What happened
On July 23, 1974, at approximately 19:20 hours, a Piper PA-18 Super Cub aircraft, registered as CS-ACC, was conducting a flight instruction mission for the Aero Clube de Chaves. The aircraft, owned by Aero Ventura and temporarily assigned to the club, was carrying an instructor pilot and a student pilot. During the training sortie, the engine ceased operation due to a lack of fuel reaching the carburetor. Because the aircraft was at a low altitude, it was impossible to glide back to the Chaves Aerodrome. Consequently, the crew was forced to execute an emergency landing in a field located approximately 1,000 meters west of the aerodrome.
The investigation
The GPIAAF investigated the circumstances surrounding the incident. The aircraft was found to be properly certified, equipped, and maintained in accordance with the regulations implemented by the Direção-Geral da Aeronáutica Civil (DGAC). The instructor pilot held a valid Commercial Pilot License and Flight Instructor qualification appropriate for the flight being conducted. Post-accident inspection revealed damage to the aircraft's belly skinning, the right wing's leading edge and tip, the landing gear, and the wooden propeller. There were no structural failures in the main airframe components.
Findings
The investigation established that the primary cause of the incident was fuel starvation. The instructor pilot reported that the fuel tank contained insufficient fuel. During a tight turn, centrifugal force prevented the remaining fuel from reaching the carburetor, causing the engine to stop. The aircraft sustained damage during the forced landing, including a broken landing gear and damaged propeller, but there were no personal injuries to the crew or any third parties.
Safety action
The source document does not record specific safety recommendations issued by the GPIAAF for this historical incident.