A Malaysian-contracted search vehicle, GO Phoenix, docked at a port near Perth, Australia, on Oct. 22. European Pressphoto Agency
CANBERRA, Australia—Disagreements among investigators over where to look for Malaysia Airlines Flight 370 are complicating an already difficult effort to recover the missing jetliner.
A search of the southern Indian Ocean seabed for the plane-which disappeared on March 8 after veering sharply off course en route to Beijing from Kuala Lumpur-resumed almost two months ago. So far it has faced technical glitches and foul weather.
But now there is an even bigger concern: ongoing differences of opinion between five teams of experts that include Boeing Co. and the Australian military have led to search vessels being deployed in two different priority search areas. These zones overlap in some places but in others are hundreds of miles apart, highlighting how efforts to solve one of modern aviation’s biggest mysteries remain little more than educated guesswork.
Searchers may only be able to scour around 80% of the probable crash sites before government funding runs out, according to Martin Dolan, chief commissioner of the Australian Transport Safety Bureau, which is coordinating the search off the country’s west coast.
A video from the Joint Agency Coordination Centre.
Australian authorities last month identified two broad areas where the jetliner is likely to have crashed, based on different models of analyzing communications between the Boeing 777 and an Inmarsat PLC satellite. One method assumed the plane flew on autopilot until it ran out of fuel, while the other assumed nothing about how the plane was being flown, seeking only to find flight paths that best fit satellite signals from the aircraft.
What authorities didn’t say, however, was that the investigators were divided: three against two, in their conclusions about where to look.
The five teams of investigators comprised Boeing, Inmarsat, France’s Thales Group , the U.S.’s National Transportation Safety Board, and the Australian Defence Science and Technology Organisation. Each was asked by the ATSB to analyze the data independently, and draw their own conclusions.
“Originally we thought we had a consensus among the five groups, based on the best data available at the time,” Mr. Dolan, head of the Australian air-accident investigator, said in an interview. “Once we refined the data again the methodologies diverged.”
Investigators haven’t made clear why using an autopilot would result in such a different flight path. Mr. Dolan declined to say which of the experts supported each of the crash site theories. The NTSB, Inmarsat, and Thales said they couldn’t immediately comment. A Boeing spokesman declined to comment.
“If you get a 1Hz variation in frequency in your assessment that leads to a 300-kilometer variation,” Mr. Dolan said of attempts to use satellite transmissions to locate the plane. “It’s hugely sensitive to initial inputs throughout any of the five models.”
Repeated shifts in the search area in the weeks and months following the jetliner’s disappearance have frustrated the families of the 239 passengers and crew aboard, with some expressing doubt over whether it will ever be found and the cause of the crash explained.
The fact that expert investigators can’t agree over a probable crash site make the chances of success even more unlikely, according to one sonar expert with recent experience in deep-sea recovery efforts.
By hedging their bets across two search areas, investigators are giving both theories a chance to be proven right, but also spreading thinly the limited funds made available to the search. Australia has set aside as much as 52 million Australian dollars (US$45 million) for the latest phase of the operation, which includes mapping of the seabed to identify potential hazards to equipment such as deep trenches and underwater volcanoes.
The underwater search for Flight 370 is planned to last 300 days and cover an area of 60,000 square kilometers (23,166 square miles) that straddles an arc drawn from a final ping transmission between the plane and the Inmarsat satellite.
Australian authorities have hired Dutch firm Fugro NV to lead the search effort at sea. It will operate two boats with towed sonar equipment to find wreckage from the plane up to three miles below the ocean surface. Another vessel, the Malaysian-funded GO Phoenix, is also involved.
Faced with differing opinions, authorities are focusing on searching both areas as a priority, with the GO Phoenix using sonar devices to scan the northern area off Australia, and Fugro exploring the southern area. The GO Phoenix was the first vessel to begin scouring the seabed on Oct. 6.
Experts say the two-year underwater hunt for Air France Flight 447-which crashed into the Atlantic Ocean in 2009-provides some lessons for the Flight 370 search team.
Disagreements among investigators also complicated that search. A so-called black box containing flight-data and cockpit-voice recorders wasn’t located until experts opted to go back and explore an area they had eliminated in an earlier search.
Air France, Airbus and French investigators repeatedly clashed over where and how to proceed with the Flight 447 recovery. In the end, it took small robotic submarines provided by the Woods Hole Oceanographic Institution nearly 60 trips under the surface before the black box was discovered.
– Andy Pasztor in Los Angeles and Jon Ostrower in Chicago contributed to this article.