It’s a terrible thing to suggest, but surfers and beachcombers in Western Australia need to be on the lookout for debris or other traces from missing flight MH370.

At this stage there is a significant but unconfirmed possibility that the jet carrying 239 persons crashed in the Indian Ocean approximately 1600-1800 kilometres from Perth on the morning of Saturday, March 8.

While there is no immediate public analysis of currents and winds available, debris from an impact could travel up to 160 kilometres a day, meaning it could wash up on the shores of nations, including Australia, with Indian Ocean coastlines.

It’s a long shot, but tissue, items of clothing, airline seats and personal effects could all yield some of the solutions to questions as to what happened on board MH370 under forensic examination.

The most critical evidence, which might have been sabotaged by the pulling of circuit breakers in the cockpit, could be inscribed in the flight data recorder — which like the shorter-duration cockpit voice recorder would have sunk to the bottom of a very deep ocean, should an impact have been in the Indian Ocean and not on land along an alternative search zone in the northern hemisphere.

If searchers can hear the pinging signal that the “black boxes” are supposed to emit for weeks from a submerged location, the task of finding them would remain challenging, but at least it would have an approximate starting point.

Why is WA so firmly yet ambiguously in frame at the moment in the hunt for MH370, a Malaysia Airlines 777-200ER that set off from Kuala Lumpur for Beijing with 239 passengers and crew and fuel for almost eight hours of flight at 12.40am local time on March 8?

Partly because United States authorities have been saying for some days, including on the public record by the White House spokesperson, that they favour a data interpretation that says it probably came down in the southern rather than northern hemisphere.

To reduce the complex to a few words: the geostationary Inmarsat satellite that registered electronic “standby” signals from the plane put the last such trace as being sent out at 8.11am KL time, or 7.11 in WA, along any point on two alternative arcs. One stretched from western Indonesia at its north-east extent to the mid-Indian Ocean at its most south-west point; the other arc extended from northern Thailand to Kazakhstan.

The satellite receives literally thousands of such messages from many hundreds of airliners within its view every day. It records the angle between the signal receipts and the satellite as well as calculating the distance travelled, and perforce, produces two alternative arcs that in their extent are equally valid as possible source points for the signal from the gigantic sphere below its antennas.

Debris in the southern hemisphere might already have reached or passed offshore oil and gas rigs, for that matter the Cocos Islands or Christmas Island.

The frustrations of the search are many — some administrative, some technical. The multinational search, co-ordinated in title by Malaysia, doesn’t have accurate fixes yet available on the path that might have been flown by MH370 to reach any of the points on the northern or southern arcs.

If it is assumed that the jet stopped flying all over the place, as it did early in its now decoded earlier movements, and went on a fairly straight heading until its fuel ran out, coming down somewhere adjacent to the south-west of WA, or southern central Asia.

Australia has been playing a critical role in the search with two of its RAAF long-range maritime reconnaissance Orions that were sent to Malaysia. One of them has already been shifted to search more southerly parts of the Indian Ocean.

Malaysia says it is seeking more naval vessel support for that part of the search, while it also continues the northern hemisphere search, and what is now revealed as a more extensive criminal probe into the backgrounds and mental and relationship states of passengers and crew that began within a day of the flight vanishing.

Prime Minister Tony Abbott this morning confirmed he would be in talks with Malaysian authorities later today to see what additional assistance Australia could give.

Asked about Australia’s semi-secret and highly sophisticated Jindalee over-the-horizon radar and other intelligence that it might have, Abbott said: “All our agencies are scouring their information to see if there is anything they can add [to the search effort].”