AirAsia pilots disabled flight computers

JAKARTA, Indonesia — The pilots of AirAsia Flight 8501 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 plane 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 the initial attempts to address the alerts, the flight crew cut power to the entire system, which is comprised of two separate computers that serve as backups to 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.

Flight 8501 climbed more than 5,000 feet 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 communicating with the ground 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 plane.

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.

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.

“The pilots were conscious when the maneuver happened,” he said. “They were trying to control the airplane.”

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 8501 because fact-findings could change rapidly, Tatang Kurniadi, head of the commission, said Thursday. Indonesia sent the preliminary findings to all countries involved in the investigation on Jan. 28, Kurniadi said.

The pilots had sought permission from air traffic control to turn left and then to 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.

The aircraft was in “good condition,” said Siswosuwarno.

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 FACs by pulling a circuit breaker in the cockpit.

Indonesian authorities have so far recovered at least 70 bodies from the search. Investigators still haven’t managed to lift the fuselage of the jet. The tail section of the plane has been retrieved. Indonesia’s military pulled out of the search this week.

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 8501 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.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

A firefighter stands in silence before a panel bearing the names of L. John Regelbrugge and Kris Regelbrugge during the ten-year remembrance of the Oso landslide on Friday, March 22, 2024, at the Oso Landslide Memorial in Oso, Washington. (Ryan Berry / The Herald)
‘Flood of emotions’ as Oso Landslide Memorial opens on 10th anniversary

Friends, family and first responders held a moment of silence at 10:37 a.m. at the new 2-acre memorial off Highway 530.

Julie Petersen poses for a photo with images of her sister Christina Jefferds and Jefferds’ grand daughter Sanoah Violet Huestis next to a memorial for Sanoah at her home on March 20, 2024 in Arlington, Washington. Peterson wears her sister’s favorite color and one of her bangles. (Annie Barker / The Herald)
‘It just all came down’: An oral history of the Oso mudslide

Ten years later, The Daily Herald spoke with dozens of people — first responders, family, survivors — touched by the deadliest slide in U.S. history.

Victims of the Oso mudslide on March 22, 2014. (Courtesy photos)
Remembering the 43 lives lost in the Oso mudslide

The slide wiped out a neighborhood along Highway 530 in 2014. “Even though you feel like you’re alone in your grief, you’re really not.”

Director Lucia Schmit, right, and Deputy Director Dara Salmon inside the Snohomish County Department of Emergency Management on Friday, March 8, 2024, in Everett, Washington. (Ryan Berry / The Herald)
How Oso slide changed local emergency response ‘on virtually every level’

“In a decade, we have just really, really advanced,” through hard-earned lessons applied to the pandemic, floods and opioids.

Ron and Gail Thompson at their home on Monday, March 4, 2024 in Oso, Washington. (Olivia Vanni / The Herald)
In shadow of scarred Oso hillside, mudslide’s wounds still feel fresh

Locals reflected on living with grief and finding meaning in the wake of a catastrophe “nothing like you can ever imagine” in 2014.

Rep. Suzan DelBene, left, introduces Xichitl Torres Small, center, Undersecretary for Rural Development with the U.S. Department of Agriculture during a talk at Thomas Family Farms on Monday, April 3, 2023, in Snohomish, Washington. (Olivia Vanni / The Herald)
Under new federal program, Washingtonians can file taxes for free

At a press conference Wednesday, U.S. Rep. Suzan DelBene called the Direct File program safe, easy and secure.

Former Snohomish County sheriff’s deputy Jeremie Zeller appears in court for sentencing on multiple counts of misdemeanor theft Wednesday, March 27, 2024, at Snohomish County Superior Court in Everett, Washington. (Ryan Berry / The Herald)
Ex-sheriff’s deputy sentenced to 1 week of jail time for hardware theft

Jeremie Zeller, 47, stole merchandise from Home Depot in south Everett, where he worked overtime as a security guard.

Everett
11 months later, Lake Stevens man charged in fatal Casino Road shooting

Malik Fulson is accused of shooting Joseph Haderlie to death in the parking lot at the Crystal Springs Apartments last April.

T.J. Peters testifies during the murder trial of Alan Dean at the Snohomish County Courthouse on Tuesday, March 26, 2024 in Everett, Washington. (Olivia Vanni / The Herald)
Bothell cold case trial now in jury’s hands

In court this week, the ex-boyfriend of Melissa Lee denied any role in her death. The defendant, Alan Dean, didn’t testify.

A speed camera facing west along 220th Street Southwest on Tuesday, Nov. 21, 2023 in Edmonds, Washington. (Olivia Vanni / The Herald)
New Washington law will allow traffic cams on more city, county roads

The move, led by a Snohomish County Democrat, comes as roadway deaths in the state have hit historic highs.

Mrs. Hildenbrand runs through a spelling exercise with her first grade class on the classroom’s Boxlight interactive display board funded by a pervious tech levy on Tuesday, March 19, 2024 in Marysville, Washington. (Olivia Vanni / The Herald)
Lakewood School District’s new levy pitch: This time, it won’t raise taxes

After two levies failed, the district went back to the drawing board, with one levy that would increase taxes and another that would not.

Alex Hanson looks over sections of the Herald and sets the ink on Wednesday, March 30, 2022 in Everett, Washington. (Olivia Vanni / The Herald)
Black Press, publisher of Everett’s Daily Herald, is sold

The new owners include two Canadian private investment firms and a media company based in the southern United States.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.