Three people were killed Thursday when a water tanker plane crashed in the Snowy Monaro region, some 110 kilometers (68 miles) south of Canberra, the New South Wales (NSW) Rural Fire Service said.

"There appear to be no survivors as a result of the crash down in the Snowy Monaro area," Rural Fire Service Commissioner Shane Fitzsimmons said. "It's impacted heavily with the ground and initial reports are that there was a large fireball associated with the impact of the plane as it hit the ground."

The Canadian-owned C130 Hercules air tanker was sent to assist with putting out a fire in a nearby national park.

"Unfortunately, all we've been able to do is locate the wreckage and the crash site and we have not been able to locate any survivors,'' Fitzsimmons said, adding that all three victims were American residents and that they did not yet know why the tanker crashed.

"There is no indication at this stage of what's caused the accident,'' Fitzsimmons said.

'Overloaded'

Geoffrey Dell, an expert in accident forensics at the Central Queensland University, said the aircraft may have been "aerodynamically overloaded" and turned or changed altitude too fast for its load, causing it to lose altitude at a rapid rate.

"It's designed to operate to certain G (gravity)-limits, and if you go over those, different parts of the structure can be overstressed," said Dell.

A spokesperson for Australia's Civil Aviation Safety Authority said the tanker went into a valley to deliver the retardant and didn't come out. 

Tracking website Flightradar24 showed the path for an air tanker suddenly stopping in Peak View, south of Canberra.

Peak View is close to an out-of-control fire in the Wadbilliga National Park, the fire service said.

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Grounding of fleet

Fitzsimmons said the aircraft had been leased by Canadian aerial firefighting company Coulson Aviation, which had another C130 Hercules working in the bushfires operation.

According to Fitzsimmons, Coulson had grounded its air tanker fleet following Thursday's crash, as it awaits a review to find out whether there was a systemic issue such as a fuel problem.

"The accident is reported to be extensive and we are deeply saddened to confirm there were three fatalities," Coulson said in an emailed statement, according to Reuters.

The Australian Transport Safety Bureau announced it was sending investigators to the crash scene to collect evidence and analyze available data. The investigation team is also expected to review weather information and interview any witnesses

The bureau said it would send out a preliminary report in about 30 days. Should a serious safety issue be identified during the probe it would immediately inform relevant stakeholders.

Suspension of commercial flights

The crash came as bushfires approached Canberra — Australia's capital — forcing its airport to suspend commercial flights and give priority to fire-fighting planes.

"Arrivals and departures are affected due to aviation firefighting operations," said the airport authority.

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The capital territory's emergency agency warned residents of three suburbs on Canberra's eastern side to "seek shelter," warning motorists that driving would be "extremely dangerous and potentially deadly."

Across NSW firefighters are tackling a total of 101 bushfires while to the south in the neighboring state of Victoria there were 17 blazes on Thursday.

'Damaging winds' forecast

Australia's Melbourne-based Bureau of Meteorology warned that despite recent rainfall, which brought relief to some areas scorched since Christmas, "damaging winds" were again driving up the fire danger in some regions.

Smoke palls and hazardous air quality levels were again forecast for Sydney.

Melbourne, now hosting tennis' Australian Open, had improved air quality after rain. Last week, a player collapsed in a coughing fit during qualifying rounds.

Devastating losses

Since September, wildfires have killed at least 31 people and an estimated 1 billion native Australian animals, gutted 2,500 homes and scorched bushland one-third the size of Germany. 

Australia's tourism industry is facing major revenue losses and economists estimate the bushfire season monetary cost could be as high as A$5 billion (€3 billion/$3.3 billion).

Victoria state's government said Thursday it would spend A$17.5 million immediately to help save wildlife mostly at risk, including Australia's unique long-footed potaroo and large brown tree frog.

mvb, ipj/sms (Reuters, AP, AFP)