Aviation Investigation Report A98H0003

2.20.3  Effect of Fire-Related Failures on Landing

At 0124:09, nearly three minutes before the earliest possible landing time, the aircraft had started to experience an increasingly rapid succession of systems-related failures. The pilots declared an emergency at 0124:42, slightly more than two minutes before the theoretical earliest possible landing time. Several additional systems-related failures, including the loss of the first officer's DUs and communications with ATS, occurred one minute later (0125:42), just prior to the stoppage of the flight recorders.

By the time the recorders stopped, the cockpit environment was rapidly deteriorating. The fire was invading the cockpit from the overhead ceiling area. Just before the recorders stopped, the pilots indicated that they needed to land immediately; however, they apparently lost their ability to navigate, as they did not steer the aircraft toward the airport. At some point within the last five minutes, the aircraft's slats became unserviceable. Based on heat damage to wires and associated CBs, it is also possible that the auto ground spoilers, auto-brakes, and anti-skid braking system would have become inoperative before the aircraft could have landed. Under such conditions, it would have been impossible to stop the aircraft on the available runway even if it could have landed.

Based on these factors, it is evident that even if the pilots had attempted a minimum-time emergency diversion starting at 0114:18, it would have been impossible for the pilots to continue maintaining control of the aircraft for the amount of time necessary to reach the airport and complete a safe landing.

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Date modified :
2012-07-27