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

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

MESH SEATS

INITIAL INSTALLATION

1. Mesh Seat Initial Installation

(2). Install ball lock pins.

Procedures in this section are for initial

(3). With release pins raised and locked,

installation of 369H90040-BSC, -501, and

insert the two vertical legs into keyhole

-503 mesh seat installations on Model 369D

fitting slots in floor.

helicopters with to replace the existing cushion

NOTE: For height adjustment, install ball lock

seats.

fittings in any of the three attachment

A. Model Applicability

holes, in the vertical support legs, and in the

aft support fittings. For fore and aft adjust

To determine the applicability of the mesh seat

ment, insert the seat back lower legs in ei

installation for use on each model helicopter,

ther pair of holes in lower frame.

consult the Optional Equipment List (Ref.

Table 202, 01-00-00).

(4). Move vertical support legs to right in

keyhole fittings and unlock release pins

B. Preparation for Installation

in legs. The pins will drop to bottom of

slots and secure support legs to fittings

(1). Check all electrical switches for OFF

in floor.

position. Ensure that BATTERY-OFF-

EXT switch is OFF.

E. Passenger Compartment Individual Seat

Installation

(2). Identify all components and hardware

to be removed for access to work areas.

(Ref. Figure 202)

Protect components from damage and

NOTE: Installation procedures for left and

foreign matter until reinstalled.

right seats are identical.

C. Helicopter Equipment Removal

(1). Position passenger seat horizontal

Prior to installing the mesh seats, a limited

support legs in aft support fittings.

number of items must be removed from the

(2). Install ball lockpins.

helicopter to accommodate seat installation.

(3). Depress pushbutton quick disconnects

(1). Clear seats of seat belts and shoulder

at front legs of seat.

straps.

(4). Insert legs into keyhole fittings in floor.

(2). Lift crew compartment seat cushions

Move legs outboard and release push

away from fuselage seat structure to

buttons to secure legs in place.

release Velcro strips and fasteners.

Remove seats from helicopter (Ref. Sec.

F. Crew Compartment Mesh Seat

25-10-00).

Installation

(3). In passenger compartment, release

(Ref. Figure 201) Installation includes

existing seat quick-disconnect fittings

installing a shim under the inboard forward

at aft bulkhead, then at floor points.

leg of the left crew seat.

Remove existing installed seats from

helicopter.

(1). Position mesh seat back halves in crew

compartment.

D. Passenger Compartment Bench Seat

Installation

(2). Attach upper ends of seat backs to

canted stations with screws and

(Ref. Figure 203)

washers.

(1). Position bench seat horizontal support

(3). Attach lower legs to helicopter seat

legs in aft support fittings.

structure with screws.

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MAINTENANCE MANUAL

(4). Position lower halves of mesh seats on

(1). Install seat belts and shoulder harness

helicopter seat structure.

in crew compartment (Ref. Sec.

25-20-00, Seat Belt/Inertia Reel

(5). Insert shim under inboard forward leg

Replacement).

of left seat. Attach leg to seat structure

with bolt and washer.

(2). Install seat belts and shoulder harness

in passenger compartment.

(6). Attach remaining forward legs of seats

to seat structure with bolts and wash

H. Weight and Balance Data

ers.

Weight and balance data resulting from -BSC,

G. Helicopter Equipment Installation

-501 and -503 mesh seat installations are

After installation of mesh seats, a limited

listed in Table 901. After installation, incorpo

number of items must be replaced in the

rate changes in helicopter weight and balance

helicopter.

records (Ref. Sec. 08-10-00).

Table 901. Weight and Balance Data

Weight

Arm

Moment

Configuration

Pounds (kg)

Inches (cm)

in−lb (kg cm)

−BSC Installation

+20.80

(+9.435)

99.7

(253.24)

+2074

(+2389.5)

−501 Installation

+20.35

(+9.231)

99.6

(252.98)

+2027

(+2335.3)

−503 Installation

+20.80

(+9.435)

99.7

(253.24)

+2074

(+2389.5)

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CSP-HMI-2

MAINTENANCE MANUAL

SEAT BELTS/INERTIA REEL

MAINTENANCE PRACTICES

1. Seat Belts/Inertia Reel Description and

shoulder strap are joined at the end into a

Operation (369D/E/FF − 500N)

single unit for ease of attachment and conve

nience. In one motion, the lap and shoulder

Inertia reel-type seat belt/harness equipment

belts together can be attached to the seat

consists of a shoulder harness, an inertia reel,

buckle.

and a two-piece adjustable seat belt for both

the pilot and copilot.

3. Crew Seat Belt/Harness Cleaning

The shoulder harnesses and seat belts are of

The harness and seat belt may be cleaned

nylon web material with sewn-in length

using a soft-bristle brush and a mild solution

adjusters and end adapters for attachment of

of warm water and laundry detergent.

the harnesses to the seat belts. Inertia reels,

furnished as part of the harnesses, are

4. Seat Belt/Inertia Reel Replacement

mounted on the Sta. 78.50 canted frame. The

(369D/E/FF − 500N)

reels permit the pilot and copilot freedom for

(Ref. Figure 201, Figure 202 and Figure 203)

slow, deliberate shoulder movement, but lock

with any sudden forward movement. Full

(1). For access to seat belt attach fittings,

extension or retraction of the straps on the

remove crew compartment seats.

spring-loaded reels is approximately 25 inches

(63.5 cm).

(2). Remove inertia reel, with harness, from

canted bulkhead lateral beam by

Some installations have a handle: with the

removing four bolts.

handle up, the inertia reel operates normally;

with the handle down, the inertia reel is locked

(3). Install replacement harness by securing

up to restrain movement.

inertia reel, with harness, to canted

bulkhead lateral beam.

2. Seat Belts/Inertia Reel Description and

Operation (600N)

(4). Install replacement seat belts and

shoulder straps as shown. Place snap

The crew seats utilize a four-point restraint

end fittings up or down to eliminate any

harness. This harness combines the lap seat

twist in seat belt.

belts with double shoulder straps attached to

an inertia reel mechanism. Both mid and aft

(5). Tongue portion of center passenger lap

passenger seats are equipped with a three-

belt must be installed on right side and

point restraint system. The lap seat belt and

buckle portion on left side as shown.

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MAINTENANCE MANUAL

FITTING

INERTIA REEL

SNAP END

FITTING

SEAT BACK

SEAT BELT FITTING

NOTE 1

ATTACHMENT

PASSENGER COMPARTMENT

INERTIA REEL

FLOOR STRUCTURE

HARNESS MUST UNREEL

IN DIRECTION SHOWN

NOTE 2

41° ±3°

90° LIMITS OF CUTOUT

IN ALUM. HOUSING

INERTIA REEL

NOTE 1

NOTES:

SHOWN WITHOUT CUSHION

FOR CLARITY.

CENTER CUSHIONS AND SEAT

BELTS ONLY FOR 3-PLACE

SEATING.

CREW COMPARTMENT

INERTIA REEL

SEAT STRUCTURE

G25-2002

Figure 201. Seat Belt/Inertia Reel Installation (Sam Browne Style) (369D)

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CSP-HMI-2

MAINTENANCE MANUAL

PASSENGER / CARGO

COMPARTMENT AFT

BULKHEAD

SNAP END FITTING

(HOOK UP)

SEAT BELTS AND SHOULDER HARNESSES

SNAP END FITTING

(HOOK DOWN)

SNAP END FITTING

(HOOK UP)

NYLON WEBBING

SHOULDER STRAP

ADAPTER

NOTE:

SLIDE BAR

(NOTE)

SNAP END FITTING

HARNESS LENGTH ADJUSTER.

(HOOK UP)

SNAP END FITTING

(HOOK DOWN)

NYLON WEBBING

SEAT BELT

INERTIA REEL

BUCKLE

LATCH

ADAPTER

SNAP END FITTING

(NOTE)

ADAPTER

(HOOK DOWN)

(NOTE)

NYLON WEBBING

SNAP END

SHOULDER STRAP

FITTING

HARNESS MUST UNREEL

IN DIRECTION SHOWN

41° ±3°

90° LIMITS OF CUTOUT

IN ALUM. HOUSING

BUCKLE

ADAPTER

LATCH

ADAPTER

FITTING

(NOTE)

INERTIA REEL

SNAP END FITTING

NYLON WEBBING

SEAT BELT

PILOT AND COPILOT SEAT BELT AND SHOULDER HARNESS ASSEMBLY

G25-2003

Figure 202. Seat Belt/Inertia Reel Installation (Yoke Style) (369D)

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MAINTENANCE MANUAL

5. Crew Seat Belt/Harness Replacement With

(2). Remove inertia reel, with harness, from

Manual Lock Option (369D/E/FF − 500N)

fiberglass mount by loosening four bolts

and upper ferrule nut.

(3). Install seatbelts by fastening snap type

(Ref. Figure 204 and Figure 205)

end fittings to bulkhead structure

fittings.

(1). Remove seatbelts by unfastening snap

(4). Install inertia reel, with harness, to

type end fittings from bulkhead

fiberglass mount with ferrule nut and

structure fittings.

four bolts, nuts and washers.

CONTROL HEAD ROTATED

90° CW FOR CLARITY

UPPER FERRULE NUT

AUTOMATIC

MANUAL LOCK

LOWER

INERTIA

FERULE

REEL ASSY

CABLE

NUT

CONTROL ASSY

ADJUSTER

TAB RELEASE

(TYP)

0101935-1 SHOULDER

HARNESS ASSY

1.88-2.12 IN. (4.776-5.385 CM)

WIDE WEBBING

ADJUSTER

2.88-3.12 IN. (7.315-7.925 CM)

END FITTING

WIDE WEBBING LAP BELT ASSY

LINK

LATCH

(0101936-1 ASSY)

ADJUSTER

G25-2006A

Figure 204. Webbed Shoulder Harness and Seat Belt Installation with Manual

Inertia Reel Lock (369D)

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MAINTENANCE MANUAL

LOW SHOULDER BEAM INSTALLATION

HIGH SHOULDER BEAM INSTALLATION

G25-2005

Figure 205. Crew Inertia Reel Installation with Manual Inertia Reel Lock

(369D/E/FF − 500N)

6. Seat Belt/Inertia Reel Testing

leased, harness strap should automati

cally reel back into reel. Exert a sudden

(Ref. Pull tests of seat belts and shoulder strap

forward pull on seat belt or shoulder

harnesses shall be accomplished in accordance

strap to ensure inertia reel locks.

with FAA AC 43.13-1B, Aircraft Inspection

and Repair for Standard Sheet Metal Repair

(2).

Inspect inertia reels, snap end fittings,

and TSO C22.

adjusters, links, buckles, latches and

belt attachment fittings for cracks,

7. Seat Belt/Inertia Reel Inspection

wear, corrosion and deformation. Check

for freedom from binding, ease of

Ensure center passenger lap

WARNING

adjustment and operation as applicable.

belt is installed with tongue

If doubt exists as to strength, perform

portion to the right of the seat and

pull test (Ref. Seat Belts/Inertia Reel

buckle portion to the left. (Quick re

lease of the lap belt and shoulder strap

Testing).

may be impaired if the assembly is im

(3).

Inspect shoulder harnesses and seat

properly installed.) If tongue and

belts for worn, frayed or deteriorated

buckle portions are reversed, remove

condition, and loose stitching.

and reinstall in correct positions and

document reinstallation in Compliance

(4).

(Manual Lock Option) Check mechani

Record of Helicopter Log Book.

cal inertia lock mechanism for proper

(1). Pull seat belt or shoulder strap out of

operation, with handle up and with

inertia reel to full extended length.

handle down. Inspect fiberglass mounts

Ensure harness strap cannot be pulled

for cracking and separation. Inspect

out of inertia reel. With tension re

laminates for debonding.

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MAINTENANCE MANUAL

8. Seat Belt/Inertia Reel Repair

(2). Remove hardware that attaches inertia

reel to mounting surface.

(1). Replace seat belts and shoulder straps

if fabric is frayed, worn, deteriorated,

(3). Remove complete seat belt restraint

stitching is loose, or if enertia reels are

harness from seat.

destroyed or do not function properly.

(2). Polish minor nicks and scratches.

B. Seat Belt/Restraint Harness Installation

Restore protective finish to aluminum

parts as required.

(1). Position lap seat belt and shoulder

(3). Repair fiberglass mounts (Ref. Sec.

harness into seat assembly.

25-30-00, Boltaron Trim Panels

Repair).

(2). Engage end fittings attaching lap seat

belts.

9. Seat Belt/Restraint Harness, Crew Seat,

Replacement (600N)

(3). Install hardware attaching inertia reel

(Ref. Figure 206)

to mounting surface.

A. Seat Belt/Restraint Harness Removal

(4). Ensure proper engagement and release

(1). Release end fittings to remove lap seat

of seat buckle and inertia reel mecha

belts.

nism.

ADJUSTOR

SHOULDER

HARNESS

SHOULDER

HARNESS

LAP

ADJUSTOR

LAP

END FITTING

SEAT BELT

BUCKLE

6G25-070

Figure 206. Seat Belt/Restraint Harness Installation, Crew Seat (600N)

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MAINTENANCE MANUAL

10. Seat Belt/Restraint Harness, Mid

11. Seat Belt/Restraint Harness, Aft

Passenger Seat, Replacement (600N)

(Ref. Figure 207) These three individual seat

(Ref. Figure 207)

belt harnesses are completely contained in the

seat assembly and attach to the seat frame.

A. Seat Belt/Restraint Harness Removal

This feature aids in the quick removal and

installation of the mid bench seat assembly.

(1). Remove hardware that attaches inertia

reel end of harness to mounting

A. Seat Belt/Restraint Harness Removal

surface.

(1). Remove hardware that attaches inertia

(2). Release end fitting that attaches lap

reel end of harness to seat back.

belt to mounting surface.

(2). Release end fitting that attaches lap

seat belt to seat frame.

(3). Release end fitting that attaches buckle

end of harness to mounting surface.

(3). Release end fitting that attaches buckle

end of harness to seat frame.

(4). Remove seat belt/restraint harness.

B. Seat Belt/Restraint Harness Installation

(1). Position seat belt/restraint harness into

seat assembly.

(2). Engage end fitting attaching buckle end

of harness to mounting surface.

of harness to seat frame.

(3). Engage end fitting attaching lap belt to

mounting surface.

seat frame.

(4). Install hardware attaching inertia reel

end of harness to mounting surface.

end of harness to seat back.

(5). Ensure proper engagement and release

of seat buckle and inertia reel mecha

nism.

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MAINTENANCE MANUAL

12. Comfort Clip Installation and Decal

position as close as possible next to

Application (369D/E/FF − 500N)

inertia reel.

(Ref. Figure 208 and Figure 209) The comfort

(4). After each flight, reposition comfort clip

clip is designed to maintain proper strap

on harness strap at original position

tension and relieve excessive pressure of the

next to buckle.

inertia reel shoulder harness on the pilot or

passenger during flight. It is available for

(5). Clean panel or door frame where decal

installation on helicopters equipped with Sam

is to be applied. Decals will not adhere

Browne style seat belt assemblies.

to a greasy or soapy film.

(1). Pry open slot on underside of clip.

(6). Mark location(s) of decal per the

illustrations.

(2). Insert harness strap in slot.

(3). After seat belt and shoulder harness

(7). Peel backing off decal and position. Use

assembly is fastened and adjusted for

a cloth to squeeze all bubbles from

individual comfort and safety, slide

under the decal, working from the

comfort clip up on harness strap and

center outward.

DECAL

CENTER DECAL BETWEEN END OF

DOOR FRAME AND FIRST SCREW

VIEW LOOKING OUTBOARD FROM

COMFORT CLIP INSTALLATION

G25-2001

Figure 208. Comfort Clip Installation and Crew Compartment Decal

Application (369D/E/FF − 500N)

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CSP-HMI-2

MAINTENANCE MANUAL

SEATING/BELTS (FOUR ON THE FLOOR)

MAINTENANCE PRACTICES

1. General

(3). Remove seat belt assemblies and

shoulder straps by unsnapping hooks at

NOTE: This option has an aircraft effectivity

structure-mounted fittings.

limit. Refer to CSP-IPC-4 for effectivity.

B. Seating/Belt Installation

The four on the floor seating and belt installa

tion is designed for maximum use of the

(Ref. Figure 902 and Figure 903)

passenger compartment for transportation of

(1). Install seat assemblies by placing seat

personnel. The installation consists of four

in position and inserting tabbed rivets

floor-installed seat assemblies with seat belts

into holes in floor stiffeners (Ref.

and shoulder straps at each position. The two

Figure 903).

aft-facing seat positions include head and

back restraint panels mounted on Cant. Sta.

(2). Install restraint panels by securing

78.50 structure.

each panel at bracket assemblies with

four screws and washers (Ref.

The shoulder strap is adjusted to cross the

Figure 902).

passenger's chest from outboard shoulder to

center of lap where it joins the seat belt

(3). Install seat belt assemblies and

assembly. Seat belts are adjusted by individual

shoulder straps by snapping hooks to

passengers for a close and comfortable fit.

structure-mounted fittings.

The installation for the early configuration is

3. Seating/Belt Inspection

designed for use with a high shoulder beam.

The current configuration installation is used

(Ref. Sec. 25-20-00, Seat Belt/Inertia Reel

for a low shoulder beam.

Inspection)

NOTE: Shoulder straps for aft-facing passen

4. Seating/Belt Cleaning

gers are installed on early configuration he

licopters only.

(Ref. Sec. 20-20-00, Fuselage Interior Trim or

Upholstery Cleaning or 25-20-00, Crew Seat

2. Seating/Belt Replacement

Belt/Harness Cleaning)

A. Seating/Belt Removal

5. Seating/Belt Repair

(Ref. Figure 902 and Figure 903)

(1). Repair minor tears and cuts to the seat

and restraint panel coverings (Ref. Sec.

(1). Remove seat assemblies by lifting

25-20-00, Seat Belt/Inertia Reel

tabbed rivets from holes in floor

Repair).

stiffeners (two per seat), then lift seat

up (Ref. Figure 903).

(2). Replace unserviceable seats and

restraint panels.

(2). Remove restraint panels by removing

four screws and washers from each

(3). Seat belts or shoulder straps that show

panel bracket assembly (Ref.

signs of wear, deterioration, fraying, or

Figure 902).

loose stitching must be replaced.

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CSP-HMI-2

MAINTENANCE MANUAL

SEATING/BELTS (FOUR ON THE FLOOR)

INITIAL INSTALLATION

1. Seating/Belts (Four on the Floor) Initial

(3). Remove passenger compartment carpet

Installation

floor covering.

NOTE: This option has an aircraft effectivity

(4). Remove aft trim panel from Cant. Sta.

limit. Refer to CSP-IPC-4 for effectivity.

78.50 and disconnect cigarette lighter

wiring.

Consult the optional equipment table (Ref.

Table 202, Sec. 01-00-00) for model applicabil

(5). Remove bulkhead trim panels or

ity for seating/belts (369H90035) installations.

insulation blankets at Sta. 124.00 in

The -501 and -503 installations are covered in

area of WL 40.00 and BL 20.00 right

the following paragraphs.

and left seats.

A. Preparation for Installation

(6).

(369D only) Remove crew compartment

outboard seat backs.

Consumable Materials

C. Seating and Belts Installation − General

(Ref. Section 91−00−00)

Item

Nomenclature

Installation of the seating and belts for four

CM318

Primer

includes procedures for installing restraint

panels on Cant. Sta. 78.50, seat assemblies,

shoulder straps, and seat belt assemblies.

(1). Ensure all electrical switches are set to

OFF position. Recheck master switch

for OFF position.

Consumable Materials

(Ref. Section 91−00−00)

(2). Identify all components and attaching

Item

Nomenclature

hardware to be removed for access to

CM318

Primer

work areas. Protect components from

damage and foreign matter until

reinstalled.

NOTE:

(3). After drilling or cutting, remove burrs

D Use Cleco clamps and fasteners as re

and metal particles. Apply a thin coat of

quired to facilitate rivet installation, and

primer (CM318) to all bare metal areas.

install rivets with wet primer (CM318).

D Rivets are equally spaced and are normal

NOTE: An application of color-matched paint

ly positioned twice the diameter of the riv

may be applied to primer painted reworked

et shank from the outside edge of the ma

areas and to installed hardware.

terial, edge joggle, or flange radius.

B. Removal of Existing Equipment

D. Cant. Sta. 78.50 Brackets, Fittings and

Prior to installing the seating and belts for

Restraint Panels Installation

four, a limited number of items must be

removed from the helicopter passenger

(Ref. Figure 901, Figure 902 and Figure 904)

compartment to accommodate installation.

(1). On Cant. Sta. 78.50, WL 22.45, remove

(1). Remove passenger compartment seats

four existing bracket rivets in area of

by releasing quick-disconnects on

LBL 8.25 and four rivets in area of LBL

seating structure at floor and firewall

19.25.

fittings.

(2). Position bracket assemblies to match

(2). Remove existing passenger compart

holes in removed rivet pattern. Locate

ment seat belt and shoulder strap

and drill four 0.1285 inch (3.2639 mm)

assemblies.

holes in each bracket.

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MAINTENANCE MANUAL

LBL 15.50

LBL 8.50

BRACKET

BRACKET ASSEMBLY

ASSEMBLY

0.50 IN. (12.7 MM) (TYP)

RIVET (2)

CANT. STA 78.50

0.75 IN. (19.05 MM)

0.83 IN. (21.082 MM)

LH SHOWN

0.50 IN. (12.7 MM)

0.42 IN. (10.668 MM)

RH OPPOSITE

RIVET (4)

CANT. STA 78.50

BRACKET ASSEMBLY

NOTES: DRILL 0.217-0.229 IN.

(5.5118-5.8166 MM) HOLES (4) IN EACH

RESTRAINT PANEL ASSEMBLY; LOCATE

PICK UP EXISTING RIVETS

FROM BRACKETS. DRILL HOLES IN TRIM

PANEL ASSEMBLIES AS APPLICABLE.

LBL

20.75

19.25

17.00

LH SHOWN

11.30

8.25

6.00

RH OPPOSITE

LBL

RBL

15.50

8.50

0.00

8.50

RESTRAINT PANEL

ASSEMBLY

BRACKET ASSEMBLY

RESTRAINT PANEL

BRACKET

ASSEMBLY

WL 45.36

BRACKET

WL 45.30

ASSEMBLY

BRACKET ASSEMBLY

FITTING

FITTING SUPPORT

SUPPORT

TRIM

SHOULDER STRAP

PANEL

SHOULDER

STRAP

WL 28.44

BRACKET

WL 22.45

ASSEMBLY

SEAT AS

WL 21.50

BRACKET ASSEMBLY

SEMBLY

LBL 20.75 LH

RBL 20.75 RH

BRACKET AS

LBL 19.25 LH

SEMBLY

RBL 19.25 RH

LBL 17.00 LH

RBL 17.00 RH

LBL 11.30 LH

RBL 11.30 RH

LBL 8.25 LH

RBL 8.25 RH

RESTRAINT PANELS BRACKET

CANT. STA 78.50

WL 13.10

LOCATION HIGH BULKHEAD

SECTION D-D

G25-2008A

Figure 901. Restraint Panel Assemblies and Hardware Installation (369D)

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MAINTENANCE MANUAL

BRACKET ASSEMBLY LBL 19.50

LBL 8.50

BRACKET

ASSEMBLY

0.50 IN. (12.7 MM) (TYP)

RIVET (2)

CANT. STA 78.50

0.94 IN. (23.876 MM)

0.42 IN. (10.668 MM)

1.02 IN. (2.59 CM)

0.50 IN. (12.7 MM)

LH SHOWN

RH OPPOSITE

RIVET (4)

CANT. STA 78.50

BRACKET ASSEMBLY

NOTES: DRILL 0.217-0.229 IN.

(5.5118-5.8166 MM) HOLES (4) IN EACH

RESTRAINT PANEL ASSEMBLY; LOCATE

PICK UP EXISTING RIVETS

FROM BRACKETS. DRILL HOLES IN TRIM

PANEL ASSEMBLIES AS APPLICABLE.

LBL

20.75

19.25

17.00

LH SHOWN

11.30

8.25

6.00

RH OPPOSITE

RBL

LBL

19.50

LBL

RBL

19.50

8.50

0.00

8.50

RESTRAINT PANEL

ASSEMBLY

RESTRAINT PANEL

BRACKET

ASSEMBLY

BRACKET

ASSEMBLY

BRACKET ASSEMBLY

WL 37.85

TRIM

PANEL

WL 28.44

BRACKET

ASSEMBLY

WL 22.45

WL 21.50

SEAT

BRACKET ASSEMBLY

ASSEMBLY

LBL 20.75 LH

RBL 20.75 RH

BRACKET AS

LBL 19.25 LH

SEMBLY

RBL 19.25 RH

LBL 17.00 LH

RBL 17.00 RH

LBL 11.30 LH

RBL 11.30 RH

LBL 8.25 LH

RBL 8.25 RH

RESTRAINT PANELS BRACKET

CANT. STA 78.50

WL 13.10

LOCATION HIGH BULKHEAD

SECTION D-D

G25-2007A

Figure 902. Restraint Panel Assemblies and Hardware Installation (369E/FF − 500N)

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MAINTENANCE MANUAL

(3). Hold brackets in position with Cleco

(8).

(369D only) Install shoulder strap

fasteners and drill four 0.1285 inch

fittings for aft-facing passenger seat as

(3.2639 mm) holes through upper flange

follow:

of each bracket and through Cant. Sta.

(a). On left side of Cant. Sta. 78.50

78.50 web.

bulkhead frame, locate four existing

(4). Install bracket assemblies with 16

nutplates in area of WL 41.06 and BL

rivets.

24.74.

(5). Repeat last four steps to install two

(b). Attach shoulder strap fitting with

bracket assemblies to opposite side.

four screws.

(6).

(369D only) Install bracket assemblies

(c). On right side of Cant. Sta. 78.50

as follows:

bulkhead frame, locate four existing

nutplates in area of WL 41.06 and BL

(a). On WL 45.33, position bracket

24.74.

assembly at LBL 15.50 and drill two

(d). Attach shoulder strap fitting with

0.1285 inch diameter holes through

four screws.

bracket and Cant. Sta. 78.50 channel.

(e). Attach L/H fitting to nutplates in L/H

(b). Install bracket assembly with two

tee using four screws.

blind rivets.

(f). Attach R/H fitting to nutplates in

(c). On WL 45.33 L/H, position bracket

R/H tee using four screws.

assembly at LBL 8.50 and drill two

0.1285 inch diameter holes through

(g). Cut out slots in removed passenger

bracket and Cant. Sta. 78.50 channel.

compartment forward trim panels to

accommodate lugs of shoulder strap

(d). Install bracket assembly with two

fittings.

blind rivets.

(9).

Drill four 0.217-0.229 inch

(e). Repeat last four steps to install two

(5.5118-5.8166 mm) holes in forward

bracket assemblies R/H opposite.

trim panel, and four holes in each

restraint panel. Locate holes from

(7).

(369E/FF only) Install bracket assem

bracket assemblies and install as in

blies as follows:

steps (1). thru (8).

(a). On WL 37.85, position bracket

(10).

Reinstall forward trim panel (connect

assembly at LBL 19.50 L/H. Drill two

cigarette lighter wiring).

0.1285 inch (3.2639 mm) holes

through bracket and Sta. 78.50

(11).

Install passenger compartment carpet

channel.

floor covering.

(b). Install bracket assembly with two

(12).

(369D only) Install fitting cap to L/H

blind rivets.

and R/H shoulder strap fittings with

two screws each side.

(c). On WL 37.85, position bracket

assembly at LBL 8.50 L/H. Drill two

(13).

Install restraint panel to L/H side over

0.1285 inch (3.2639 mm) holes

trim panel with four washers and

through bracket and Cant. Sta. 78.50

screws.

channel.

(14).

Install restraint panel to R/H side over

(d). Install bracket assembly with two

trim panel with four washers and

blind rivets.

screws.

(e). Repeat last four steps to install R/H

(15).

Reinstall crew compartment seat back

bracket assemblies.

assemblies.

Page 904

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

E. Seat Assemblies Installation

NOTE: All seat belt assemblies are to be in

stalled as shown and as noted on cloth iden

(Ref. Figure 903)

tification labels attached to each seat belt

assembly. The two center belts are installed

NOTE: Seat assemblies are position-inter

with hooks down.

changeable.

(7). Connect adjustable portion of seat belt

(1). Position seat assemblies on floor

assembly to the R/H fitting and nonad

structure to locations specified.

justable portion to center fitting.

(2). Secure seats in position by pressing

(8). Connect adjustable portion of seat belt

tabbed rivets into holes in floor stiffen

assembly to L/H fitting and nonadjust

ers.

able portion to center fitting.

F. Aft Seat Belt Assemblies and Shoulder

G. Forward Seat Belt Assemblies and

Straps Installation

Shoulder Straps Installation

(Ref. Figure 903)

(Ref. Figure 904)

(1). On both left and right sides of Cant.

(1).

(369D only) Connect a shoulder strap to

Sta. 128.00 locate four existing nut

each shoulder strap fitting on Cant.

plates in areas of WL 40.0 and BL 20.0.

Sta. 78.50.

(2). Attach a shoulder strap support fitting

NOTE: Adjust shoulder strap to cross passen

on each side, using four washers and

ger's chest from outboard shoulder to inner

screws for each fitting.

center lap area.

(3). Cut out slots in removed trim panels or

(2). Locate the four tiedown fitting holes on

insulation blankets to accommodate

the first floor stiffener aft of Cant. Sta.

lugs of new support fittings.

78.50.

(4). Reinstall trim panels or insulation

(3). Install a cargo tiedown fitting in each

blankets.

floor stiffener hole.

(5). Connect a shoulder strap to each

(4). Connect adjustable portion of seat belt

fitting.

assembly to the L/H fitting and the

NOTE: Adjust shoulder strap to cross passen

nonadjustable portion to the L/H center

ger's chest from outboard shoulder to inner

fitting.

center of lap.

(5). Connect adjustable portion of seat belt

(6). Locate the three existing cargo floor

assembly to the R/H fitting and the

seat belt fittings on the passenger

nonadjustable portion to the R/H center

compartment floor at Sta. 124.00.

fitting.

Page 905

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

H. Weight and Balance Data

(Ref. Table 901) After installation, incorporate

changes to helicopter weight and balance

records as instructed (Ref. Sec. 08-10-00).

Table 901. Weight and Balance Data

Weight

Arm

Moment

Configuration

Pounds (kg)

Inches (cm)

in−lb (kg cm)

369H90035−501

Added

+30.2

(+13.698)

+93.5

(+237.49)

+2824

(+3253.6)

Removed

− 32.7

(−14.832)

+108.6

(+275.84)

− 3551

(−4091.2)

369H90035−503

Added

+31.2

(+14.152)

+92.1

(+233.93)

+2874

(+3311.2)

Removed

Seat Belts (2)

− 5.1

(−2.313)

+117.2

(+297.69)

− 598

(−689.0)

Bench Seat

− 24.7

(−11.204)

+111.0

(+281.94)

− 2742

(−3159.1)

Page 906

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

SHOULDER STRAP

ATTACH FITTING

L.H. SHOWN

R.H. OPPOSITE

SCREW (4 REQ'D)

HIGH BULKHEAD

WASHER (4 REQ'D)

STA. 124.00 SHOULDER STRAP FITTING

SHOULDER STRAP

ATTACH FITTING

R.H. SHOWN

L.H. OPPOSITE

FITTING CAP

R.H. SHOWN

L.H. OPPOSITE

SCREW (4 REQ'D)

SCREW (2 REQ'D)

LOW BULKHEAD

STA. 78.50 SHOULDER STRAP FITTING

SHOULDER STRAP

(TYP)

STA. 78.50

WL 28.44

WL 32.00

STA. 124.00

STA. 78.50 SHOULDER STRAP AND FITTINGS

STA. 124.00 SHOULDER STRAP AND FITTINGS

NOTE:

PICK UP EXISTING NUTPLATES LO

CATED ON CANT. STA. 78.50 BULKHEAD FRAME

AND CANT. STA. 124 BULKHEAD FRAME.

G25-2009

Figure 904. Shoulder Straps and Fittings Installation (369D/E/FF − 500N)

Page 908

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25-21-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

INTERIOR TRIM

MAINTENANCE PRACTICES

1. Interior Trim

A. Cyclic Stick Control Cover Replacement

(L/H Command)

Trim panels, covers, and applicable attaching

devices are found in the following locations:

(Ref. Figure 201)

(1). Models 369D/E/FF - 500N crew

compartment (Ref. Figure 201).

(1). Remove four upper attaching cover

screws. Remove velcro attached boot

(2). Models 369D/E/FF - 500N passenger

assemblies from cover. Tip cover

compartment (Ref. Figure 202).

forward to remove two lower attaching

screws.

(3). Model 369D crew and passenger

compartments - R/H command helicop

ters with center console (Ref.

(2). Remove cover from cyclic stick assem

Figure 203).

bly and slip boot assemblies over cyclic

stick grips.

(4). Floor trim covering and applicable

methods of attachment (Ref.

(3). To replace, slip boot assemblies over

Figure 204).

cyclic stick grips and position cover in

A. Cyclic Stick Control Cover

place. Attach boot assemblies to cover

with the velcro fasteners.

(Ref. Figure 201) A cyclic stick control cover

protects the cyclic control linkage from objects

(4). Tip cover forward and install two lower

that might jam or foul control linkage. The

attaching screws. Install four upper

cover extends between the pilot's and copilot's

attaching screws.

cyclic sticks at the seat bulkhead and covers

the cyclic control linkage. Cyclic stick openings

B. Copilot’s Collective Pitch Stick Cover

in the cover are protected by boot assemblies

Replacement (L/H Command)

(dust covers) secured to the cover with Velcro

hook and pile fasteners. The cyclic sticks pass

through elastic ringed openings in the dust

(Ref. Figure 201)

covers.

(1). Remove crew seats.

B. Copilot’s Inboard Collective Pitch Stick

Cover

(2). Remove attaching hardware. While

The inboard collective pitch stick cover on L/H

carefully removing cover, ensure sliding

command helicopters provides access to the

protective cover remains fixed to

underseat flight controls linkage and forms a

collective pitch stick. Partial removal of

protective guard for the collective friction

the cyclic stick control cover may be

mechanism on the inboard collective pitch

required.

stick. A sliding protective cover at the collec

tive pitch stick slotted opening guards against

(3). Spread sliding cover at collective stick

foreign object entry.

and remove. If necessary, remove nylon

grommet on stick (Ref. Sec. 67-10-00,

2. Interior Trim Replacement

Pilot's Collective Pitch Stick Replace

ment).

NOTE: Electrical wires from passenger com

partment cigarette lighter, optional utility

light, and running time meter must be dis

(4). To replace, install nylon grommet on

connected before removing and reconnected

collective stick. Spread sliding cover at

before installing associated trim panel or

collective stick hole and fit over nylon

cover (Ref. Chap. 96).

grommet.

Page 201

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

VELCRO FASTENER

CONTROL TUNNEL PANEL

(NOTES 1, 5)

CAP

(NOTE 2)

VELCRO

FASTENER

4 PLCS

MAP CASE

SHOULDER BEAM PANEL

TRIM COVER

(NOTE 4)

6 PLCS

MAP POCKET

LH BOOT

RH BOOT

ASSEMBLY

CYCLIC STICK CONTROL COVER

LID

3 PLCS

VELCRO

FASTENER

MAP CASE COVER

COLLECTIVE STICK COVER

NOTES:

USED ONLY WITH OPTIONAL DUAL CONTROLS.

USED ONLY WITH SINGLE CONTROLS.

REMOVED FOR OPTIONAL UTILITY LIGHTS.

COPILOT'S COLLECTIVE PITCH STICK COVER

TRIM COVER SHORTER ON HIGH BULKHEAD MODELS.

(NOTE 1)

TRIM COVER LONGER ON HIGH BULKHEAD MODELS.

G25-3001-1

Figure 201. Crew Compartment Interior Trim (Sheet 1 of 2)

Page 202

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

VELCRO FASTENER

ASSIST STRAP

CANTED BULKHEAD PANEL

(RIGHT SIDE)

3 PLCS

2 PLCS

DOOR PANEL

UPPER SIDE PANEL

ASSIST HANDLE

NOTE 6

VELCRO FASTENER

LOWER INSTRUMENT

4 PLCS

HOUSING PANEL

8 PLCS

FORWARD PANEL

NOTES: (CONT.)

USED FOR RUNNING TIME METER ON MODEL 369D ONLY.

UNLESS OTHERWISE INDICATED, LEFT SIDE ITEMS ARE

OUTBOARD AFT PANEL

SHOWN (EQUIVALENT RIGHT SIDE ITEM IS APPROXIMATELY

MIRROR IMAGE OPPOSITE).

DOOR MAIN TRIM PANELS NOT SHOWN.

G25-3001-2

Figure 201. Crew Compartment Interior Trim (Sheet 2 of 2)

Page 203

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

VELCRO FASTENER

COVER

(8 PLCS)

(2 PLCS)

VELCRO FASTENER

SCREW

(4 PLCS)

SCREW

(2 PLCS)

STANDOFF

BRACKET

(2 PLCS)

HIGH FORWARD BULKHEAD PANEL

(LOOKING FORWARD)

VELCRO FASTENER

STANDOFF

(2 PLCS)

SCREW

(2 PLCS)

BRACKET

LOW FORWARD BULKHEAD PANEL

(LOOKING FORWARD)

BRACKET

LIGHTER

BLANK COVER

SCREW

(6 PLCS)

ASHTRAY

LOW BULKHEAD CONVENIENCE PANEL

NUT

(12 PLCS)

WASHER

(12 PLCS)

SCREW

(4 PLCS)

SCREW

PLUG

(12 PLCS)

AFT DOOR FRAME

(LEFT SIDE)

HIGH BULKHEAD CONVENIENCE PANEL COVER

BULKHEAD PANEL

(NOTES 1, 2)

POCKET

NOTES:

NOT USED WITH OPTIONAL ROTOR BRAKE EQUIPMENT.

LITERATURE POCKET

FOR INFORMATION ON OPTIONAL EQUIPMENT USED ON

THIS PANEL, REFER TO OPTIONAL EQUIPMENT LIST

(REF. SEC. 01-00-00).

G25-3002-1

Figure 202. Passenger Compartment Interior Trim (Sheet 1 of 2)

Page 204

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

(5). Position cover over collective stick and

F. Carpeting

start upper end of sliding cover into

cover tracks.

Consumable Materials

(Ref. Section 91−00−00)

(6). Slowly lower cover and guide remainder

Item

Nomenclature

of sliding cover upward in cover tracks.

CM405

Adhesive

(7). Secure with screws and washers.

CM718

Tape, double-faced

(8). Install crew seats.

Carpeting is secured in place with dou

NOTE:

ble-faced tape or bonded with adhesive, and

C. Inboard Collective Pitch Stick Cover

should not be removed unless replacement

Replacement (R/H Command)

or repair is required.

(Ref. Figure 203) At installation, tuck bottom

(1). Tear away carpeting (if bonded) and

edge of lower curtain under support.

clean surface with wire brush. Bond

replacement carpeting using adhesive

Curtains must not fold inward

CAUTION

(CM718).

through full travel of the collec

tive stick. Folding inward may result in en

(2). Lift carpeting (if taped) away from floor

tanglement with collective stick friction

and remove double-faced tape. Apply

gear mechanism.

new double-faced tape (CM718) and

press replacement carpeting in position.

D. Transmission Panel

3. Interior Trim Inspection

(Ref. Figure 203) Remove low or high bulkhead

convenience panel before removing transmis

(1).

Inspect interior trim for tears, cuts,

sion panel.

breaks, or other evidence of unservice

able condition.

E. Log Book Holder (Optional for R/H

(2).

Inspect trim panels and covers for

Command)

loose, damaged, or missing Velcro

fasteners, as applicable.

(Ref. Figure 203)

(3).

Inspect fuselage structure for loose,

damaged, or missing Velcro fasteners,

Consumable Materials

rivnuts or isolator nut mounts, as

(Ref. Section 91−00−00)

applicable.

Item

Nomenclature

CM217

Isopropyl alcohol

(4).

Inspect carpeting for cuts, tears, or

other unserviceable condition.

CM432

Dichloromethane

CM433

Ethylene chloride

(5).

Inspect foot fairings, floor trim, and

access doors for cuts, breaks or cracks.

(1). Remove upper two screws and loosen

(6).

Inspect Velcro fasteners on access flap

the bottom screws.

for security of attachment or other

damage.

(2). Lift holder up and out.

(7).

(L/H command helicopters) Inspect

sliding cover of copilot's collective pitch

(3). Repair cracks or separation by cleaning

stick cover for freedom of movement in

with isopropyl alcohol (CM217); then

cover tracks. Inspect stowage lid for

apply ethylene dichloride (CM433) or

condition and positive fastening.

dichloromethane (CM432) to patch or

mate surfaces.

A. Interior Trim Cleaning

(4). Join immediately with light pressure to

(Ref. Sec. 20-20-00, Fuselage Interior Trim

cement joint.

and Upholstery Cleaning)

Page 206

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

TRANSMISSION PANEL

INSTALLATION

OIL LEVEL

CHECK COVER

PLUG BUTTON

(BOTH SIDES)

MAIN TRANSMISSION

ACCESS PANEL

CHIP DETECTOR

COVER PLUG

TRANSMISSION

PANEL

AFT BULKHEAD INSTALLATION

UPPER BULKHEAD PANEL

(RIGHT HAND)

UPPER BULKHEAD PANEL

CHECKLIST

(LEFT HAND)

LOWER BULKHEAD PANEL

MAGNETIC

COMPASS

CARD

SEAT FITTING COVER

LOGBOOK HOLDER

CONVENIENCE PANEL

INSTALLATION

LOGBOOK HOLDER

INSTALLATION

PLUGS

CONVENIENCE PANEL

ISOLATOR NUT MOUNT

INSTALLATION

BLANK COVER

CONVENIENCE

TRIM PANEL NUT

PANEL COVER

MOUNT

G25-3003-1

Figure 203. Crew and Passenger Compartment Interior Trim − R/H Command (Sheet 1 of 2)

Page 207

25-30-00

Revision 23

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

CIRCUIT BREAKER

PANEL

ASH RECEIVER AND

CIGARETTE LIGHTER

PANEL

STICK COVER

SUPPORT TUBE

CLAMP

PILOT COLLECTIVE PITCH

SUPPORT TUBE

STICK COVER ASSEMBLY

ASSEMBLY

FLEXIBLE CLOSURE

ASSEMBLY

LOWER CURTAIN

PILOT'S INBOARD COLLECTIVE

PITCH STICK COVER

UPPER CURTAIN

CURTAIN STOP

COTTER PIN

SLIDER

FASTENER STUD

FASTENER BUTTON

EXPLODED VIEW

(ROTATED)

PILOT'S CYCLIC

STICK GUARD

CYCLIC CONTROLS

CENTER GUARD

COPILOT'S CYCLIC

STICK GUARD

CYCLIC STICK GUARDS

(ROTATED)

G25-3003-2

Figure 203. Crew and Passenger Compartments Interior Trim − R/H Command (Sheet 2 of 2)

Page 208

Revision 23

25-30-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

4. Interior Trim and Carpeting General

(1).

Remove damaged panel.

Repair

(2).

Stop-drill end(s) of crack.

Consumable Materials

(Ref. Section 91−00−00)

(3).

Deburr stop drill(s) and clean any

Item

Nomenclature

jagged area of crack.

CM219

Methyl-ethyl-ketone

CM405

Adhesive

(4).

Cut patch from fiberglass cloth to

CM718

Tape, double-faced

overlap damaged area or crack, mini

mum 1 inch (2.54 cm) in all directions.

(1). Remove and replace broken or missing

rivnuts or isolator nut mounts, as

(5).

Cut second patch to overlap first,

applicable.

minimum 1/2 inch (12.7 mm) in all

directions. If required, cut third patch

(2). Bond loose insulation material on

to overlap second, minimum 1/2 inch

underside of trim panel or cover using

(12.7 mm) in all directions.

adhesive (CM405).

(3). Repair cut or torn floor trim or carpet

(6).

Abrade surface of panel in area to be

ing with new application of double-

patched with emery cloth (CM804).

faced tape (CM718) or adhesive

(CM405), as applicable.

(7).

Clean surface by wiping with cloth,

dampened not saturated, with

MEK solvent is flammable.

WARNING

1,1,1-trichloroethane (CM222) or

Use only in well-ventilated

surface cleaner (CM228).

area and away from heat and flame.

NOTE: Loosened Velcro fasteners may be reac

(8).

Place panel in horizontal position. Tape

tivated for adhesion by wiping original

around area to be repaired with

adhesive with MEK (CM219).

masking tape, to catch residual resin.

(4). Replace unserviceable Velcro fasteners

on access flap using adhesive (89).

(9).

Apply glass cloth (CM501) to panel one

ply at a time.

5. Boltaron Trim Panels Repair

(10).

Apply resin (CM505) to material with a

A. Fiberglass Patch Method

brush or squeegee.

(Ref. Figure 205)

(11).

Continue adding material and resin

until desired thickness has been

Consumable Materials

achieved.

(Ref. Section 91−00−00)

Item

Nomenclature

NOTE: Heat lamp should be placed a minimum

CM222

1,1,1-Trichloroethane

of 12 inches from fiberglass repair area.

CM228

Surface cleaner

CM501

Fiberglass cloth

(12). Allow repair to cure, minimum 45

CM505

Polyester laminating resin

minutes, at 265° ±10°F (129° ±5°C). Or

CM804

Emery cloth, fine

alternatively, heat lamp may be used

(minimum 2 hours).

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

NAUGAHYDE

HANDLE (2)

FLOOR CARPETING

STA. 78.50

BULKHEAD

ACCESS DOOR

CARPETING

DOUBLE

FOOTWELL PANEL

FACE TAPE

ASSEMBLY

FLOOR STRUCTURE

FLOOR ACCESS DOOR

ACCESS FLAP

RIGHT SIDE TRIM

CARPETING (2) (NOTE)

CARPETING

CREW COMPARTMENT

VELCRO

FASTENER

CUTOUT FOR

LEG OF SEAT

STRUCTURE (2)

LEFT SIDE TRIM

PASSENGER COMPARTMENT

CARPETING

FLOOR STRUCTURE

FLOOR CARPETING

CENTER TRIM

CARPETING

BULKHEAD TRIM (NOTE)

NOTE:

CARPETING IN THIS AREA

IS BONDED IN PLACE.

DOUBLE

FLOOR PAN

FACE TAPE

PASSENGER COMPARTMENT

G25-3004A

Figure 204. Floor Trim and Covering

Page 210

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

B. Solvent Bonding Patch Method

(10). After forcing out bubbles, adjust clamps

to minimum pressure required to hold

(Ref. Figure 205)

parts together.

(11). If solvent has evaporated at or near

Consumable Materials

edge of patch, apply more solvent

(Ref. Section 91−00−00)

between mating surfaces using syringe

Item

Nomenclature

or eye dropper.

CM220

Naphtha aliphatic

CM435

Tetrahydrofuran

(12). Leave clamps in place for a minimum of

20 minutes.

(1). Remove damaged panel.

(13). Allow the panel to cure for 24 hours

prior to reinstallation.

(2). Stop-drill end(s) of crack.

C. Epoxy Adhesive Patch Method

(3). Deburr stop drill(s) and clean any

jagged area of crack.

(Ref. Figure 205)

(4). Select a piece of boltaron material with

Consumable Materials

same contour as patch area. Plating

(Ref. Section 91−00−00)

surfaces must provide a snug fit. Patch

Item

Nomenclature

material to overlap damaged area a

minimum of 1 inch (2.54 cm) in all

CM228

Surface cleaner

directions.

CM411

Adhesive, epoxy

CM804

Emery cloth, fine

(5). Clean mating surfaces with aliphatic

naphtha (CM220). Ensure surfaces are

free from oil, grease or other contami

(1).

Remove damaged panel.

nates.

(2).

Stop-drill end(s) of crack.

(6). Assemble patch with mating surface of

patch in contact with panel but without

(3).

Deburr stop drill(s) and clean any

application of pressure.

jagged area of cracks.

Tetrahydrofuran bonding

(4).

Select a piece of boltaron material with

WARNING

solvent is a flammable liq

same contour as patch area. Mating

uid. Care must be exercised in handl

surfaces must provide a snug fit. Patch

ing.

to overlap damaged area a minimum of

1 inch (2.54 cm) in all directions.

Solvent shall be applied careful

CAUTION

ly so no excess material will run

(5).

Lightly abrade mating surfaces with

over other surfaces and mar the finish.

emery cloth (CM804) and clean with

surface cleaner (CM228).

NOTE: On larger parts, solvent shall be applied

evenly to mating surfaces with brush.

(6).

Air dry for 30 minutes at ambient

(7). Inject tetrahydrofuran (CM435)

temperature. Apply adhesive (CM411)

between mating surfaces by means of

within 2 hours of drying.

syringe or eye dropper.

(7).

Thoroughly mix equal parts of adhesive

(8). Assemble mating surfaces as quickly as

by weight. Color should be uniform

possible by firmly pressing together.

green. Use unwaxed disposable contain

er and wooden tongue depressor or

(9). Apply clamps to assembly immediately

metal spatula for mixing. Pot life of

after solvent application. Use sufficient

mixed adhesive is 45 minutes at

pressure to force out air bubbles.

ambient temperature.

Page 211

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

FIBERGLASS PATCH METHOD A

0.50 IN.

1.0 IN.

(12.7 MM)

(2.54 CM)

STOP DRILL

SOLVENT BONDING AND EPOXY

ADHESIVE PATCH METHOD B & C

1.0 IN.

(2.54 CM)

1.0 IN.

(2.54 CM)

STOP DRILL

BOND AND RIVET PATCH METHOD D

4-6 X O.D.

PANEL

PATCH

RIVETS

2 X O.D.

BOND AND RIVET PATCH METHOD D

STOP DRILL

+0.030 IN.

(0.762 MM)

2 X O.D.

+0.030 IN.

(0.762 MM)

WASHER

(NOTE)

NOTE:

USE AN960 WASHER, OF PROPER

SIZE TO FIT RIVET DIAMETER, TO PRECLUDE

4-6 X O.D.

RIVET TAIL FROM PULLING THROUGH BOLTA

RON PANEL.

G25-3005A

Figure 205. Boltaron Panel Repair

Page 212

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(8). Spread thin uniform layer (0.002-0.010

(3). Lay out rivet pattern on patch and drill

inch) (0.0508-0.254 mm) of adhesive

holes. Position patch on panel and drill

lightly on mating surfaces and clamp

holes.

lightly together.

(4). Deburr all holes on both sides of patch

and panel.

(9). Wipe excess adhesive from bond line.

(5). Countersink holes on patch if using

(10). The clamps are to remain in place for 8

MS20426A4 rivets.

hours minimum at ambient tempera

ture or 2 hours at 160° ±10°F (72°

(6). Comply with the following procedures if

±5°C).

using Solvent Bonding Patch Method

(tetrahydrofuran).

(11). Allow panel to cure for 24 hours prior to

(a). Clean mating surfaces with naphtha

installation.

aliphatic (CM220). Ensure surfaces

are free from oil, grease or other

D. Bond and Rivet Patch Method

contaminates.

(Ref. Figure 205) The following procedure may

(b). Set patch in place. Use a minimum

be used in conjunction with one of the above

amount of clecos required to hold

bonding procedures (Ref. Solvent Bonding

patch in contact with panel without

Patch Method or Epoxy Adhesive Patch

applying too much pressure.

Method). If cracks are excessive and/or a piece

of boltaron is not available that fits contour in

Tetrahydrofura bonding sol

WARNING

repair area, rivets may be used to help secure

vent is a flammable liquid.

patch to panel.

Care must be exercised in handling.

Solvent shall be applied careful

CAUTION

Consumable Materials

ly so no excess material will run

(Ref. Section 91−00−00)

over other surfaces and mar the finish.

Item

Nomenclature

NOTE: On larger parts, solvent shall be applied

CM220

Naphtha aliphatic

evenly to mating surfaces with brush.

CM228

Surface cleaner

(c). Inject tetrahydrofuran (CM435)

CM411

Adhesive, epoxy

between mating surfaces by means of

CM435

Tetrahydrofuran

syringe or eye dropper.

CM804

Emery cloth, fine

(d). Assemble mating surfaces as quickly

as possible by firmly pressing togeth

er.

(1). Cut patch to proper size.

(e). Apply clamps to assembly immedi

(2). Determine rivet spacing.

ately after solvent application, with

sufficient pressure to force out air

(a). Rivet spacing to be 4-6 times rivet

bubbles.

diameter.

(f). After forcing out bubbles, adjust

clamps to minimum pressure re

(b). Minimum edge distance to be 2 times

quired to hold parts together.

rivet diameter ±0.030 inch (0.762

mm).

(g). If solvent has evaporated at or near

edge of patch, apply more solvent

Example :For #4 rivet, minimum

between mating surfaces using

edge distance is 0.028 inch (0.7112

syringe or eye dropper.

mm). Rivet diameter 0.125 inch

(3.175 mm) X 2 + 0.030 inch (0.762

(h). Leave clamps in place for a minimum

mm) = 0.280 inch (7.112 mm).

of 20 minutes.

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

NOTE: If gap exists between patch and panel

(c). Thoroughly mix equal parts, of

prior to installing rivets, inject tetrahydro

adhesive by weight. Color should be

furan between mating surfaces in immedi

uniform green. Use unwaxed dispos

ate area of each rivet hole that has a gap us

able container and wooden tongue

ing a syringe or eye dropper.

depressor or metal spatula for

mixing. Pot life of mixed adhesive is

(i). Rivet patch to panel.

45 minutes at ambient temperature.

(d). Spread a thin uniform layer,

(j). Allow panel to cure for a minimum of

0.002-0.010 inch (0.0508-0.254 mm),

24 hours prior to installation.

of adhesive on mating surfaces. Try

to keep adhesive out of the rivet

(7). Comply with the following procedures if

holes.

using the Epoxy Adhesive Patch

Method.

(e). Install the patch on the panel with

clecos.

(a). Lightly abrade mating surfaces with

(f). Rivet the patch to the panel.

emery cloth (CM804) and clean with

surface cleaner (CM228).

(g). Wipe excess adhesive from bond line

and from around the rivets.

(b). Air dry for 30 minutes at ambient

temperature. Apply adhesive

(h). Allow the panel to cure for 24 hours

(CM411) within 2 hours of drying.

prior to installation.

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HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369D/E/FF-500/600N HELICOPTERS (ISSUED: 1990) - page 8