What happened
On August 2, 2023, at approximately 17:55 UTC, a Robinson R44 II helicopter, registration PP-PVC, was conducting a private flight in the vicinity of Delfinópolis, Minas Gerais. The flight originated from an unregistered area in Cravinhos, São Paulo, with the intention of visiting a friend's property.
As the pilot approached the destination, they decided to deviate from the direct route to fly over a nearby reservoir. The pilot reported that the water surface was exceptionally calm and lacked significant waves. During this low-altitude approach, the aircraft's skid inadvertently struck the water surface, leading to a collision and the subsequent total submersion of the helicopter. The aircraft sustained substantial damage, though the pilot emerged from the wreckage uninjured.
The investigation
CENIPA's investigation confirmed that the pilot was properly licensed and held a valid medical certificate. The aircraft was also in compliance with all regulatory requirements, including a valid airworthiness certificate, up-to-date maintenance logs, and operation within proper weight and balance limits. Meteorological conditions at the time of the accident were well above the minimum requirements for VFR flight.
The investigation focused on the pilot's decision to fly over the water and the physiological effects of the environment. Investigators analyzed the impact of flying over a reflective, featureless surface, which can lead to significant sensory errors. The investigation also reviewed compliance with ICA 100-4, which regulates minimum altitudes for helicopter operations to ensure safety.
Findings
- The primary cause of the accident was the occurrence of visual illusions caused by the calm, reflective surface of the reservoir, which obscured the pilot's perception of true altitude.
- The pilot's decision-making process and flight planning contributed to the accident, specifically the choice to execute a flight profile over water rather than proceeding directly to the landing site.
- Factors such as impaired perception, judgment, and the lack of visual references (visual stasis) played a critical role in the unintended descent.
- The pilot's attitude and application of flight controls during the approach were identified as contributing factors.