Incident Overview
A helicopter (Helitak 368) and an airplane (Bomber 359) came within approximately 500 meters horizontally and 400 feet vertically of each other during firefighting operations. The helitak pilot had not previously been to the fireground and was unaware of the operational tactics in place, which involved aircraft holding and entering from the north. The air attack supervisor (AAS) expected the helitak to track east of the fireground and enter from the stack in the north, but did not specifically instruct the pilot to do so. The helitak pilot believed they had been cleared to enter the fireground and assumed the AAS had ensured no conflict with other aircraft, allowing them to commence reconnaissance and rappelling from the south.
Sequence of Events
Helitak 368 tracked north through the fireground without the AAS's awareness. Meanwhile, Bomber 359 was on a drop run. Both aircraft were monitoring the Fire Common Traffic Advisory Frequency (Fire-CTAF). Any clearances issued by the AAS for Helitak 368 to enter the fireground and for Bomber 359 to conduct a drop would have occurred within a 3-minute period and been broadcast on that frequency. Bomber 359's pilot also broadcast twice (on and off the drop) during the run. However, neither pilot was aware of the other's presence or increasing proximity.
A rappel dispatcher aboard Helitak 368 sighted Bomber 359 and instructed the pilot to go left. When the helitak pilot saw the airplane, they maneuvered to increase separation. The two aircraft passed within about 500 meters horizontally and 400 feet vertically of each other.
Communication and Coordination Issues
The reason neither pilot recognized the conflict could not be conclusively determined. Potential factors included the presence of other aircraft on the fireground generating additional communications on the Fire-CTAF, terrain shielding that may have affected the ability of both pilots to hear all transmissions, and the helitak pilot's unfamiliarity with operational tactics, reporting points, and geographical references used in communications. This likely prevented them from understanding that Bomber 359 was operating in their vicinity.
Aftermath
The pilot of Helitak 368 did not alert the AAS to the incident but continued through the fireground. This increased the risk of a subsequent separation issue, as the AAS still expected the helicopter to be flying east of the firebombing area. However, no subsequent separation issues were reported. Because the AAS was unaware of the incident at the time, required post-incident actions—including advising the incident controller and potentially standing down personnel—were not conducted.