There has again been no sign of a 49-year-old New Zealander and two Australians, feared dead after a helicopter disappeared in Papua New Guinea.
The helicopter carrying Captain Antony Annan and his Australian colleagues was reported missing about 4.30pm on Friday.
New Zealand Defence Force Papua New Guinea advisor, Lieutenant Colonel Richard Taylor said many commercial helicopters have been searching the rugged jungle terrain, and search teams had a very "difficult task'' ahead of them.
He said often with helicopter crashes the blades "sheared off'' and the wreckage fell into the dense jungle canopy, making it very difficult to locate.
"In reality we are still finding wreckages from World War II. It's a very large and very difficult area to locate aircrafts in ... and helicopters can be even harder to find.''
The Papa New Guinea Defence Force has offered ground search personnel to help in the rescue effort, however Mr Taylor said the search area had not been narrowed down yet.
"At a time when they have located or believe they are close to locating the wreckage then ground search personnel will be involved.''
The Bell 206 Helicopter, operated by aviation charter service Hevilift, was reported missing somewhere near the town of Wabag in the mountainous Enga Province.
About five minutes after the helicopter left the InterOil Drill Rig, a mayday call was broadcast. It is believed the three men were heading to Hou Creek to re-fuel and then were to return to their main base at Mt Hagen.
There was low cloud and reduced visibility at the time of the crash and the pilots were flying on sight rather than instruments.
Hevilift Group Managing Director Colin Seymour would not comment on company protocol for flying in dangerous conditions.
He said the cause of the crash was unknown but Hevilift was in contact with and supporting the men's families.
A second full day of searching has ended unsuccessfully, and will resume at first light tomorrow