SERVICE

BULLETIN

Date: October 22, 2015 (M)

NO. 1273A

PIPER CONSIDERS

COMPLIANCE MANDATORY

Piper Aircraft, Inc.

2926 Piper Drive

Vero Beach, FL, U.S.A. 32960

ATA: 5300

(OVER)

Service Bulletin (SB) 1273A supersedes SB 1273 and SB 636A in their entirety. Aircraft that have previously 

complied with SB 636A must also comply with SB 1273A. Aircraft that have previously complied with SB 1273 are 

already in compliance with SB 1273A.

Subject: Bulkhead Modification at Fuselage 

Station 317.75

Reason for Revision: SB 1273A specifies Piper Kit No. 764-028 Rev. 10/26/2015, 

whereas SB 1273 specified Rev. 04/03/2015. Kit 764-028 

Rev. 10/26/2015 contains radius block configuration 

options which may provide a better fit on some aircraft. 

Models Affected: Serial Numbers Affected:

PA-31/PA-31-300/325 Navajo 31-2 thru 31-900; 31-7300901 thru 31-8312019

PA-31-350 Chieftain/T-1020 31-5001 thru 31-5004; 31-7305005 thru 31-8553002

Compliance Time: For aircraft with 2,000 or more hours of time in service (TIS), compliance is to 

coincide with the next regularly scheduled maintenance event, but not to exceed 

the next 100 hours TIS.

Approval: The engineering aspects of this service document have been shown to comply 

with the applicable Federal Aviation Regulations and are FAA approved.

Purpose: A review of service history reveals that cracks may develop in the bulkhead 

assembly located at fuselage station (FS) 317.75, Piper part number (P/N) 

40682-008. This service bulletin provides instructions for repair of these cracks, 

as well as installation of structure which has been shown to prevent cracks from 

developing.

Safety Intent: The safety intent of this service bulletin is to reduce the likelihood of cracks 

developing in the bulkhead assembly at FS 317.75. If not identified and repaired, 

such a crack in the airframe structure could expand to a critical length and result in 

loss of structural integrity of the vertical fin front spar attachment. 

1
SERVICE BULLETIN NO. 1273A PAGE 2 of 6

CONFIGURATION

DESCRIPTION: Incorporating this service bulletin results in installing a doubler and supporting 

structure on the forward upper surface of the bulkhead assembly located at 

FS 317.75. Depending on the existing configuration of the aircraft, this doubler 

may replace a smaller doubler at the same location. For some aircraft, the required 

doubler may already be installed. For these aircraft, no airframe modification is 

required.

Instructions:

NOTE: Some steps in these instructions are identified as “required for compliance” (RC). If this service bulletin 

is mandated by an airworthiness directive (AD), the steps identified as RC must be done to comply with 

the AD. Steps not identified as RC are recommended and may be deviated from, done as a part of other 

actions, or done with accepted methods different from those given in this SB, if the RC steps can be done 

and the airplane can be put back in a serviceable condition.

NOTE: Temporary removal of some components and/or access panels may be required in order to accomplish 

the instructions described in this service bulletin.

NOTE: The part number naming convention used by Piper has changed over the years. A dash number with zeros 

in front is equivalent to the same dash number with no zeros in front. For example, part number (P/N) 

40682-008 is equivalent to P/Ns 40682-08 and 40682-8. All three part numbers describe the same part. 

Part I. Inspection and Repair

1. RC – Gain visual access to the bulkhead assembly at FS 317.75, as shown in Figure 1, Sheet 1. 

2. RC – Inspect

a. Prior to inspection, wipe surfaces clean using a soft cloth dampened with isopropyl alcohol, mineral spirits, 

naphtha, or other suitable cleaning agent or method. 

b. Examine the area shown in View A–A labeled “INSPECTION AREA” for cracks. The inspection shall be 

accomplished using a 10X magnifier, a mirror and a suitable light source or other equipment capable of 

providing equal or better resolution. 

3. RC – Assess inspection results

a. If a crack is found, follow repair instructions described in Piper Kit P/N 764-028 Rev. 10/26/2015, “Bulkhead 

Reinforcement and Drag Angle Installation.” Repairs must be accomplished prior to next flight. 

WARNING: FLIGHT WITH KNOWN CRACKS IN THE AIRCRAFT STRUCTURE IS NOT ALLOWED. AN 

AIRPLANE WITH A CRACK IN STRUCTURE NO LONGER MEETS ITS TYPE DESIGN AND 

MAY NO LONGER POSSESS ITS TYPE DESIGN STRENGTH. ANY CRACKS DISCOVERED 

IN THE AIRCRAFT STRUCTURE MUST BE REPAIRED PRIOR TO THE NEXT FLIGHT.

b. If no cracks are found, complete one of the following steps: 

1) Prior to next flight: accomplish Part II – Modification.

2) Continuing inspection until modification

a) Make a logbook entry documenting the initial inspection. 

b) Within 500 hours TIS, accomplish Part II – Modification. 

Until modification is accomplished, the inspection from Step 2 must be performed on a recurring 

basis, at an interval not to exceed every 100 hours TIS. Make a logbook entry for each recurrent 

inspection. If any cracks are found during any inspection, they must be repaired prior to the 

next flight.
SERVICE BULLETIN NO. 1273A PAGE 3 of 6

Figure 1, Sheet 1

Aft Fuselage Inspection Area

FS

317.75

WL

0

A

A

B

B

FWD

UP

BULKHEAD ASSEMBLY

VIEW A−A

LOOKING AFT AT FS 317.75

INSPECTION AREA

INSPECTION

AREA RIVET

(TYPICAL)

NOTE: Fuselage skins omitted for clarity.

RBL

4.70

LBL

4.70

BL

00.00
SERVICE BULLETIN NO. 1273A PAGE 4 of 6

Figure 1, Sheet 2

Aft Fuselage Inspection Area

CONFIGURATION 1

FWD

VIEW C−C

BULKHEAD

ASSEMBLY

40682-008

DOUBLER

40682-010

RADIUS BLOCK

40682-011

FUSELAGE SKIN

& DOUBLER

SPACER

40682-009

CONFIGURATION 2

C

C

See Part II, Step 1.b.2), 

for disposition

CONFIGURATION 3

VIEW B−B

LOOKING AFT AT F.S. 317.75

CONFIGURATIONS 1 – 3
SERVICE BULLETIN NO. 1273A PAGE 5 of 6

Part II. Modification 

1. RC – Examine the existing configuration of the bulkhead assembly at FS 317.75. Match it with one of the three 

configurations shown in View B–B. Complete Step a., b. or c., depending on the existing configuration. 

a. Configuration 1: Order Piper Kit P/N 764-028 Rev. 10/26/2015, “Bulkhead Reinforcement and Drag Angle 

Installation,” and install per kit instructions.

b. Configuration 2: Order Piper Kit P/N 764-028 Rev. 10/26/2015, “Bulkhead Reinforcement and Drag Angle 

Installation,” and install per kit instructions, with the following exceptions: 

1) Remove these parts from the airplane, and discard: 

•	 P/N 40682-009 Spacer

•	 P/N 40682-010 Doubler – Reinforcement

•	 P/N 40682-011 Block – Radius

2) Removal of the parts listed in Step 1), above, results in two (2) open holes not addressed by the 

instructions in Piper Kit P/N 764-028 Rev. 10/26/2015. These holes are identified in View B–B, 

illustration “Configuration 2” with the text “See Part II, Step 1.b.2), for disposition.” 

a) At the two fastener locations, match drill 0.144 inch diameter holes in the new P/N 71681-002 

Reinforcement Doubler to match existing holes in the P/N 40682-008 Bulkhead Assembly. 

b) Install NAS1739B4-3 rivets (or other industry standard rivets of equivalent or higher strength) 

through the reinforcement doubler and bulkhead assembly.

3) Discard the following kit components, which are already installed on the airplane: 

•	 P/N 71059-006 Angle – Drag, Left

•	 P/N 71059-007 Angle – Drag, Right

c. Configuration 3: No rework is required. Piper Kit P/N 764-028, “Bulkhead Reinforcement and Drag Angle 

Installation,” has already been installed. 

2. Make a logbook entry documenting compliance with Part II of this service bulletin. 
SERVICE BULLETIN NO. 1273A PAGE 6 of 6

MATERIAL REQUIRED: On condition, one (1) each per aircraft, Piper P/N 764-028 Rev. 10/26/2015, 

Bulkhead Reinforcement and Drag Angle Installation Kit 

AVAILABILITY OF PARTS: Your Factory Authorized Piper Service Facility

Effectivity date: This service bulletin is effective upon receipt. 

Summary: Please contact your Factory Authorized Piper Service Facility to make 

arrangements for compliance with this service bulletin in accordance with the 

compliance time indicated. 

Note: Please notify the factory of any address/ownership corrections. Changes should include aircraft model, 

serial number, and current owner’s name and address. 

Corrections and/or changes should be directed to:

PIPER AIRCRAFT, INC.

Attn: Customer Service

2926 Piper Drive

Vero Beach, FL 32960