What happened
On 29 January 2014, a Cessna C-140, registration PP-DFW, was conducting a closed-circuit navigation flight for a Commercial Pilot course. The flight, operated by Aero Agrícola Santos Dumont Ltda., included an instructor-pilot and a student. After performing touch-and-go landings at SSSC, the aircraft returned toward SSKS.
As the aircraft approached the traffic pattern at SSKS, the instructor notified other pilots on a free frequency that they were experiencing elevator problems and intended to land within three minutes. Shortly after joining the downwind leg, the aircraft performed an abrupt pitch-up maneuver and entered a spin. Although the crew managed to recover from the first spin, the aircraft entered a second spin, resulting in a 90-degree pitch-down impact into a soybean plantation. The two fatalities were the only occupants on board.
The investigation
CENIPA's investigation focused on the mechanical failure of the flight controls and the operational environment of the flying school. Investigators examined the wreckage and found that the aircraft's elevator had sustained plastic deformation, causing it to become stuck in a pitch-up position. This deformation led to the breakage of the elevator-trim cable due to overload.
The investigation also scrutinized the organizational culture of the flight school. Evidence suggested a lack of standardized procedures and a permissive environment regarding unsafe flight practices. The investigation considered whether unauthorized maneuvers, such as aerobatics, had subjected the airframe to loads exceeding its operational limits.
Findings
- The primary cause of the accident was a system/component failure where the elevator became stuck due to structural deformation.
- The elevator-trim cable broke in flight following an overload.
- The instructor's excessive self-confidence and motivation may have led to the performance of non-prescribed maneuvers.
- The flying school's organizational culture lacked sufficient monitoring and standardized operational procedures.
- A permissive group culture among instructors and students reinforced unsafe behaviors and flight indiscipline.
- The instructor's workload and the lack of formal training programs for instructors contributed to a routine based on improvisation.