A final report by the National Transportation Safety Committee concluded that the AirAsia Flight 8501 pilots strayed from their training
Credit: Achmad Ibrahim/AP

Officials have revealed that the way pilots responded to a technical malfunction led to the crash of AirAsia Flight 8501 that killed all 162 people on board in December 2014.

In a report released on Tuesday, the National Transportation Safety Committee said that a rudder control system problem and the pilots’ response to it caused the Singapore-bound flight from Indonesia to crash into the Java Sea on Dec. 28.

The jetliner disappeared from radar during heavy storms, sending no distress calls.

The main flight control computer on the aircraft had a cracked joint that caused it to malfunction four times during the flight – and 23 times the previous year, the report states.

Warning messages prompted the crew to reset the computer by pulling a circuit breaker, an act not recommended in the plane’s operating manual.

“Subsequent flight crew action resulted in inability to control the aircraft causing the aircraft to depart from the normal flight envelope and enter a prolonged stall condition that was beyond the capability of the flight crew to recover,” investigator Nurcahyo Utomo said at a news conference, per NBC News.

Utomo said that the malfunction itself should not have been dangerous, but when a crewmember tried to reset the system, the autopilot became disengaged and the aircraft began to roll.

He added that the voice recorder recovered from the aircraft showed that the pilot said “pull down,” when the plane was actually ascending.

“It seemed that there was a miscommunication between the pilot and co-pilot after the fourth fault,” he said.

Initial reports blamed stormy weather for the crash, but the NTSC has concluded that the plane was “airworthy” and the crew should have been able to recover from the plane’s stall had they followed their training, the Associated Press reports.

AirAsia Indonesia said in a statement that additional pilot training and a new system providing real-time monitoring of aircraft warning messages have been implemented.

Tony Fernandes, AirAsia CEO, posted a series of tweets following the release of the report.

“There is much to be learned here for AirAsia, the manufacturer and the aviation@ industry,” he tweeted. “We will not leave any stone unturned to make sure the industry learns from this tragic incident.”