Missing Malaysia Airlines Flight MH370: Now we know the plane came down and hopes are extinguished, what task will be ahead?

A family member of a passenger aboard Malaysia Airlines MH370 cries as she is surrounded by journalists after watching a television broadcast of a news conference, at the Lido hotel in Beijing (Reuters)

Investigations into aviation disasters are based on previous calamities, looking closely at similar losses to created hypotheses about the cause. In the past decade, there have been crashes with which MH370 shares some elements: in 2005, a Helios jet flew on across Greece on autopilot until it ran out of fuel and crashed, and in 2009 a large Air France aircraft was lost in the ocean, mid-cruise. But the circumstances of the Malaysia Airlines plane are so far beyond the experience of the aviation community that the search for clues becomes all the more critical.

As the relatives of the people aboard the lost Boeing 777 learned that their hopes had been extinguished, tangible evidence of the lost aircraft remained elusive. Military and civil aircraft continue to sweep the ocean west of Australia, with ships moving towards the search zone.

The search for traces of Air France flight 447, which crashed in the Atlantic between Rio and Paris, was challenging – but MH370 is an order of magnitude more challenging. The distance from the shore is much greater, the sea conditions much heavier and the clues about possible locations much less certain.

A United Nations of ships, aircraft and satellites are focusing on the area: military aircraft and executive jets from Australia, a wide-bodied plane from China, naval vessels from Australia and the US Pacific Fleet as well as a Chinese icebreaker and European merchant shipping. Those are the assets we know about; they may be supplemented with intelligence from submarines, if that can be achieved without revealing the location of the clandestine vessels and their sophisticated instruments.

Once a fragment of debris is found, whether a seat cushion or a fragment of cargo, the search area can be narrowed down. While that goes on, the debris will be minutely examined for clues about the loss. When the crash site is finally located, the recovery of the remains of the aircraft – and the 239 people on board – can begin.

The recovery teams will home in on the flight data recorder, which keeps details of commands from the flight deck, and the cockpit voice recorder. The latter, though, may not yield many clues since it has only a two-hour capacity, and therefore cannot reveal what happened over the Gulf of Thailand.

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While the search gains intensity, so too do the theories about the cause. While some early speculation – that MH370 was shot down by a missile, or downed by a terrorist bomb – have been ruled out, conjecture is rife about the possible reason for an abrupt change of course.

One of the leading theories is that a fire broke out, and the crew responded by turning the aircraft in a bid to reach the nearest landing strip. If they were then incapacitated before broadcasting a Mayday message, the cabin crew would be unable to access the flight deck due to the locked cockpit door. Yet the fire would then need to have extinguished itself, rather than downing the aircraft.

Others point to the presumed course of the plane, which looks as though it could have been designed to minimise the chance of detection.

Yet if a human hand was involved, and passengers became aware of a sinister development, some would presumably switch on their mobile phones – a few of which would be expected to register on networks, even while briefly flying over the Malayan peninsula.

While the search continues, the mystery of MH370 is becoming to the early 21st century what the JFK assassination was to the 20th century.