Engine blade that caused hole in Ryanair plane cabin may have broken due to metal fatigue

US air safety investigators found evidence of metal fatigue in an engine fan blade that fractured on a Ryanair subsidiary’s Boeing 737-800 on July 10, sending debris through the cabin after departure from Thessaloniki, Al Jazeera and AP reported.

The National Transportation Safety Board said in a preliminary report that “about 37 percent of the fracture surface on the failed blade showed features consistent with fatigue”. Investigators traced the damage to an area near the root of the blade and found signs of high-amplitude fatigue caused by repeated stress. The agency has not yet determined the root cause of the failure.

The aircraft was operated by Malta Air, a Ryanair subsidiary, and was flying from Thessaloniki, Greece, to Memmingen, Germany. It was climbing through 16,000 feet (4,877 metres) when pilots received a high-vibration alert from the right engine. The vibration rapidly increased before the crew heard a loud bang and the cabin lost pressure.

Fragments from the engine struck the fuselage and penetrated the cabin, shattering the window at row 11. A flight attendant responding to calls for help found a 61-year-old passenger in seat 11F partially lodged in the missing window opening. Passengers pulled him back into the cabin, and a doctor on board treated him for neck and shoulder injuries and friction burns as the aircraft returned to Thessaloniki.

Passengers used a metal box from the galley to try to block the opening. Investigators found feathers and bird remains in several parts of the engine, but have not concluded that a bird strike caused the blade to break. Maintenance records showed four suspected bird strikes involving the engine over the previous year, and its fan blades passed ultrasonic inspections in November 2025 and May 2026. The NTSB investigation remains ongoing.