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Interim Recommendation issued to: Qantas Airways Limited

Recommendation details
Output No: IR19990050
Date issued: 27 May 1999
Safety action status:
Background: Why this Interim Recommendation was developed

Output text

The Bureau of Air Safety Investigation recommends that Australian operators of Boeing 737 note the above safety deficiency and interim recommendations and take appropriate action as considered necessary to ensure the integrity of Boeing 737 main landing gear trunnion pin assemblies.

As a result of the investigation of this safety deficiency, the Bureau simultaneously issues the following interim recommendations:

IR990046

The Bureau of Air Safety Investigation recommends that Boeing Commercial Airplane Group alert Boeing 737 operators to this safety deficiency and implement an appropriate inspection program.

IR990047

The Bureau of Air Safety Investigation recommends that Boeing Commercial Airplane Group review the effectiveness of Service Bulletin 737-32A1198 revision 2.

IR990048

The Bureau of Air Safety Investigation recommends that the Federal Aviation Administration note the above safety deficiency and interim recommendations and take appropriate action as considered necessary to ensure the integrity of Boeing 737 main landing gear trunnion pin assemblies.

IR990049

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority note the above safety deficiency and interim recommendations and initiate appropriate action to ensure the integrity of Australian Boeing 737 main landing gear trunnion pin assemblies.

Initial response
Date issued: 10 May 1999
Response from: Qantas Airways Limited
Action status: Closed - Accepted
Response text:

Qantas issued Engineering Instruction (EI) No. 737-032-0105 on 06 May 1999 to address this issue. Pertinent sections of the EI were as follows:

EI 737-032-0105

1. Title: TRUNNION PIN - INSPECTION OF ACTUATOR ATTACH LUGS

2. Reason: ULTRASONIC INSPECTION OF TRUNNION PIN LUGS FOLLOWING LUG FAILURE ON INSERVICE QANTAS AIRCRAFT.

3. S.L. Ref: 81205 SB 737-32-1198 02/NSC06

4. Applicability: 737-376, 476, 3Q8, 4Q8, 4L7

12. Accomplishment Instructions:

INTRODUCTION

Qantas aircraft VH-TAK suffered a fracture of the actuator attach lugs of the trunnion pin on the right gear on the 4th April 1999. Subsequent inspection of the failure surface and surrounding material revealed corrosion. This caused pitting and development of a fatigue crack and eventual failure. This EI targets pins that have accumulated approximately 10,000 cyc since new or overhaul, for an ultrasonic examination of the lugs.

12.1 Ensure all gear locks are installed per AMM 32-00-01.

12.2 Ultrasonically inspect the Trunnion Pin part no. 65C32964-(), 65-46113-(), 737R32-06-01-() and 737R32-28-01-() for cracking per NDT technique U-42

If cracks are detected, replace the trunnion pin prior to further flight.

12.3 NDT inspector to notify Principal Mech. Systems Eng'r if cracks are found.

 
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Last update 01 April 2011