Emergency services may not have been able to be alerted any earlier to the Orroral Valley fire in January last year, with new details emerging about the circumstances.
Crew of the MRH-90, which sparked the fire, had an immediate responsibility to ensure the safety of life on board and aircraft, Defence said on Thursday following the release of photographs taken from onboard.
The photographer could not have alerted emergency services any earlier, Defence claims, due to restricted radio traffic while on board.
The photographs were taken by a passenger, not a member of the operating crew of the MRH-90. That passenger was an ADF member but "passengers do not have the means of external communication to air traffic control or civil services while aboard an aircraft," the Defence spokesperson said. "Only the aircrew are on external radio nets while in flight."
The role of the passenger was part of the reconnaissance team identifying potential landing zones in the Namadgi National Park as part of the ADF's support to Operation Bushfire Assist.
"Addressing the potentially catastrophic risks to crew and aircraft was the crew's immediate priority, and the focus of their radio traffic during the flight to safety," the spokesperson said.
Defence claims ACT Emergency Services responded within 20 minutes of the fire's ignition, immediately following the crew's emergency landing at Canberra Airport.