MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

INSPECTION OF SHORT EDGE MARGIN CONDITION ON

369D23500 TAILBOOM ASSEMBLY

1. PLANNING INFORMATION

A. Aircraft Affected:

Model 369D, Model 369E and Model 369F/FF Helicopters with tailboom assembly serial

numbers listed below:

7604−0001 to 7604−0003

7604−0006 to 7604−0047

7604−0049 to 7604−0082

7604−0084 to 7604−0113

B. Assembly/Components Affected By This Notice:

Model 369D: Tailboom Assembly − 369D23500−505 and −511

Model 369E: Tailboom Assembly − 369D23500−505 and −511

Model 369F/FF: Tailboom Assembly − 369D23500−507 and −513

C. Reason:

Improper installation of the frame ring at STA 209.78 can result in a short edge margin

condition with the rivets that attach the installed longerons. Failure to inspect and correct

short edge margin condition could result in reduced structural strength of the tailboom.

D. Description:

Procedures in this Bulletin give owners and operators information to find if a short edge

margin condition exists and install repair doubler.

E. Time of Compliance:

Perform Part I of this Service Bulletin within 6 months or 100 hours after SB release,

which ever comes first.

Perform Part II based on the results of the Part I inspection.

F. FAA Approval:

The technical design aspects of this Bulletin are FAA Approved.

G. Manpower:

Part I − Inspection: Four (4.0) man−hours

Part II − Modification: Eight (8.0) man−hours

H. Interchangeability:

None.

I. Points of Contact:

For further assistance, contact the Field Service Department at MDHI, Mesa, Arizona.

Telephone 1−800−388−3378 or 480−346−6387. DATAFAX: 480−346−6813.

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 1 OF 8
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

J. Material/Part Availability:

Contact MDHI Warranty Repair Department to order required items

REPLACEMENT PARTS/SUPPLIES 

Nomenclature Part No. Qty. Source

Repair Material 2024−T3 Alclad per QQ−A−250/5

Stock size 3.0” x 5.5” x 0.063” thick

1 Commercial

Rivet MS20470AD4 8 Commercial

Rivet MS20470AD5 2 Commercial

Primer CM318 / MIL−P−85582 AR Commercial

Chemical Coating CM206 / MIL−C−5541 AR Commercial

Structural Adhesive EA9394 AR Commercial

K. Warranty Policy:

N/A

L. Disposition of Parts Removed:

N/A

M. Tooling:

TOOLS AND EQUIPMENT 

Nomenclature Source

Inspection Light Commercial

Inspection Mirror Commercial

Steel Rule or Caliper Commercial

N. Weight and Balance:

N/A

O. Electrical Load Data:

N/A

P. Other Publications Affected:

CSP−IPC−4, Illustrated Parts Catalog

CSP−SRM−6, Structural Repair Manual

Q. Reference Publications:

Refer to the latest revision of this publication for procedures and additional information:

CSP−HMI−2, Basic Handbook of Maintenance Instructions − Servicing and Maintenance

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 2 OF 8
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

2. ACCOMPLISHMENT INSTRUCTIONS

A. Prepare Aircraft

(Ref. Figure 1)

(1). Remove the access door from the lower left−hand side of the tailboom assembly.

(2). Remove the tail rotor transmission and tail rotor drive shaft as a unit

(Ref. CSP−HMI−2, Section 63−15−00).

If there is sufficient access after Step 2.A.(2). is complete, do not remove tail rotor control

rod.

(3). Remove tail rotor control rod (Ref. CSP−HMI−2, Section 67−20−10).

ACCESS DOOR

88−795

STA. 209.78 CANTED

Figure 1. Tailboom Assembly

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 3 OF 8

NOTE:
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

B. PART 1 − Inspection

(Ref. Figure 2)

(1). Measure the distance from the forward face of the STA 209.78 frame ring to the center

of the two aft rivet locations on each longeron.

0.50 INCH (12.7 MM)

STA. 209.78 CANTED

FRAME RING

MS20470AD5 RIVET

88−796

> = FAIL

Figure 2. STA 209.78 Frame Ring to Rivet Measurement

(2). Record each rivet measurement in the table below:

Longeron Location (Looking Forward)

12 O’Clock: Rivet No. 1 Rivet No. 2 Pass / Fail

3 O’Clock: Rivet No. 1 Rivet No. 2 Pass / Fail

6 O’Clock: Rivet No. 1 Rivet No. 2 Pass / Fail

9 O’Clock: Rivet No. 1 Rivet No. 2 Pass / Fail

(3). For each longeron location, record if each rivet inspection passes or fails, based on the

following criteria:

If either of the two aft rivets for a longeron is more than 0.50 inches (12.7mm) from the

forward face of the frame ring, there is an unsatisfactory edge margin condition.

(4). Record the pass or fail result for each rivet in the last column of the table above.

(5). Mark each rivet that fails the edge margin inspection.

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 4 OF 8
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

C. PART 2 − Modification

(Ref. Figure 3 and Figure 4)

Do the following modification at each longeron location that failed the Step B.(1). inspection.

(1). Carefully remove the ten rivets shown in Figure 3.

(2). Fabricate a T−shaped" repair doubler using 0.063 inch thick 2024−T3 Alclad, 

per QQ−A−250/5.

(3). Size the repair doubler such that there is a 0.250 inch (6.35mm) to 0.280 inch (7.11mm)

edge margin around the perimeter of the repair doubler.

(4). Shape the repair doubler so it has a radius of approximately 5.722 inches (145.34mm)

to agree with the shape of the tailboom. See Figure 4.

(5). Put the repair doubler on the tailboom assembly and drill pilot holes in the repair

doubler at existing rivet locations.

(6). Remove the repair doubler and drill full size holes at each hole location to match final

rivet diameter.

(7). Clean and deburr all hole locations on the repair doubler and tailboom assembly.

(8). Remove paint from tailboom, clean area and prepare surfaces for bonding.

(9). Apply chemical coating (CM206) to all areas of the repair doubler and any exposed

material of the tailboom assembly, per CSP−HMI−2, Section 20−40−00.

MS20470AD5 RIVET (2 EA)

MS20470AD4 RIVET (8 EA)

REPAIR DOUBLER

88−797

0.75 IN

0.50 IN R (2 PL)

0.12 IN

0.25 IN R (6 PL)

0.28 IN

0.25 IN (6 PL)

Figure 3. Repair Doubler

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 5 OF 8

NOTE:
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

(10). Apply primer (CM318) to all non faying surfaces of the repair doubler.

(11). Apply structural adhesive (EA9394) to the faying surfaces of the repair doubler.

(12). At the 6 O’Clock and 12 O’Clock longeron location, apply structural adhesive (EA9394)

to the tailboom surface as shown in Figure 4.

(13). Install the repair doubler with eight (8) MS420470AD4 rivets and two (2) MS20470AD5

rivets. Install all rivets with wet primer (CM318) and allow adhesive and primer to cure.

(14). Fillet seal the edges of the repair doubler with structural adhesive (EA9394).

(15). If necessary, touch up the finish of all parts per CSP−HMI−2, Chapter 20.

88−798

5.722 INCH R

12 O’CLOCK OR 6 O’CLOCK

LONGERON LOCATION

VIEW LOOKING FORWARD

STRUCTURAL ADHESIVE STRUCTURAL ADHESIVE

Figure 4. Repair Doubler Installation

D. Job Close−Up

(1). If necessary, reinstall tail rotor control rod (Ref. CSP−HMI−2, Section 67−20−10).

(2). Reinstall the tail rotor transmission and tail rotor drive shaft as a unit

(Ref. CSP−HMI−2, Section 63−15−00).

(3). Reinstall the access door on the lower left−hand side of the tailboom assembly.

E. Compliance Record

(1). Record compliance to this Service Bulletin in the Compliance Record section of the

Rotorcraft Log Book.

(2). Complete Bulletin Completed Record form (attached) and FAX or e−mail to MHDI Field

Service Department.

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 6 OF 8
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

Bulletin Completed Record

[Part 1] − INSPECTION OF SHORT EDGE MARGIN CONDITION ON

369D23500 TAILBOOM ASSEMBLY

MD Helicopters, Inc.

Field Service Department

4555 E. McDowell Road

Mesa, AZ 85215−9734

800−388−3378 Phone (U.S. and Canada)

480−346−6387 Phone (International)

480−346−6813 Fax

FAX this form to MDHI (480) 346−6813 or E−mail to ServiceEngineering@mdhelicopters.com

Owner

/Operator:

Helicopter

Serial No:

Address:

Helicopter

Total Time:

Date Complete:

Location:

Phone:

E−mail:

[Part 1 of ] This bulletin is

complete:

Part 2 Required: Y / N

(circle one)

(Signature)

(Print Name)

(Title)

Serial Number of tailboom: 

Comments: 

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 7 OF 8
MANDATORY MANDATORY MANDATORY

MANDATORY MANDATORY MANDATORY

SERVICE BULLETIN

Copyright 1999−2010 by MD Helicopters Inc.

This document may be reproduced and distributed provided no fee is charged,

the text is not modified, and this copyright notice is included.

Bulletin Completed Record

[Part 2] INSPECTION OF SHORT EDGE MARGIN CONDITION ON

369D23500 TAILBOOM ASSEMBLY

MD Helicopters, Inc.

Field Service Department

4555 E. McDowell Road

Mesa, AZ 85215−9734

800−388−3378 Phone (U.S. and Canada)

480−346−6387 Phone (International)

480−346−6813 Fax

FAX this form to MDHI (480) 346−6813 or E−mail to ServiceEngineering@mdhelicopters.com

Owner

/Operator:

Helicopter

Serial No:

Address:

Helicopter

Total Time:

Date Complete:

Location:

Phone:

E−mail:

[Part 2 of ] This bulletin is

complete: (Signature)

(Print Name)

(Title)

Serial Number of modified tailboom: 

Comments: 

SB369D−207

SB369E−102 SB369F−087

DATE: 20 JULY 2010

PAGE 8 OF 8