What happened
On the morning of the incident, a single-engine aircraft departed Tokyo-Haneda Airport at 0850 local time for a local training flight. The weather was marginal, with visibility significantly reduced by fog. Approximately five minutes after takeoff, while executing an approach maneuver back to Haneda, the aircraft collided mid-air with a Mitsubishi Ki-1 (Hanriot HD-14). The Mitsubishi was also conducting a local training sortie out of the same airport.
The Fokker involved in the accident was registered J-BIDH and operated by the Japan Flying School. It carried two pilots, one student, and one instructor. Following the impact, the Mitsubishi Ki-1 lost control and crashed into a residential house in the Morigasaki district. Simultaneously, the Fokker plunged out of control onto the factory grounds of the Yamamoto Rush Manufacturing Company, located less than 3 km northwest of Haneda Airport.
The accident resulted in 85 fatalities. Both pilots aboard the Mitsubishi were killed. All three crew members on board the Fokker perished. Additionally, 80 people on the ground lost their lives, primarily employees of the manufacturing company and local residents who had gathered to assist with rescue operations.
Findings
Official investigations determined that the collision occurred due to limited visibility caused by fog in the vicinity of Haneda Airport. The crew of the Fokker was originally scheduled to perform a touch-and-go maneuver but initiated a go-around procedure at the time of the impact. It is concluded that this deviation likely caused the aircraft to cut across the flight path of the Mitsubishi Ki-1, leading to the mid-air collision.