China Airlines Flight 006

China Airlines Flight 006

Damage to N4522V's horizontal stabilizers after it experienced a free fall of 30,000 ft.
Accident summary
Date	19 February 1985
Summary	High altitude stall, upset and 30,000 ft. dive pilot error after Engine 4 flameout
Site	Pacific Ocean, near San Francisco, California, United States
Passengers	251
Crew	23
Fatalities	0
Injuries (non-fatal)	24 (2 serious)
Survivors	274 (all)
Aircraft type	Boeing 747SP-09
Operator	China Airlines
Registration	N4522V
Flight origin	Chiang Kai Shek Int'l Airport
Destination	Los Angeles Int'l Airport

China Airlines Flight 006 (callsign "Dynasty 006") was a daily non-stop flight from Taipei to Los Angeles International Airport. On February 19, 1985, the Boeing 747SP used to conduct the flight was involved in an aircraft upset accident, following the flame-out of the No. 4 engine, while cruising at FL 410 (41,000 ft.)(12,500 m). The plane rolled over and plunged 30,000 ft (9,100 m), experiencing high speeds and g-forces (approaching 5g) before the captain was able to recover from the dive, and then to divert to San Francisco International Airport.

The accident occurred ten hours into the service that departed Taipei at 16:15. The Boeing 747SP-09 was 350 miles (550 km) northwest of San Francisco, cruising at an altitude of 41,000 ft (12,500 m). The cockpit crew, consisted of Captain Min-Yuan Ho (55), First Officer Ju Yu Chang (53), Flight Engineer Kuo-Win Pei (55), Relief Captain Chien-Yuan Liao (53), and Relief Flight Engineer Po-Chae Su Shih Lung (41). Captain Ho had approximately 15,500 flight hours. The first officer had more than 7,700 hours, and the flight engineer had approximately 15,500 hours of flight time. The accident occurred while the main crew was on duty.

The sequence began when the No. 4 engine stalled at a low thrust setting and flamed out. That engine had failed twice during previous flights (while cruising at FL 410 and 430). In each of those cases, the engine was restarted after descending to a lower altitude. The maintenance response to the logbook entries that noted the problems included engine inspection, fuel filter drainage and replacement, vane controller inspection and replacement, water drainage from Mach probes, insufficient modules, and other filter replacements. None of those acts fixed the recurrent stalling and flameout problem of the No. 4 engine.

After the flameout, the captain instructed the flight engineer to attempt to restart the engine, while the plane remained at FL 410 (41,000 feet) with the autopilot still engaged and the bleed air on. This was contrary to the flight manual procedure, which required the plane to be below 30,000 feet (9,100 m) before any attempt to restart a flamed-out engine. The attempt failed.