Orroral Valley bushfire inquiry in ACT Coroner's Court adjourned as chief coroner Lorraine Walker contracts COVID

ACT Coroner's Court emails on Tuesday morning said the circumstances meant Ms Walker "is unable to continue with the hearing today".

"Practitioners and others attending the courtroom are encouraged to monitor for symptoms and take all reasonable precautions," one of the emails reads.

The inquiry into the fire, which tore through about 80 per cent of the Namadgi National Park, came before the court on Monday when it heard that an MRH90 Taipan helicopter codenamed ANGEL21 made an unplanned landing in a remote area of the park about 1.30pm on January 27, 2020 for a "whiz break".

At the time, the Australian Army aircraft was being used to conduct a reconnaissance exercise with the ACT Emergency Services Agency as part of the Commonwealth's Operation Bushfire Assist.

Kylie Nomchong SC, The counsel assisting Ms Walker, on Monday said the Commonwealth conceded the fire was sparked by the aircraft's searchlight, which had reached about 550 degrees celsius, after it landed on dry vegetation.

She said there was a live issue about when the army advised the territory's emergency services about the fire's ignition, the manner of the ignition, and the coordinates of the fire.

Ms Nomchong said the brief of evidence contained no material that those onboard the aircraft "notified anyone in the ESA command centre of the fact that they were intending to land in the Orroral Valley or the fact that they had landed or the fact that they had ignited the fire."

Played to the court was an in-flight recording in which one of the crew members said "What are the chances of a whiz break?" about two hours into the exercise.

The co-pilot, also a major, then sought authorisation to land "for the guys to get out and have a piss".

After making the unplanned landing and disembarking, the audio recorded "we've started a fire, we've started a fire" and "turn the searchlight off" before the crew decided to fly to Canberra Airport.

The two pilots - one of whom was the captain - gave evidence on Monday in relation to their roles, including not immediately informing air traffic control or the ACT Emergency Services Agency about igniting the fire.

The captain admitted he did not do so because "in the triage of things going on", including the safety of those onboard and trying to land a damaged aircraft, it was a lower priority.

"Pretty much all of my brain space was dedicated to monitoring systems in the aircraft," he said.

He said his decision not to report the fire while still airborne was not a conscious decision.

The co-pilot denied knowing the temperature of the searchlight could reach 550 degrees celsius.

He said it was his decision to turn it on and keep it on despite there being no poor visibility because it helped with "traffic de-confliction".

He said "correct" about no one onboard having direct communication with a Defence liaison officer embedded within the emergency services agency.

A non-publication order has been placed on the names of all Defence personnel onboard the aircraft.

The ACT emergency agency had tasked the Defence Force with aerial reconnaissance to examine a network of remote helicopter landing zones in the territory's west.

The goal was to determine if these zones were still capable of deploying firefighters and other resources in case of a bushfire.

A concurrent task was remediating the zones and other bushfire mitigation activities, including improving containment lines, if needed.

The Commonwealth provided ANGEL21, which was based at the RAAF base at Richmond near Sydney, after the ACT requested for non-financial help to help identify new hotspots and monitor surrounding fires in NSW during the 2019-20 summer season.

The inquiry was set to run until Friday and listed a number of Defence personnel and ACT Emergency Services Agency commissioner Georgeina Whelan as witnesses.

A date for the inquiry in 2023 will be set.

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