Mark Townsend
The Observer
5 April 2014

With the batteries powering the black box from missing Malaysia Airlines flight MH370 expected to expire as early as Monday, experts have warned that the international hunt for the aircraft’s wreckage may be looking in the wrong area.

The flight recorders of the Boeing 777 emit a ping that can be detected by sonar equipment, but the devices have a battery life of around 30 days, which means ships hoping to locate the signal are rapidly running out of time.

Finding the data recorders after that remains possible, but experts say it will become significantly more challenging if the signal beacons stop working.

Underwater attempts to pinpoint the ping continued, four weeks to the day after the airliner vanished, with the Australian navy’s Ocean Shield and Britain’s HMS Echo trawling an identified area using sophisticated underwater detection equipment.

However, some experts warn that they could be scouring the wrong stretch of remote Indian ocean. Aviation expert and former RAF Hercules pilot David Learmount said the failure to locate any floating wreckage meant that the search effort was effectively still working blind.

Finding floating wreckage is paramount to shrinking the search area: analysts can use data on ocean currents to rewind to the location where the plane entered the water.

Learmount, who is operations and safety editor of information website Flightglobal, said: “If they don’t find any floating wreckage they have no idea where to look. How much more clearly can I put it than that? We don’t know where to look, we think we know and we’re doing our best, but we may be wrong.”

He said that previous satellite reports indicating debris in a remote stretch of the Indian Ocean signified little because there was no evidence it was linked to MH370.

“The only thing was that there was a very indeterminate, very simple piece of information from a satellite system. It was not intended to be a location system but we’ve used it as such. It doesn’t give us a location. We’ve been looking for nearly a month and we haven’t found anything.”

Learmount said that one vital variable was the speed at which the aircraft hit the ocean, citing the case of Air France 447, which crashed into the Atlantic in 2009. In that case it took investigators two years to recover the black box: when they did, data revealed that the plane had “belly-flopped” on to the sea surface, meaning its impact was less severe and that larger pieces had survived.

He said: “We don’t know how this one hit the water. If it was an intentional effort to kill themselves and everybody else – and we have no proof but that’s the Malaysian government’s best guess – I doubt they would have attempted to belly-flop it.

“They might have put the aircraft into a very much higher-speed impact with the water, so the pieces would be smaller and much harder to see,” added Learmount, who served with the Royal Air Force for 10 years.

The multinational search team will continue to try to identify faint sound signals from the recorders that could lead them to the aircraft. The task is complicated by the fact that the search ships have to get within range of the plane’s data recorders to hear the. This is a tall order given the size of the search area and the fact that the pinger locator must be dragged slowly through the water at between one and five knots (one to six miles an hour).

“It would be brilliant if they heard the pinger, but they’s have to be very lucky because the water there is very deep,” said Learmount. “I honestly think in a case like this that if we don’t find the pingers and locate any wreckage there is little point searching the seabed. It would take forever and the cost would be astronomical.”