New Data Raises Critical Questions in China Eastern MU5735 Crash
Photo: Xinhua via Global China Daily
More than three years after the devastating crash of China Eastern Airlines flight MU5735, new technical findings are sharpening the focus of an investigation that has remained unusually opaque.
According to recently disclosed analysis by the National Transportation Safety Board (NTSB), both engine fuel control switches on the aircraft were moved from the “Run” position to “Cutoff” while the jet was cruising at 29,000 feet—an action that would have immediately starved the engines of fuel.
“It was found that while cruising at 29,000 ft, the fuel switches on both engines moved from the run position to the cutoff position… Engine speeds decreased after the fuel switch movement,” the NTSB report stated.
A Deliberate Action
On a Boeing 737-800, fuel control switches are positioned on the center pedestal between the pilots. They are not automated systems or software-driven controls—they require a conscious, physical movement to change position.
Moving both switches to “Cutoff” in quick succession is not consistent with routine operations or standard emergency procedures. The immediate consequence is a dual-engine flameout, resulting in a total loss of thrust.
The NTSB analysis further indicates that both switches were moved almost simultaneously.
Timeline of a Catastrophe
Flight tracking data paints a stark picture of the aircraft’s final moments:
- 06:20 UTC — Cruising normally at 29,100 ft
- 06:21 UTC — Fuel switches moved to cutoff; engines begin to spool down
- 06:22 UTC — Aircraft descends rapidly past 7,400 ft, reaching extreme speeds
- 06:23 UTC — Impact in Tengxian County, Guangxi
The descent profile was highly unusual—nearly 30,000 feet lost in under two minutes—suggesting a steep, uncontrolled dive. Radar data indicated the aircraft approached transonic speeds before briefly leveling off, followed by a final near-vertical descent.
Silence from Beijing
Despite the involvement of the NTSB—standard procedure given Boeing’s role as the manufacturer—the primary authority for the investigation remains the Civil Aviation Administration (CAAC).
In its most recent public update in 2024, marking the second anniversary of the crash, the CAAC reiterated several key points:
- No mechanical faults were identified
- The flight crew was properly certified and medically fit
- Weather conditions were not a contributing factor
Notably absent from the CAAC’s statements is any reference to the fuel switch data now highlighted in the NTSB findings.
A Growing Information Gap
The omission has created a widening gap between the technical evidence emerging from U.S. analysis and the official narrative from Chinese authorities. By ruling out mechanical failure while not addressing cockpit switch activity, the investigation leaves open difficult—but increasingly unavoidable—questions.
The data aligns with earlier reports from Western sources suggesting that inputs from within the cockpit may have played a role in initiating the aircraft’s fatal dive.
Still, without a final report from the CAAC, the official cause of the crash remains listed as undetermined.
