Two previous missions by autonomous underwater vehicle Bluefin 21, a US Navy probe equipped with side-scan sonar, to map the ocean floor were cut short by technical problems and deep water, without making any “significant” detection.

Bluefin-21 has searched approximately 90 square kilometres to date and the data from its latest mission is being analyzed. Bluefin 21 is searching in an area defined by four acoustic signals picked up by an Australian search team.

Today’s search operation would be carried out by up to 10 military aircraft, two civilian plane and 11 ships. The Australian Maritime Safety Authority has planned a visual search area totaling approximately 40,349 square kilometres, as the multi-nation search entered into the 41st day. The centre of the search areas lies approximately 2,170 kilometres north west of Perth.

The search for the missing plane could take up to two months as the robotic mini-submarine takes six times longer to cover the same area compared to the towed pinger locater, officials said.

“It is estimated that it will take the AUV (autonomous underwater vehicle) anywhere from six weeks to two months to scan the entire search area,” Lt. J.G. Daniel S. Marciniak, a spokesman for the U.S. Seventh Fleet, had said in a statement. JACC also said the oil sample collected by Australian defence vessel ‘Ocean Shield’ had now arrived in Perth and will be subject to detailed testing and analysis.

“We will provide details of the results when they become available,” JACC said.

The mystery of the missing plane continued to baffle aviation and security authorities who have so far not succeeded in tracking the aircraft despite deploying hi-tech radar and other gadgets.