Jump to Content

Following flap retraction shortly after the Boeing 747 departed Sydney, the crew reported a flap disagreement indication. The flaps could not be extended and were stuck in the up position. The aircraft returned to Sydney where the crew carried out a flapless landing.

An inspection revealed that the right inboard fore-flap carriage stop had failed. This resulted in extensive damage to the fore flap, mid flap, and overload failure of the right flap drive torque tubes.

Specialist examination found that the fore-flap carriage stop failed due to stress corrosion cracking. The cracking initiated at the bolt hole surface. The manufacturer's instructions require that the bolt should be installed with wet sealant, however inspection indicated that the sealant did not cover the centre portion of the bolt, potentially allowing moisture to enter.

 
General details
Date: 16 March 1999 Investigation status: Completed 
Time: 1400 hours ESuT Investigation type: Occurrence Investigation 
Location   (show map):Sydney, Aero. Occurrence type:Flight control systems 
State: New South Wales Occurrence class: Technical 
Release date: 02 January 2001 Occurrence category: Accident 
Report status: Final Highest injury level: None 
 
Aircraft details
Aircraft manufacturer: The Boeing Company 
Aircraft model: 747 
Aircraft registration: DQ-FJI 
Serial number: 22145 
Type of operation: Air Transport High Capacity 
Damage to aircraft: Substantial 
Departure point:Sydney, NSW
Destination:Nadi, FIJI
 
 
 
Share this page Provide feedback on this investigation
Last update 13 May 2014