What happened
On 11 January 2008, a PA-25-235 performing agricultural spraying operations crashed in the municipality of São Bento do Abade, Minas Gerais. The aircraft, registered as PR-FBA, was conducting a crop dusting mission over the Canário Farm.
After completing an initial spraying pass, the pilot attempted a reverse turn, commonly known as a balloon maneuver, to position the aircraft for a second pass. During this maneuver, the pilot reported a loss of engine power and a reduction in airspeed to approximately 75 mph. In an attempt to maintain terrain separation while navigating an area with a 30-degree slope, the pilot increased the pitch angle. However, the airspeed continued to decay, leading the aircraft into a pre-stall condition. The aircraft subsequently entered a spin, completing a 210-degree roll before impacting the ground with the right wing first.
The pilot sustained serious injuries, and the aircraft was partially destroyed.
The investigation
CENIPA's investigation focused on the aerodynamic performance of the aircraft and the pilot's decision-making during the maneuver. Investigators examined the aircraft's engine, which had undergone a non-homologated conversion to operate on hydrated ethanol (AEHC). This modification included an unapproved replacement of the carburetor with a modified fuel injection unit to increase fuel flow.
The investigation also reviewed the pilot's preparation and the available technical documentation. It was noted that the pilot lacked precise performance data for the aircraft at the specific altitude of the operation and did not have updated maps or photography of the terrain. Furthermore, the investigation found that the aircraft's manual lacked critical information regarding stall speeds relative to bank angles, weight, and altitude.
Findings
- The in-flight loss of control was caused by the pilot's failure to adequately evaluate the aircraft's performance capabilities relative to the terrain's topography and altitude.
- The pilot's judgment was a contributing factor, as the maneuver was initiated at a speed that was already trending below the necessary threshold for the turn.
- Inadequate flight planning contributed to the accident, specifically the lack of reconnaissance or detailed terrain analysis for the hilly area.
- The use of a fixed-pitch propeller, which the pilot found difficult to manage during the power loss, limited the ability to regain airspeed.
- The aircraft's engine had been modified for ethanol use without official approval or updated performance data for the pilot.
- The aircraft manual lacked essential data concerning stall speeds under varying configurations and environmental conditions.