The helicopter's engines began screaming, its rotors seemed to droop, and the pilots were heard to swear.

"It was either 'Oh shit' or 'Oh f..k, then I heard them start talking to each other really quickly and I could tell they were trying to sort it out," one of the Black Hawk's crew yesterday told the board of inquiry into last November's crash off Fiji, which claimed the lives of two Australian soldiers, pilot Captain Mark Bingley and Special Air Service Trooper Joshua Porter.

The crew member, codenamed Trooper Charlie, told the hearing the flight had been without incident but moments before the Black Hawk was to land there were signs the aircraft was in trouble. "When I looked out, I noticed that the rotors ... weren't as high as they usually were. They were drooping down, almost level or maybe below me," said Trooper Charlie, who was seated at the rear left door of the six-tonne helicopter.

"White puffs of mist were coming off the rotors ... it felt like the rotors were spinning and not grabbing on to anything."

The chopper then hit the deck of the ship with a violent thud, losing its tailshaft in the process, before plunging into the ocean.

Having not been fitted with flotation devices, the Black Hawk began to sink immediately, forcing the 10 soldiers on board to scramble for their lives.

Trooper Charlie, who sustained spinal injuries in the crash, told the inquiry of the frightening descent and his amazing escape.

"It felt like I was hanging out of a car at 100 or 200km/h," he said of his underwater ordeal.

But despite escaping from the chopper at an estimated depth of about 30m, Trooper Charlie realised he was being pulled towards the ocean floor by his communications headset, which was attached to the aircraft. He quickly released the strap on his helmet, and swam to the surface.

Another crew member, codenamed Trooper Echo, said he was underwater for almost 45 seconds. After hauling himself out of the helicopter, he began swimming to the surface but came up directly beneath Kanimbla, forcing him to swim further to safety.

Earlier, the Australian Defence Force's deputy director of safety and airworthiness, Pierre Blais, who led the ADF investigation into the crash, told the inquiry several of the survivors reported having difficulties with the helicopter's life-support equipment.

The inquiry continues.

[MG Note: Military aviation is always dangerous and flying on and off ships is especially so.  Things can go mightly wrong in the blink of an eye and in two blinks someone has died.  My condolences to the families of the gallant troopers who were killed in the accident. 

When a helicopter goes into the water, it typically goes inverted and screws up your senses so you do not know which way to go to get to the surface.  There is also a lot of interior junk in a helicopter that can trap you as the aircraft sinks.  Flight crews that fly over water are periodically subjected to simulated helicopter crashes in trainers in a pool with safety divers so that they will know how to react when the unimaginable happens.  In case the crew member becomes entangled or disoriented, the safety diver can rescue him so he can repeat the training exercise.  I hope that the passengers that have to fly in helicopters over water are given similar training.]