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Visibility plunged during ill-fated plane's landing: council

Visibility plunged during ill-fated plane's landing: council

Taipei, Dec. 26 (CNA) A TransAsia Airways flight that crashed in Penghu County amid inclement weather on July 23 faced a sudden drop in visibility as it was attempting to land but was not alerted to the change by the control tower, the Aviation Safety Council said Friday. The council also acknowledged that the airport may have had an equipment problem that prevented the control tower from getting accurate visibility data to the arriving aircraft in time. The new revelations were part of the council's "GE222 Occurrence Investigation Factual Data Collection Group Report," an initial report on the crash that occurred just outside the main airport on the Penghu Islands after aborting a landing attempt in harsh weather left behind by Typhoon Matmo.
Of the 58 people on board, 48 passengers and crew members were killed. In its initial report, the council did not try to explain the cause of the accident but rather presented details on the conditions that prevailed around the time of the crash at 7:06 p.m.
According to the council, a cloud band with thunderstorms approached the airport at around 7 p.m., just as TransAsia Airways flight GE222 was approaching Magong Airport when it thought there was an opening in the weather.
Visibility readings abruptly dropped below 1,600 meters, the minimum standard for landings at the airport.
Airport runway instruments showed runway visual range -- one measure of visibility -- plummeting to 600 meters at 7:02 p.m. and close to 400 meters just before the crash, according to the report. But as the weather changed, there was some debate among the flight controllers over whether the data was accurate, and they decided not to pass on the information to the pilots of the ill-fated plane, instead giving them the green light to land at 7:03 p.m. At the same time the control tower decided to record visibility manually, but that took time and did not yield a visibility reading of 800 meters until 7:10 p.m. By then it was too late.
"There were indeed problems concerning the controllers' decision in choosing which data to offer," said Thomas Wang, the council's managing director. They had doubts about the instruments' accuracy, the council said, because its readings had not been consistent with the controllers' visual observations during the day. Visibility fell to 800 meters in the wake of Typhoon Matmo between 5:30 p.m. and 6:30 p.m. but improved to 1,600 meters between 6:40 p.m. and 7 p.m., yet during that hour the instrument put the runway visual range at above 2,000 meters. Still, the council stressed that the pilots were the ones who had the best idea of visibility, and said if they could not see the runway, they should have aborted the landing. They in fact tried. After being given the go ahead to land, they reached a designated missed approach point -- meaning the landing should be aborted -- just seconds after taking over manual control of the plane at 7:05 p.m. The plane crashed about a minute later when the pilots tried to fly a go-around after being unable to spot the runway.
The Aviation Safety Council said a final report on the crash will be published in October 2015. (By Wang Shu-fen and Lee Hsin-Yin)


Updated : 2021-10-25 23:08 GMT+08:00