What happened
On June 29, 2015, at 12:25 UTC, an Eurocopter AS350 B3, registration CS-HMH, was engaged in firefighting operations near Paços de Ferreira, Portugal. After successfully delivering a five-member rescue brigade to a fire site, the pilot proceeded to a small quarry pond at Pedreira do Lamoso to refill the aircraft's suspended water bucket.
While performing the final approach to the water, the pilot was suddenly dazzled by the intense reflection of the sun on the water's surface. This solar glare occurred at a time when the sun was near its zenith, maximizing the intensity of the reflection. The pilot attempted to execute a go-around by pulling the collective up, but the maneuver was initiated too late. The suspended bucket struck the water first and filled rapidly, pulling the aircraft down. The helicopter subsequently impacted the water at a high rate of descent and sank. The impact caused the fuselage to roll onto its right side, leading to the collapse of the main rotor and a fuel leak into the pond. The pilot managed to escape the wreckage without serious injuries.
The investigation
The GPIAAF investigation examined the flight sequence, the environmental conditions, and the pilot's actions. The investigation confirmed that there were no mechanical failures on the aircraft. Investigators analyzed the timing of the accident, noting that the sun's position at midday during that season created a particularly dangerous angle of reflection. The investigation also considered the pilot's familiarity with the specific site and the fact that this was the first mission of the 2015 firefighting season.
Findings
- The primary contributing factor was the pilot being dazzled by sunlight reflecting off the water during the most critical phase of the final approach.
- The timing of the accident, with the sun at its zenith, increased the intensity of the solar glare.
- The pilot was operating at a specific site for the first time, which contributed to the lack of familiarity with the terrain.
- The accident occurred during the pilot's first mission of the new firefighting season, meaning the crew was not yet fully acclimated to the seasonal flight routines and procedures.