A Navy submersible remotely-operated vehicle (ROV) is expected to start operating at Lake Sumner, in North Canterbury today in the search for a missing helicopter and pilot.

Canterbury Police operations manager Inspector Craig McKay says the ROV was expected to arrive on site at Lake Sumner on Thursday and Navy personnel are making preparations to support the ROV operation.

The Navy Operational Diving Team and the Police National Dive Squad will be putting rigid hull inflatable boats (RHIB) on to the water to provide a platform from which the ROV will be operated and monitored.

The RHIBs will be anchored as close as possible to the site where the helicopter is believed to be located - in 125 metres of water, offshore from Breaksea Bay on the northern side of the lake.

'All being well, we will be able to get the actual search under way this morning.”

Craig says it is not possible to tell how long it will take to locate the Hughes 500 helicopter, or even if it will be located.

'There are so many variables in this operation. We are working in very deep water, and while we are reasonably confident we know the approximate location of the aircraft, there are no guarantees.

'However the Navy Operational Diving Team has considerable expertise in this type of search and we are grateful for their assistance.”

If the aircraft is located, searchers plan to use the ROV manipulator arm to attach a line and with airbags manoeuvre the aircraft into shallower water, where it could be retrieved by divers.

The weather forecast for today is fine and conditions should not be an issue for the operation.

An investigator from the Civil Aviation Authority has also arrived at the Lake Sumner site.

Craig says the family of the missing pilot, Michael Mehrtens, has been fully briefed on plans for the ROV search operation.

Source: New Zealand Police.