detach control tunnel cover from

4. Firewalls Inspection

structure and slide out of way.

No unrepaired damage is permissible. (For

NOTE: Use bright light and 5-power magnify

repairs to forward firewall, Ref. FAA AC

ing glass to carefully inspect areas described

43-13-1A & 2A or Structural Repair Manual.)

in steps below for evidence of cracks.

For repairs of the upper firewall (Ref. Silver

Brazing Upper Firewall Shelf Patch).

(4). Inspect visible areas of mast support

fitting, mast base and mast tube, with

(1). Inspect forward firewall for punctures

particular attention to base attachment

and corrosion.

areas and shaded areas.

(2). Inspect upper firewall for punctures,

(5). Inspect both side of channels on aft

corrosion and evidence of contact with

canted bulkhead from mast support

discoloration. If contact with discolor

fitting down to waterline 34.00 with

ation is observed on the firewall

particular attention to points of

attachment button heads, remove the

attachment.

upper firewall and inspect the attach

frames for discoloration or damage;

(6). Inspect side channels and fore and aft

contact MDHI for further directions.

webs of controls tunnel, from mast

support fitting down to top of pilot's

(3). Inspect for complete seal around

seatback (canted bulkhead waterline

openings for overrunning clutch, engine

45.36).

compressor air inlet and oil cooler.

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CSP-HMI-2

MAINTENANCE MANUAL

TAIL ROTOR DRIVE SHAFT FAIRING

REMOVABLE PANEL

CANTED STA. 124.00

CHANNEL

ENGINE AIR INLET

WATERLINE 34.96 RIB

INSTALLATION

(PLENUM CHAMBER)

AFT SECTION UPPER FIREWALL

(NOTE)

FORWARD ENGINE

AIR INLET PANEL

ENGINE AIR INLET SIDE PAN

DRAIN FITTING

ENGINE AIR

AFT SECTION FORWARD FIREWALL

INLET PAN

(NOTE)

369D/E/FF SHOWN

NOTE:

AFT SECTION FIREWALL IS A REMOVABLE ASSEMBLY. BOTTONHEAD FASTENERS

G53-3008A

ARE WITHDRAWN FROM INSIDE SURFACE OF FIREWALL SHELL TO REMOVE

Figure 202. Firewall and Aft Section

A. Firewall, Station 124.00 Insulation and

(4). Check that all individual panels are

Soundproofing

securely attached to firewall and

plenum areas with no loose edges.

(Ref. Figure 201, Sheet 1 of 2) Engine compart

ment forward firewall is insulated and

(5). Check panels in passenger compart

soundproofed for heat and noise reduction in

ment of defects, tears, looseness, or

passenger/cargo compartment.

missing panels.

5. Firewall and Plenum Chamber

Soundproofing Panel Inspection

(6). For applicable repairs refer to Plenum

Chamber Hole Sealing reference.

(Ref. Figure 201, Sheet 1 of 2 and Figure 202)

(1). Remove trim (Ref. Sec. 25-30-00,

A. Engine Air Inlet Fairing

Interior Trim Replacement) for access

to passenger/cargo compartment

The engine air inlet fairing on top of the

firewall areas. Open engine access

fuselage structure directs ambient outside air

doors to inspect engine compartment

to the engine air inlet and oil cooler blower.

panels.

The fairing installation consists of a forward

(2). Check for defective, torn, loose or

fairing section and an aft fairing section. Right

missing panels.

and left halves of forward fairing are remov

able. The aft fairing is riveted to fuselage

(3). Inspect aft firewall for security, punc

structure. A UHF/VHF antenna is bonded to

tures and corrosion.

the aft vertical face and is part of aft fairing.

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MAINTENANCE MANUAL

Engine Air Inlet (Plenum Chamber)

(1). Negligible Damage (Ref. Table 201,

Inspection

53-00-00).

(1).

For access, open bypass door on right

(2). Replacement. Replace fittings according

side of engine air inlet and engine

to Structural Repair Manual.

compartment access doors for view of

rear side of plenum (Ref. Figure 202).

7. Aft Section Strut Repair

(2).

Inspect all panels for evidence of

Repair of strut is limited to smoothing out

corrosion, security of rivets and punc

minor dents, scratches or nicks. Replace strut

tures.

if it is badly damaged according to Structural

Repair Manual.

(3).

Inspect engine air shield mounting clips

for secure attachment.

8. Silver Brazing Procedure − Upper Firewall

Shell Patch

(4).

Inspect aft section strut for rivet

corrosion and edge clearance where it

(Ref. Figure 203)

passes through cutout in forward panel.

For applicable repairs (Ref. Aft Section

Consumable Materials

Strut Repair).

(Ref. Section 91−00−00)

Item

Nomenclature

(5).

Ensure that removable forward panels

are secure. Inspect rubber seals for

CM234

Solvent, dry-cleaning

security and partial compression.

CM721

Tape, aluminum foil

(6).

Inspect drive shaft tube fairing for

CM817

Brazing flux

dents, buckled or wrinkled areas and

CM818

Brazing alloy

signs of corrosion.

(7).

Close engine compartment access doors

(1). Remove aft section upper firewall (Ref.

and two air inlet access doors.

Upper Firewall Replacement).

A. Upper Aft Section General Repair

(2). Remove tape and ceramic fiber blankets

from firewall shell.

Ref. FAA AC 43.13-1B and FAA AC 43.13-2B

Inspection and Repair for Standard Sheet

(3). Clean firewall shell with stiff bristle

Metal Repair and Alterations and Structural

brush moistened with solvent (CM234)

Repair Manual for additional repair proce

and wipe dry with clean, dry cloth.

dures.

(4). Smooth out rigidized pattern in area on

B. Aft Fuselage Fittings

which patch will be brazed.

Mast support structure fitting and fuselage

boom fairing frame fitting are critical fatigue-

(5). Cut suitable repair patch for Type 321

loaded parts. Any damage in excess of negligi

stainless steel sheet in thickness range

ble limits specified in (Ref. Aft Section Strut

of 0.0015-0.0018 inch (0.0381-0.04572

Repair) requires replacement of part.

mm).

C. Aft Fuselage Fittings General Repair

(6). Contour patch to match contour of

firewall shell repair area.

Repair of cast and forged fittings should only

be temporary and be performed only when

Use only stainless steel wire

replacement components are not immediately

CAUTION

brush in next step. Particles

available. Replacement of bushings or inserts

from bristles of other metals can contami

that become part of fitting assembly are

nate the patch area and cause brazing to

considered insertion repairs. (Insertion repairs

fail.

are described in FAA AC 43.13-1B and FAA

AC 43.13-2B Inspection and Repair for

(7). Use stainless steel wire brush to clean

Standard Sheet Metal Repair and Alterations

and abrade inner and outer surfaces of

and Structural Repair Manual.)

stainless steel patch and firewall.

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CSP-HMI-2

MAINTENANCE MANUAL

STA. 197.78 BOOM FAIRING

CANTED FRAME FITTING

BOOM FAIRING RING

AFT SECTION STRUT

AFT SECTION

UPPER FIREWALL

ENGINE AIR INLET

INSTALLATION

(PLENUM CHAMBER)

G53-3006

Figure 203. Major Bulkheads and Structural Members − Aft Fuselage

(8). Rinse patch and firewall shell thor

Use extreme care not to over

CAUTION

oughly with clean water and allow to

heat and burn through firewall

air dry.

shell.

(11). Braze patch in place with Class 8 silver

(9). Coat surfaces to be joined with a thin

brazing alloy (CM818), using suitable

even coating of silver alloy brazing flux

torch to heat patch area to temperature

(CM817).

moderately above 1295°F (707°C) flow

point of brazing alloy.

(10). Use clamp or other suitable device to

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

hold patch in place during brazing

seconds before removing clamping

operation.

device.

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MAINTENANCE MANUAL

(13). Remove flux by immersing repaired

area in water at 160°-212°F

Consumable Materials

(72°-101°C) for 40 minutes.

(Ref. Section 91−00−00)

Item

Nomenclature

(14). Thoroughly rinse in clear, running

CM318

Primer

water; air dry, or wipe dry with clean,

dry cloth.

(1). Remove engine inlet forward fairing

(15). Install ceramic blanket on outer surface

assemblies from helicopter (Ref. Engine

of firewall shell.

Inlet Fairing Replacement).

(16). Install aft section upper firewall shell

(2). Remove interior trim panels and wire

(Ref. Upper Firewall Replacement).

harnesses, as applicable, to gain access

to work area at forward area at forward

(17). Install tape (CM721) on flanges of

attach nutplate assembly for L/H and

firewall shell.

R/H engine inlet forward fairings.

9. Plenum Chamber Hole Sealing

(3). Remove existing forward nutplate (for

both L/H and R/H fairing assemblies)

(Ref. Figure 203)

from fuselage frame structure.

(4). Inspect upper fuselage skin for cracks

Consumable Materials

or damage at area of forward nutplate

(Ref. Section 91−00−00)

attachment holes. Also inspect repair

Item

Nomenclature

doublers if, previously installed, on

CM418

Cement, epoxy

upper fuselage skin.

CM424

Sealing compound

CM713

Tape, pressure sensitive

NOTE: If cracking or damage to fuselage skin

or repair doublers is noted, perform the fol

lowing:

All tape must be applied to out

CAUTION

side of inlet surfaces, so that

(a). Stop drill all cracks or remove

any subsequently loosened tape cannot en

damaged skin area or damaged

ter plenum chamber to cause engine dam

repair doublers prior to rework.

age.

Perform all work in accordance with

FAA AC 43.13-1B and FAA AC

(1). Using 10 mil by 1 inch (2.54 cm)

43.13-2B Inspection and Repair for

pressure-sensitive tape (CM713), tape

Standard Sheet Metal Repair and

all 0.130 inch (3.302 mm) diameter or

Alterations and Structural Repair

larger holes.

Manual.

(2). Using sealant (CM424), seal all holes

(b). Field fabricate and install doublers

less than 0.130 inch (3.302 mm)

on outer fuselage skin. Drill

diameter.

0.196-0.204 inch (4.978-5.182 mm)

diameter hole in each doubler to

(3). Rebond loose rubber seals with adhe

match existing hole in fuselage skin

sive (CM418) according to container

for fairing attach screw. Use existing

instructions.

rivet pattern as shown; install

MS20470AD3 rivets with primer

10. Forward Fuselage Section Structure

(CM318).

Rework

(c). Prime and paint double to match

(Ref. Figure 204) The following information is

finish color of helicopter.

a procedure for installing support assemblies

to the fuselage frame structure to provide

(5). Inspect fuselage frame structure

reinforcement at the forward attach points for

(channel) for cracks or damage at

the engine inlet fairing assemblies.

forward nutplate attach areas.

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MAINTENANCE MANUAL

NOTE: If no cracking or damage to fuselage

11. Transmission Compartment Air Baffle,

frame is noted, install 80-369D22400-3 and

Seal and Cover Initial Installation

-4 support assemblies at FWD side of frame

(Ref. Figure 205) (Serial No. 0003D thru

structure using rivets. Drill holes in support

0333D only)

assemblies for nutplates and for conduit

clearances as required. Install nutplate

Consumable Materials

rivets (MS20470AD3) through support,

(Ref. Section 91−00−00)

frame, upper skin and doubler, if installed.

Item

Nomenclature

N/A

Calking compound

CM425

Sealing compound

(6). If cracking or damage to fuselage frame

CM712

Tape, pressure sensitive

is noted, perform the following:

(1). Remove engine air inlet forward

(a).

Stop drill all cracks or remove

fairings.

damaged area prior to installation of

(2). Remove cooling fan inlet screen.

repair angles and support assem

blies. Perform all work in accordance

(3). Remove aft compartment interior trim

panels and blower access door.

with FAA AC 43.13-1B and FAA AC

43.13-2B Inspection and Repair for

(4). Install PN 369D26541-19 upper baffle

Standard Sheet Metal Repair and

assembly as follows;

Alterations and Structural Repair

(a). Position baffle between main trans

Manual.

mission and mast support structure.

Align four attach holes in baffle with

existing holes in structure.

(b).

Field fabricate and install repair

angles at AFT side of fuselage frame

(b). Install baffle with screws, washers

structure (channel) and install

and nuts. Seal screw heads with

sealant (CM425).

80-369D22400-3 and -4 support

assemblies at FORWARD side of

(5). Install PN 369D26542 lower baffle to

frame structure using MS20470AD3

upper baffle with two screws and

rivets. Drill 0.096 inch (2.4384 mm)

washers at matching nutplates in upper

diameter holes in angles to match

baffle.

support assemblies.

(6). Disconnect 5/8 inch (15.875 mm)

diameter drain tube at mast support

base and insert tube though hole in

(c).

Drill holes in support assemblies and

baffle. Safetywire drain tube to struc

repair angles for nutplates and for

ture.

conduit clearance as required. Install

(7). Reinstall blower access door.

nutplate rivets through support,

frame, angle, upper skin and doubler,

(8). Position and install PN 369D26543-11

if installed.

and -12 seal assemblies at lower baffle

and blower access door as shown.

Install seal assemblies with screws and

(7). Check installation of 80-369D22400-3

washers at matching clipnuts on lower

baffle and on blower.

and -4 assemblies and repair angles

and doublers, if installed, for discrepan

NOTE: If excessive gap, 0.060 inch (1.524 mm)

cies.

or more, exists between structure and rub

ber extrusion on seals, fill gap by bonding

strip of adhesive-backed gasket to struc

(8). Reinstall removed components.

ture.

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MAINTENANCE MANUAL

(9).

Position PN 369D26545-11 and -21

NOTE: Not applicable if modified rotor brake

cover assemblies as shown; align cover

handle trim cover panel has already been in

attach holes with existing fairing attach

stalled.

nutplates. Temporarily secure cover

(a). Carefully trim modified trim cover

assemblies with screws and washers, 5

panel assembly (for LH or RH rotor

places each.

brake handle assembly). Locate and

drill screw attach holes in modified

(10).

Using caulking compound, seal all gaps

panel.

between fuselage structure and baffle;

seal and cover assemblies.

(b). Slide modified trim panel boot over

brake handle. Align screw holes and

check panel for fit. Remove panel and

(11).

Remove screws securing cover assem

make minor trim adjustments as

blies. Reinstall engine air inlet forward

required.

fairings.

(c). Install panel if removed and secure

panel with attaching hardware.

(12).

Reinstall aft compartment trim.

(d). Push panel boot aft on brake handle

(13).

For helicopters equipped with Rotor

approximately two inches and secure

Brake Kit, perform the following;

with fastener tape.

Table 201. Weight and Balance Data

Weight

Arm

Moment

lbs

(kg)

inches

(cm)

in−lbs

(kg−mm)

+1.5

(+0.681)

110.2

(279.908)

+169

(+1947.0828)

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CSP-HMI-2

MAINTENANCE MANUAL

DOUBLER (NOTE 1)

0.030 INCH (0.762 MM)

2024-T3 AL ALY SHEET

6.00

CANTED

STA 78.50

0.196-0.204 INCH

(4.978-5.182 MM) HOLE

OUTER SKIN

TO MATCH EXISTING

SCREW HOLE

369A2400-5 ANGLE

STA.

89.39

DOUBLER

369H2508 FRAME

VIEW

3 RIVETS EACH SIDE

OF DAMAGE (AD3)

SKIN

80-369D22400-3, -4

SUPPORT FORWARD

SIDE OF FRAME

NUTPLATE

(NOTE 3)

ANGLE 0.020 INCH

(NOTE 5)

(0.508 MM) AFT

SIDE OF FRAME

FRAME

(NOTES 2, 3)

SUPPORT

(LH SHOWN)

DOUBLER

ANGLE

VIEW

(NOTES 2, 3)

INBOARD

SKIN

80-369D22400-3, -4

SUPPORT FORWARD

SIDE OF FRAME

(NOTE 3)

NOTES:

DOUBLER ON OUTER SKIN TO PICK UP EXISTING RIVETS.

FRAME

REPAIR ANGLE INSTALLED ONLY IF FRAME DAMAGE IS NOTED.

DRILL HOLES IN SUPPORT/ANGLE AS REQUIRED FOR CONDUIT

CLEARANCES.

STOP DRILL ALL CRACKS OR REMOVE DAMAGED AREA.

VIEW

INSTALL NUTPLATE RIVETS THRU SUPPORT, FRAME, ANGLE

G53-3007A

(IF INSTALLED) SKIN AND DOUBLER

Figure 204. Forward Fuselage Section Structure Rework

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MAINTENANCE MANUAL

369D26541-19 BAFFLE

SHIP STRUCTURE

RUBBER

EXTRUSION

GASKET

369D26543 SEAL

369D26541-19

369D26543-11 SEAL

GAP (NOTE 3)

BAFFLE

(LH SHOWN)

NOTE 1

369D26543-21 SEAL

NAS603-8 SCREW (4)

AN960PD10L WASHER (4)

(LH SHOWN)

NOTE 2

369D26542

BAFFLE

369D22070

ACCESS DOOR

369D22070

369D26545-21 COVER

ACCESS DOOR

NAS608-3 SCREW

(-11 OPPOSITE)

AN960PD10L WASHER

369D26542 BAFFLE

369D26543-11 SEAL

NAS602-8 SCREW (2)

369D22025-3 FAIRING PLATE

AN960PD10L WASHER (2)

(NOTE 5)

VIEW B-B

NOTE 4

369D22025 FAIRING

VIEW D-D

(TYP BOTH SIDES)

369D26541-19 BAFFLE

NAS603-8 SCREW (4)

VIEW C-C

AN960PD10L WASHER (4)

MS21043L3 NUT (4)

NOTES:

DURING INSTALLATION OF 369D26542 BAFFLE, DISCONNECT

AND INSERT HEATER DUCT THRU HOLE IN BAFFLE.

AFTER 369D26542 BAFFLE IS INSTALLED, DISCONNECT AND

ROUTE DRAIN TUBE THRU HOLE IN BAFFLE.

IF EXCESSIVE GAP (0.06 X 1.00 OR MORE)EXISTS BETWEEN

STRUCTURE AND RUBBER EXTENSION ON SEALS, FILL GAP BY

BONDING STRIP OF ADHESIVE-BACKED GASKET TO STRUCTURE.

NO. 10 SCREW HOLE IN FAIRING ON SHIPS. DO NOT USE THIS

G53-3009-2

HOLE TO INSTALL COVER OR FAIRING.

TRIM PLATE, AS REQUIRED, TO CLEAR SCREW HEAD.

Figure 205. Installation of Air Baffle, Seal and Cover Assemblies (Sheet 2 of 2)

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MAINTENANCE MANUAL

UPPER AFT SECTION FUSELAGE (500/600N)

MAINTENANCE PRACTICES

NOTE: For all the following items, refer to Sec.

the engine plenum chamber area. With the

53-30-00.

installation of a particle separator, ejector

Upper Firewall

outlets are positioned on each side of the

Firewall and Plenum Chamber Panels

plenum cover.

General Inspection

On the 500N, the R/H side of the aft fairing is

Mast Support Structure

the inlet bypass door which remains on the

Main Rotor Mast

fuselage when the aft fairing is removed.

Firewalls

Firewall Insulation and Soundproofing

On the 600N, the inlet bypass door is just aft

of the mast assembly and just forward of the

1. Engine/Anti−Torque Air Inlet Fan Fairings

engine plenum access cover.

When working near or around

A removable fan hub and transmission gear

CAUTION

engine air and cooling inlets,

box fairing is also located in the fan plenum

use care to prevent entry of foreign objects.

chamber.

(Ref. Figure 201) On the 500N, the engine air

For general maintenance practices for the

inlet fairing on top of the fuselage structure

upper aft section (Ref. Sec. 53-30-00).

directs ambient outside air to the engine air

inlet and the oil cooler blower. The fairing

2. Engine Air and Fan Inlet (Plenum

installation consists of a forward fairing

Chamber Area) Inspection

section and an aft fairing section. Right and

left halves of forward fairing are removable.

(Ref. Figure 201 and Figure 202)

(Ref. Figure 202) On the 600N, the engine air

Avoid FOD, Cover compressor

CAUTION

inlet fairing on top of the fuselage structure

inlet prior to working in plenum

chamber area. Vacuum all FOD debris out of

directs ambient outside air to the engine air

the plenum chamber before removing the

inlet bypass door and the oil cooler blower. The

protective cover from the inlet bell. Severe

fairing installation consists of a forward inlet

damage to the engine may result from entry

fairing sections and an aft fairing section. The

of foreign objects.

controls cover and right and left halves of

forward fairing are removable.

(1). Open the plenum chamber bypass door

by pulling the handle located in the

On the 600N, the engine inlet or particle

cockpit. Open the engine access doors to

separator is mounted aft of the inlet fairings

inspect the rear side of the plenum

and wraps around the engine plenum for

panels.

increased air flow due to the larger engine

installation.

(2). For access, remove the fan air inlet

screen and engine plenum fairing

The aft section consists of an air inlet screen

assemblies.

on top of the fuselage structure which directs

ambient air to the anti-torque fan assembly.

(3). Inspect all panels for evidence of

The engine plenum access cover bolted to the

corrosion, punctures and security of

fuselage and is removable to provide access to

rivets and fasteners.

the engine plenum, particle separator and mist

eliminator (optional equipment) if installed.

(4). Inspect the engine air inlet bypass door

attaching hardware and installation

The engine plenum access cover on the 600N

(Ref. Sec. 71-10-10, Engine Air Intake

helicopter mounts to the aft end of the particle

System).

separator/bypass door frame. The plenum

cover directs air downward for the engine air

(5). Inspect engine air shield mounting for

intake and when removed provides access to

secure attachment.

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MAINTENANCE MANUAL

(6).

Inspect aft section strut for rivets

B. Upper Fuselage Controls Fairing

corrosion and edge clearance where it

Installation

passes though cutout in forward panel.

(1). Inspect upper fuselage controls fairing

(7).

Inspect engine air cooling inlet screen

for cracks, delaminations and overall

for damage, seal deterioration and

general condition.

security.

(2). Position controls fairing to align with

(8).

Inspect fan transmission driveshaft

holes in mounting surfaces.

tube fairing and access panel for dents,

(3). Install attaching hardware.

buckled or wrinkled areas and signs of

corrosion.

5. Engine Inlet Fairings Replacement

(9).

Inspect the fan inlet screen mesh for

The R/H and L/H engine inlet fairings are

condition and security.

made of a lightweight Kevlar fabric and are

used on the 500/600N installation only.

(10).

If fan inlet screen needs repair, re

welded using 0.063 inch (1.600 mm)

A. Engine Inlet Fairing Removal

annealed cres 302 or 304 wire per

(1). Remove hardware from left-hand inlet

AMS5336 or AMS5639.

fairing and remove fairing.

(11).

Visually inspect through the fan inlet

(2). Remove hardware from right-hand

screen for security of the transmission

inlet fairing and remove fairing.

fairing and FOD.

B. Engine Inlet Fairing Installation

(12).

Ensure that forward removable inlet

fairings and engine access doors are

(1). Inspect fairings for cracks, delamina

secure.

tions and condition of pressure sensi

tive tape.

A. Upper Aft Section General Repair

(2). Install right-hand inlet fairing and

(Ref. FAA AC 43.13-1B and FAA AC 43.13-2B

attaching hardware.

Inspection and Repair for Standard Sheet

Metal Repair and Alterations and Structural

(3). Install left-hand inlet fairing and

Repair Manual for additional repair proce

attaching hardware.

dures.

(4). Ensure that 1-1/2 threads protrude

3. Upper Fuselage Controls Fairing (600N)

through nutplates.

6. Anti−Torque Fan Air Inlet Screen

The Upper Fuselage Controls Fairing covers

the flight control rods that travel longitudinal

Replacement

ly aft along the roof of the fuselage for the

A. Fan Air Inlet Screen Removal

rotor collective and cyclic controls.

(1). Remove attaching hardware and

4. Upper Fuselage Controls Fairing

remove air inlet screen.

Replacement (600N)

B. Fan Air Inlet Screen Installation

The Upper Fuselage Controls Fairing is made

of a lightweight Kevlar fabric and is used on

(1). Install air screen and attaching

the 600N installation only.

hardware.

A. Upper Fuselage Controls Fairing

7. Fan Hub and Transmission Cover Fairing

Removal

Replacement

(1). Remove hardware that attaches upper

A. Fan Hub and Transmission Cover

fuselage controls fairing to mounting

Removal

surfaces.

(1). Remove attaching hardware on the fan

(2). Remove controls fairing.

hub transmission fairing.

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HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369D/E/FF-500/600N HELICOPTERS (ISSUED: 1990) - page 15