Missing chopper pilot: Navy sub called in

Mike Mehrtens was spraying gorse in his Hughes 500 when he disappeared. Photo / Supplied

A remote-operated navy submersible may be used to recover the wreckage of a helicopter that crashed into deep water on a remote south Canterbury lake, police say.

Michael Graeme Mehrtens, 35, was the only occupant of the Hughes 500 helicopter which is believed to have crashed near Breaksea Bay in Lake Sumner on Monday afternoon.

Police said the helicopter was thought to be in deep water, out of the reach of dive teams.

Inspector Craig McKay said searchers had called on the navy to provide equipment and expertise to aid the recovery operation.

They were looking at using a remote-operated submersible vehicle with a grappling hook attached to manoeuvre the crashed chopper into shallower water, he said.

"We are now reasonably confident that we know the approximate location of the aircraft, based on the oil slick and debris that has been found so far.

"We believe the lake in this area is up to 125 metres in depth - which is well beyond the level at which our conventional dive squad can operate."

Mr McKay said search teams had been stood down after confirming the likely location of the helicopter.

"As soon as further assistance is available we will resume the operation to recover the pilot and the aircraft, if this can be achieved."

Rob Kittow, the principal of Way To Go Heliservices Ltd, confirmed yesterday that the aircraft was one of his company's.

The company was supporting the search and rescue effort by emergency services, and was co-operating with investigating authorities, he said.

Staff and friends were deeply shocked and were doing everything possible to support Mr Mehrtens' family and friends.

"We are a close-knit company and Mike was a highly valued and much-respected team member,'' Mr Kittow said in a statement.

"The aircraft was on a routine agriculture operation and there is nothing at this stage to indicate the cause of the accident."