SYDNEY - Australian authorities looking for Malaysia Airlines Flight 370 said Thursday that an oil slick detected in the search zone and collected by the Australian vessel Ocean Shield was not engine oil or hydraulic fluid from an aircraft.
The sample was collected Sunday night more than 3 miles from the area where the Ocean Shield had picked up underwater acoustic signals.
“Preliminary analysis of the sample collected by ADV Ocean Shield has confirmed that it is not aircraft engine oil or hydraulic fluid,” the Joint Agency Coordination Center said in a statement Thursday.
The Malaysia Airlines jet veered off course March 8 during an overnight flight from Kuala Lumpur to Beijing with 239 people on board. To date, no wreckage has been found.
The strongest leads so far are four acoustic signals from underwater, the last of which was picked up April 8 as the Ocean Shield towed a pinger locator through the Indian Ocean. The Ocean Shield is about 1,000 miles northwest of Perth, the capital of Western Australia, while the main search area for potential wreckage is almost 1,500 miles northwest of the city.
The acoustic signals are thought to have come from the plane’s flight data recorders.
At a briefing Monday, search leader Angus Houston said searchers would use a remote-controlled submersible, the Bluefin-21, to scan the floor of the Indian Ocean, which is believed to be up to 2.8 miles deep in the search area, for the plane’s wreckage.
On Monday, the search for additional acoustic signals was abandoned in favor of deploying the Bluefin submersible, but it had to return to the surface on its first mission after exceeding its maximum depth of 2.8 miles. On Wednesday morning, the Bluefin was again forced to resurface after technical problems. It was redeployed Wednesday and overnight Thursday and completed a full mission in the search area.
“Initial analysis of the data downloaded indicates no significant detections,” the Australian agency said in a statement.
The submersible, towed by the Ocean Shield and operated by a U.S. team from the contractor Phoenix International, crawls just above the seabed, with each deployment lasting up to 20 hours. It takes two hours for the Bluefin to descend, 16 hours to conduct the search and two hours to return to the surface. Analysts then need four hours to download and analyze the data.
On the Bluefin’s first mission, it was expected to cover an area of just 15 square miles. Authorities said the underwater search area had narrowed, and risks to the Bluefin from diving deeper than 2.8 miles had now been assessed as “small but acceptable.”
“This expansion of the operating parameters allows the Bluefin-21 to search the sea floor within the predicted limits of the current search area,” the agency said Thursday.
The coordination center also said news reports stating it would take six weeks to two months for the Bluefin to complete the search were incorrect, but it did not provide an estimated time frame.
Detailed acoustic analysis of the four signals picked up by the Ocean Shield on April 5 and April 8 “has allowed the definition of a reduced and more focused underwater search area,” the agency said. “This represents the best lead we have in relation to missing Flight MH370 and where the current underwater search efforts are being pursued to their completion so we can either confirm or discount the area as the final resting place of MH370.”
In all, 12 planes and 11 ships were involved in the search Thursday. The Bluefin has scoured about 34 square miles of seabed in an area covering about 40,000 square miles.
Front Section, Pages 6 on 04/18/2014