The Australian Transport Safety Bureau did not conduct an on
scene investigation of this occurrence. The information presented
below was obtained from information supplied to the Bureau.
The crew of a Boeing 737, registered VH-TAH, reported that, on
15 May 2004, during the takeoff roll on runway 34 Left at Sydney
Kingsford Smith Airport, they felt shuddering from the nose wheel.
The crew of a subsequent landing aircraft reported debris on the
runway. An inspection found tyre segments and pieces of aircraft
structure. The 737 crew were notified and elected to return for a
landing.
An investigation by the operator found that the 737 struck a
Boeing 747 thrust reverser blocker door that had fallen from an
aircraft that had previously used the runway. That door damaged the
737 nose landing gear tyre and gashed the aluminium skin of the
fuselage. The investigation was unable to identify the 747 and
whether the loss of the door occurred during take-off or
landing.
This was the second reported occurrence of a blocker door
falling from a 747 aircraft. At least two 747 operators (one
Australian and one international) are known to have found that an
earlier 747 blocker door modification had a deficient
metal/composite bond. The Australian 747 operator has initiated a
project to scope and implement a new modification program to repair
or replace all blocker doors.