What happened
On 28 March 2022, a Boeing 767-322ER, registration N675UA, was performing a scheduled commercial flight from Newark to Zurich when the aircraft's right engine experienced several surges. The incident occurred while the aircraft was cruising at 37,000 feet within the Shanwick Oceanic Airspace.
At the time of the surges, the flight crew consisted of four pilots, two of whom were on a scheduled rest break. The active crew identified the instability in the right engine and reduced power to idle to mitigate vibration. Upon realizing the severity of the situation—noted by abnormal instrument readings and a smell of burning in the cockpit—the crew implemented the 'Severe Damage' checklist and shut down the engine.
The flight crew declared a MAYDAY and diverted to Shannon Airport. During the descent, the aircraft performed a single-engine approach and landed safely. No injuries were reported to the 116 passengers or the 10 crew members on board.
The investigation
The AAIU examined flight data from the Digital Flight Data Recorder, which confirmed four distinct surges in the No. 2 engine. The investigation focused on the mechanical state of the engine following the event.
Upon removal and teardown of the engine, investigators found substantial damage to the right engine and minor damage to the aircraft's horizontal stabilizer. The stabilizer damage was caused by a low-pressure turbine blade that had been ejected from the engine exhaust during the failure.
Technical analysis of the engine components revealed that the No. 1 bearing assembly had suffered significant distress, including overheating and the loss of the spherical profile of the rolling elements. Furthermore, the investigation identified a fracture in the No. 1 oil supply tube.