"Over the years there have been a number of searches but what makes this one different is that we have spoken to one of the original radar controllers to get a better appreciation of what was happening and perhaps a more detailed idea of where the plane was heading," Superintendent Thurtell (pictured) said.

"We have also been working with those members of the community who have dedicated many years in bushwalking and trying to locate the wreckage and drawing upon their experience to identify where we haven't searched, and that could be the difference.

"With the evolvement of online and digital mapping, and cross referencing previous search areas, we believe we have narrowed the scope."

"We are under no illusion about what we are up against. We know the terrain is rugged, covered by thick canopy where no-one has perhaps ever been, but it will test us and if nothing else will enhance our capability."

More than 150 police and emergency service personnel will take part in the search and rescue exercise including NSW Police Rescue Squad, the National Parks and Wildlife Service, Fire and Rescue NSW, NSW Volunteer Rescue Association, Bushwalkers Wilderness Rescue Squad, Ambulance Service of NSW, NSW Rural Fire Service, Police Aviation Support Branch and Marine Area Command, and WYCEN (Wireless Institute Civil Emergency Network).

Supt Thurtell said that the families of the men have been contacted about the search.

"We don't want to give false hope but we had to let the families know what we were doing and they appreciate the effort."

"If we can provide closure then that would be extremely satisfying, but if not at least we can enhance our ability to conduct extreme searches with full time operatives and volunteers, and that's something the public can have confidence in," Supt Thurtell said.

The four passengers on the plane were NSW police inspector Ken Price, 54, Rhett Bolsler, 33, Noel Wildash, 40, and Phillip Pembroke, 43.

The pilot was 52-year-old Mick Hutchins.