Prevailing Cultural / Organizational Factors

The A320 was the first commercial airliner to be equipped with a fly-by-wire control system. The airplane is highly dependent on computerized systems, and flight deck controls are not connected directly to control surfaces, but rather cause the controls to move via electronic commands. As a result of the highly automated design, Airbus employed a number of protection envelopes to prevent exeedences of airplane limits. In the fully functional flight control mode, the airplane is protected from stalling, exceeding maximum speed limits, or pitch and roll limits. If onboard computer failures occur, some of the protection features function in a degraded state, or become non-functional. One of the features of the airplane is the thrust control system, which uses non-moving thrust levers.

Normal use of the thrust levers requires that they be placed in a "detent", and remain in the detent until just before landing. This implementation of thrust control (non-moving throttles) was also new for commercial transport airplanes. The thrust levers are capable of being used in a more conventional manner, by leaving the thrust levers out of the detents, and operating them as more conventional throttles for thrust adjustments. Manual use of the thrust levers precludes use of the autothrust system, however. The airplane also makes use of a sidestick for control of pitch and roll, rather than the more common control column and yoke. The sidestick is located outboard of the pilot positions - to the left of the captain, and to the right of the first officer. The sidestick does not normally provide force feedback, and is not backdriven. Control inputs made by the pilot flying are not reflected on the other pilot sidestick.

The Indian court of Inquiry attributed the Flight 605 accident to have been largely the result of an incomplete understanding of the autoflight/autothrust system.

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