The head of the search for Malaysia Airlines Flight MH370 has raised the possibility that no wreckage from the passenger jet may ever be found, revealing authorities have a very poor understanding about how fast or far it travelled.
Speaking to media on Tuesday, Air Chief Marshal (rtd) Angus Houston compared the search for the aircraft to the disappearance of HMAS Sydney, which took 60 years to locate.
"We have a starting point and we need to pursue the search with vigour and we need to do that for some time to come," the former head of Australia's Defence Forces said.
"Inevitably, if we don't find wreckage on the surface, we are eventually going to have to, probably, in consultation with everybody who has a stake in this, review what we do next."
Hopes of a breakthrough had been raised after the Australian Maritime Safety Authority revealed a new search area about 1100 kilometres north-east of the previous zones on Friday after analysis that the plane had been travelling faster than previously thought, and would therefore have burnt more fuel and crashed earlier.
But Air Chief Marshal Houston, head of the new Joint Agency Coordination Centre (JACC), said this analysis - described last week as the "most credible" lead to date - was a "very inexact science".
"We don't know what altitude the aircraft was travelling at. We don't really know the speed it was going," he said.
He said the ground speed of a plane travelling at sea level was half that of a plane travelling at 40,000 feet even if both aircraft had "the same indicated airspeed".
Air Chief Marshal Houston is a former Chief of Air Force and aviator who spent much of his career as a search and rescue helicopter pilot.
With no wreckage found after three and a half weeks despite a multinational effort now involving nine ships, 10 aircraft and 1000 personnel, the search for flight MH370 was by far the most challenging he had come across, he said.
While noting that technology had advanced considerably, he compared the search for MH370 with the sinking of HMAS Sydney off the coast of Western Australia during World War II.
"There were eyewitness who saw the ship disappear over the horizon but it took us about 60 years to find HMAS Sydney on the bottom of the ocean," he said.
Captain Allison Norris, commander of HMAS Success, told Fairfax Media that conditions were rough on Tuesday with high winds and swell of up to four metres. Nonetheless, her crew were scouring the ocean around the clock, using all available personnel on the vessel regardless of their normal jobs.
Crew were using night vision equipment when it was dark, she added.
Air Chief Marshal Houston will brief Malaysia's Prime Minister Najib Razak on the search and recovery effort, with the leader scheduled to arrive in Perth on Wednesday.
Mr Najib will tour RAAF Pearce with Prime Minister Tony Abbott, among other engagements during his two-day visit.
Meanwhile, Danica Weeks, the wife of one of the 239 missing passengers and crew on MH370, arrived at RAAF Pearce on Tuesday and complained she was not getting enough information about the search and recovery operation.
Air Chief Marshal Houston said he had given Ms Weeks his personal mobile number and invited her to come to JACC headquarters for a personal briefing.
- FFX Aus