What happened
On April 5, 2015, at approximately 11:30 UTC, a CAP-4 aircraft, registration PT-KYM, was performing a local flight instruction mission at the São Joaquim da Barra Aerodrome (SDJO) in São Paulo, Brazil. The flight was being conducted for Private Pilot training with an instructor and a student on board.
During the taxi phase, the student pilot applied the brakes with excessive force. Because the taxiway featured a specific slope, this sudden braking caused the tail of the conventional gear aircraft to lift, resulting in the propeller making contact with the ground. The instructor took control of the aircraft and shut down the engine to prevent further damage. The impact caused damage to the propeller tips, but both occupants escaped without injury.
The investigation
The investigation conducted by SERIPA IV confirmed that the aircraft was airworthy, with valid documentation for the airframe, engine, and propeller. The crew members held valid medical certificates, and the instructor held valid commercial and flight instructor ratings. The aircraft was within weight and balance limits, and meteorological conditions were favorable for flight.
Investigators examined the braking system and found no mechanical abnormalities. The investigation focused on the interaction between the aircraft's conventional landing gear configuration, the slope of the taxiway, and the crew's handling of the controls. The analysis highlighted that the student's lack of experience and the instructor's ineffective intervention were key elements in the sequence of events.