If missing Malaysia Airlines flight MH370 is in the Gulf of Thailand or the South China Sea, which is receiving special attention by search activities today, those on board and the wreckage of the 777-200 in which they were flying will be disappearing and being dispersed, making it increasingly difficult to identify the exact location of the crash and its causes.

This is day four of the search. Only if the much-expanded search area — which includes thousands of kilometres of coastlines — gives up a wreck on land will finding the “black box” flight data and cockpit voice recorders become much more straightforward.

Those recording devices would show whether MH370, which was on its way from Kuala Lumpur to Beijing with 239 people on board early last Saturday morning, fell to an act of terrorism or a massive mechanical or systems-related failure.

The unresolved issues concerning passengers with stolen or fake passports, and a peculiar reported gap between when the flight was last seen by radar and heard by radio, make it more likely that it crashed because of criminal activity on the plane.

The last radar confirmed location of the MH370 was 162 kilometres north-east of Kota Bharu, on the east side of the Malaysia Peninsula, heading across the Gulf of Thailand toward the southern tip of Vietnam. The farther away from that location any crash site is found to be, the more certain it will be that the 777 was flown in radio silence and most likely with its radar transponder (which identifies it to air traffic control) disabled.

However, MH370 was approaching a boundary beyond which Malaysia ATC radar didn’t reach, and there is no evidence that it was ever seen on Vietnamese radars, at least not as a clearly identified commercial flight.

The last radio conversation with the flight, conducted through an intermediary airliner using the emergency broadcast frequency, appeared normal, but there was “muttering” in the background, and that link went silent (according to Malaysia media reports) eight minutes after it was set up by the Malaysian controllers, who were concerned when they lost radar contact sooner than they would have normally expected.

There are numerous inconsistencies and conflicting indications in everything that has been said by the airline and the Malaysia authorities at the technical level, as well as confusion over the security processes that were supposed to be in place at Kuala Lumpur’s major international airport, whether they were followed, and whether they were adequate in either event.

All of those issues may yet prove totally irrelevant if something completely unexpected went wrong with the airliner itself, which has an outstanding operational record for being a robust and highly successful design.

The high-speed crash of a Silkair 737 MI185 into a river mouth near Palembang in Indonesia in 1997 bodes badly for efforts to identify and recover anything from MH370. Despite that crash site being known and promptly subjected to a massive recovery operation, most of the debris and human remains of MI185 were rinsed out to sea, while dredges were used to sift through mud to recover those fragments driven into the river bed.

Halfway through day four of the disappearance of MH370, any recovery operation doesn’t yet have a starting point.