China Airlines Flight 120

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China Airlines Flight 120
Burnt-out wreckage of Flight 120 at Naha Airport.
Accident summary
Date 20 August 2007 (2007-08-20)
Summary Bolt failure caused by fuel leak set on fire
Site Naha Airport, Okinawa, Japan
Passengers 157
Crew 8
Injuries (non-fatal) 4 (and 1 ground crew)[1]
Fatalities 0
Survivors 165 (all)
Aircraft type Boeing 737-809[2]
Operator China Airlines
Registration B-18616[3]
Flight origin Taiwan Taoyuan International Airport, Taipei, Republic of China
Destination Naha Airport, Okinawa, Japan

China Airlines Flight 120 was a regularly scheduled flight from Taiwan Taoyuan International Airport in Taoyuan County, Republic of China in Taiwan to Naha Airport in Okinawa, Japan. On August 20, 2007, the Boeing 737-800 aircraft operating the flight caught fire and exploded after landing and taxiing to the gate area at Naha Airport. Four people (three from the aircraft and one ground crew) sustained injuries in the accident.

Background[edit]

The China Airlines aircraft, with registration number B-18616,[3] had been delivered in July, 2002. Like other Next Generation Boeing 737 aircraft, it was equipped with CFM56-7B26 engines.[4]

There were 157 passengers aboard, including 2 infants. Of the number, 110 passengers were from Taiwan, 23 were from Japan, and 24 were from other countries.[5] The crew of eight[3] were mostly Taiwanese, with one Japanese flight attendant.

Most of the Taiwanese passengers had also taken packaged tours from travel agencies operating on Taiwan. Travel agencies that sold packages to CI120 passengers included Daiei Travel Service (大榮旅行社), Gloria Tours (喜美旅行社), Mic Travel Co (萬達旅行社), and South East Travel Service (東南旅行社).[6]

Accident sequence[edit]

The plane landed normally at 10:26 a.m. local time and taxied to the gate area by 10:34. Ground crew noticed flames coming from engine number 2 as captain You Chien-kou shut it down in anticipation of gate connection.[7] Informed about the situation by air-traffic controllers, the captain ordered an emergency evacuation.[8][9] All passengers and flight attendants managed to leave the aircraft safely through the four hatches using slides. The first officer and the captain left the aircraft through the cockpit windows when the last flight attendant had fled from the right aft hatch. Immediately after the evacuation of the last person (the Taiwanese captain), the number 1 engine and right wing fuel tanks exploded and burst violently into flames, igniting a blaze that destroyed the aircraft. A statement from the airline confirmed that all passengers and crew members were evacuated safely.[10][11] A 57-year old Taiwanese man suffered from hypertension and an 8-year-old girl from Hong Kong felt unwell; both were sent to a hospital nearby. An airport ground crew member was hurt during evacuation on the ground, and a flight attendant, who was the last person to leave the cabin, fell over on the ground when the aircraft exploded.[8]

The taxiways of Naha Airport were closed until 11:03 a.m. because of the accident.

According to Naha Airport air traffic control, the status of the aircraft was normal in that there was no report of any abnormal situation during cruising or landing.

Following the accident, the Republic of China Civil Aeronautics Administration grounded all 14 remaining Boeing 737-800s of China Airlines, Mandarin Airlines and the Republic of China Air Force for inspection of the fuel systems. The Japan Civil Aviation Bureau asked Japanese operators of 737-700 and 737-800 aircraft to similarly inspect their aircraft. No anomalies were found and the aircraft returned to service.[12]

George Ishizaki recorded a raw video of the accident.[13] Another raw video from a different angle captured by Katsutoshi Yuasa has been submitted to Sankei Shimbun.[14][15]

Since no people were killed in the fire, China Airlines continues to operate Flight 120 from Taipei to Okinawa/Naha.

Sequence of events regarding fire fighting[edit]

The long sequence of events from the start of the fire to the arrival of the first fire fighting equipment at the scene, led to questions being asked about the slow reaction of emergency services.[16]

  • The fire was spotted at about 10:33, about 6 minutes after touchdown.
  • At 10:33:58, the fire was reported to the fire station at Naha airport.
  • At 10:35 two airport fire engines left the fire station.
  • Close to one minute later the first fire engine tried to contact the tower, but got no response.
  • At about 10:36 the first explosion occurred, causing the first officer, who was leaving the cockpit through the window, to fall to the ground.
  • About 30 seconds later the first fire engine tried to contact the tower for the second time, and did not get a response either.
  • At 10:38:25 the first fire engine (No. 6) began discharging foam onto the burning fuselage.
  • 30 seconds later the second fire engine arrived.

From the fire first being spotted by the tower, to the start of fire fighting actions, six minutes passed. There was no contact between the tower and the fire engines until then, and three explosions took place in the meantime. The plane went from a burning engine to fully involved and broken in half.[16]

Investigation[edit]

The cause of the accident was investigated by the Aircraft and Railway Accidents Investigation Commission of Japan.[3][4] The crew, as confirmed by the recording in the cockpit voice recorder, did not observe any abnormalities before the incident.[7]

The investigating team confirmed that the aircraft caught fire in the gate area and there was no sign of fuel leakage during taxiing to the gate. The investigation focused on the possibility that a fuel leak led to the fire.[4] At a news conference on August 24, investigators revealed that a bolt, which had come loose from the slat track,[17] had punctured the right wing fuel tank, creating a hole 2–3 centimetres in diameter.[18]

Aftermath[edit]

China Airlines stated they would compensate passengers NT$1000 for every kilogram of luggage lost, for a maximum of NT$20,000 for checked-in pieces of luggage and another NT$20,000 maximum for carry-on luggage.[19]

In the stock trading after the accident, China Airlines stock fell along with Taiwan Fire & Marine Insurance Co.[20]

Due to the accident, on August 25, the United States Federal Aviation Administration (FAA) ordered emergency inspections of wing leading-edge slat tracks on all Next Generation Boeing 737 aircraft. The Emergency Airworthiness Directive (EAD) from the FAA requires operators to inspect the slat track downstop to check for missing parts, ensure proper installation, and check the inside of the slat can for foreign object debris and damage. The directive requires operators to inspect within 24 days and every 3000 flight cycles thereafter.[17] Following feedback from completed inspections revealing loose parts in several other aircraft and one with a damaged slat can, the FAA issued a new emergency airworthiness directive on August 28. Airlines were then required to perform the inspection on Next Generation Boeing 737 aircraft within 10 days instead of 24 days. In addition, the AD required a one-time torquing of the nut and bolt in the downstop assembly for the slat track within 24 days.[21]

On 28 August 2009, the Japan Transport Safety Board (JTSB) published the results of the investigation. It is considered highly probable that this accident occurred through the following causal chain: When the aircraft retracted the slats after landing at Naha Airport, the track can that housed the inboard main track of the No. 5 slat on the right wing was punctured, creating a hole. Fuel leaked out through the hole, reaching the outside of the wing. A fire started when the leaked fuel came into contact with high-temperature areas on the right engine after the Aircraft stopped in its assigned spot, and the Aircraft burned out after several explosions.

With regard to the cause of the puncture in the track can, it is certain that the downstop assembly having detached from the aft end of the above-mentioned inboard main track fell off into the track can, and when the slat was retracted, the assembly was pressed by the track against the track can and punctured it.

With regard to the cause of the detachment of the downstop assembly, it is considered highly probable that during the maintenance works for preventing the nut from loosening, which the Company carried out on the downstop assembly about one and a half months prior to the accident based on the Service Letter from the manufacturer of the aircraft, the washer on the nut side of the assembly was omitted, following which the downstop on the nut side of the assembly fell off and then the downstop assembly eventually fell off the track.[22] It is considered highly probable that a factor contributing to the detachment of the downstop assembly was the design of the downstop assembly, which was unable to prevent the assembly from falling off if the washer is not installed.

With regard to the detachment of the washer, it is considered probable that the following factors contributed to this: Despite the fact that the nut was in a location difficult to access during the maintenance works, neither the manufacturer of the aircraft nor the Company had paid sufficient attention to this when preparing the Service Letter and Engineering Order job card, respectively. Also, neither the maintenance operator nor the job supervisor reported the difficulty of the job to the one who had ordered the job.

The Japan Transport Safety Board recommended the Civil Aeronautics Administration of Taiwan to supervise China Airlines to take the following actions: When planning and implementing maintenance jobs, the scope of jobs should be fully ascertained and the working conditions and environments should be appropriately evaluated, and the countermeasures to prevent maintenance errors including the actions taken in 2009 against the recurrence of this accident should be steadfastly implemented and enhanced.[23]

See also[edit]

References[edit]

  1. ^ "4人受傷 兩乘客一地勤一機組員 (Four injuries, including two passengers, one ground crew and one flight crew)" (in Chinese). ETtoday. 2007-08-20. Retrieved 2007-08-24. [dead link]
  2. ^ Accident description at the Aviation Safety Network
  3. ^ a b c d "Brief". National Transportation Safety Board. 2007-08-20. Retrieved 2007-08-23. [dead link]
  4. ^ a b c Francis, Leithen (2007-08-23). "Fuel leak focus of investigation into CAL 737-800 fire". Flight International. Retrieved 2007-08-23. 
  5. ^ "Fire Erupts on China Airlines Jet at Japanese Airport"[dead link]
  6. ^ Shan, Shelley and Jessie Ho. "China Airlines jet bursts into flames." Taipei Times. Tuesday August 27, 2007. Page 1. Retrieved on April 29, 2012.
  7. ^ a b "爆発・炎上の中華航空機、駐機後に燃料が一気に漏れる (China Airlines aircraft explosion: fuel leaked suddenly after parking)" (in Japanese). Yomiuri Shimbun. 2007-08-21. Retrieved 2007-08-24. [dead link]
  8. ^ a b "剛滑出機外 爆炸聲響 (Explosion occurred just after escaping from the aircraft)" (in Chinese). United Daily News. 2007-08-21. Retrieved 2007-08-24. [dead link]
  9. ^ "Miracle escape from blazing jet". Herald Sun. 2007-08-21. Retrieved 2007-08-24. [dead link]
  10. ^ "All safe after fire guts airliner". CNN. 2007-08-20. Retrieved 2007-08-24. 
  11. ^ Cooper, Chris and Sun, Yu-Huay (2007-08-20). "All safe after fire guts airliner". Bloomberg.com. Retrieved 2007-08-24. 
  12. ^ Francis, Leithen (2007-08-21). "CAL completing inspections of 737-800 fuel systems". Flight International. Retrieved 2007-08-23. 
  13. ^ Raw Video of Plane Exploding As Passengers Flee on YouTube
  14. ^ "那覇空港で中華航空機炎上 乗員乗客は全員無事" (in Japanese). Sankei Shimbun. 2007-08-20. Retrieved 2008-08-08. 
  15. ^ China Airline flight 120 fire accident at Naha Airport on YouTube[dead link]
  16. ^ a b http://www.mlit.go.jp/jtsb/eng-air_report/B18616.pdf Official report on the investigation
  17. ^ a b Warwick, Graham (2007-08-27). "FAA orders wing slat checks on all Boeing 737NGs". Flight International. Retrieved 2007-08-28. 
  18. ^ Francis, Leithen (2007-08-24). "CAL 737-800 that caught fire had punctured fuel tank". Flight International. Retrieved 2007-08-24. 
  19. ^ "Trip Payment and Baggage Compensation Set for CI 120 Passengers". China Airlines. 2007-08-23. Retrieved 2007-08-29. 
  20. ^ "Taipei Shares close weaker". Forbes. August 21, 2007. Retrieved 2007-08-21. 
  21. ^ "FAA orders quicker 737 wing inspections". Flight International. 2007-08-29. Retrieved 2007-08-29. 
  22. ^ "China Airlines Downstop Failure Animation". FAA. 
  23. ^ http://www.mlit.go.jp/jtsb/eng-air_report/B18616.pdf

External links[edit]