A NSW inquest into the 2019-20 horror fire season resumed on Monday to examine their deaths.
Calls played to the inquest recorded the local incident controller telling the Rural Fire Service state area command aircraft were grounded on the morning of the crash.
"Let's just get LATs (large air tankers) up there and see what they can do," came the response.
Captain Ian McBeth, 44, first officer Paul Clyde Hudson, 42, and flight engineer Rick DeMorgan Jr, 43, were killed when their Lockheed EC-130Q LAT crashed northeast of Cooma in southern NSW on January 23, 2020.
The trio were experienced aviators and have been memorialised by the US National Fallen Firefighters Foundation.
Mr McBeth spent years as an aerial firefighter, including with the Wyoming and Montana Air National Guard branches.
He had performed 994 tanker drops across 3010 hours piloting C-130s.
"He had just handed in his resignation. This was Ian's last shift," counsel assisting the inquiry Adam Casselden SC said on Monday.
Mr Hudson and Mr DeMorgan both worked on C-130 planes during their respective careers with the US Marine Corps and Air Force, and had recently begun working for Coulson Aviation.
Coulson was among companies that provided the 38 privately owned and operated aircraft engaged by the RFS through the National Aerial Firefighting Centre during the fire season.
The three men were hailed as heroes and posthumously awarded an RFS commissioner's commendation.
NSW State Coroner Teresa O'Sullivan began the hearing on Monday by praising their bravery and generosity for coming to protect Australia.
She acknowledged the presence of Mr McBeth and Mr Hudson's widows. Mr DeMorgan's family was unable to attend.
The inquest heard on a day of extreme fire danger, when aircraft had been grounded for several hours already, two LATs were tasked to southern NSW from Richmond RAAF base, without any supervising aircraft, about 11am on January 23, 2020.
Mr McBeth had a US "initial attack" firefighting qualification certifying him to drop fire retardant without a supervising aircraft or "birddog".
The RFS does not have an equivalent certification but recognises the overseas one, Australian Transport Safety Bureau investigator-in-charge Laura Henwood told the inquest.
A Boeing 737 LAT, known as B137, took off first at 11.27am, followed by the C-130, dubbed B134, about half an hour later.
A birddog pilot rejected the task one minute before B134 took off.
B137 dropped retardant on a fire at Adaminaby at 12.20pm, refusing further tasking to the site 12 minutes later.
The two planes came into communication range of one another about 12.35pm just outside Canberra.
The pilot of B137 told authorities in a sworn statement he communicated the deteriorating conditions at Adaminaby to Mr McBeth.
"I'll go take a look," he responded.
About 1pm, B134 radioed to say it would head to the nearby Good Good fireground due to the poor conditions at Adaminaby, and again three minutes before it crashed to say it would carry out multiple runs on the fire.
The plane likely stalled as it climbed after dropping fire retardant, a separate ATSB investigation found.
The inquest will aim to provide answers to the family of the three American firefighters, while assessing how a similar incident could be avoided as Australia becomes increasingly reliant on LATs to fight fires.
The hearing continues.
