PARIS - Recovering the black boxes from the Malaysia Airlines jet that crashed into the southern Indian Ocean is a Herculean task, even with the wealth of sophisticated equipment being deployed.
Any hope of finding survivors from the missing plane was extinguished on Monday when Malaysia's prime minister announced satellite data showed MH370's journey had "ended in the southern Indian Ocean" off the west coast of Australia.
Seventeen days after the Boeing 777 disappeared, distraught relatives were forced to accept what they had long feared - that the 239 passengers and crew on board were never coming home.
The plane's two black boxes are key to solving the mystery of why the plane veered so far off course and its final fate, but experts say that the search for them will be long and difficult.
In theory, the black boxes containing flight data and cockpit voice recordings will continue emitting tracking signals for about another two weeks, with an average audible range of two to three kilometres (nearly two miles).
But with no debris in the remote search area confirmed as linked to the plane, it is still a case of looking for a needle in a haystack.
"Picking up a signal from the beacon seems an outside chance," said a member of the team that hunted the black boxes from Air France flight AF447 that crashed in the Atlantic in 2009.
Vast search zone
The investigator, who asked to remain anonymous, noted that in the Air France case the signals were not heard at all. One transmitter had failed and the other had fallen off on impact and was never found, he said.
"So I'm fairly pessimistic about this approach," he said, recommending that the immediate priority should be to catalogue every piece of debris that is discovered.
"Then, ideally, data buoys should be deployed," he said. These instruments, commonly used for meteorological data, are tracked by satellite and give an idea of ocean currents in the area to help confirm mathematical models.