What happened
On August 9, 1992, a P-56-C1 Paulistinha, registration PP-HRL, operated by Aeroclube de Catanduva, was conducting a local flight near Urupês, São Paulo. The flight, which included the pilot and one passenger, had been in the air for approximately two hours when the pilot initiated a fuel transfer from the upper tank to the lower tank. To facilitate this, the pilot set the fuel selector valve to the "both" position.
After the fuel from the upper tank had overflowed into the lower tank, the pilot attempted to return the selector valve to the "lower" position. Approximately four minutes after this adjustment, the engine began to run irregularly. During the subsequent emergency procedures, the pilot realized the selector valve had not been properly seated in the correct position. Although the pilot corrected the valve setting, the engine failed to restart, likely because the fuel lines had run dry.
Unable to maintain flight, the pilot opted for a forced landing on the Chafik Saab Highway. During the ground roll, the right wing struck a traffic sign, causing the aircraft to veer and eventually collide with an embankment. The aircraft sustained light damage, and both occupants were uninjured.
The investigation
CENIPA's investigation focused on the sequence of events during the fuel transfer and the pilot's handling of the engine failure. Investigators examined the fuel system mechanics, noting that once the lines had dried, restarting the engine required the use of a fuel booster to restore pressure. The investigation also reviewed the pilot's training and experience, noting that while the pilot held a valid private pilot license and medical certificate, his experience with this specific aircraft type was limited.
Findings
- The engine failure was caused by the interruption of fuel flow due to the incorrect positioning of the fuel selector valve.
- The pilot's lack of proficiency in managing the fuel transfer process led to the valve being left in an improper setting.
- Inadequate flight planning and a failure to verify the valve position after the transfer contributed to the incident.
- The pilot's limited experience with the aircraft type resulted in an inability to properly manage the fuel system during the procedure.