What happened
During a training flight at Norrtälje airport on April 3, 2014, a Piper PA28-181 was performing a series of landings, including a planned "touch-and-go." As the student pilot prepared for the landing, the intention was to switch the fuel source from the right tank to the left tank to ensure the engine was fed from the tank with the highest fuel volume.
During this process, the student inadvertently moved the fuel selector valve to the "OFF" position. While the engine continued to run briefly on the residual fuel remaining in the lines, the supply was effectively severed. After touching down and attempting a rolling takeoff, the engine lost power abruptly at an altitude of approximately five to ten meters. The instructor took control and attempted to force the aircraft back onto the runway, but the aircraft could not be stopped on the asphalt and veered into the surrounding vegetation, coming to rest 50 meters past the runway end. There were no injuries to the crew.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the mechanical state of the fuel selector and the cockpit environment. The investigation focused on why the fuel selector was moved to the incorrect position and why the mechanical safeguards failed to prevent such an error. Investigators also looked into the cockpit workload, noting that the instructor was heavily focused on navigating the specific local traffic pattern requirements at Norrtlye, which differed from standard procedures.
Findings
- The primary cause of the incident was the unintentional shutdown of the fuel supply during landing preparations.
- A contributing factor was a mechanical failure of the fuel selector assembly; the metal stop, designed to prevent the valve from reaching the "OFF" position, was ineffective due to insufficient overlap.
- The plastic housing of the selector was damaged, which prevented the metal stop from springing back into its functional position.
- The student's recent training in a different aircraft type (Cessna 172) meant they were using a different mental model for the selector's physical movement and function.
- High cockpit workload, driven by the need to adhere to complex local traffic pattern rules, likely prevented the instructor from verifying the valve position.