Toa Domestic Airlines Yonago Airport overrun accident

The Toa Domestic Airlines Yonago Airport overrun accident is an aviation accident that occurred on 10 January 1988 (Showa 63). Toa Domestic Airlines Flight 670 (YS-11-109), from Yonago Airport to Osaka International Airport, overran the runway during take-off from Yonago Airport due to malfunction of the elevator, and came to a stop after plunging into Nakaumi. 8 of the 52 passengers and crew were injured.

Accident aircraft

The accident aircraft was a Nihon Aircraft Manufacturing YS-11-109 (nickname: Naruto), an airliner powered by two Rolls-Royce "Dart 542-10" turboprop engines. Its registration was JA8662; it was manufactured on 9 May 1966 and made its first flight in the same year. From May 1966 it was operated by Japan Domestic Airlines, the predecessor of Toa Domestic Airlines, and by the time of the accident it had flown a cumulative total of about 47,209 hours.

After the accident, it became a cutaway model and was exhibited at the Train and Bus Museum in Kawasaki, Kanagawa Prefecture. Until the museum's renewal in 2016 it was exhibited as a flight simulator.

Flight before the accident

On the day, the accident aircraft, with the same crew, took off at 7:55 as Flight 671 from Osaka International Airport to Yonago Airport. It landed on runway 25 at Yonago Airport at 9:05. About 7 minutes after landing it was parked on the apron. Then, with the same aircraft and crew, preparations for take-off began in order to operate Flight 670 from Yonago Airport to Osaka International Airport.

Accident

At around 9:32, the aircraft taxied to runway 25 with the captain at the controls. At the time, the temperature was about 1 degree and light snow showers were falling. At 9:34, control was handed over to the first officer, a control check was carried out, and the take-off roll began. 23 seconds later the aircraft reached take-off decision speed (V1), and a few seconds later reached the take-off speed of 95 kn. The first officer pulled back on the control column to raise the nose, but there was no response. In response, the first officer said "It's heavy". The pilots attempted to abandon the take-off, but because the speed had reached nearly 112 kn, the aircraft did not stop within the runway; it overran and plunged into Nakaumi 50 metres offshore from the end of the runway. As a result of the accident, 8 passengers were slightly injured, but no one was killed. The controller immediately contacted the Miho Airport Office, and office staff notified the police and fire services.

Cause of the accident

As the cause of the accident, the report cited the freezing of slush adhering to the elevator, which made it difficult to raise the nose. It also stated that the take-off was rejected at a high speed exceeding the take-off safety speed (the speed at which the aircraft can climb safely even if one engine fails, V2), and that because there was slush on the runway and the weight borne by the main gear was small, the braking effect was reduced and the aircraft could not stop within the runway.