What happened
On August 22, 2020, a Morane-Saulnier MS-893A Rallye Commodore 180, registered CS-AJB, was performing advertising banner towing services along the Algarve coast. The flight, operated by Aeroplano, Lda, was part of a mission traveling from Portimão to Punta Umbria, Spain, and back. After completing several hours of flight time, while flying at approximately 900 feet near Benfarras, Boliqueime, the engine began to lose power, with RPM dropping to 1500.
The pilot attempted to recover the engine by applying maximum power and ensuring a rich mixture, which provided only a brief period of normal operation before a subsequent power loss. Recognizing the engine failure was irreversible, the pilot shut off the fuel mixture and selected an open area near a railway for an emergency landing. The aircraft touched down in a 40-meter clearing, decelerating over the final 20 meters before colliding with a medium-sized tree. The pilot egressed the aircraft without significant injuries, though their head struck the instrument panel during the impact.
The investigation
The GPIAAF investigation focused on the aircraft's fuel system and the pilot's operational procedures. Investigators examined the fuel levels and the specific configuration of the aircraft's fuel tanks. The investigation also reviewed the pilot's training and the operator's authorization for banner towing operations.
Findings
- The aircraft's fuel system configuration was a critical factor; unlike earlier Rallye models that featured a central feeder tank, this specific model utilized a three-position selector valve (Left/OFF/Right) that required manual switching between tanks.
- Upon inspection, investigators found approximately 60 liters of AVGAS 100LL in the right tank, but noted a complete absence of fuel in the left tank.
- The pilot had refueled the aircraft with 129.5 liters, distributed equally between both tanks, but the engine failure was caused by fuel mismanagement leading to the depletion of one tank.
- There was no evidence of a formal training process or a specific request for authorization to the regulator (ANAC) regarding the banner towing operation.
- The pilot, while holding a valid CPL/IR (A) and SEP rating, was performing his first flight on the specific aircraft CS-AJB that day.
- The aircraft sustained significant damage, including deformations to both semi-wings, the main landing gear, and the engine mount, while the nose gear collapsed and a propeller blade was bent upon impact.
Safety action
- Safety recommendation PT.SIA 2021-001: The operator, Aeroplano Lda, should develop and implement an operational procedure to ensure all pilots are properly trained and familiarized with the specific differences and characteristics of each aircraft in their fleet through a formal training and adaptation plan.