Metal fatigue and corrosion were found in pieces of wreckage from a Hong Kong-bound China Airlines (CAL) jetliner that broke apart and fell into the Taiwan Strait shortly after taking off from Taipei last year, the Cabinet's Aviation Safety Council (ASC) said in a "factual data report" released yesterday.
CAL flight CI-611, a Boeing 747-200, crashed into the sea about 22km north of Makung, Penghu Island, on May 25 last year, killing 209 passengers and 16 crew.
After collecting 1,432 pieces of wreckage, making up nearly 80 percent of the aircraft, the council yesterday ruled out terrorism, pilot error and the weather as causes of the crash.
While investigators said they would not conclude until next year why the airliner broke up mid-flight, they confirmed that fatigue cracks and corrosion were found near where the aircraft is thought to have first broken apart.
The report, published on the council's Web site, said that several cracks had been found on a piece of wreckage that contained an aluminum patch that had been used to repair damage sustained when the plane's tail struck the runway in Hong Kong in February 1980.
Under the patch, investigators found a 38cm continuous crack that they suspect had been there for some time.
Paint was also found under the patch, although investigators would not say whether this indicated the patch had been improperly attached to the plane.
Corrosion was also found at multiple sites around the patch.
ASC Managing Director Yong Kay (
A pressurization control switch was set to manual rather than automatic, suggesting an anomaly in the cabin pressure, he said.
"We still need time to probe the cause based on available evidence," Yong said.
Yong said that nothing unusual about the way the plane had been flown was found in data collected from the flight data recorder. However, Yong said, the recorder lacked information on cabin pressure.
Yong yesterday declined to make a direct link between the metal fatigue and the crash.
After the 1980 accident, Yong said, the jet flew back from Hong Kong to Taiwan with a temporary patch, which was replaced with a permanent patch in May that year.
"When we asked for documentation about the 1980 repair, CAL provided us with only limited information," Yong said.
Yong said a preliminary draft of the analysis report would be released by the end of this year and a final report would be published by October next year.
RSS