Race to find black box recorders of flight MH370

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The huge challenge facing efforts to locate the wreckage of Malaysia Airlines Flight MH370 is not just about the conditions in some of the planet’s most inhospitable oceans. It is about narrowing down the area of the search, which at present encompasses 469,407 sq nautical miles of ocean, or almost 622,000 sq miles or 1.6m sq km – an area just slightly smaller than Alaska.

“We’re not searching for a needle in a haystack. We’re still trying to define where the haystack is,” Mark Binskin, vice-chief of the Australian Defence Forces, told reporters at Pearce, the air force base near Perth that is the base for the international aircrews and their aircraft.

Tony Abbott, the Australian prime minister, said on Wednesday his government was “throwing everything we have” into the operation, which resumed after the weather in the Indian Ocean improved.

“We owe it to the families, we owe it to an anxious world to do everything we can to finally locate some wreckage and to do whatever we can to solve the riddle of this extraordinarily ill-fated flight,” he said.

The size of the search area has come down in recent days, helped by the new analysis of satellite data and various as yet unidentified debris spotted in the southern Indian Ocean.

But to have any hope of finding out what happened on board the aircraft, investigators need to find the passenger jet’s two flight recorders, which are assumed to be lying at depths of up to 4,000m on the seabed below the search area that is 2,500km southwest of Perth.

They are both fitted with transponders, which typically have a battery life of 30 days, but the crucial technology needed to find them will not arrive in the search area until April 5, which is 28 days after the aircraft is thought to have crashed.

On top of that, the specialist US Navy equipment – one of just two such systems in the world – can only cover a small area of ocean in a day.

“Ideally we would deploy the system when we have a good idea of where to look. At a speed of 3 knots we can cover an area of 150 square miles per day,” a US Navy spokesman said. “We still don’t know what the operational profile is for this mission.”

This is why Malaysian investigators said on Tuesday they had set up an international working group to try to see if they can make further use of the analysis by Inmarsat of the satellite data to “attempt to determine the final position of the aircraft.”

Last week, Rémi Jouty, head of the Bureau d’Enquêtes et d’Analyses pour la sécurité de l’aviation civile (BEA), the French air accident investigation branch, said much more work was needed before any undersea search could start.

In depth

The hunt for Flight MH370

The largest international search effort in aviation history is attempting to locate the whereabouts of the missing Malaysia Airlines aircraft

The BEA was the lead agency in the long search for Air France Flight 447, which crashed in the middle of the South Atlantic in 2009. Although some parts of that aircraft were found floating on the surface within days of it crashing, it took two years to find most of the wreckage – and the crucial black boxes – at depths of up to 4,000 metres.

French investigators were also pretty certain of the last known location of the Air France aircraft and narrowed down the search area to a radius of 75km within a few weeks of the crash. Even then, they failed to locate the flight recorders from the transponder signals before the batteries went flat. It emerged later that search, which employed the previous generation of the US Navy’s hydrophone system, did get quite close to the main debris field on the sea floor.

The latest version of the US Navy kit, which like its predecessor can operate in up to 6,000 metres of water, has a range that can detect a signal one mile either side of the device. It is towed behind a ship and typically dives down to a position 1,000 metres above the sea floor. Oceanographers have warned that large parts of the search area in the Indian Ocean are uncharted.

The US Navy flew out the equipment, known as the Towed Pinger Locater-25, on a commercial flight to Perth from New York’s JFK airport on Monday night. They have also sent two officers, including the Navy’s head of salvage and diving, and eight contractors to operate the system.

Additional reporting by John Aglionby in London