What happened
On February 26, 2019, a Bell 412, registration EC-MAQ, operated by Babcock MCS España S.A.U, was engaged in aerial firefighting operations near Belmonte, Asturias. The aircraft was performing its second flight period of the day, tasked with transporting water to combat active wildfires.
During a water refilling maneuver in a section of the Narcea River near Llongoria, the crew attempted to fill the helibucket in a river pool. While maintaining a hover, the aircraft drifted backward by approximately 32 meters. This movement caused the tail rotor to strike nearby vegetation along the riverbank. Upon detecting the impact, the pilot immediately reduced power and performed an autorotation, bringing the helicopter down to a level attitude on the riverbed, where the water depth was approximately one meter.
Both occupants of the aircraft were uninjured and were able to egress the aircraft on their own.
The investigation
The investigation examined the flight's sequence of events, the crew's adherence to operational procedures, and the environmental conditions at the site. Investigators analyzed GPS data from the aircraft's fleet tracking system, which revealed that the crew had not performed the required high or low reconnaissance orbits for the chosen refilling point, as mandated by the company's Operations Manual.
Technical analysis of the river conditions indicated a water current speed of approximately 1 m/s. The investigation also noted that the pilot's visual references were compromised; the sun was positioned at an angle of 27 degrees to the left and relatively low (36.3 degrees above the horizon), and the pilot's primary visual references were distant. Furthermore, the investigation found that the crew did not follow the standard operating procedures (SOPs) for approaching the refilling site.
Findings
- The selection and reconnaissance of the water refilling points were not conducted in accordance with the company's established procedures.
- The refilling maneuver took place in shallow water (approximately 1 meter deep) with an active current.
- The aircraft drifted 32 meters backward during the hover, leading to the tail rotor impact with vegetation.
- The pilot's emergency response, including the decision to perform an autorotation and the subsequent evacuation, was executed correctly and in accordance with the aircraft's flight manual.