DAVID LEARMOUNT / LONDON
Miami incident also involved an overstressed American Airlines A300-600 tail-fin
The US National Transportation Safety Board (NTSB) is studying a 1997 near-accident which, like the 12 November American Airlines crash near New York, may have overstressed an Airbus A300-600R tail fin. But in the earlier event - involving an American Airlines aircraft inbound to Miami on 12 May 1997 - the tail fin did not separate.
The NTSB is revisiting the Miami event because the aircraft in that incident was also likely to "have experienced high vertical stabiliser airloads", and the agency still retains the flight data recorder (FDR) information.
Over West Palm Beach, Florida, the aircraft "entered a series of pitch, yaw and roll manoeuvres as the flight controls went through a period of oscillations for about 34s, during which the aircraft dropped from 16,000ft [4,880m] to 13,000ft," says the Board. The NTSB determined that the aircraft stalled because the crew failed to manage airspeed during a level-off and then failed to use correct stall recovery techniques.
"The Board is now reviewing the FDR data from that incident to calculate the forces to which the stabiliser was subjected," says the NTSB. The Board adds that, "as a safety precaution", American and Airbus have taken the tail fin off the aircraft concerned (N90070) to carry out non-destructive testing on it.
To continue investigating the 12 November accident, the NTSB is still seeking a used A300-600 tail fin for destructive testing. It says it has obtained a used A300-600 rudder for that purpose.
Setting to rest press reports that bogus parts from Italy may have played a part in the November accident, the NTSB reveals that it has "traced the source" of all the parts on the crashed aircraft, and that they were all obtained from the original equipment manufacturers.
Source: Flight International