Japan Coast Guard training aircraft emergency landing

The Japan Coast Guard training aircraft emergency landing (Kaijō Hoanchō kunrenki fujichaku jiko) was an aviation accident involving a Japan Coast Guard light aircraft (trainer) that occurred on 18 April 2023 (Reiwa 5) in Usa, Ōita Prefecture. Owing to engine trouble, it made a forced landing on farmland.

Course of the accident

A training aircraft (type: Cessna 172, registration: JA395A; hereafter “the aircraft”) belonging to the Kitakyushu Aviation Training Center of the Miyagi Branch of the Japan Coast Guard School departed from Kitakyushu Airport at around 9:15 am on 18 April. On board were 2 people, an instructor in his 40s and a trainee in his 20s.

The purpose of the flight was training, and the trainee was flying the aircraft until the trouble occurred. After take-off, while they were conducting training over Usa to develop a feel for handling, including raising engine power to 100%, they heard a “bang” from the front and power dropped. The instructor radioed Tsuiki Air Base, which was responsible for air traffic control, saying “Engine power won't come up. We will make an emergency landing”, and at around 10:02 the aircraft landed in a field in Matsuzaki, Usa. According to Flightradar24 records, it had begun to descend at around 9:53, and at 10:01 it set its transponder squawk to 7700.

The forced landing was carried out with the instructor at the controls. After landing, the crew themselves reported to the fire department.

The original plan had been to return to Kitakyushu Airport at around 10:30.

The aircraft ended up upside down after the forced landing, but the 2 crew suffered only minor injuries (neck sprains), and their lives were reportedly not in danger.

Investigation of the accident

Following the occurrence of the accident on 18 April 2023, the Japan Transport Safety Board appointed aircraft accident investigators and carried out interviews with the people involved, examinations of the aircraft and the weather, analysis of various flight records and so on. Representatives of the United States, the state of design and manufacture of the aircraft, and of Germany, the state of design and manufacture of the engine, took part in the investigation.

Because the investigation was taking time and it would be difficult to complete it within 1 year of the accident, the Japan Transport Safety Board published an interim report on 28 March 2024, adopted the aircraft accident investigation report on 25 September 2025, and published it on 30 October of the same year.

The report presumed that because the loss of engine power made it impossible to maintain altitude, the aircraft made a forced landing on farmland, flipped forward after touching down, and was heavily damaged when the vertical stabiliser struck the ground. As for the cause of the loss of engine power, it presumed that the intake hose had come off, resulting in a naturally aspirated condition that led to incomplete combustion, and as the background to the intake hose detaching, it pointed to the possibility that the intake hose, which had been removed during maintenance work carried out the previous day, had not been reattached properly.

Regarding piloting and decision-making, the report found that the instructor, feeling that actual engine power was lower than indicated, judged that the aircraft could not reach Kitakyushu Airport and switched to an emergency landing on farmland in Usa, and that he selected and approached a spot facing directly into the wind, without obstacles such as high-voltage lines and where the impact could be expected to be reduced, which was an appropriate approach meeting the factors set out in the FAA handbook. In addition, taking into account that he had prepared for the forced landing, anticipating a flip on touchdown, by checking seat belts and instructing a safety posture, it assessed that the occupants did not suffer serious injury because the instructor's judgement and piloting skills were appropriate.

As measures to prevent recurrence, the report called on the Japan Coast Guard to ensure thorough maintenance and post-maintenance checks in accordance with the maintenance manuals and other documents specified by the designers and manufacturers of the aircraft and engine. It also stated that the engine's designer and manufacturer (the STC holder) needed to enable the pilot to recognise intake system abnormalities through warnings or the like, and to modify the FADEC software and so on so that accurate engine power values are displayed even when the intake hose has come off.

This instructor was killed in the line of duty the following year while serving as first officer in the Haneda Airport ground collision.