What happened
On August 25, 2022, at 14:55 UTC, a Puma Audaz (registration LV-X764) was conducting a general aviation training flight departing from the Alta Gracia aerodrome in Córdoba, Argentina. After approximately 30 minutes of flight under visual meteorological conditions, the aircraft performed a touch-and-go maneuver. During the subsequent takeoff attempt, the engine ceased operation, forcing the pilot to perform an emergency landing in an unprepared field.
The impact resulted in significant damage to the aircraft's wings, landing gear, and struts, while the propeller was destroyed. The engine sustained minor damage. Both the pilot and the passenger escaped the incident without injuries.
The investigation
The investigation by the JST focused on two primary technical issues: the operation of the fuel selector valves and the structural integrity of the passenger seatbelt anchorage.
Investigators examined the aircraft's fuel system, which consists of two 40-liter tanks. The fuel selector valves are located beneath the pilot's seat, making them difficult to monitor while wearing a three-point safety harness. The investigation established that during the initial approach to runway 20, the pilot noticed fuel leaking from the right tank vent. To balance the fuel levels, the pilot closed the left tank valve, under the mistaken assumption that both valves were previously open. This action inadvertently cut off the fuel supply to the carburetor.
Additionally, the investigation scrutinized the passenger's seatbelt attachment. During the sudden deceleration of the crash, the steel cable terminal anchoring the seatbelt to the airframe detached due to insufficient pressure during the manufacturing/machining process.
Findings
- The operation of the fuel selector valve was the primary triggering factor of the accident.
- The engine failure was caused by a lack of fuel supply following the pilot's attempt to level the tanks.
- The pilot had unknowingly taken off with only the left tank valve open, leading to the right tank overflowing through the vent.
- A secondary safety risk was identified when the passenger's seatbelt anchor failed under the load of deceleration due to a manufacturing defect in the cable terminal.