The National, January 21, 2015
JAKARTA // Revelations that AirAsia Flight QZ8501 climbed too fast before stalling and plunging into the sea, show “striking” similarities between that accident and the 2009 crash of an Air France jet, analysts said on Wednesday.
The same day, a crash investigator said that warning alarms on the flight were “screaming” and going off “for some time” as the pilots desperately tried to stabilise the plane just before it plunged into the Java Sea last month.
The noise of several alarms – including one that indicated the plane was stalling – can be heard going off in recordings from the cockpit, said the investigator from Indonesia’s National Transportation Safety Committee which is looking into the crash.
“The warning alarms, we can say, were screaming, while in the background [the pilot and co-pilot] were busy trying to recover,” the investigator said.
Earlier this week the Transportation Safety Committee said it was now focusing on human or aircraft error as probable causes, after analysing data from the cockpit recorder.
On Tuesday, Indonesian transport minister Ignasius Jonan said the Airbus A320-200 was ascending at a rate of 6,000 feet a minute before stalling, as it flew in stormy weather last month from the Indonesia city of Surabaya to Singapore.
“In the final minutes, the plane climbed at a speed which was beyond normal,” he said.
According to experts, that ascent is about two to three times the normal climb rate for a commercial jetliner.
Indonesian divers recovered the plane’s black box recorders a week ago, after an arduous search for the jet that crashed on December 28 with 162 people on board. The cockpit voice recorder and the flight data recorder are now being analysed, with a preliminary report due next week.
While they stressed the difficulty of drawing conclusions without seeing the full black box data, analysts said on Wednesday that the accident had strong echoes of the crash of Air France flight 447 into the Atlantic in 2009, which killed 228 people.
“The similarities are pretty striking,” said Daniel Tsang, founder of Hong Kong-based consultancy Aspire Aviation.
In that case, the Airbus A330 en route from Rio to Paris vanished at night during a storm. The aircraft’s speed sensors were found to have malfunctioned, and the plane climbed too steeply, causing it to stall.
As with the AirAsia disaster, the accident happened in what is known as the “intertropical convergence zone”, an area around the equator where the north and south trade winds meet, and thunderstorms are common.
The investigation into AF447 found that both technical and human error were to blame. After the speed sensors froze up and failed, the pilots failed to react properly, according to the French aviation authority who said they lacked proper training.
On Tuesday, Mr Jonan likened the doomed plane’s ascent to a fighter jet, although experts noted that warplanes can climb considerably faster – 10,000 feet per minute when at altitude.
Tom Ballantyne, Sydney-based chief correspondent for Orient Aviation magazine, said the rate of the AirAsia jet’s climb was “just phenomenal”, adding: “I’m not sure I’ve heard of anything that dramatic before.”
He said it would be unusual for weather alone to cause such a rapid ascent, but added that it was possible if the jet hit “some bizarre unprecedented storm cell”.
“It is possible that the aircraft could have got caught in some sort of updraft that lifted it thousands of feet,” he said.
However, while acknowledging the plane’s rapid ascent showed that there was “something very wrong”, Gerry Soejatman, a Jakarta-based independent aviation analyst, said it was too early to have a firm read on the cause of the crash.
“Although there are similarities with Air France, and the weather seems to be a factor, we can’t make any conclusions that this is caused by the weather or icing – it’s too early,” he said.
Nevertheless, Mr Tsang said the investigation was unfolding as analysts had predicted, with no explosions or loud bangs registered on the cockpit voice recorder, and thus no indication that terrorism played a role.
* Agence France-Presse
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do 22 jan 2015 - 2:01