Blackhawk Crash Inquiry

An Australian Defence Force Blackhawk helicopter had been briefed to approach a ship's deck from a relative angle and with a tailwind component that virtually guaranteed an accident, an ADF Inquiry was told today. In a graphic video taken from the deck of the HMAS Kanimbla the aircraft is seen in the initial stage of its approach and then, in the final six seconds descending very rapidly, as it's in the grip of vortex ring or "settling with power". Courtesy of the 15kt tailwind, the aircraft was descending within its own rotor downwash. That's a condition where increased power tends to accelerate the aircraft in a downward direction, the only escape being to incline the rotor disc via a forward cyclic stick input and accelerate horizontally out of the vortex - height permitting. In last November's accident off Fiji, the transition into the vortex ring condition was so rapid, it's likely that neither pilot realized it for what it was. After striking the deck hard and losing its tail-rotor, the rapidly rotating helo plunged off the far side of the deck into very deep water. Being an Army helo, the aircraft didn't have flotation gear and the troopers onboard escaped from as deep as 30m beneath the surface. Two died in the accident. Asymmetric Vortex ring, causing a rapid unrecoverable roll, is also the acknowledged Nemesis of the USMC's tilt-rotor Osprey. The video-clip can be viewed at this link