What happened
On July 3, 2024, a SEAMAX M22 aircraft, registration CS-XBC, departed from Vilar da Luz (LPVL) for a navigation flight to Ponte de Sor (LPSO). While enroute over the Carvalhal – Abrantes region at approximately 2,000 feet MSL, the engine began operating irregularly and subsequently shut down.
The pilot attempted to restart the engine using the emergency starter; while the engine ran for several seconds, it failed again shortly after. Following emergency procedures, including landing gear and full flap extension, the pilot identified a suitable landing site to the right. However, during the final approach, the lower fuselage struck the upper cable of a medium-voltage powerline. This impact diverted the aircraft from its intended path, causing it to come to rest in dense vegetation. The contact between the live cable and the ground ignited a small forest fire in the surrounding area. The pilot sustained no injuries, though the aircraft suffered substantial damage to the wing and landing gear.
The investigation
The GPIAAF investigation focused on the fuel management and the circumstances leading to the engine failure. Investigators reviewed the pilot's flight records, which showed the pilot held a valid ATPL and Class 1 medical certificate. The aircraft had been refueled with 98 liters of 95 RON gasoline on January 25, 2024.
Analysis of the fuel consumption indicated that, based on an average consumption rate of 19 liters per hour, the fuel remaining on board was insufficient for the flight duration. The pilot reported that the fuel indicator tube had become opaque, making it difficult to visually verify the fuel levels. During the flight, the pilot had performed tank selections, switching from the right tank to the left and back to the right, but eventually ran out of usable fuel.
Findings
- The engine failure was caused by fuel exhaustion.
- The pilot's ability to monitor fuel levels was compromised by an opaque indicator tube.
- The aircraft's fuel reserves were insufficient for the intended flight duration.
- The emergency landing resulted in contact with a medium-voltage powerline, causing significant aircraft damage and a small ground fire.
Safety action
Following the investigation, the Original Equipment Manufacturer (OEM), Seamax Aircraft, initiated several manual updates to mitigate identified risks. These include:
- Updating the Pilot's Operating Handbook (POH) with a more detailed description of the fuel system, specifically regarding the operation of the header tank and low-level sensor.
- Implementing clearer warnings and procedures for both pre-flight and in-flight fuel management.
- Providing more detailed information regarding the instrument panel, including the fuel low-level indicator light.