Indonesia says faulty component, crew response factors in AirAsia crash

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Equipment Glitch, Pilot Response Led To AirAsia Crash

Chronic problems with a faulty rudder system and the way pilots tried to respond were among a string of factors contributing to the crash of an Indonesian AirAsia jet last year that killed all 162 on board, investigators said on Tuesday.

The Airbus A320 crashed into the Java Sea on Dec. 28, less than halfway into a two-hour flight from Indonesia's second-biggest city of Surabaya to Singapore.

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In their first public report on the disaster, Indonesian investigators did not pinpoint a single underlying reason why flight QZ8501 disappeared from the radar, but set out a sequence spotlighting the faulty component, maintenance and crew actions.

See photos from the search and recovery of the AirAsia plane:

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Indonesia says faulty component, crew response factors in AirAsia crash
SURABAYA, INDONESIA - DECEMBER 30: A relative of a passenger looks out over the waters of the Java Sea near Pangkalan Bun, Kalimantan on December 30, 2014 in Surabaya, Indonesia. Debris and dead bodies have reportedly been sighted in the Java Sea during search operations for the missing AirAsia flight QZ 8501. AirAsia flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Ulet Ifansasti/Getty Images)
Indonesian personnel hoist a section of recovered wreckage belonging to AirAsia flight QZ8501 onto a truck at port in Kumai on January 11, 2015. Indonesian divers on January 11 found the crucial black box flight recorders of the AirAsia plane that crashed in the Java Sea a fortnight ago with 162 people aboard, the transport ministry said. AFP PHOTO / ADEK BERRY (Photo credit should read ADEK BERRY/AFP/Getty Images)
SINGAPORE - DECEMBER 28: A relative of a missing family member on board AirAsia flight QZ8501 speaks to the media outside the holding area at Changi Airport on December 28, 2014 in Singapore. AirAsia announced that the flight from Surabaya, Indonesia to Singapore lost contact with air traffic control on the morning of December 28. (Photo by Suhaimi Abdullah/Getty Images)
SURABAYA, INDONESIA - DECEMBER 29: Indonesian naval officers prepare the operational air navigation map during the investigation of missing AirAsia flight QZ8501 outside the crisis center of Juanda International Airport Surabaya on December 29, 2014 in Surabaya, Indonesia. AirAsia announced that flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Robertus Pudyanto/Getty Images)
PANGKALAN BUN, INDONESIA - JANUARY 06: Indonesia Sea and Coast Guard display recovered seats from the AirAsia flight QZ8501 crash from the Royal Malaysian Navy KD Kasturi at Port of Kumai on January 6, 2015 in Pangkalan Bun, Indonesia. A massive recovery operation is underway in waters off Borneo to recover bodies and debris from the missing AirAsia plane. AirAsia announced that flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Oscar Siagian/Getty Images)
PANGKALAN BUN, INDONESIA - JANUARY 01: Members of Indonesian search and rescue team carry the body of a victim of the AirAsia flight QZ8501 crash at Iskandar Airbase on January 01, 2015 in Pangkalan Bun, Central Kalimantan, Indonesia. A massive recovery operation has begun following confirmation from Indonesian officials that remains and debris found in waters off Borneo are from the missing AirAsia plane. Flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Ulet Ifansasti/Getty Images)
PANGKALAN BUN, INDONESIA - JANUARY 02: Members of an Indonesian search and rescue team carry derbis of the AirAsia flight QZ8501 crash at Iskandar Airbase on January 02, 2015 in Pangkalan Bun, Central Kalimantan, Indonesia. A massive recovery operation has begun following confirmation from Indonesian officials that remains and debris found in waters off Borneo are from the missing AirAsia plane. Flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Ulet Ifansasti/Getty Images)
PANGKALAN BUN, INDONESIA - JANUARY 3: Members of an Indonesian search and rescue team carry a coffin containing a victim of the AirAsia flight 8501 crash on January 3, 2015 at Iskandar Airbase in Pangkalan Bun, Indonesia. The remains are being flown to Surabaya, Indonesia by the Indonesian Air Force. A massive recovery operation is underway in the waters off Borneo to recover bodies and debris from the missing AirAsia plane. AirAsia reported that flight 8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control on the morning of December 28. (Photo by Oscar Siagian/Getty Images)
SURABAYA, INDONESIA - JANUARY 02: Indonesian Army carry the coffin of Grayson Herbert Linaksita, a victim of the AirAsia flight QZ8501, after he was handed over to his family at the police hospital on January 2, 2015 in Surabaya, Indonesia. A massive recovery operation has begun following confirmation from Indonesian officials that remains and debris found in waters off Borneo are from the missing AirAsia plane. Flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Oscar Siagian/Getty Images)
SURABAYA, INDONESIA - JANUARY 02: Subekti, a tomb caretaker cleans up Hayati Lutfiah Hamid's grave (L), the first identified victim of the AirAsia flight QZ8501 crash at Sawo Tratap Islamic cemetery on January 2, 2015 in Surabaya, Indonesia. A massive recovery operation is underway in waters off Borneo to recover bodies and debris from the missing AirAsia plane. AirAsia announced that flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Robertus Pudyanto/Getty Images)
An Indonesian worker (top C) cuts the tail of the AirAsia flight QZ8501 in Kumai on January 12, 2015, after debris from the crash was retrieved from the Java sea. Indonesian divers retrieved the flight data recorder of the AirAsia plane that went down in the Java Sea a fortnight ago with 162 people on board, a crucial breakthrough that should help explain what caused the crash. AFP PHOTO (Photo credit should read STR/AFP/Getty Images)
PANGKALAN BUN, INDONESIA - JANUARY 04: Members of Indonesian search and rescue team carry the part of the plane of the AirAsia flight QZ8501 crash from Singaporean navy helicopter at Iskandar Airbase on on January 4, 2015 in Surabaya, Indonesia. A massive recovery operation is underway in waters off Borneo to recover bodies and debris from the missing AirAsia plane. AirAsia announced that flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Oscar Siagian/Getty Images)
SURABAYA, INDONESIA - DECEMBER 31: Surabaya residents pray for victims of the AirAsia flight QZ8501 crash on December 31, 2014 in Surabaya, Indonesia. A massive recovery operation has begun following confirmation from Indonesian officials that remains and debris found in waters off Borneo are from the missing AirAsia plane. Flight QZ8501 from Surabaya to Singapore, with 162 people on board, lost contact with air traffic control at 07:24 a.m. local time on December 28. (Photo by Oscar Siagian/Getty Images)
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The crash was part of a string of aviation disasters in Southeast Asia's biggest economy, where rapid growth in air travel has overcrowded airports and stirred safety concerns.

Investigators said a system controlling rudder movement had cracked soldering that malfunctioned repeatedly, including four times during the flight and 23 times the previous year.

RELATED COVERAGE: AirAsia Indonesia says upgrades training, enhances safety after crash

Officials told reporters there were indications from the black box data recorder that crew had tried to shut off power to the computer that controls the rudder system by resetting a circuit breaker, something not usually done during flight.

But they cautioned there was no proof of this.

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The interruption of power to the computer caused the autopilot to disengage and removed automated protections that prevent an upset, handing manual control to the crew, they said.

"Subsequent flight crew action resulted in inability to control the aircraft...causing the aircraft (to) depart from the normal flight envelope and entering a prolonged stall condition that was beyond the ability of the flight crew to recover," the National Transportation Safety Committee said in a statement.

The airline's maintenance system was "not optimal", investigators said, adding that the airline had carried out 51 safety measures to improve conditions since the crash.

RELATED COVERAGE: Indonesia investigators say circuit breaker pulled before AirAsia jet crash

In Europe, Airbus declined immediate comment.

"Airbus has just received the final accident report. We are now carefully studying its content," a spokesman said by email.

The report is not intended to attribute blame but rather to make recommendations to avoid future accidents. Recommendations were addressed to the airline, Airbus and regulators.

Indonesia has seen two other major crashes in the past year, including a military cargo aircraft that went down in an urban area in northern Sumatra in July, killing more than 140 people.

(Additional reporting by Randy Fabi and Michael Taylor in JAKARTA and Tim Hepher in PARIS; Editing by Clarence Fernandez)

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Indonesia says faulty component, crew response factors in AirAsia crash
A photo taken on July 23, 2014 shows the crash site of the downed Malaysia Airlines flight MH17, in a field near the village of Grabove, in the Donetsk region. The first bodies from flight MH17 arrived in the Netherlands on July 23 almost a week after it was shot down over Ukraine, with grieving relatives and the king and queen solemnly receiving the as yet unidentified victims. AFP PHOTO/ BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Firefighters (L) inspect a house damaged by fire caused after a light plane crashed into a residential area in Tokyo on July 26, 2015. The light single-engine plane crashed into a residential area in Tokyo, setting fire to several houses and reportedly killing three people. JAPAN OUT -- AFP PHOTO / JIJI PRESS (Photo credit should read JIJI PRESS/AFP/Getty Images)
VENICE, CA - MARCH 05: A general view at the Penmar Golf Course after a single-engine plane piloted by actor Harrison Ford crashed on March 5, 2015 in Venice, California. Ford was reportedly taken to a nearby hospital in fair to moderate condition. (Photo by Albert L. Ortega/Getty Images)
Iranian security forces react next to the remains of a plane as they secure the scene of a crash near Tehran's Mehrabad airport on August 10, 2014. A civilian airliner crashed on take-off near the Mehrabad airport in the capital, Iranian news agencies said, with reports that almost 50 people were killed. AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images)
GAITHERSBURG, MD - DEC 08: Three people were killed in this house after it caught fire due to a plane that crashed just yards away. A plane crashed into houses on Drop Forge Lane in Gaithersburg, Maryland today. Three persons were killed in the plane and 3 persons were killed in one of the homes. (Photo by Michael S. Williamson/The Washington Post via Getty Images
Indonesian rescuers search through wreckage of the Trigana Air ATR 42-300 twin-turboprop plane at the crash site in the mountainous area of Oksibil on August 18, 2015. A plane that crashed in eastern Indonesia was found on August 18 'completely destroyed' with the bodies of all 54 passengers and crew strewn amid the wreckage in a fire-blackened jungle clearing, officials said. AFP PHOTO (Photo credit should read STR/AFP/Getty Images)
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