What happened
On September 26, 2019, a Piper PA-11, registration LV-YQF, was parked at Ezpeleta Aerodrome in Buenos Aires for a scheduled local flight instruction. The crew consisted of a flight instructor and a student pilot. During the engine start sequence, the student was positioned in front of the propeller to manually swing it. After an initial failed attempt to start the engine, the student attempted to reposition the propeller. During this movement, the engine unexpectedly ignited, causing the propeller to strike the student's left leg. The student sustained a superficial laceration, which was treated at a local hospital.
The investigation
The investigation examined the coordination between the crew and the procedures used during the start sequence. It was established that the instructor was seated in the rear cockpit, managing the brakes and ignition. Following the first failed start, the instructor had to move from the pedals to reach the ignition switch, momentarily releasing the brakes. The student, attempting to prepare for a second start, moved the propeller without first confirming that the magnetos were in the 'off' position or communicating with the instructor.
Investigators also reviewed the operational documentation used by the flight school. They found that the checklist being utilized for the Piper PA-11 was actually adapted from a different aircraft model and did not include the necessary steps for a secondary start attempt. Furthermore, the flight school, which was in the process of obtaining its formal certification, lacked a specific pre-flight briefing protocol for engine starting procedures.
Findings
- The engine failed to start during the first manual rotation.
- There was a lack of coordination between the instructor and the student during the transition between the first and second start attempts.
- The second start attempt was not performed in accordance with the aircraft's flight manual.
- The checklist used by the crew was inconsistent with the requirements of the aircraft's official manual.
- The flight school did not have an established briefing procedure specifically for engine starting maneuvers.
Safety action
- Flight schools should include specific engine start briefings in their operational documentation.
- Checklists must be verified to ensure they include all critical items found in the aircraft's flight manual.
- Training programs should emphasize the importance of standardized pre-flight briefings as a defensive barrier against operational errors.