Chopper crash: Detailed survey of lake bed to be carried out

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

A more detailed search of a north Canterbury lake bed will begin next week, after the wreckage of a missing helicopter was found there earlier this week.

The wreckage was located at a depth of 127 metres by a Navy remotely operated vehicle (ROV) on Monday.

The search was then suspended, but Inspector Craig McKay today said a more detailed sonar survey would commence next week.

Michael Graeme Mehrtens, 35, was the only occupant of a Hughes 500 helicopter that crashed near Breaksea Bay in Lake Sumner on Monday afternoon last week while spraying gorse for the Department of Conservation.

It is unknown if his body is still in the wreckage.

"We are now looking at options that will help us get a fuller picture of what is on the lake bed, and allow us to retrieve the helicopter and the missing pilot, if that is possible,'' Mr McKay said.

"As a first step we will bring the Police National Dive Squad back in with a Radial Sonar device. This will give us a more detailed scan of the debris field, and hopefully help to locate Mr Mehrtens.''

If the radial sonar was not able to find Mr Mehrtens, consideration would be given to bringing in specialist lake bed survey equipment to map the area.

If Mr Mehrtens was located the ROV would be brought in with a manipulator arm to retrieve the body.

Police hope to be back in the lake early next week.