THE pilots of AirAsia Bhd 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 action appears to have helped trigger the events of Dec. 28, when the Airbus Group NV A320 climbed so abruptly that it lost lift and it began falling with warnings blaring in the cockpit, the people said. All 162 aboard were killed.
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 people 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 people 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 computerized aircraft are interconnected and turning off one component can affect others, John Cox, a former A320 pilot who is now a safety consultant, said in an interview.
'Steep Climb'
“Particularly with an Airbus you don’t do that,” said Cox, chief executive officer of Washington-based industry consultant Safety Operating Systems.
Flight 8501 climbed more than 5,000 feet (1,524 meters) in less than 30 seconds, rising above the altitude where it was authorized to fly, Ertata Lananggalih, an investigator with Indonesia’s National Transportation Safety Committee, said in Jakarta on Thursday.
The co-pilot, with 2,247 hours of flying experience, was at the controls and talking to controllers while the captain, who had 20,537 hours, was monitoring, said Mardjono Siswosuwarno, the lead investigator of the crash. The account was the first description of the last moments of the flight.
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.
'No Denial, Confirmation'
“About the flight augmentation computer, I can’t deny, nor confirm it,” Lananggalih said today when asked about the pilots disabling critical computers. “It’s technical and it’s in investigation territory. Currently, flight augmentation computer is still being further investigated.”
The aircraft was slanting and ascending and there was a stall alarm, he said.
“There was chime, but again, this is investigation territory,” he said. “Why should we open it for the public, because it’s still being investigated.”
Airbus is barred from commenting on the accident under international investigation treaties, the company’s North American spokesman, Clay McConnell, said in an e-mail.
From a cruising altitude of 32,000 feet, the single-aisle A320 climbed to 37,400 feet as pilots probably tried to avoid bad weather, Lananggalih said. The aircraft then descended slowly for three minutes before it disappeared, he said.
'Pronounced Stall'
“The pilots were conscious when the maneuver 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-based AirAsia, disappeared from radar 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 Thursday. Indonesia sent the preliminary findings to all countries in the investigation on Jan. 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 storm clouds that reached as high as 44,000 feet, according to investigators.
'Flight Computers'
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 getting 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 8501 entered the steep climb and stalled, the two people said.
Investigators are still trying to determine why the pilots would cut power to the flight augmentation computers by pulling a circuit breaker in the cockpit.
Indonesian authorities have so far recovered at least 70 bodies. Investigators still haven’t managed to lift the jet’s fuselage. The tail section of the plane has been retrieved. Indonesia’s military pulled out of the search this week.
'Without Permission'
The cockpit-voice recorder captured the pilots’ voices and no explosion was heard, Nurcahyo Utomo, an investigator with the committee, said last week. The flight-data recorder captured 1,200 parameters and the voice-recorder captured the last two hours and four minutes of the flight, the investigators said. The two devices are called the black boxes. After studying data from the black boxes, authorities ruled out terrorism as a factor that brought down the plane.
Flight QZ8501 appeared to have stalled after climbing steeply, Minister of Transportation Ignasius Jonan said earlier this month. A stall occurs when airflow over the wings is disrupted or becomes too slow to provide lift and keep a plane aloft.
Indonesia has said it intends to shut the agency responsible for coordinating aircraft flight slots in three months. That’s after the AirAsia flight took off on a Sunday, without a Ministry of Transportation permit to fly that day.
The government has suspended the license of AirAsia for that route, found other airlines in breach of permits and removed officials involved from the ministry, AirNav Indonesia and state airport company PT Angkasa Pura 1.
AirAsia made an administrative error in flying QZ8501 on Sunday, AirAsia Indonesia Chief Executive Officer Sunu Widyatmoko said Jan. 13. The carrier didn’t inform the Directorate of Air Aviation on the schedule revision, he told parliament in a hearing.
Bloomberg
Fri Jan 30 2015
All Airbus models produced since the 1980s are designed to prevent pilot errors from causing crashes. - File Photo
[TERKINI] Seorang maut dalam kejadian pokok tumbang di Jalan Sultan Ismail
Sebatang pokok besar di Jalan Sultan Ismail tumbang susulan hujan lebat dan angin kencang sehingga menyebabkan beberaoa kenderaan remuk akibat dihempap.
NACS bukan sekadar strategi, jadikan Malaysia negara hebat tatakelola
Perdana Menteri tegaskan Strategi Pembanterasan Rasuah Nasional (NACS) bukan sekadar strategi tetapi bakal melonjakkan kedudukan Malaysia sebagai negara dengan pengurusan tatakelola terhebat di rantau ini.
NACP: Ketirisan RM277 bilion dalam lima tahun sangat menggemparkan – PM Anwar
Jumlah ketirisan sehingga mencecah RM277 bilion dalam tempoh lima tahun (2018 – 2023) seperti yang didedahkan Suruhanjaya Pencegahan Rasuah Malaysia (SPRM) adalah angka yang menggemparkan, dan membuktikan gejala rasuah semakin membengkak, kata Perdana Menteri Datuk Seri Anwar Ibrahim.
Seorang maut, seorang cedera dihempap pokok tumbang di Jalan Sultan Ismail
Seorang lelaki berusia 47 tahun maut manakala seorang lagi berusia 26 tahun cedera dalam insiden pokok besar tumbang di Jalan Sultan Ismail pada petang Selasa.
Penjenamaan PPR bakal jadikan PRR setanding HDR di Singapura, Jepun dan Korea - Nga Kor Ming
KPKT dalam proses menjenamakan semula PPR kepada PRR di mana model pembinaannya setanding perumahan rakyat di Singapura, Jepun dan Korea Selatan.
Faisal Halim jalani pembedahan jam 5 petang
PEMAIN sayap kebangsaan, Faisal Halim akan menjalani satu lagi pembedahan pada jam 5 petang ini.
Bukit Aman ambil alih kes simbah asid Faisal Halim, suspek kedua direman 5 hari
Ketua Polis Selangor, Datuk Hussein Omar Khan berkata, suspek yang merupakan lelaki warga tempatan sebelum itu dibawa ke Mahkamah Petaling Jaya bagi tujuan permohonan reman.
Prinsip ESG asas penting untuk industri pertahanan - Khaled
Menteri Pertahanan Datuk Seri Mohamed Khaled Nordin berkata adalah penting bagi industri pertahanan untuk mendukung prinsip Alam Sekitar, Sosial dan Tadbir Urus (ESG).
Pokok tumbang hempap landasan monorel, kereta di Jalan Sultan Ismail
Sebatang pokok besar di Jalan Sultan Ismail tumbang dan menghempap sebahagian landasan monorel serta beberapa kereta di kawasan itu pada petang Selasa.
Caprice, isteri henti kongsi mengenai anak di laman sosial
Menerusi Instastory, Caprice berkata dia dan isterinya iaitu Farra Inalis seronok dengan perkongsian daripada ibu bapa yang turut memberi tips penjagaan bayi.
AirAsia yakin mampu harungi pergerakan mata wang tidak menggalakkan, kenaikan harga bahan api
AirAsia yakin mampu tangani kenaikan harga bahan api dan pergerakan mata wang tidak menggalakkan yang berpanjangan, yang terus meningkatkan cabaran global.
Segmen penerbangan Capital A catat 90 peratus faktor muatan, 15.4 juta penumpang pada suku pertama 2024
Prestasi kukuh itu adalah selari dengan fokus strategik AirAsia untuk mengembangkan kapasiti dan membina semula rangkaiannya.
Capital A akan jual 100 peratus kepentingan dalam AirAsia Aviation Group, AirAsia dengan harga RM6.8 bilion
Ia memeterai perjanjian jual beli saham bersyarat dengan AAG untuk menjual AAAGL bernilai RM3 bilion manakala AAB dengan harga RM3.8 bilion.
Gunung Ruang meletus: Beberapa penerbangan AirAsia kembali beroperasi
AirAsia turut menyediakan pilihan kepada penumpang yang terjejas akibat penerbangan yang terpaksa dibatalkan.
Letusan Gunung Ruang: Malaysia Airlines, AirAsia batal penerbangan Kuala Lumpur ke Sabah, Sarawak
Malaysia Airlines umum pembatalan 11 penerbangan Sabah dan Kuala Lumpur serta lapan penerbangan laluan Sarawak dan Kuala Lumpur dibatalkan.
Pembatalan penerbangan: AirAsia sedia pilihan kepada penumpang
Bo Lingam berkata penumpang yang ingin melakukan perubahan tempahan secara dalam talian boleh berbuat demikian di airasia.com atau AirAsia MOVE.
AirAsia tawar menu nasi lemak dua kali saiz
Santan memperkenalkan Nasi Lemak Pak Nasser Terpaling Istimewa (Double Special), hidangan ikonik yang kini bersaiz dua kali ganda berbanding asal.
Trafik penumpang udara diunjur berkembang 2% menjelang akhir 2024 - MIDF
Tinjauan menunjukkan bahawa faktor muatan selepas wabak adalah setanding dengan, jika tidak lebih tinggi daripada, tahap prapandemik.
Aidilfitri: AirAsia tawar lebih 22,000 tempat duduk tambang tetap ke Sabah, Sarawak
AirAsia menawarkan lebih 22,000 tempat duduk pada tambang rendah tetap untuk penerbangan lewat malam sempena sambutan Hari Raya antara Semenanjung, Sabah dan Sarawak.
AirAsia sasar hak trafik dua hala ke beberapa bandar di India
Tumpuan untuk meluaskan rangkaian penting bagi AirAsia kerana bandar utama di India telah mencapai puncak pengembangan.