China Airlines Flight 006
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Damage to N4522V's horizontal stabilizers after it experienced a free fall of 30,000 ft.
|Date||19 February 1985|
|Summary||Crew disorientation, pilot error, Number 4 engine flameout.|
|Site||Pacific Ocean, near San Francisco, California, United States|
|Injuries (non-fatal)||24 (2 serious)|
|Aircraft type||Boeing 747SP-09|
|Flight origin||Chiang Kai Shek Int'l Airport|
|Destination||Los Angeles Int'l Airport|
China Airlines Flight 006 (callsign "Dynasty 006") is a daily non-stop flight from Taipei to Los Angeles International Airport. On February 19, 1985, it was involved in an aircraft upset accident after the No. 4 engine flamed out. 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 rapid dive, and then to divert to San Francisco International Airport.
The accident occurred ten hours into the service that departed Tapei 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 flight was in the hands of a seasoned crew, consisting 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 was a highly experienced pilot with approximately 15,500 flight hours. The first officer was also experienced, with more than 7,700 hours to his credit, and the flight engineer, like the captain, had approximately 15,500 hours of flight time. The incident occurred while the main crew was on duty.
The sequence began when the No. 4 (starboard outermost) 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.
The airspeed continued to decrease, while the autopilot rolled the control wheel to the maximum left limit of 23 degrees. As the speed decreased even further, the plane began to roll to the right, even though the autopilot was maintaining the maximum left roll limit. By the time the captain disconnected the autopilot, the plane had rolled over 60 degrees to the right and the nose had begun to drop. Aileron control was the only means available to the autopilot to keep the wings level as the autopilot does not connect to the rudder during normal cruise flight. To counteract the asymmetrical forces created by the loss of thrust from the No. 4 engine, it was essential for the pilot to manually push on the left rudder. However, the captain failed to use any rudder inputs at all, before or after disconnecting the autopilot. The resulting uncontrolled flight path is depicted in the diagram.
As the plane descended through clouds, the captain's attention was drawn to the artificial horizon which displayed excessive bank and pitch. Because such an attitude is highly irregular, the crew incorrectly assumed the indicators to be faulty. Without any visual references (due to the clouds) and having rejected the information from the ADIs, the crew became spatially disoriented. The plane entered a steep dive at a high bank angle. Altitude decreased 10,000 ft (3,000 m) within only 20 seconds, a vertical descent averaging 30,000 feet per minute (150 m/s). The crew and passengers experienced g-forces reaching as much as 5g.
Only after breaking through the bottom of the clouds at 11,000 feet (3,400 m) did the captain orient himself and bring the plane under control, leveling out at 9,600 feet (2,900 m). They had descended 30,000 ft (9,100 m) in under two and a half minutes. The flight crew were under the impression that all four engines had flamed out, but the National Transportation Safety Board believes only engine No. 4 had failed. After leveling out, it was found that the three remaining engines were supplying normal thrust. A restart attempt brought No. 4 back into use. They began climbing and reported to air traffic control "condition normal now" and they were continuing on to Los Angeles. They then noticed that the inboard main landing gear was down and one of the plane's hydraulic systems was empty. Because they did not have sufficient fuel to reach Los Angeles with the drag added by the landing gear, they diverted to San Francisco. Learning there were injured people on board, an emergency was declared and they flew straight in to the airport and landed without further incident.
There were two serious injuries on board: a fracture and laceration of a foot, and an acute back strain requiring two days of hospitalization. The aircraft was significantly damaged by the aerodynamic forces. The wings were permanently bent upwards by 2 inches (50 mm), the inboard main landing gear lost two actuator doors, and the two inboard main gear struts were left dangling. Most affected was the tail, where large outer parts of both horizontal stabilizers had been ripped off. The entire left outboard elevator had been lost along with its actuator, which had been powered by the hydraulic system that ruptured and drained.
After substantial investigation, this accident brought to international attention the problem of pilots suffering jet lag as a contributing factor to pilot errors. The captain was considered to be an experienced pilot and had flown six international flights in the previous two weeks. Though he testified that he did not believe he was tired, NTSB investigators suggest that his inability to sleep during his rest period and the fact that the accident took place at 2 am Taipei time contributed to his inability to focus on and process important details about the aircraft's behavior that could have averted the accident.
After repairs were made to correct the significant damage to the plane, it returned to service on April 25, 1985. It continued in service for nearly 12 years until it was leased to China Airlines' sister company, Mandarin Airlines, on January 1, 1997. This plane remained in daily service with Mandarin Airlines until the end of 1997 when the carrier retired it and sent it to McCarran International Airport for storage. From April 2002 it was owned and operated by a religious organization known as Gospel to the Unreached Millions (GUM), headed by K. A. Paul, and was christened 'Global Peace One'. On July 17, 2005 the FAA suspended its operating certificate due to insufficient maintenance. It was then due for major maintenance work, which was never completed. As of May 20, 2010[update], the aircraft is kept in a large hangar at General Abelardo L. Rodríguez International Airport in Tijuana, Baja California, and it is possible that it will be scrapped as it is reported to be in very poor condition. The aircraft can be seen using Google Earth at the coordinates .
In popular culture
- The flight was documented on an episode of the television program Mayday (otherwise known as Air Emergency or Air Crash Investigation) titled "Panic Over the Pacific".
- NTSB report courtesy of University of Bielefeld - Faculty of technology html version by Hiroshi Sogame Safety Promotion Comt. All Nippon Airways
- Accident Brief by the U.S. National Transportation Safety Board.
- Full Accident Report by the U.S. National Transportation Safety Board.
- Summary and comments in Risks Digest.
- Time Magazine story
- German article with pictures of the damaged airplane after landing in Der Spiegel