The U.S. National Transportation Safety Board (NTSB) has released data indicating that the fuel supply was switched off to both engines of a China Eastern Airlines Boeing 737 jet before it crashed into a hillside in southern China in March 2022, killing all 132 people on board. The NTSB stated on Wednesday that its investigation into China's deadliest air disaster in three decades found no safety issues with the aircraft.
Fuel switches on Boeing 737 aircraft are physical controls that regulate fuel flow to the engines. A pilot must pull the switch up before moving it from the run position to the cutoff position. The data, obtained from the plane's flight data recorder and released by the NTSB in response to a Freedom of Information request, showed that the fuel switches for both engines moved simultaneously from run to cutoff before the jet began its descent.
Investigative Findings
The NTSB report stated: "It was found that while cruising at 29,000 feet, the fuel switches on both engines moved from the run position to the cutoff position. Engine speeds decreased after the fuel switch movement." This is the first significant investigative update on the deadly crash since it occurred. In March, China's aviation regulator chose not to release an annual update on its investigation for the second consecutive year, allowing the fourth anniversary to pass without providing any insight into the cause.
Reuters reported in 2022 that investigators were focusing on the actions of the flight crew and had not found any evidence of technical malfunctions. The crash of the Boeing 737-800, operated as China Eastern flight MU5735, was China's deadliest air disaster in decades.
Context of Deliberate Crashes
Deliberate crashes are exceptionally rare. In March 2015, a Germanwings co-pilot deliberately flew an Airbus A320 into a French mountainside, killing all 150 on board. More recently, the actions of the captain in the June crash of an Air India Boeing 787 in Ahmedabad, India, which killed 260 people, have been under scrutiny. A preliminary investigation report by the Aircraft Accident Investigation Bureau (AAIB) showed that the plane's fuel-engine switches had almost simultaneously flipped from run to cutoff just after takeoff. The cockpit recording of dialogue between the two pilots supported the view that Captain Sabharwal had cut the flow of fuel to the engines, according to a source briefed on U.S. officials' early assessment of evidence in July.
Chinese Response
Chinese regulators have not released a full report detailing the findings of their investigation into the crash and have given no update on the probe for more than two years. The Civil Aviation Administration of China (CAAC) and China Eastern Airlines did not respond to Reuters' request for comment on the NTSB report. A spokesperson for China's Ministry of Foreign Affairs declined to answer a question about the U.S. findings at a regular press briefing on Wednesday.
The flight data recorder is one of the two black boxes recovered from the wreckage. It was sent to the NTSB laboratory in Washington for analysis because Boeing is an American aircraft manufacturer.
