Investigation Summary
During a routine ILS approach, the First Officer accidentally bumped the TO/GA lever. This caused the autopilot to increase thrust and attempt a climb. The crew tried to force the nose down manually by pushing the control columns, a standard override technique on many other aircraft. However, on this specific A300-600R software version, the autopilot would not disengage through yoke pressure while in TO/GA mode; it could only be deactivated by pressing the autopilot disconnect button or moving the throttles. The autopilot's trim system fought the pilots by trimming the horizontal stabilizer to its maximum nose-up limit (12.3 degrees) to maintain the commanded climb. When the crew finally disconnected the autopilot and applied full power for a manual go-around, the extreme mistrim caused the aircraft to pitch up to 52 degrees, resulting in a low-altitude stall from which recovery was impossible.
Final Conclusions
The accident was caused by the crew's lack of understanding of the A300's autopilot logic and the 'fight' between manual column inputs and automated trim systems. Contributing factors included inadequate training on the specific TO/GA override characteristics and the failure of the crew to recognize the extreme out-of-trim condition before it reached a critical state.
Video Analysis
264 Dead Due to an Avoidable Error: What Happened on China Airlines 140? — An in-depth look at how a simple accidental lever bump led to a catastrophic conflict between man and machine at Nagoya Airport.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
First Officer
Systems & Failure Modes
TO/GA (Take-Off/Go-Around) Mode
An autopilot/autothrust mode that provides maximum thrust and a specific pitch command for climbing away from the ground.
THS (Trimmable Horizontal Stabilizer)
The movable tail surface used to trim the aircraft; in this case, it moved to a full nose-up position to counter the pilots' nose-down inputs.
Alpha Floor Protection
An automated safety feature that increases engine thrust to prevent a stall when a high angle of attack is sensed.
Interesting Facts
- 01It remains the deadliest accident in the history of China Airlines.
- 02The A300's autopilot logic at the time did not automatically disengage when manual pressure was applied to the yoke if TO/GA was active.
- 03Only 7 passengers survived the crash, all of whom were seated in rows 7 through 15.
- 04The Captain had over 8,000 flight hours, but only 1,300 were on the Airbus A300-600R.
- 05Airbus had previously issued a service bulletin regarding the autopilot override logic, but the accident aircraft had not yet been modified.
Safety Actions & Advisories
Autopilot Logic Modification
Airbus modified the flight control software to ensure that manual override of the control column would automatically disconnect the autopilot, even in TO/GA mode.
Enhanced Crew Training
Airlines updated training programs to emphasize the dangers of 'fighting' the autopilot and to improve recognition of stabilizer mistrim conditions.
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.