What happened
On August 20, 2020, at approximately 18:20 UTC, an Air Tractor AT-502B, registration PR-BSR, was engaged in a specialized aerial firefighting mission near São Desidério, Bahia. The aircraft had departed from Aeródromo Fazenda Serrana to combat a fire approximately 22 NM away. After successfully dropping 1,500 liters of water on the fire, the pilot began the return flight to the base.
During the return leg, while flying at a very low altitude, the aircraft encountered a turbulent region. This turbulence caused the pilot to lose control of the aircraft, leading to a collision with the ground. The right wingtip made the initial contact with the terrain, and the aircraft came to a stop approximately 4/0 meters from the impact point. The aircraft sustained substantial damage, but the pilot emerged uninjured.
The investigation
CENIPA investigators examined the aircraft's maintenance records, the pilot's credentials, and the environmental conditions at the time of the accident. The investigation confirmed that the pilot was fully qualified, with valid medical and agricultural pilot certifications, and possessed significant experience in the aircraft model. The Air Tractor AT-502B was found to be airworthy, with all maintenance logs up to date, and was operating within its proper weight and balance limits.
Investigators also analyzed the meteorological conditions. While no significant widespread weather phenomena were reported, the presence of dust devils (small, rotating columns of air) was observed by the investigation team during the initial response. The high temperatures and dry ground in the region were highly conducive to the formation of such phenomena. Furthermore, the investigation noted that the pilot was flying at an altitude between 100 and 150 feet, which was below the minimum required altitude of 500 feet for VFR operations in that area.
Findings
- The pilot's judgment of piloting contributed to the accident by choosing to fly at an altitude below the regulatory minimum of 500 feet.
- The aircraft encountered turbulence, potentially caused by dust devils, which led to the loss of control.
- The low altitude of the flight prevented the pilot from having sufficient margin to recover the aircraft after the encounter with turbulence.