Flight Recorder Data Shows Fuel Supply Cut Off Before Deadly China Plane Crash That Killed 132

A Chinese jet’s flight controls were still being moved during its final dive and both engine fuel switches were moved to the cutoff position before the Boeing 737-800 jet crashed into a mountainside in southern China in 2022, according to a newly released National Transportation Safety Board report.

The March 21, 2022, crash of China Eastern Airlines Flight MU5735 killed all 132 people aboard.

The NTSB report detailed the extraordinary effort investigators undertook to recover data from the cockpit voice recorder and flight data recorder after both devices suffered severe damage in the crash. The U.S. agency assisted China’s Civil Aviation Administration.

Investigators wrote that the cockpit voice recorder’s memory board had crushed connectors, broken pins, and damaged memory chips. The flight data recorder also suffered cracked memory chips and damaged circuitry. Engineers ultimately removed memory chips individually and reconstructed portions of the final flight data by hand.

Despite the damage, investigators recovered high-quality cockpit audio and enough flight data to reconstruct the aircraft’s final minutes. The report doesn’t include a transcript of the audio.

The report stated that both engine fuel switches moved “from the run position to the cutoff position” during the flight. The switches control fuel flow to the engines. The report also stated engine speeds decreased after the switches were moved.

Flight recorder graphs included in the report showed repeated control movements during the aircraft’s rapid descent, indicating the aircraft was still being actively controlled as it plunged toward the ground.

“The data stopped with the aircraft still in flight,” investigators wrote.

The report itself does not determine a probable cause for the crash or explicitly conclude that a pilot intentionally caused the disaster.

The report also revealed that investigators had to reconstruct missing data after one damaged memory chip became unrecoverable. Engineers manually aligned portions of the final 12 minutes of flight data to rebuild the aircraft’s final flight path and control activity.

The cockpit audio quality for all four channels was rated “excellent,” according to the report, meaning investigators likely recovered clear pilot conversations and cockpit sounds from the final moments before impact. The NTSB defines “excellent” audio as “virtually all of the crew conversations could be accurately and easily understood.”

The newly released NTSB report provides the most detailed public account yet of the recovered black box evidence from the crash.

The Civil Aviation Administration of China reported in 2022 that major pieces of the plane’s wreckage, including the vertical stabilizer, left and right engines and wings, and the landing gear, have been recovered.

Chinese aviation authorities said in 2022 that before the plane deviated from the cruising altitude, radio communications between the crew and the air traffic control department did not “show any abnormality.”