NORFOLK, Va. — The US Navy says a sailor who died aboard an aircraft carrier was struck by the turning propeller of a plane.

The Navy said in a statement Wednesday that Airman Apprentice Joseph Min Naglak had just secured an E-2C Hawkeye radar plane to the flight deck. Naglak’s death occurred Monday aboard the USS George H.W. Bush while it was in the Atlantic Ocean.

The Navy said the incident remains under investigation and that his death has been a heartbreaking experience for those on board the carrier.

The 21-year-old enlisted in the Navy in his home state of New Jersey in April 2017. Four months later, he had completed his training in Pensacola, Florida, and reported to the ship.

The ship remains at sea, and flight operations have resumed.