Two U.S. warplanes apparently lost two pieces of external equipment during a flight drill over Japan last week, but no damage was reported on the ground, Kanagawa prefectural officials said Saturday.
The U.S. Navy found an F/A-18F Super Hornet fighter without an aluminum fin and an EA-6B Prowler electronic warfare plane without part of a ladder after they returned to the Navy's Atsugi base in Kanagawa Prefecture, the officials said.
The U.S. military notified local authorities through the Defense Facilities Administration Agency.
The flight path included Sagami Bay and Mount Fuji, the officials said.
The aluminum fin -- 15 cm long and 10 cm wide -- is used to stabilize the course of mock warheads, while the ladder is 1.2 meters long and weighs 7 kg, they said.
The prefectural government will lodge a protest if it turns out the parts did in fact fall during the flight, a prefectural official said.
The U.S. military plans to conduct a search on the ground along the flight route, officials said.