Event Details

Title:Boeing 747-419 ZK-NBS flight NZ 2, in flight flap separation over Manukau Harbour by Auckland International Airport, 30 August 2002
Micro summary:On takeoff, about 70% of the right inboard trailing edge fore flap separated from the airplane.
Event Time:2002-08-30 at 2122 NZST
File Name:2002-08-30-NZ.pdf
Publishing Agency:Transport Accident Investigation Commission (TAIC)
Publishing Country:New Zealand
Report number:02-010
Site of event:Over Manukau Harbour by Auckland International Airport
Latitude/Longitude:S3703' E17444'
Departure:Auckland International Airport, Auckland, New Zealand
Destination:Los Angeles International Airport, Los Angeles, California, USA
Airplane Type(s):Boeing 747-419
Flight Phase:Takeoff
Operator(s):Air New Zealand
Type of flight:Revenue
Serious Injuries:0
Other Injuries:0
Executive Summary:On Friday 30 August 2002 at 2120, ZK-NBS (flight NZ 2), a Boeing 747-419, took off from runway 23 at Auckland International Airport for Los Angeles. On board were 355 passengers and 17 crew, including 3 pilots on duty in the cockpit.

During a left turn shortly after departure at night, with the flaps still extended to the take-off setting, about 70% of the right inboard trailing edge fore flap separated from the aircraft. The pilots did not receive any cockpit indications of anything untoward and only felt some slight bumps they thought to be from turbulence. The crew were unaware of the separation until the landing approach at Los Angeles some 12 hours later, when the flaps were selected for landing. The pilots took the appropriate action and carried out a go around procedure. The aircraft was repositioned for a further approach and landed safely. The safety of the aircraft and its occupants was not compromised by the incident. No one was injured.

The flap separated because its inboard attachment link failed. The link failed because a pre-existing stress corrosion crack had grown to a critical size, probably in a short period of time. The operator had inspected the flap assembly routinely and specifically as the aircraft manufacturer required, but neither the start of the crack nor its growth could be detected during those inspections.

A safety issue identified was the design adequacy of the fore flap attachment links. The aircraft manufacturer has completed a design change to overcome the limitations of the links.

Learning Keywords:Operations - Maintenance
Systems - Flight Control System
Systems - Flight Controls - Spoilers - Slats - Flaps
Close match:Failure of flap deflection control track, Boeing 767-319 ZK-NCH, approach to Auckland International Aerodrome, 19 May 2001
Excessive right aileron required on Boeing 737-400, EI-BXB, at Dublin Airport
Flight control system failure, Report on the incident to Airbus A320-212, G-KMAM, London Gatwick Airport, on 26 August 1993
Loss of engine and stall on takeoff, American Airlines, Inc., DC-10-10, N110AA, Chicago-O'hare International Airport, Chicago, Illinois, May 25, 1979
Uncommanded roll, McDonnell Douglas DC-9-15, July 12, 1997
Roll control difficulties, McDonnell Douglas MD-11F, N583FE, January 15, 2003


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