Aviation safety issues and actions
Interim Recommendation issued to: Boeing
|Date issued:||16 September 1997|
|Safety action status:||Closed|
SUBJECT: Boeing 747 Aileron Cable Failure
The Bureau of Air Safety Investigation recommends that Boeing
Commercial Airplane Group issue service information and appropriate
corrective action to applicable B747 operators requiring fleet
(i) correct placement of aileron control cables on the cable drum located at WS776.98; and
(ii) correct installation of aileron cable position decals at WS767 and WS780.
|Date issued:||14 November 1998|
|Response from:||Boeing Co|
|Action status:||Closed - Accepted|
The reference cover letter provided a copy of your report of an incident involving a 747-300 airplane, Serial Number 23029. The report indicates that one of the left aileron cables was broken during taxi prior to departure. The report stated that the aileron cable failures may be due to misroutng which may occur as a result of incorrectly installed markers. A check by the Australian Bureau of Air Safety Investigation found eight airplanes with incorrectly installed markers.
Your report recommended that Boeing initiate a fleet check for proper placement of the aileron control cables at Wing Station (WS) 776.98 and correct installation of aileron cable markers at WS 767 and 780.
It has not been determined whether the incorrect marker installations occurred during or after manufacture. As a result of these findings, we plan to issue a service bulletin to 747 operators recommending fleet checks of all 747 airplanes prior to Line Position 1130, except Line Position 1122, for
1, Correct routing of aileron control cables on the aileron
cable drum located at wing station 777
Airplane Line Position 1130 was delivered in September 1997. Airlane Line Position 1122 was checked at Boeing.
A review of the applicable engineering drawings shows that the marker installation and cable installation drawings are correct, and have always been correct. In addition, a check of airplanes in the factory and on the flight line indicates that both the markers and cables are currently being installed per drawing.
If you have any questions, please do not hesitate to contact me at any time.
ATSB Note: Airworthiness directive 99 - 11- 15 was issued by the FAA which implemented the suggested action.