Three United States crew members have died after their water-bombing aircraft crashed while fighting bushfires in the Snowy Mountains region of NSW, premier Gladys Berejiklian has confirmed.
The NSW Rural Fire Service said local ground crews lost contact with the C130 Hercules in the Snowy Monaro region on Thursday afternoon.
NSW Premier Gladys Berejiklian confirmed the aircraft - which was owned by a private company and contracted by the fire service - had crashed killing three people.
The plane - which could carry 15,000 litres of water - was operated by Coulson Aircrane which is based in Canada.
"All three occupants on board were US residents," RFS commissioner Shane Fitzsimmons said in Sydney, noting the cause of the crash is unknown.
"Tragically there appear to be no survivors as a result of the crash. It's impacted heavily with the ground and initial reports are that there was a large fireball."
Five road ambulances and two rescue helicopters joined the search for the plane after receiving reports of a plane crash in Peak View, a NSW Ambulance spokeswoman said earlier in the afternoon.
“It was operating as it routinely does with water bombing activities and we simply lost contract with the machine and the flight tracker we used stopped,” Mr Fitzsimmons said.
“It was very difficult to locate the wreckage of the plane and it was some hours after we lost contact and after we had the reports from the field of witnessing a crash that we were ail to locate and get some vision of the crash scene,” he said, noting the area is still an active fire ground.
Mr Fitzsimmons said the plane had been used in NSW for a number of years under contract.
The Australian Transport Safety Bureau's investigation will include an examination of the crash site and debris before the aircraft and the bodies are retrieved.
Ms Berejiklian said the crash was a "stark and horrible reminder" of the dangerous conditions facing firefighters on a daily basis.
A flight radar website suggests the tanker took off from the Richmond RAAF base northwest of Sydney before heading south to the Snowies on Thursday.
High temperatures increase bushfire conditions
A return of hot and windy conditions resulted in seven bushfires being elevated to emergency warning level across NSW and the ACT on Thursday afternoon as temperatures soared into the 40s.
Blazes at Clyde Mountain and Badja Forest on the South Coast, Adaminaby in the Snowy Mountains and Big Jack Mountain and Glen Allen in the Bega Valley area remain at emergency level along with another fire burning near Canberra Airport.
The fire at Box Hill in Sydney's northwest was downgraded to "watch and act" after 1pm.
Although fire grounds across the state have received rainfall in the past week, hot temperatures and high winds on Thursday led to an increase in fire activity.
Temperatures reached 42C in western Sydney at Penrith and Richmond and further inland at Coonamble and Bourke.
Seven NSW fire regions stretching from the Queensland border to the Victoria border are under total fire bans including greater Sydney. All seven regions were deemed to have a "severe" or "extreme" bushfire risk.
There were 84 fires burning across NSW with 40 yet to be contained at 3pm.
"Today will be a return to the bad old days we've seen over the course of the past few months," NSW Emergency Services Minister David Elliott told reporters on Thursday morning.
"Our appeal, of course, is for people to ensure they remain vigilant."
RFS Commissioner Shane Fitzsimmons said conditions on the ground had improved over the past week due to rainfall but not all fire-affected communities had enjoyed a drenching.
The commissioner predicted fires on Sydney's perimeter - including the large Gospers Mountain and Green Wattle Creek fires - had the potential to deteriorate again.
The unprecedented blazes in NSW have killed 21 people this fire season and razed more than 2000 homes.
Crew honoured as heroes
Numerous people took to social media to pay tribute to the three crew members after Mr Fitzsimmons broke the tragic news.
“Forever in our hearts. A tragic day for Australia and USA. RIP heroes,” one person wrote.
“This is awful. Devastating,” another said.
“This is a huge tragedy. I'm so sorry for their loved ones. The people who fight the fires are immensely brave,” a third wrote.
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