China Airlines Flight 611

China Airlines Flight 611 (CAL 611, CI 611, callsign Dynasty 611) was a regularly scheduled flight from Chiang Kai-shek International Airport (now Taiwan Taoyuan International Airport) in Taoyuan to Hong Kong International Airport in Hong Kong. On 25 May 2002, the Boeing 747-209B disintegrated in mid-air and crashed into the Taiwan Strait just 20 minutes after taking off, killing 225 people. The cause of the crash was improper repairs to the aircraft 22 years earlier.

The Taipei to Hong Kong route is one of the most heavily-travelled routes on Earth; it is so profitable that it is referred to as the "Golden Route."

Flight and disaster
The flight on Saturday, 25 May 2002 took off at 14:50 local time and was expected to arrive at Hong Kong at 16:28. The flight crew consisted of Captain Ching-Fong Yi (易清豐, Hanyu Pinyin: Yì Qīngfēng), First Officer Yea Shyong Shieh (謝亞雄, Hanyu Pinyin: Xiè Yàxióng), and Flight Engineer Sen Kuo Chao (趙盛國, Hanyu Pinyin: Zhào Shèngguó). The names of the pilot and first officer, respectively, are alternatively romanized as "Yi Ching-Fung" and "Hsieh Ya-Shiung".

About 25 minutes after takeoff, the aircraft disappeared from radar screens, suggesting it had experienced an in-flight breakup at FL350 (approximately 35,000 feet or 7 miles) near the Penghu Islands in the Taiwan Strait (co-ordinates 23.98°N, 119.67°E).

The crash occurred at a time between 15:37 and 15:40; Chang Chia-juch (張家祝, Hanyu Pinyin: Zhāng Jiāzhù), the Republic of China (ROC) Vice Minister of Transportation and Communications, said that two Cathay Pacific aircraft in the area received B-18255's emergency location-indicator signals. All 19 crew members and all 206 passengers died.

Passengers
The passengers included a former legislator and two reporters from the United Daily News. All of the passengers on board were ethnic Chinese except the passenger from Switzerland. 114 of the passengers were members of a group tour to Hong Kong or PRChina organized by five travel agencies.

Recovery and identification of remains
The Republic of China government kept statistics of the passengers who were recovered.

The remains of 175 of the 206 passengers aboard were recovered and identified. The first 82 bodies, those of 76 passengers and 6 cabin crew, were found floating on the surface of the ocean, and were recovered by fishing vessels, the Coast Guard, and military vessels.

Autopsies were conducted on three flight crew members, while ten bodies and some human remains were X-rayed.

Most of the recovered passengers in the rear of the jet (Zones D through E) were found naked, since their clothes were torn off due to the forces of explosive decompression. Most of the recovered passengers in the front of the jet (Zones A through C) still had clothes on. Of the recovered passengers, 66 were fully clad, 25 were partially clad and 50 were completely naked. Two of the fully clad passengers were travelling with infants on their laps; the clothing situation of the infants was not stated.

Some passengers were found floating, while some remained strapped in their seats. Of the recovered passengers, 54 did not float and were not seated, 7 did not float and were still seated, 81 floated and did not decompose (1 held an infant; the infant's condition is not stated) while 25 floated and decomposed (1 held an infant; the infant's condition is not stated). 92% of the passengers initially found floating on the ocean surface had assigned seats located in and between Rows 42 and 57 (Zone E).

Some passengers had injuries predominantly on one side per body. Of these passengers, 10 sustained injuries predominantly on their left side (1 held an infant; the infant's condition is not stated) while 10 sustained injuries predominantly on their right side. Fifty-one sustained tibia and/or fibula bone fractures. Some passengers sustained back and/or hand abrasions. Of these, 27 sustained only hand abrasions, 10 sustained only back abrasions and 16 sustained back and hand abrasions.

Search, recovery and investigation
At 17:05, a military C-130 aircraft spotted a crashed airliner 20 nautical miles (37 km) northeast of Makung. Oil slicks were also spotted at 17:05; the first body was found at 18:10.

Searchers recovered 15% of the wreckage, including part of the cockpit, and found no signs of burns, explosives or gunshots.

There was no distress signal or communication sent out prior to the crash. Radar data suggests that the aircraft broke into four pieces while at FL350. This theory is supported, by the fact that articles that would have been found inside the aircraft, were found up to 80 miles (130 km) from the crash site in villages in central Taiwan. The items included magazines, documents, luggage, photographs, Taiwan dollars, and a China Airlines-embossed, blood-stained pillow case.

The flight data recorder from Flight 611 shows that the plane began gaining altitude at a significantly faster rate in the 27 seconds before the plane broke apart, although the extra gain in altitude was well within the plane's design limits. The plane was supposed to be leveling off then as it approached its cruising altitude of 35,000 feet. Shortly before the breakup, one of the aircraft's four engines began providing slightly less thrust. Coincidentally, the engine was the only one recovered from the sea floor. Pieces of the aircraft were found in the ocean and on Taiwan, including in the city of Changhua.

The Republic of China and the People's Republic of China co-operated in the recovery of the aircraft; the People's Republic of China allowed personnel from Taiwan to search for bodies and aircraft fragments in those parts of the Taiwan Strait controlled by the People's Republic of China.

China Airlines requested relatives to submit blood samples for DNA testing at the Criminal Investigation Bureau of National Police Administration and two other locations.

The United Daily News stated that some relatives of passengers described the existence of this flight to Hong Kong as being "unnecessary". They said this because most of the passengers intended to arrive in Mainland China, but because of a lack of direct air links between Taiwan and Mainland China, the travellers had to fly via Hong Kong; the relatives advocated the opening of direct air links between Taiwan and Mainland China.

Metal fatigue
The final investigation report found that the accident was the result of metal fatigue caused by inadequate maintenance after a previous incident.

The report indicated that on 7 February 1980, the aircraft used on the flight had a tailstrike accident while landing in Hong Kong. Part of the plane's tail was damaged in the incident. The aircraft was de-pressurized, ferried back to Taiwan on the same day, and a temporary repair done the day after. A more permanent repair was conducted by a team from China Airlines from 23 May through 26 May 1980. However, the permanent repair of the tail strike was not carried out in accordance with the Boeing Structural Repair Manual (SRM). The area of damaged skin in Section 46 was not removed (trimmed) and the repair doubler plate that was supposed to cover in excess of 30% of the damaged area did not extend beyond the entire damaged area enough to restore the overall structural strength.

Consequently, after repeated cycles of depressurization and pressurization during flight, the weakened hull gradually started to crack and finally broke open in mid-flight on 25 May 2002, exactly 22 years to the day after the faulty repair was made upon the damaged tail. An explosive decompression of the aircraft occurred once the crack opened up, causing the complete disintegration of the aircraft in mid-air. However, this was not the first time that a plane had crashed because of a faulty repair following a tailstrike. On August 12, 1985, 17 years before the Flight 611 crash and five years after the accident aircraft's repair, Japan Airlines Flight 123 had crashed when the tailfin was torn off and the hydraulic systems severed by explosive decompression, killing 520 of the 524 people onboard the aircraft. That crash had been attributed to a faulty repair to the rear pressure bulkhead, which had been damaged in 1978 in a tailstrike incident. In both crashes, the faulty repair had been an incorrectly installed doubler plate.

China Airlines disputed much of the report, stating that investigators did not find the pieces of the aircraft that would prove the contents of the investigation report.

One piece of evidence of the metal fatigue is contained in pictures that were taken during a routine inspection of the plane years before the crash. The photos showed visible brown nicotine stains around the doubler plate. This nicotine was deposited by smoke from the cigarettes of people who were smoking about seven years before the disaster (smoking was allowed in a pressurized plane at that time). The doubler plate had a brown nicotine stain all the way around it that could have been detected visually by any of the engineers when they inspected the plane. The stain would have suggested that there might be a crack caused by metal fatigue behind the doubler plate, as the nicotine slowly seeped out due to pressure that built up when the plane reached its cruising altitude. The stains were apparently not noticed and no correction was made to the doubler plate, which caused the crash to happen.

Flight number
It is a common practice to retire flight numbers following loss of aircraft and Flight 611 no longer exists. Shortly after the accident, China Airlines changed the flight number to 919, which now serves the Taipei-Hong Kong route along with existing flights 903, 641, 605, 909, 913, 915, 617, 679, 923, 927 and 2927.

Aircraft history
The aircraft B-18255 (originally registered as B-1866) involved, MSN 21843, was the only Boeing 747–200 passenger aircraft left in the China Airlines fleet at the time. It was delivered to the airline in 1979, and had logged 64,810 hours of flight time. Prior to the crash China Airlines had sold B-18255 to Orient Thai Airlines for US$1.45 million. The accident flight was the aircraft's penultimate flight for China Airlines as it was scheduled to be delivered to Orient Thai Airlines after its return flight from Hong Kong to Taipei. The contract to sell the aircraft was voided after the crash.

The remaining four 747-200 freighters in China Airlines fleet were grounded immediately by the ROC's Civil Aviation Administration (CAA) after the crash. The airline returned the jets to service a few days later after maintenance checks.

Dramatization
The story of the disaster was featured on the seventh season of Canadian National Geographic Channel show Mayday (known as Air Emergency in the US, Mayday in Ireland and Air Crash Investigation in the UK and the rest of world). The episode is entitled "Scratching the Surface".

Official investigation reports

 * Ballistic Trajectory Analysis for the CI611 Accident Investigation (Archive)

China Airlines

 * 0525 Flight CI 611 Status Updates
 * China Airlines Statement on CI 611 Accident Investigation Report

Media

 * "Cracks blamed for 2002 China Airlines crash", CBC News, 25 February 2005
 * Crashed China Airlines Plane Said to Break up in Sky, People's Daily
 * "CAL 747 crashes with 225 aboard," Taipei Times
 * "China Airlines back in the dock," BBC
 * Between the Shores of Life and Death
 * Set the Kite Free
 * Taiwan says crashed China Air jet missed check-ups

Other

 * B-18255 Seat Plan
 * China Airlines flight 611 disaster Tzu Chi mobilizes volunteers from all over Taiwan to help Tzu Chi
 * Jiang Expresses Condolence Over Victims of China Airlines Crash (05/27/02)