11 fatalities

Maritime patrol aircraft crash in Pacific Ocean near Choshi (4651)

Chōshi, JapanFlight

On July 16, 1971, a Lockheed P-2 Neptune (registration 4651) operated by Japan Maritime Self-Defense Force - Kaijō Jieitai was involved in an aviation accident near Chōshi, Japan in flight. 11 people were killed. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 2026-06-12Data APIEditorial standards

An aircraft conducting a maritime patrol mission crashed into the Pacific Ocean off the coast of Choshi, resulting in no survivors.

What happened

During a scheduled maritime patrol operation, an unidentified aircraft went down in the Pacific Ocean. The incident occurred in the waters situated near the city of Chōshi. At the time of the impact, the aircraft was engaged in its patrol mission when it struck the ocean surface.

All 11 occupants on board the plane were killed in the accident. The specific circumstances surrounding the descent and subsequent crash remain undetermined at this time.

Findings

The exact cause of the crash into the Pacific Ocean is currently unknown, as the precise sequence of events leading to the loss of the aircraft has not been established.