A lifeless goose was found in a part of the flight management system of a medical helicopter that crashed in western Oklahoma, killing all three folks on board, in accordance with a preliminary report by the National Transportation Safety Board.

The report doesn’t cite a suspected reason behind the crash, however famous one goose was found in the helicopter’s flight management system and others have been found in the particles subject.

A report on the possible trigger might take as much as two years to finish, in accordance with the NTSB.

The helicopter crashed Jan. 20 in a pasture close to Hydro, about 60 miles (97 kilometers) west of Oklahoma City, because it was returning to Weatherford after taking a affected person to an Oklahoma City hospital.

The pilot and each Air Evac Lifeteam crew members, a flight nurse and a paramedic, have been killed.