Technical assistance to the Civil Aviation Authority of New Zealand - Data recovery from a navigational GPS unit following a collision with terrain - Hughes 500D, ZK-HNA, on 13 December 2013

On 13 December 2013, a Hughes 500D helicopter, registration ZK-HNA, was flying from Rat Point on Lake Wakatipu, 16 km South West of Queenstown, New Zealand, to Dumpling Hut on the Milford Sound walking track. When the helicopter did not arrive at its
destination, the alarm was raised, and after a short search, the wreckage of the helicopter was found near the top of the Glade Burn Valley. The pilot, who was the sole occupant of the helicopter, had been fatally injured.

The Civil Aviation Authority of New Zealand (CAANZ) is undertaking a formal investigation into this accident. As part of that work, the CAANZ requested technical assistance from the Australian Transport Safety Bureau (ATSB), in the recovery of data from a damaged
navigational GPS unit recovered from the accident site. To protect the information supplied by the CAANZ, and any data recovered from the GPS unit, the ATSB initiated an investigation under the provisions of the Transport Safety Investigation Act 2003.

Following examination and disassembly, it was evident that the GPS unit had sustained circuitry damage sufficient to prevent its download by conventional means. Subsequently, the discrete device (chip) containing the track memory was identified, removed, and a raw data file downloaded using specialised techniques. Decoding of the raw information showed that the entire track memory had been recovered, including the accident flight and several previous flights. The data and a report detailing the download procedure was provided to the CAANZ on 26 June 2014 for use in their investigation.

For further information on this occurrence and investigation, please contact the Civil Aviation Authority of New Zealand.

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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.