What happened
On August 26, 2020, an AB-115 aircraft, registration PP-GHD, was conducting a local instructional flight at Guaratinguetá Aerodrome in São Paulo, Brazil. The flight was operated by a flight school with a flight instructor and a student pilot on board.
During the landing phase, the aircraft was performing a "slipping" approach to manage the descent. During this maneuver, the flight instructor retracted the flaps from 45° to 30° without communicating this change to the student pilot. This sudden configuration change, combined with varying winds from the right, resulted in a steeper-than-normal approach slope. Upon touchdown, the right main landing gear assembly failed due to an overload at the attachment point. This structural failure caused the aircraft to lose directional control, leading to a runway excursion where the aircraft veered to the right and came to a stop in a grassy area. The aircraft sustained substantial damage, including damage to the landing gear and the right wingtip, but both crew members escaped without injury.
The investigation
CENIPA's investigation focused on the structural failure of the landing gear and the operational decisions made during the final approach. Investigators analyzed the aircraft's maintenance records, which showed the last 50-hour inspection had been completed approximately 125 flight hours prior. The investigation also examined the flight manual, which recommended a 45° flap setting for landing, contrasting with the 30° setting used during the accident.
Findings
- Inadequate piloting judgment: The instructor's decision to retract the flaps to 30° during the final approach deviated from the manufacturer's recommended landing configuration.
- Crew Resource Management (CRM) failure: There was a critical lack of communication between the instructor and the student regarding the sudden change in aircraft configuration.
- Control skills: The combination of the unexpected configuration change and the student's limited experience in the aircraft type made it difficult to stabilize the aircraft for a smooth touchdown.
- Structural failure: The right main landing gear broke due to an overload in the attachment region during the landing impact.