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Re: Recording of last moments of QZ8501 - comms bet Air Traffic Control and First Off
AirAsia QZ8501 pilots cut power to airplane's 'safety' computer system before crash
Twin system designed to prevent human error may have been turned off when flight QZ8501 got into difficulty, causing loss of control
PUBLISHED : Saturday, 31 January, 2015, 5:15am
UPDATED : Saturday, 31 January, 2015, 11:53am
Bloomberg
The recovery process of the flight data recorder is shown during the press conference of preliminary accident report of AirAsia QZ8501. Photo: Xinhua
The pilots of AirAsia flight QZ8501 cut power to a critical computer system that normally prevents planes from going out of control shortly before it plunged into the Java Sea, two people with knowledge of the investigation said.
The development comes as France opened a formal criminal investigation after it was found the French co-pilot was at the controls.
The action appears to have helped trigger the events of December 28, when the Airbus climbed so abruptly it lost lift and it began falling with warnings blaring in the cockpit, the two said. All 162 aboard were killed and only 72 bodies have so far been recovered.
The pilots had been attempting to deal with alerts about the flight augmentation computers, which control the A320's rudder and also automatically prevent it from going too slow.
After initial attempts to address the alerts, the flight crew cut power to the entire system, which is comprised of two separate computers that back-up each other, the sources said.
While the information helps show how a normally functioning A320's flight-protection system could have been bypassed, it doesn't explain why the pilots pulled the plane into a steep climb, the two said. Even with the computers shut off, the pilots should have been able to fly the plane manually, they said.
Airbus discourages pilots from cutting power to systems because electronics in the highly-computerised aircraft are interconnected and turning off one can affect others, said John Cox, a former A320 pilot now a safety consultant. "Particularly with an Airbus you don't do that," said Cox, chief executive of Washington-based industry consultant Safety Operating Systems.
Flight QZ8501 climbed more than 1,524 metres in less than 30 seconds, rising above the altitude where it was authorised to fly, Ertata Lananggalih, an investigator with Indonesia's National Transportation Safety Committee, said in Jakarta on Thursday.
The co-pilot, Remi Emmanuel Plesel, with 2,247 hours of flying experience, was at the controls and talking to controllers while the captain, Iriyanto, who had 20,537 hours, was monitoring, said Mardjono Siswosuwarno, the lead investigator of the crash. The account was the first description of the flight's last moments.
The investigators didn't address whether pilots had cut power to the flight augmentation computer system and said they wouldn't release more information on the case.
Meanwhile, a judge in France will investigate possible “manslaughter” in connection with the crash.
Plesel’s family in France separately filed charges against AirAsia Indonesia for “endangering the life of others” as the airline did not have permission to carry out the flight between Surabaya and Singapore on the day of the crash.
“Remi Plesel’s family are delighted at this criminal investigation which, we hope, will reveal the truth,” said their lawyer Eddy Arneton. “It will allow us to finally ask the right questions.”
Airbus is barred from commenting on the accident under international investigation treaties, the company's North American spokesman, Clay McConnell, said.
From a cruising altitude of 9,750 metres, the A320 climbed to 11,400 metres as pilots probably tried to avoid bad weather, Lananggalih said. The aircraft then descended slowly for three minutes and disappeared, he said.
"The pilots were conscious when the manoeuvre happened," he said. "They were trying to control the airplane."
Such an abrupt climb would almost certainly cause a rapid loss of speed and a "very pronounced stall", Cox said.
The aircraft, operated by the Indonesian affiliate of Malaysia's AirAsia, disappeared en route to Singapore from Surabaya.
Indonesia won't release a preliminary report on its investigation into flight QZ8501 because fact-findings could change rapidly, Tatang Kurniadi, head of the commission, said on Thursday. Indonesia sent the preliminary findings to all countries in the investigation on January 28, Kurniadi said.
The pilots had sought permission from air traffic control to turn left and then climb to 38,000 feet because of storm clouds. Four minutes after the request, a controller cleared the pilots to climb to 34,000 feet, he said.
Satellite imagines showed clouds that reached 13,400 metres, according to investigators.
The aircraft was in "good condition", Siswosuwarno said.
All Airbus models produced since the 1980s are designed to prevent pilot errors from causing crashes. The planes are controlled by multiple flight computers, which limit pilots from overly steep turns or flying too slow.
In the event of a malfunction or loss of power, the flight protections will shut down and leave the pilots to fly the plane manually. That appears to be what happened before flight QZ8501 entered the steep climb and stalled, the two said.
Investigators are still trying to determine why the pilots would cut power to the computers by pulling a cockpit circuit breaker.
Indonesian authorities have so far recovered at least 70 bodies. The country's military pulled out of the search this week.
With additional reporting from Agence France-Presse
AirAsia QZ8501 pilots cut power to airplane's 'safety' computer system before crash
Twin system designed to prevent human error may have been turned off when flight QZ8501 got into difficulty, causing loss of control
PUBLISHED : Saturday, 31 January, 2015, 5:15am
UPDATED : Saturday, 31 January, 2015, 11:53am
Bloomberg
The recovery process of the flight data recorder is shown during the press conference of preliminary accident report of AirAsia QZ8501. Photo: Xinhua
The pilots of AirAsia flight QZ8501 cut power to a critical computer system that normally prevents planes from going out of control shortly before it plunged into the Java Sea, two people with knowledge of the investigation said.
The development comes as France opened a formal criminal investigation after it was found the French co-pilot was at the controls.
The action appears to have helped trigger the events of December 28, when the Airbus climbed so abruptly it lost lift and it began falling with warnings blaring in the cockpit, the two said. All 162 aboard were killed and only 72 bodies have so far been recovered.
The pilots had been attempting to deal with alerts about the flight augmentation computers, which control the A320's rudder and also automatically prevent it from going too slow.
After initial attempts to address the alerts, the flight crew cut power to the entire system, which is comprised of two separate computers that back-up each other, the sources said.
While the information helps show how a normally functioning A320's flight-protection system could have been bypassed, it doesn't explain why the pilots pulled the plane into a steep climb, the two said. Even with the computers shut off, the pilots should have been able to fly the plane manually, they said.
Airbus discourages pilots from cutting power to systems because electronics in the highly-computerised aircraft are interconnected and turning off one can affect others, said John Cox, a former A320 pilot now a safety consultant. "Particularly with an Airbus you don't do that," said Cox, chief executive of Washington-based industry consultant Safety Operating Systems.
Flight QZ8501 climbed more than 1,524 metres in less than 30 seconds, rising above the altitude where it was authorised to fly, Ertata Lananggalih, an investigator with Indonesia's National Transportation Safety Committee, said in Jakarta on Thursday.
The co-pilot, Remi Emmanuel Plesel, with 2,247 hours of flying experience, was at the controls and talking to controllers while the captain, Iriyanto, who had 20,537 hours, was monitoring, said Mardjono Siswosuwarno, the lead investigator of the crash. The account was the first description of the flight's last moments.
The investigators didn't address whether pilots had cut power to the flight augmentation computer system and said they wouldn't release more information on the case.
Meanwhile, a judge in France will investigate possible “manslaughter” in connection with the crash.
Plesel’s family in France separately filed charges against AirAsia Indonesia for “endangering the life of others” as the airline did not have permission to carry out the flight between Surabaya and Singapore on the day of the crash.
“Remi Plesel’s family are delighted at this criminal investigation which, we hope, will reveal the truth,” said their lawyer Eddy Arneton. “It will allow us to finally ask the right questions.”
Airbus is barred from commenting on the accident under international investigation treaties, the company's North American spokesman, Clay McConnell, said.
From a cruising altitude of 9,750 metres, the A320 climbed to 11,400 metres as pilots probably tried to avoid bad weather, Lananggalih said. The aircraft then descended slowly for three minutes and disappeared, he said.
"The pilots were conscious when the manoeuvre happened," he said. "They were trying to control the airplane."
Such an abrupt climb would almost certainly cause a rapid loss of speed and a "very pronounced stall", Cox said.
The aircraft, operated by the Indonesian affiliate of Malaysia's AirAsia, disappeared en route to Singapore from Surabaya.
Indonesia won't release a preliminary report on its investigation into flight QZ8501 because fact-findings could change rapidly, Tatang Kurniadi, head of the commission, said on Thursday. Indonesia sent the preliminary findings to all countries in the investigation on January 28, Kurniadi said.
The pilots had sought permission from air traffic control to turn left and then climb to 38,000 feet because of storm clouds. Four minutes after the request, a controller cleared the pilots to climb to 34,000 feet, he said.
Satellite imagines showed clouds that reached 13,400 metres, according to investigators.
The aircraft was in "good condition", Siswosuwarno said.
All Airbus models produced since the 1980s are designed to prevent pilot errors from causing crashes. The planes are controlled by multiple flight computers, which limit pilots from overly steep turns or flying too slow.
In the event of a malfunction or loss of power, the flight protections will shut down and leave the pilots to fly the plane manually. That appears to be what happened before flight QZ8501 entered the steep climb and stalled, the two said.
Investigators are still trying to determine why the pilots would cut power to the computers by pulling a cockpit circuit breaker.
Indonesian authorities have so far recovered at least 70 bodies. The country's military pulled out of the search this week.
With additional reporting from Agence France-Presse
