Three and a half years after the deadliest Chinese aviation disaster in decades, newly released U.S. investigation data has shed fresh light on the 2022 crash of China Eastern Airlines flight MU5735, which claimed all 132 lives on board when the Boeing 737 plummeted into a hillside in southern China.
According to data obtained by the U.S. National Transportation Safety Board (NTSB) via a Freedom of Information Act request, fuel flow to both of the jet’s engines was intentionally cut while the aircraft was cruising at 29,000 feet, a finding that lends credibility to unconfirmed theories that the crash was deliberate. The data, pulled from one of the plane’s recovered black boxes that was sent to the NTSB’s Washington D.C. lab for analysis, confirms that both engine fuel control switches were manually moved to the “cut-off” position, after which the engines’ rotational speeds dropped sharply.
Fuel switches are purpose-built cockpit controls designed to regulate the flow of jet fuel into the engines, used almost exclusively by flight crew to start engines during pre-flight preparation or shut them down after landing. No mechanical malfunction is known to automatically shift both fully functional fuel switches into the cut-off position during cruise flight.
The timeline of the disaster, recorded by independent flight tracking service FlightRadar24, aligns with the new data: on March 21, 2022, the flight departed Kunming, Yunnan’s provincial capital, on a routine scheduled domestic trip to Guangzhou, southern China’s major trade hub. After more than an hour of uneventful flight, the aircraft suddenly entered an uncontrolled, rapid descent. In just two minutes and 15 seconds, it dropped from a cruising altitude of 29,100 feet to under 10,000 feet, with its final recorded altitude logged at 3,225 feet at 14:22 local time. Air traffic controllers made repeated attempts to contact the flight crew during the descent but received no response.
China’s Civil Aviation Administration (CAA), which is leading the official investigation into the crash, has yet to publish a final public report, justifying the delay on grounds of national security concerns. Shortly after the crash, CAA officials confirmed that the flight crew held valid operating licenses, had passed required pre-flight health checks, and were properly rested, ruling out basic fatigue or certification issues. When media speculation emerged that the crash was an act of pilot suicide, the CAA issued an official denial, stating that such baseless rumors misled the public and disrupted the ongoing investigation.
As the aircraft was manufactured by American aerospace firm Boeing, the NTSB was granted authority to assign a senior investigator to assist the Chinese-led probe, a standard arrangement for international aviation accident investigations. Prior to the release of the NTSB data, the disaster’s cause had remained a subject of global speculation, with possible causes ranging from structural failure and mid-air collision to pilot error and deliberate action. The new NTSB findings are the first official verified data to publicly support the deliberate action theory, though Chinese authorities have not yet commented on the newly released information.
China has seen dramatic improvements in commercial aviation safety over the past three decades, with fatal air crashes remaining extremely rare. The 2022 MU5735 crash was the deadliest air disaster to occur in Chinese airspace since 1992.