What happened
On a scheduled flight from Fukuoka to Tokyo-Haneda, the Boeing 747 began its descent from cruising altitude toward the destination. During the approach to runway 33R, the crew configured the aircraft by extending flaps and lowering the landing gear. By 08:42, the aircraft was descending through 1,000 feet with a wind of 20 knots.
As the flight progressed toward the decision height, the aircraft's airspeed dropped to 133 knots while passing through 300 feet. Although the co-pilot noted the approaching decision height, the captain failed to confirm that the approach was stabilized according to operational procedures. At 08:43:56, the radio altimeter warning activated, and the flight engineer called out the 200-foot decision height shortly thereafter.
At 08:44:01, while descending through 164 feet, the captain disconnected the autopilot, pushed the controls forward, and moved the throttles to idle. Despite efforts by the co-pilot to recover the aircraft, the plane struck the shallow waters of Tokyo Bay approximately 510 meters before reaching the runway 33R threshold. The impact caused the nose and the right wing to separate from the fuselage.
Findings
The investigation highlighted that the approach was not stabilized in accordance with company regulations. The captain's failure to maintain a stabilized approach and improper manual control inputs were critical factors. Additionally, reports indicated that the captain had been on medical leave for a psychosomatic disorder prior to the incident, suggesting potential mental impairment during the flight.