China Airlines Flight 611 was a regularly scheduled international passenger flight from Chiang Kai-shek International Airport (now Taoyuan International Airport) in Taiwan to Hong Kong International Airport that disintegrated midair and crashed into the Taiwan Strait, northeast of the Penghu Islands, 20 minutes after takeoff, killing all 225 people on board. The in-flight breakup was caused by metal fatigue cracks from a tail strike at Kai Tak Airport on 7 of February 1980 after which the aircraft was not properly repaired according to Boeing policies and manuals. Metal fatigue from over 22 years of service and repeated depressurizations caused tiny cracks that led to the aircraft's breakup.

The crash remains the deadliest in Taiwan, as well as the most recent accident with fatalities involving China Airlines, and the second-deadliest accident in China Airlines history, behind China Airlines Flight 140 with 264 fatalities.

Aircraft

The aircraft involved, registered as , was the only Boeing 747-200 passenger aircraft left in China Airlines's fleet at the time. The plane was delivered new to the airline on 2 August 1979, and spent its entire life with the airline. The aircraft had logged more than 64,800 hours of flight time at the time of the accident. The plane was equipped with 4 Pratt and Whitney JT9D-7AW engines and had a 355-seat configuration. The accident flight was to be 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.

Accident

The flight took off at 15:08 Taipei local time (07:08 UTC), and was originally scheduled to arrive at Hong Kong at 16:45 Hong Kong Time (08:45 UTC). The flight crew consisted of 51-year-old Captain Yi Ching-Fong, 52-year-old First Officer Shieh Yea-Shyong, and 54-year-old Flight Engineer Chao Sen-Kuo. All three pilots were highly experienced – both pilots had more than 10,100 hours of flying time and the flight engineer had logged more than 19,100 flight hours.

At 15:16 Taipei local time, the flight was cleared to climb to flight level 350—about . At 15:33, contact with the plane was lost. Chang Chia-juch, the Taiwanese Vice Minister of Transportation and Communications at that time, said that two Cathay Pacific aircraft in the area received B-18255's emergency location-indicator signals. All 206 passengers and 19 crew members on board the aircraft were killed.

Passengers

The passengers included Taiwanese politician You Jih-cheng. and two reporters from the United Daily News.

{| class="sortable wikitable" style="margin:0 0 0.5em 1em; float:right;"

!Nationality

!Total

|-

|Taiwan||209

|-

|China||9

|-

|Hong Kong||5

|-

|Singapore||1

|-

|Switzerland||1

|-

!Total!!225

|}

Of the 225 passengers and crew on board, remains of 175 were recovered and identified. The first 82 bodies were found floating on the ocean surface of the Taiwan Strait, and were recovered by fishing boats and military vessels. Contracted recovery vessels were subsequently used for the recovery of the aircraft wreckage and the remaining bodies. Radar data suggest that the aircraft broke into four pieces whilst at FL 350. This theory is supported by the fact that some lighter articles that would have been found inside the aircraft were found up to from the crash site at villages in central Taiwan. The items included magazines, documents, luggage, photographs, New Taiwan dollars, aircraft safety cards and a China Airlines-embossed, blood-stained pillow case.

The plane was supposed to be leveling off then, as it approached its cruising altitude of . Shortly before the breakup, two of the aircraft's four engines began providing slightly higher thrust, which was later found to have been within the normal ranges of deviation. All four engines were recovered from the sea and found not to have suffered any malfunction prior to the crash. Pieces of the aircraft were found in the ocean and on Taiwan, including in the city of Changhua.

The governments of Taiwan and the People's Republic of China co-operated in the recovery of the aircraft; the Chinese 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 (now National Police Agency) 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". 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,

Consequently, after repeated cycles of pressurisation and depressurisation during flight, cracks began to form around the exposed scratches until finally, on 25 May 2002, coincidentally 22 years to the day after the faulty repair was made on the damaged tail, the hull broke open in midair. A rapid decompression occurred once the crack opened up, causing the separation of the aircraft's fuselage at section 46 (aft of the main wingbox). The remainder of the aircraft forward of section 46 entered an abrupt descent, causing all four engines to separate from the wings near-simultaneously, as the engine fuse pins failed at about . After this point, the wings and fuselage forward of the initial breakpoint remained connected until impact with the sea.

This was not the first time that a 747 had crashed because of a faulty repair following a tailstrike. On 12 August 1985, 17 years before Flight 611's crash and 7 years after the accident aircraft's repair, Japan Air Lines Flight 123 from Tokyo to Osaka with 524 people on board had crashed when the vertical stabiliser was torn off and the hydraulic systems severed by explosive decompression, leaving only four survivors. That crash had been attributed to a faulty repair to the rear pressure bulkhead, which had been damaged in 1978 in a tail strike incident. In both crashes, a doubler plate was not installed according to Boeing standards at the time.

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 during the investigation that came up was the discolouration on the damaged section of the tail from photographs from maintenance records. The discolouration was determined to be tar stains from cigarette and cigar smoke. Smoking was permitted onboard China Airlines' flights until 1995. Had the stains been investigated, the cracks in the fuselage would have been discovered, and the plane might have avoided the fateful flight.

The accident was featured in a Season 7 episode of the Canadian documentary series Mayday (Air Disasters in the U.S.), entitled "Scratching the Surface".