What happened
On January 15, 2023, at approximately 08:50 UTC, a Thrush S2R-H80 (registration PR-YLA) was performing a takeoff from an agricultural landing strip at Fazenda Santa Joana, in Boa Esperança do Sul, Brazil. The aircraft, operated by Aplimax Aeroagrícola Eireli, was engaged in an aerial application mission.
During the takeoff roll, the aircraft climbed an incline on the runway. As the pilot reached the highest point of the terrain, the sun, positioned to the front-left, suddenly struck the pilot's face. This intense solar glare caused a momentary visual impairment, preventing the pilot from perceiving the end of the runway. Consequently, the aircraft continued on its path without a sufficient climb command, causing the spray boom to collide with a sugarcane crop at an altitude of approximately one meter. The pilot was uninjured, but the aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the operational environment and the pilot's decision-making process. The investigation found that the takeoff was performed in an uphill direction (uphill climb) rather than utilizing the downhill slope of the runway, which would have facilitated faster acceleration and lift. This decision was likely influenced by the fixed position of ground support equipment, specifically a refueling truck parked at the lower end of the strip.
The investigation also reviewed the operator's Safety Risk Management (GRSO) documentation. It was noted that the runway's declared headings were approximately 60 degrees offset from the actual runway axis. Furthermore, the risk management plan failed to account for the sun's position relative to the terrain elevation or the risk of visual illusions caused by glare. While the pilot was fully qualified and the aircraft was airworthy, the investigation highlighted that the lack of a more detailed risk assessment regarding solar positioning contributed to the event.
Findings
- Visual illusions caused by sudden solar glare and subsequent retinal adaptation.
- Impaired judgment regarding the takeoff direction, opting for an uphill takeoff instead of utilizing the downhill slope.
- Inadequate risk management as the operational safety plan did not contemplate the danger of solar glare or the specific terrain elevation changes.
- Operational inflexibility caused by the fixed positioning of refueling equipment at the lower end of the strip, which influenced the pilot's takeoff choice.
- Inaccurate runway data in the safety management documents regarding the actual runway headings.