June 11 (UPI) -- A U.S. Air Force base in Japan grounded its fleet of F-15 fighter jets Monday after a crash that seriously injured a pilot.
The pilot was on a routine training mission at Kadena Air Base in Japan when he was forced to eject. The plane crashed and the pilot was recovered.
The base has temporarily grounded its fleet of F-15s, Kadena Air Base said Monday.
The cause of the crash is unknown and officials said a board of officers will investigate. Kadena has halted training while the 18th Wing reviews operational, maintenance and safety procedures.
Sunday's incident came as the Air Force finished its first wave of one-day safety stand-downs of flying and maintenance wings, which were ordered in the wake of other mishaps this year.
Sunday's was the 12th crash involving a U.S. military aircraft this year.