Precursors

January 9, 1989 - A300-B4 - Helsinki, Poland (Incident)

During an ILS approach with the autopilot (AP) and auto-throttle engaged, the pilot accidentally engaged go-around. To remedy the situation, the pilot disconnected the auto-throttle and pulled back on the thrust levers after four seconds while countermanding the AP by pushing forward on the control column for ten seconds to avoid having passengers undergo a sudden change in attitude. The trimmable stabilizer reached 8° nose-up pitch (the initial approach value was 5.5° nose-up pitch). Subsequently, the AP was disconnected, or disconnected itself without the crew noticing. Then, seeing that the approach had not stabilized, the pilot performed a go-around by selecting the auto-throttle go-around mode. The combined effect of the pitch-up moment of the engines and the nose-up pitch of the trimmable stabilizer took the airplane to an attitude of 35.5°, and 94 kt indicated airspeed in spite of the crew's pushing forward on the control column. Not long before reaching these values, the crew moved the trimmable stabilizer to 0°. The speed increased again while the attitude decreased.

February 14, 1990 - A320-231 - Bangalore, India (Accident)

During a "captain's" inspection flight, the pilot at the controls made a visual approach with the auto-throttle and the flight director active (in mode V Speed: vertical speed holding). On final approach, he requested display and selection of a vertical descent speed of 700 ft/mn on the Flight Control Unit (FCU). For unknown reasons, the pilot not flying, who was an instructor displayed an altitude below that of the airfield on the FCU (instead of the vertical speed requested), and did not make the call-outs required when making a change to the FCU. Subsequent to this action, the active mode of the automatic flight systems went from Speed Vspeed (speed holding-vertical speed) to Idle Open Desc (Open Descent - engine in flight idle- change of level in descent). The pilot at the controls was not aware of this, and the instructor did not call it out clearly. To maintain the descent path visually, the pilot at the controls pulled the control column gradually back, causing the landing angle to increase and the speed to decrease. The anti-stall function led to an increase in the rate of descent, and the alpha floor initiated an automatic go-around. This occurred at too low a level, and the airplane touched the ground and hit a mound. The airplane caught fire, and 92 persons were killed and 22 were seriously injured.

See accident module

February 11, 1991 - A310 D-ADAC - Moscow, Russia

During a go-around procedure in autopilot mode (CMD mode), the pilot tried to limit the pitch-up attitude, which he thought to be excessive, by pushing on the control column (14° nose down). The autopilot then ordered the trim to -12 nose up in an attempt to maintain the specified parameters. On arrival at the safety altitude, the autopilot went into Altitude Acquire mode and disconnected automatically because of the effort on the controls exerted by the pilot (disconnection is inhibited below the safety altitude). The crew then found itself in manual control with a significant pitch-up moment caused by the out-of-trim pitch, to which was added the pitch up moment caused by the engines in go-around power mode. The movement of the elevator control was insufficient to countermand this combined pitch-up and prevent an increase in attitude. The airplane stalled three times in a row, pitching down and recovering at 2.5 g each time. The pilot regained control of the airplane by reducing engine power. The out-of-trim correction phase occurred later.

July 2, 1993 - 747-128A - Air France - Santo Domingo

This incident occurred just three months before the Air France accident. In this incident, the crew failed to stabilize the approach. As a result, the airplane landed very long and at a higher than normal speed, overrunning, and stopping just off the end of the runway. The major similarity between this accident and the Tahiti accident was that the VFR weather conditions precluded the flight crews from considering go-around options from a non-stabilized approach. As a result of the Santo Domingo accident, Air France had launched a campaign to heighten crews' awareness of the dangers inherent to non-stabilized approaches.

December 27, 1991 - MD-81 - Scandinavian Airlines System (SAS) - Stockholm

The airplane was not properly de-iced before the flight, and shortly after take-off ice from the wing was ingested in the rear-fuselage-mounted engines, causing both of them to fail. The manufacturer had included a common feature that reduced engine thrust during takeoff for noise abatement considerations. However, unbeknownst to the flight crew, the manufacturer had also included a feature that applied full thrust to both engines if an engine failure was detected, during the time frame of reduced thrust. In this case, with a dual-engine failure from ice ingestion, it was inappropriate to increase thrust on the badly damaged engines. The pilots, not realizing what was happening to the engines, failed to reduce thrust manually. The engines could not operate at full thrust with the damage they had sustained, and failed due to turbine damage.

See accident module

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