Broken engine parts shattered a window on a Ryanair flight shortly after takeoff in Greece last month, causing a man's head to be sucked through the opening before fellow passengers pulled him back inside, U.S. investigators said Thursday.

A fan blade in the Boeing 737-800's right engine broke loose, sending fragments flying out of the engine that broke the window and damaged the fuselage in several other places, according to a preliminary report by the National Transportation Safety Board. Greece turned the investigation over to the U.S. agency under international aviation rules. The July 10 accident happened after the flight departed the northern Greek city of Thessaloniki.

Investigators found bird remains inside the engine, suggesting the plane may have struck birds during takeoff, though they haven't determined what caused the fan blade to break loose. The 61-year-old passenger suffered neck and shoulder injuries and friction burns. Flight attendants told investigators they heard and felt loud, continuous vibration and saw smoke or fog fill the cabin before the oxygen masks dropped from the ceiling.

The NTSB last month reprimanded Ryanair CEO Michael O'Leary after he told investors the investigation was focused on foreign object damage rather than the plane's age or maintenance history. Boeing and CFM International, the engine maker, said they are assisting with the investigation. The FAA had ordered fixes after similar accidents, including a 2018 Southwest Airlines incident that killed a passenger. The directives, which took effect in April 2025, require changes aimed at keeping pieces of the engine covering from breaking away and striking the plane if a fan blade breaks loose, with airlines given until July 2028 to complete the major modifications.