Sea Dragon and other probes that can go deeper may take over if mini-sub fails, says CNN

The

search for Malaysia Airlines flight MH370 is nearing the end of its 40th day without any significant development and CNN aviation consultant Mary Schiavo said underwater probes which can go deeper may be deployed if current efforts using a high-tech mini-submarine fails.

The mini-submarine or autonomous underwater vehicle (AUV), known as Bluefin-21, is currently scouring the Indian Ocean seabed after two previous attempts ended prematurely.

The Joint Agency Coordination Centre (JACC) in Perth said today in a statement that the mini-submarine was forced to resurface this morning to rectify a technical issue.

While on deck, its data was downloaded but there were no significant detections.

The Bluefin-21 has since been deployed for the third time.

"If the Bluefin cannot bring back the kind of sonographic images they (search authorities) want and the information that they want, then they're going to have to move on to the next level of vehicles with names like Alvin, Remora and the Sea Dragon, and those can go deeper," she said in a report on the global news network.

"The Sea Dragon can go down to 7,000 metres. And that is the next step that you have to do, go down to that level in a different kind of vehicle."

The mini-submarine was deployed for the second time last night from the Australian navy ship, Ocean Shield, after its first mission on Monday had to be aborted after six hours following a breach in the machine's maximum operating depth, the US navy had said.

Data from that first dive also showed nothing of interest.

Today, the Australian Maritime Safety Authority had planned a visual search area totalling approximately 55,151 square kilometres, the JACC statement said.

Up to 11 military aircraft, three civil aircraft and 11 ships were involved in today's search.

The centre of the search areas lies approximately 2,087 kilometres northwest of Perth.

Here, the CNN report looks at some issues related to the latest search efforts.

Why are they not listening for pings from MH370's flight recorders anymore?

Because the batteries powering the boxes' locator beacons are probably dead, according to the manufacturer and other experts.

The batteries were supposed to last at least 30 days, and the plane has now been missing for 40 days.

The batteries could have continued powering the beacons for a few more days but would almost certainly have run out by now.

Searchers using devices to listen for the pings went six days without hearing anything, so they are now focused on the underwater search.

What happens if they find the black boxes?

The flight data recorders, or FDRs, will be transferred to fresh water and then dried before the data they contain would be pulled out, Schiavo told CNN.

"Then they will discover on the FDR what they are dealing with and how much of the wreckage they really have to bring up to solve the mystery."

It will be a long search as the MH370 hunt is often compared to the hunt for wreckage from Air France Flight 447, which plunged into the South Atlantic Ocean in 2009, killing all 228 people aboard. It took investigators nearly two years to recover the black boxes in that case.

Is the surface search continuing?

It is, but maybe not for much longer. The head of the JACC, retired Air Marshal Angus Houston, had said on Monday that the surface search is likely to end in the next few days.

Has that search turned up anything?

Searchers found an oil slick in the area over the weekend and are shipping a 2-litre sample back to Australia for analysis.

If it is oil typically used in aircraft, the slick could be an important lead. But it may not be. A slick found in the early days of the search for MH370 in the South China Sea turned out to be fuel oil from a freighter.

Any other new details?

A US official told CNN on Monday that co-pilot Fariq Abdul Hamid's cell phone was on and made contact with a cell tower in Malaysia about the time the plane disappeared from radar.

However, the US official – who cited information shared by Malaysian investigators – said there was no evidence Fariq had tried to make a call, CNN reported.

The details do appear to reaffirm suggestions, based on radar and satellite data, that the plane was off course and was probably flying low enough to obtain a signal from a cell tower. – April 16, 2014.