History of Flight
On March 26, 2016, about 1315 Pacific daylight time, a Cessna 172L, N1151M, nosed over during a forced landing in a field on McNeil Island, Washington. The airplane experienced a total loss of engine power. The student pilot was not injured, and the airplane sustained substantial damage. The solo cross-country instructional flight departed Bowerman Airport, Hoquiam, Washington, about 1250, with a planned destination of Tacoma Narrows Airport, Tacoma, Washington. Visual meteorological conditions prevailed, and a visual flight rules flight plan had been filed.
The pilot was gaining aeronautical experience for his private pilot rating and was on the second-to-last leg of his first 150 nautical mile solo cross-country flight when the accident occurred. Prior to departure from his home base at Pierce County Airport – Thun Field, Puyallup, he serviced the airplane with 6 gallons of fuel and confirmed using a dipstick that the tanks contained 36 gallons of fuel. He performed a preflight inspection, and his flight plan was checked by a certified flight instructor at the flight school. At 1030 he departed from Thun Field.
The route of flight took him north towards the Strait of Juan de Fuca at 3,000 ft mean sea level (msl). Due to low clouds, he was unable to land at his first intended destination of William R Fairchild International Airport, Port Angeles, so he continued west and landed at Sekiu Airport. After departing Sekiu, he followed the coast south around the Olympic Peninsula and landed at Bowerman. While en route to Bowerman, he noticed that the left fuel tank gauge was indicating almost empty; however, he was not concerned, recalling that during flight training he had been taught that the fuel gauges could be unreliable.
He did not visually confirm the fuel tank quantity with a dipstick while at Bowerman. After takeoff, he followed waypoints inland. As he approached McNeil Island at about 2,000 ft msl, the engine began to sputter and operate intermittently at reduced power. He confirmed the throttle control was full forward and declared an emergency with the Tacoma Airport control tower. Concerned that performing troubleshooting steps could further exacerbate the situation, he did not follow any emergency checklists. For the next 5 minutes, the engine continued to operate intermittently as the airplane gradually descended. Once over the island, the engine lost all power. He guided the airplane toward a field for landing, and during the landing roll, the airplane nosed over.
Tests and Research
The airplane was equipped with two rigid metal fuel tanks installed inboard of each wing. Total fuel capacity was 38 usable gallons, and fuel flowed by gravity to a four-position selector. Tank ventilation was accomplished by a check valve-equipped overboard vent line in the left tank and a crossover line on the inboard top sides of both tanks which connected their air spaces. Fuel quantity transmitters were installed on the top of both tanks. The fuel selector positions were "OFF", "BOTH", "LEFT", and "RIGHT". According to the Cessna 172L Owner's Manual, both the before start and before takeoff checklists required that the both position be selected.
Following the accident, the airplane remained upside-down in the field and was recovered four days later. During recovery, 12 gallons of fuel was removed from the right tank and 5 gallons from the left. At that time, the fuel selector switch was found in the left tank position. Both the pilot and first response personnel from the local Fire Department stated that they did not change the position of the fuel selector after the accident.
The pilot reported that he always flew with both tanks selected, in compliance with the flight school's policy, and that he confirmed this position was selected prior to departing from Thun Field, but not at any other time during the remaining flights.
The total distance flown since departure from Thun Field was about 295 miles. According to the Owner's Manual, at an altitude of 2,500 ft, a weight of 2,300 lbs., and engine speed of 2,500 rpm, the airplane will cruise at 128 mph true airspeed and burn 7.8 gallons of fuel per hour.
The airplane was examined by an FAA Inspector following recovery. All fuel and vent lines were clear, and no mechanical anomalies were noted. The engine was then operated utilizing fuel fed to each wing root supply line (the wings were removed during recovery). The engine ran uneventfully at various speeds for about 7 minutes with both the left and right tank positions selected.