Accident Overview
On Sunday, July 26, 2015, at approximately 10:58 Japan Standard Time (JST), a privately owned Piper PA-64-350P, registered JA4060, crashed into a private house in Fujimi Town, Chōfu City, shortly after takeoff from Runway 17 of Chōfu Airport. The aircraft was destroyed and a fire ensued. The house into which the aircraft crashed was consumed by fire, and neighboring houses sustained damage from the fire and other factors.
Aircraft and Occupants
The aircraft carried five people: the captain and four passengers. The captain and one passenger died; three passengers sustained serious injuries. On the ground, one resident died and two residents had minor injuries.
Probable Cause (Official Findings)
The Japan Transport Safety Board determined that it is highly probable that the accident occurred because the aircraft's speed decreased during takeoff and climb, leading to a stall and subsequent crash into a residential area near Chōfu Airport. The decreased speed was highly probably caused by the aircraft exceeding its maximum takeoff weight, taking off at a low speed, and maintaining an excessive nose-up attitude.
Additional factors considered somewhat likely include: the captain may have had insufficient understanding of the risks involved and lacked adequate safety awareness regarding compliance with relevant regulations; the low takeoff speed may have resulted from the captain's decision to take off at such a speed or from his reaction to the aircraft approaching the runway threshold; the continued excessive nose-up attitude may have been influenced by a center of gravity close to the aft limit or by the captain prioritizing climb over speed. Furthermore, analysis using mathematical models suggests that decreased engine power may have contributed to the speed loss, but no evidence of engine malfunction was found, and thus this could not be conclusively determined.