The October crash of an F-4 Phantom fighter that killed two Air Self-Defense Force pilots was most probably caused by the pilots' over-concentration on radar instruments or by the vertigo they suffered in midair, the ASDF said Friday.
1st Lt. Tomohiro Suetake, 28, and 2nd Lt. Masahiro Ogasawara, 26, died when their two-seater crashed into the sea during a formation-flying exercise off Misawa Air Base in Aomori Prefecture on the night of Oct. 9.
ASDF inspector Major Gen. Kunihiro Oda explained that the jet lost control as it plunged into a cumulus clouds-shrouded airspace at an altitude of 8,000 feet.
Oda said that although the air force was unable to conclude what exactly caused the accident, it believes that the pilots were over-concentrating on radar screens due to the bad weather conditions, or that they fell into vertigo and failed to recover by the time the plane hit the water.