Firefighting aircraft near miss blamed on miscommunication
By Andrew Curran
The Australian Transport Safety Bureau (ATSB) said an operational misunderstanding and inadequate situational awareness were behind two firefighting aircraft coming into proximity while attempting to extinguish a bushfire in the Victorian High Country earlier this year.
On May 5, the ATSB released its final report into the incident. The report detailed a January 18 event in which the pilot of a Bell 212 helicopter, VH-KHO (msn 31181), was forced to change course and descend after sighting a PZL M18B air tanker, VH-VWF (msn 1Z027-26), ahead on a conflicting track.
The two aircraft passed within 500 metres horizontally and 400 feet vertically of one another, with the air tanker pilot unaware of the helicopter. Both aircraft were among ten fixed- and rotary-wing aircraft fighting fires northwest of Razor Ridge near Mount Hotham, which had been burning for three days.
A complex operating environment for firefighting aircraft
Aircraft are regularly used to fight bushfires in Australia, especially in remote and inaccessible terrain. Often, multiple aircraft operate at low altitudes and varying airspeeds in challenging environmental conditions. These factors, combined with high traffic density, increase the complexity of flight crew tasks.
The air tanker pilot described the Razor fireground as highly technical, with “cliffs, steep escarpments, tumbling air and severe turbulence”, as well as a complex mix of aircraft.
The Bell 212 was tasked with rappelling firefighters onto the northern side of the mountain, while the air tanker was dropping retardant on the southern side. Elsewhere, an air operations supervisor in a Eurocopter AS350 helicopter was responsible for the safe and efficient tactical coordination of all aircraft.
The air tanker pilot told ATSB investigators that inbound pilots could hear communications from the air operations supervisor, but generally not from other aircraft until they were within the fireground due to terrain shielding. He also noted that pilots entering from the north would have been unable to see aircraft in the south because of smoke.
The Razor fireground map showing firebombing drops, the holding area and virtual fence. Source. ATSB.
Pilots required to use see-and-avoid principles
While radio communications are used to maintain situational awareness, pilots are also required to maintain vigilance using ‘see-and-avoid’ principles.
The ATSB report found that the air operations supervisor did not provide tracking instructions to the Bell 212 pilot as it approached the fireground.
Additionally, the Bell 212 pilot believed they had separation assurance and were cleared to conduct rappelling operations, leading to the conflict with the air tanker.
Despite communications on the fireground’s common traffic advisory frequency, both pilots were unaware they were on conflicting tracks. However, the ATSB noted that the Bell 212 pilot took evasive action once the air tanker was sighted.
The report also found that the Bell 212 pilot did not inform the air operations supervisor of the incident and continued tracking north through the fireground without confirmed separation from other aircraft.
The helicopter pilot had not previously operated at the Razor fireground and had not expected to operate there that day.
However, when nearing the fire, the pilot contacted air dispatch twice, first at ten nautical miles and again at five nautical miles, stating words to the effect of “we are five miles out, are we okay to approach?” and confirming which aircraft (if any) were in the area.
The air operations supervisor advised that they were cleared to enter the fire zone. The supervisor later told investigators that he was were aware air tankers were operating in the area but expected them to be on the other side of the mountain.
Meanwhile, the air tanker pilot understood that they had been cleared to leave their holding area and proceeded southwest to drop retardant, bringing them into conflict with the helicopter.
On January 19, the helicopter operator reported the “near miss”, triggering the investigation.
Closest proximity of the air tanker to the Bell helicopter. Source. ATSB.
ATSB concludes there was a communication misunderstanding
The ATSB said there was a misunderstanding between the Bell 212 pilot and the air operations supervisor.
“When the air attack supervisor cleared the Bell 212 to enter the fireground, they expected the helicopter to first track east of the fireground so they too could enter from the north,” said ATSB Director of Transport Safety Stuart Macleod.
“However, the air attack supervisor did not specifically instruct the helicopter to enter this way, and the pilot instead entered from the south, believing they had separation assurance and were cleared to conduct rappelling operations.”
“While the reason the pilots were unaware of one another could not be conclusively determined, several factors may have limited the crews’ ability to identify each other’s presence,” Macleod added.
“The effectiveness of radio communications can be limited by factors such as the number of aircraft operating on the frequency and terrain shielding. Ultimately, see-and-avoid procedures were effective in maintaining separation.”
The ATSB concluded that the air operations supervisor did not provide tracking instructions to the Bell 212 pilot when approaching the fireground.
Additionally, the pilot believed they had separation assurance and were cleared to conduct rappelling operations, resulting in the separation conflict with the air tanker conducting firebombing operations.
Despite communications on the advisory frequency, both pilots remained unaware of the conflict. However, upon sighting the aeroplane, the Bell 212 pilot took action to maintain safe separation.
Helicopter pilot failed to immediately report incident
While it did not directly contribute to the occurrence, the ATSB noted that the helicopter pilot did not immediately notify the air operations supervisor of the incident. The report did not specify why there was no immediate notification.
“Aerial firefighting is a critical capability for managing and suppressing bushfires in Australia, often involving multiple aircraft operating at low altitudes and varying airspeeds in challenging conditions,” Macleod said.
“As such, it is vital that pilots understand where other aircraft are operating and promptly communicate any issues so that all participants share a common mental model of the fireground.”
You can read the full ATSB report here.
Photo: AI-Generated
Contact the writer: andrew@aerosouthpacific.com