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A pilot’s difficulty experienced while escaping an aerial firebombing helicopter after it had impacted and sank in a reservoir following an engine failure highlights the potential value of emergency breathing systems, an ATSB investigation highlights.
Using a 1,400 liter water bucket on a 100 foot long-line, the UH-1H helicopter was collecting water from the Ben Boyd Reservoir to assist bush-fire clean-up operations near Eden on the NSW south coast on Jan. 9, 2020.
As the helicopter arrived in a 100 ft hover over the water, the pilot heard a grinding noise. In response they jettisoned the long-line and bucket and applied forward cyclic to fly towards land.
However, the helicopter experienced a complete loss of engine power and immediately descended into the water. On impact, the helicopter’s chin-bubbles fragmented, and the helicopter rolled inverted, filled with water, and sank.
Unable to open the pilot, co-pilot, or sliding cabin doors, the pilot punched out the right sliding door rear window and escaped the helicopter. The pilot inflated their lifejacket and swam to shore, surviving the accident with minor injuries.
While the pilot was not carrying, and was not required to carry, an emergency breathing system (EBS), during the escape they found a pocket of air in the cabin, allowing them to take ‘a couple of breaths’.
“Research into helicopter overwater accident survival consistently reports drowning as the leading cause of fatalities, due to the inability of the occupant to hold their breath long enough to escape,” said ATSB Chief Commissioner Angus Mitchell.
“In this accident, the pilot found an air pocket in the cabin, which enabled the escape time to extend beyond the initial breath-hold time. While it could not be determined if the pilot would have drowned without the air pocket, it would have increased that likelihood.
“Although the pilot was able to successfully escape from underwater after finding the air pocket, an emergency breathing system would have reduced the risk of drowning.”
The pilot had conducted a number of helicopter underwater escape training (HUET) courses, a condition of the operator’s contract with the NSW Rural Fire Service. At interview, the pilot told ATSB investigators they ‘would have been dead without HUET’.