WPR24LA039

The flight instructor’s inadequate preflight planning, which resulted in fuel exhaustion and a total loss of engine power.

The student pilot used a fuel dipstick ruler to measure the quantity of fuel in each wing tank and reported 13 and 9 gallons, respectively, during the preflight. Shortly after, the student and the flight instructor departed the local airport to practice steep turns and slow-flight maneuvers, including an introduction to power-off stalls and recovery. About an hour into the flight, during a stall maneuver recovery (with carburetor heat on), the instructor increased the throttle setting but the engine remained at idle. As the power remained unchanged, the instructor decided to execute an off-airport landing to a nearby field. Shortly after touchdown, the landing gear separated and the airplane nosed over, resulting in substantial damage to the aft fuselage. Postaccident examination of the airframe and engine did not reveal any mechanical anomalies. Flight control and valvetrain continuity were established. No fuel was recovered at the accident site. The fuel system was traced from each wing tank to the carburetor at the engine through the fuel selector, which rotated normally and was unobstructed. The fuel filter bowl remained secured to its mount and had about 2 oz of fuel consistent with 100LL avgas. Although weather conditions were conducive to serious carburetor icing at cruise power, the flight instructor reported that carburetor heat was applied during the stall maneuvers. The operator reported that the airplane was not refueled after the previous flight or before the accident flight. Based on the engine time that accrued since the last fueling, and the minimal amount of fuel found in the airplane after the accident, the student pilot’s fuel reading was likely incorrect and did not accurately account for the amount of fuel available for the flight. As a result of the accident, the operator updated their procedures requiring all flight instructors to verify and sign off on the reported fuel level after each student preflight.

On November 18, 2023, about 1522 Pacific standard time, a Cessna 150M, N6266K, was substantially damaged when it was involved in an accident near Woodland, Washington. The flight instructor and student pilot sustained no injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that about 1425 they departed from Pearson Field Airport (VUO), Vancouver, Washington, to practice steep-turns and slow flight maneuvers, including an introduction to power-off stalls and recovery. About 3,500 ft mean sea level (msl), the instructor executed an additional stall maneuver (with carburetor heat applied); as the instructor released the back pressure on the yoke and advanced the throttle setting to full to recover from the maneuver, the airplane’s power setting remained idle. The instructor subsequently increased the throttle setting incrementally after decreasing it to increase engine power. As the engine power remained unchanged, the instructor made the decision to execute an emergency landing. The instructor maneuvered the airplane to a nearby field and, shortly after touchdown, the nose landing gear separated, and the airplane nosed over. The airplane sustained substantial damage to the aft fuselage.   According to the flight instructor, the student reported that he dipped the fuel tanks right before the flight and read 13 gallons in one wing and 9 gallons on the other, which translated to about ½ on each of the left and right fuel gauges. The fuel quantity was verified by dipping a dipstick straight into each tank and reading the amount off the ruler. The flight instructor added that company policy did not require instructors to dip the tanks after students do, as the students were already trained. She stated that it was the responsibility of the instructors to decide whether the fuel amount reported by their students was sufficient for the planned lesson. The instructor calculated that the student-reported fuel amount was sufficient for their planned training flight, which would have provided at least an extra hour and forty-five minutes of flight time. Postaccident examination of the airplane and engine did not reveal any preimpact mechanical anomalies. The fuel system was traced from each wing tank to the carburetor at the engine through the fuel selector, which rotated normally and was unobstructed. The fuel filter bowl remained secured to its mount and had about 2 oz of fuel consistent with 100LL avgas. The fuel lines that had not been damaged from impact or removed to transport the airplane were secure. The recovery company reported that no fuel was recovered at the accident site. Mechanical continuity was established throughout the rotating group, valvetrain, and accessory section as the crankshaft was manually rotated at the propeller by hand. Thumb compression was achieved at all four cylinders and the valves displayed normal lift when the crankshaft was rotated. Examination of the cylinders’ combustion chamber interior components using a lighted borescope revealed normal piston face and valve signatures, and no indications of catastrophic engine failure. The operator reported that the student likely angled the fuel dipstick improperly instead of straight down into the tank, which resulted in a higher reading level. The operator stated that the airplane’s hour meter indicated that it flew about 2.4 hours before the accident flight and was not refueled before the accident flight. He reported that the airplane’s hour meter indicated that airplane had flown 3.5 hours from the time the airplane was last refueled until it landed in the field; at least part of that time involved the airplane conducting maneuvers. As a result of the accident, the operator developed a new process that required every flight instructor to check and sign off on the fuel level of each tank before departure. At 1453, the weather reported at Scappoose Airport (SPB), Scappoose, Oregon, located about 9 nautical miles from the accident site, included a temperature of 11°C and a dew point of 4°C. A review of the icing probability chart contained within FAA Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were "conducive to serious icing at cruise power."