Incident Overview
On October 6, 2017, at about 18:50 Japan Standard Time, a privately owned Cessna 172K, registration JA3500, suffered an engine stoppage while flying at approximately 1,500 ft over Ishikari City, Hokkaido. The aircraft subsequently made a forced landing on the sands of Ishikari Beach. The Japan Transport Safety Board (JTSB) investigated the serious incident.
Flight History
The aircraft took off from Sapporo Airfield at about 18:23 for a familiarization flight. The passenger, who had not flown in about a year, operated the aircraft from the left pilot seat, with the captain in the right seat. After flying over Sapporo and Otaru, the aircraft proceeded along the coast toward Ishikari City. While turning near the Sapporo VOR, the engine stopped, and power decreased with a corresponding reduction in engine sound. The passenger attempted to restart the engine by switching the fuel selector from the BOTH position to left and right and activating the starter, but the engine did not restart. The passenger also pulled the carburetor heat lever without effect. The captain then took control and, unable to restart due to low altitude, decided to land on the beach. After turning seaward and confirming the landing site, the captain executed a forced landing without flaps. The aircraft came to a stop on soft sand at about 18:54.
Post-Incident Examination
Investigation revealed that after the incident, no fuel remained in the right fuel tank, while approximately 21 liters of fuel (with water present) were found in the left tank. The fuel selector lever was found in the BOTH position, and the selector valve operated normally with no internal blockage. However, excessive play was found at the hinges of the mechanical linkage connecting the selector lever to the valve body, meaning that rotating the lever to the BOTH position would not precisely set the valve body in its detent. Nevertheless, no obstruction to fuel flow was confirmed in the fuel lines. Water was also found in small amounts in the fuel strainers. The fuel filler caps had sealant applied, preventing water infiltration through the caps. The vent line in the left tank was clear, and the vent valve worked properly. The captain had confirmed fuel quantity indicators showing about one-quarter before the flight but did not visually check the fuel level. During the flight, the crew did not notice uneven fuel consumption between tanks.
Personnel and Aircraft Information
The captain, age 63, held a commercial pilot certificate with about 13,005 total flight hours, including 11,000 hours on the same aircraft type. The passenger, age 49, held a private pilot certificate with 525 total flight hours. The aircraft, a 1968 Cessna 172K, had a total flight time of 7,895 hours and was within weight and balance limits. No injuries to persons or damage to the aircraft were reported.
Meteorological Conditions
The weather at the time was reported by the captain as slightly cloudy with an easterly wind of about 5 kt. Observations from the nearby Ishikari station recorded a southeast wind of 2.2 m/s and a temperature of 13.6°C at 18:50.