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Interim Recommendation issued to: Federal Aviation Administration (FAA)

Recommendation details
Output No: IR19990021
Date issued: 19 March 1999
Safety action status:
Background: Why this Interim Recommendation was developed

Output text

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 actuator beam arm assemblies.

As a result of investigation into this occurrence, the Bureau simultaneously issues the following interim recommendations:

IR990019

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.

IR990020

The Bureau of Air Safety Investigation recommends that Boeing Commercial Airplane Group review the effectiveness of Service Bulletin 737-32A1224.


IR990022

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority initiate appropriate action to ensure that Australian operators of Boeing 737 aircraft immediately inspect all main landing gear actuator beam arm assemblies for evidence of cracking.

IR990023

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 actuator beam arm assemblies.

Initial response
Date issued: 24 May 1999
Response from: Federal Aviation Administration (FAA)
Action status: Closed - Accepted
Response text:

The US Federal Aviation Administration issued an Airworthiness Directive (AD 99-10-12) as Amendment 39-11165 to all B737 operators, effective 27 May 99:

SUMMARY: This amendment supersedes all existing airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, that currently requires repetitive inspections to detect cracking, plating degradation, and corrosion of the main landing gear (MLG) actuator beam arms and actuator beam attach bolts; and rework or replacement, if necessary. The existing AD also provides for optional terminating action for the repetitive inspections. This amendment removes the requirement to inspect the actuator beam attach bolts, expands the applicability of the existing AD to include additional airplanes, and removes the optional terminating action. This amendment is prompted by reports of cracked MLG actuator beam arms. The actions specified in this AD are intended to detect and correct corrosion and cracking of the MLG actuator beam arm, which could result in damage to the control cables for the aileron and spoiler and consequent reduced controllability of the airplane.

 
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Last update 01 April 2011