Flight-data recorder information released by the National Transportation Safety Board on May 1 shows that both engines on the Boeing 737-800 lost power and someone in the cockpit sent the plane into a steep dive and a 360-degree roll before it hit the ground. The report, obtained through a public-records request, provides the most detailed account to date of the final minutes of China Eastern Flight 5735, which slammed into a mountainside in Guangxi province after departing Kunming for Guangzhou. The NTSB joined the investigation because the aircraft and its engines were manufactured in the United States, and its engineers are considered the global standard for analyzing flight recorders after crashes.
The fuel levers on a 737 are designed to prevent accidental activation. “By design the fuel levers in a 737 cannot be easily bumped or shut off inadvertently — someone has to pull them out to release them before they will move,” said John Cox, CEO of Safety Operating Systems, a Washington-based aviation consultancy. “The levers lock into place, so it’s likely that someone deliberately moved them both to the cutoff position.” The data shows the cutoff occurred before the nosedive, and the flight recorder and all hydraulic systems lost power while the plane was still at 26,000 feet, ending the data feed after twelve minutes of recording.
The cockpit voice recorder, which had a battery backup, continued operating, but the NTSB did not release a transcript of what the pilots said. Chinese authorities control that information and have not made any recording public. The Civil Aviation Administration of China has yet to issue a final report into a crash that happened more than four years ago, well beyond the one-year target set by international standards.
Jeff Guzzetti, who spent decades investigating crashes for both the NTSB and the Federal Aviation Administration, said the flight-data recorder’s control-wheel movements pointed to a fight over the aircraft. “Typically when you want to roll an airplane, it’s a smooth movement of the control wheel in one direction. But here you have it moving back and forth, back and forth, as if someone is trying to counter the initial movement of the roll,” he said. “So it’s not conclusive, but it sure has the earmarks of a struggle in the cockpit.” Guzzetti said the crash could have been a pilot suicide, echoing the 2015 Germanwings disaster, when a co-pilot locked his captain out and flew an Airbus into the French Alps, killing all aboard.
The details resurrect longstanding worries about pilots’ mental health and the industry’s ability to spot warning signs. Many pilots avoid seeking help because they fear losing their medical certification — and with it, their paycheck — for months or longer while they undergo an intensive recertification process. “Clearly pilots — and very understandably so — are oftentimes reluctant to come forward, knowing that to get recertified after having gone through a mental health evaluation, it can be very arduous and very lengthy,” Cox said. In some countries, pilots are barred from taking common antidepressants.
Guzzetti noted that the co-pilot on an EgyptAir flight that crashed off New York in 1999 is widely believed to have deliberately pushed the plane into the ocean. In 2023, an off-duty pilot who had taken psychedelic mushrooms days earlier tried to cut the engines of a Horizon Air flight while riding in the cockpit jump seat; he was subdued by the crew and the plane landed safely.
The China Eastern jet was cruising at roughly 29,000 feet when it abruptly pitched into a nosedive, managing a momentary recovery before hitting the mountain at high speed and leaving a 65-foot crater that set the surrounding forest on fire. The pilots had not reported any malfunctions before losing contact with air traffic control. Chinese investigators said shortly after the accident that they had found no anomalies with the aircraft, the crew, or the weather, and the NTSB’s new report also points to no mechanical failure. The crash was a rare failure for China’s airline industry, which dramatically improved its safety performance after a series of fatal accidents in the 1990s.