Investigation Summary
The accident sequence began approximately 10 hours into the flight when the No. 4 engine flamed out at FL410. The flight engineer attempted a restart without closing the bleed valve, a deviation from the checklist that reduced the likelihood of success at high altitude. As the aircraft slowed, the autopilot attempted to maintain wings-level flight by applying left aileron to counter the right-hand yaw caused by the dead engine. However, the autopilot on the 747SP does not control the rudder during cruise. The captain, preoccupied with the engine malfunction, did not apply manual left rudder. When the autopilot reached its maximum aileron deflection of 23 degrees, the aircraft began a right roll and nose-down pitch. The captain disconnected the autopilot when the bank angle exceeded 60 degrees, but without visual references in the clouds, he and the first officer became spatially disoriented. The aircraft entered a steep spiral dive, reaching vertical acceleration forces of 4.8g and 5.1g. The dive was so severe that the landing gear was forced down by aerodynamic loads and parts of the horizontal stabilizer were torn off. The captain finally recovered the aircraft at 9,500 feet after visual contact with the ocean was established.
Final Conclusions
The NTSB determined the probable cause was the captain's preoccupation with an in-flight malfunction and his failure to monitor flight instruments, resulting in a loss of control. A contributing factor was the captain's over-reliance on the autopilot following the loss of thrust on the No. 4 engine. The investigation also evaluated the captain's sleep cycle and noted he may have been suffering from jet lag and fatigue after crossing several time zones, though this was not listed in the formal probable cause statement. The aircraft was substantially damaged, including permanently bent wings and the loss of large sections of the horizontal stabilizers, but was eventually repaired and returned to service.
Photographic Evidence (1)
Video Analysis
China Airlines 006 Plunges Into Pacific Dive | Mayday Air Disaster — A detailed reconstruction of the 30,000-foot plunge of China Airlines Flight 006, featuring survivor interviews and NTSB findings regarding the crew's spatial disorientation.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Age 55, Min-Yuan Ho
First Officer
Age 53, Ju-Yu Chang
Flight Engineer
Age 55, Kuo-Pin Wei
Systems & Failure Modes
Autopilot
The system attempted to maintain level flight using only ailerons and spoilers, masking the developing yaw until it reached its physical limits.
Attitude Director Indicator (ADI)
The captain incorrectly assumed the ADIs were faulty because the extreme pitch and bank angles they displayed seemed impossible.
Pratt & Whitney JT9D-7A Engines
The No. 4 engine suffered a flameout; the other three engines remained functional throughout the dive despite the crew's belief they had all failed.
Interesting Facts
- 01The aircraft descended 31,500 feet in approximately two and a half minutes.
- 02The g-forces during the dive were high enough to permanently bend the wings upward by 2 inches.
- 03The No. 4 engine had a history of previous failures on earlier flights that maintenance had not successfully resolved.
- 04The autopilot on the 747SP does not have rudder authority in cruise mode, requiring manual pilot intervention for asymmetric thrust.
- 05Large sections of the horizontal stabilizers and the entire left outboard elevator were lost during the high-speed descent.
- 06During the descent, the crew erroneously believed that all four engines had flamed out, though only the No. 4 engine had actually failed.
Safety Actions & Advisories
Crew Training Enhancement
The incident highlighted the need for better training regarding the limitations of autopilots during engine-out scenarios and the importance of manual rudder use.