What happened
On August 25, 2022, during wildfire suppression operations in Lobeira, Ourense, two separate loss of separation incidents occurred involving multiple firefighting aircraft. At approximately 19:00 UTC, a formation of fixed-wing aircraft, including a Thrush Aircraft S2R-T6/60, registration EC-NET, was approaching a fire flank to perform water drops. Simultaneously, several helicopters were performing a "carousel" maneuver near a water loading point.
As the EC-NET aircraft approached the drop zone, it encountered a Bell 412 EP, registration EC-JXQ, head-on at a distance of less than 500 meters. Both the pilot of the EC-NET and the crew of the EC-JXQ performed evasive maneuvers, turning to the left. During this maneuver, the EC-NET aircraft overflew another helicopter, a Bell 412, registration EC-HZD, with a vertical separation of approximately 140 feet. No injuries were reported, and no aircraft sustained damage.
The investigation
The CIAIAC investigation examined the communications and coordination between the various aerial assets. The investigation focused on the actions of the air coordinator (operating an EC-MVU), the pilots of the fixed-wing aircraft from the Doade base, and the helicopter crews from the Tabuyo base.
Investigators analyzed radio communications and flight tracking data. It was noted that the terrain and hills surrounding the water loading point caused radio shielding, which hindered clear communication. The investigation also reviewed the Standard Operating Procedures (Schedules) of the operators involved, including Babcock, Plysa, and Airworks, specifically regarding radio discipline and message read-backs (collation).
Findings
- The air coordinator instructed the four helicopters in the carousel to remain at the water loading point to allow the fixed-wing aircraft to enter the area.
- Two helicopters, EC-JXQ and EC-HZD, did not acknowledge or read back the coordinator's instruction, and therefore continued their flight pattern toward the fire flank.
- The coordinator authorized the EC-NET formation to proceed with the drop despite not receiving read-backs from all participating helicopters.
- The deficient coordination and lack of message read-backs between the participating aerial assets resulted in the two consecutive loss of separation incidents.
- Reduced visibility due to smoke from the wildfire further complicated the operational environment.