Rotor strike led to copter crash
Video sheds light on Port Hills firefighting tragedy
An interim report into the helicopter crash which killed Steve Askin as he helped put out February’s Port Hills fires has found the cables holding the monsoon bucket struck the tail rotor and damaged it, causing the craft to crash.
The Transport Accident Investigation Commission (TAIC) yesterday released its interim report into the crash.
On the afternoon of February 13, wildfires broke out on the Port Hills between Lyttelton Harbour and the southeastern suburbs of Christchurch.
That evening Askin was among those who helped survey the extent of the fires. The next day the 38-year-old flew in from Rangiora to rejoin the firefighting operation and was appointed the lead pilot for one group of helicopters because of his experience.
The former SAS soldier was at the controls of a Eurocopter AS350-BA machine.
His total helicopter flying experience was about 2350 hours, of which about 80 video camera strop hours was firefighting experience.
According to the report, about 2pm that day an abbreviated mayday call was heard by several pilots, but it was not clear on which radio frequency the call was made.
The supervisor asked for a roll call of all the aircraft involved, but Askin did not respond.
After a brief search, another pilot in the group found the helicopter wreckage on a steep slope near the head of a gully east of the Sugarloaf. Askin, who was awarded the New Zealand Gallantry Star for his service in Afghanistan, had died in the crash as he returned to the dipping pond to refill the monsoon bucket.
Evidence showed that the monsoon bucket suspension cables struck the tail rotor, damaging the rotor and causing the loss of the entire vertical stabiliser from the tail boom, the report said.
After the loss of the vertical stabiliser, the helicopter rolled to the right and descended until it hit the ground.
The damage to the tail rotor blades was consistent with them striking the wire suspen- hook
Amonsoon bucket vertical stabilser sion cables of the monsoon bucket where the cables were joined to the lifting strop. There was corresponding damage on the cable cluster.
A video camera that had been mounted under the forward fuselage, pointing back toward the monsoon bucket, recorded the entire flight. The video showed the bucket had flown up towards the tail while the helicopter was returning to the dipping pond.
The report said underslung loads flying back into the tail rotor was a known risk to helicopter sling operations.
In 41 per cent of the crashes reported in the past six years, the cause was the sling or cargo attached to the helicopter’s hook striking the helicopter, according to Eurocopter.
In the report the commission recommended the Civil Aviation Authority use the interim report, a service letter from Eurocopter on the dangers of carrying items below the aircraft on a sling and any other pertinent material to remind the aviation industry of the lessons learned from accidents involving sling loads, in particular the use of monsoon buckets.