A preliminary US investigation has concluded that metal fatigue in an engine fan blade was behind a July 10 Ryanair flight incident in which debris shattered a cabin window and a passenger was partially pulled out of the aircraft.
The National Transportation Safety Board (NTSB) reported that roughly 37% of the fracture surface of the failed blade showed signs consistent with fatigue. The breakdown was traced to an area near the blade’s root, where investigators identified high-amplitude fatigue caused by repeated stress. The agency said the root cause of the failure has not yet been determined.
The Boeing 737-800, operated by Ryanair subsidiary Malta Air, was climbing through about 16,000 feet (4,877 meters) after departing Thessaloniki, Greece, for Memmingen, Germany, when pilots received a high-vibration alert from the right engine. The vibration intensified, followed by a loud bang and a sudden loss of cabin pressure, according to the NTSB’s preliminary report.
Fragments from the failed engine struck the fuselage and entered the cabin, destroying the window at row 11. A 61-year-old Serbian passenger, Ljubisa Karović, sitting in seat 11F, had his head and right shoulder forced through the missing window opening. The NTSB said he was left seriously injured and in shock. His wife, Svetlana Grković Maksimović, told BBC Serbia that she and two other passengers held onto his legs for several minutes until they could pull him back inside. A doctor on board provided treatment, with the passenger sustaining neck and shoulder injuries and friction burns.
The crew’s account in the report describes reducing engine power and running checks after the initial vibration alarm. When vibrations ceased, they resumed the climb on autopilot, but the shaking returned and amplified, producing a loud bang that prompted an emergency declaration and descent. Flight attendants reported hearing and feeling the vibrations, seeing light smoke, and the deployment of oxygen masks before discovering the passenger partially lodged in the window.
The NTSB found feathers and bird remains in several parts of the engine, but has not concluded that a bird strike caused the blade to break. Maintenance records show the engine had been involved in four suspected bird strikes over the preceding year, with remains found after two of them. Ultrasonic inspections in November 2025 and May 2026 detected no damage. Ryanair chief executive Michael O’Leary had earlier suggested foreign object damage as a possible cause. The Greek authorities delegated the investigation to the NTSB, which said the probe is ongoing. The aircraft returned to Thessaloniki for an uneventful emergency landing, and no fatalities were reported.