Chances of finding Malaysian flight MH370 fade away
MALAYSIA – Hopes of finding the wreckage of the missing Malaysian flight MH370 at the bottom of the Indian Ocean diminished yesterday after the search area proved too deep for the robotic submarine being used in the hunt. The U.S. Navy’s Bluefin-21 autonomous underwater vehicle was sent down some 2000km north west of Perth to begin scouring the seabed for the missing Boeing 777 after no possible black box pings were detected for six days.
But just six hours into its planned 16-hour mission on the sea bed, it exceeded its maximum depth limit of 4.5 km and its built-in safety feature automatically returned it to the surface. The data it had collected was analysed but nothing of interest was found, the U.S. Navy said in a statement. Search crews were hoping to send it back under water today, if weather conditions permit.
The autonomous underwater vehicle was due to scour the Ocean floor for 16 hours – but it was brought back up after just six hours because it had reached and then exceeded its maximum operational depth of 4.5 km. Any lower and the water pressure could have caused major damage to the mini submarine. ‘Its built-in safety feature returned it to the surface,’ the joint search committee said in a statement.
Authorities knew that any possible wreckage from Flight 370 would likely be lying at the limit of the Bluefin’s dive capabilities. Deeper diving submersibles have been evaluated, but none is yet available to help. The Bluefin was programmed to hover 30 meters over the seafloor as it moved through the search area, but ended up reaching its maximum depth, triggering the safety feature that returned it to the surface, the U.S. Navy said.
It wasn’t damaged and is being reprogrammed to account for the inconsistencies in the seafloor’s depth.A safety margin would have been included in the sub’s program to protect the device from harm if it went a bit deeper than its 4,500-meter limit, said Stefan Williams, a professor of marine robotics at the University of Sydney.
He said: ‘Maybe some areas where they are doing the survey are a little bit deeper than they are expecting. ‘They may not have very reliable prior data for the area, so they have a general idea. But there may be some variability on the sea floor that they also can’t see from the surface.’
Meanwhile, officials were investigating an oil slick about 5.5km from the area where the last underwater sounds were detected, said Angus Houston, the head of a joint agency coordinating the search off Australia’s west coast. Crews have collected an oil sample and are sending it back to Perth in western Australia for analysis, a process that will take several days. Mr Houston said it does not appear to be from any of the ships in the area, but cautioned against jumping to conclusions about its source.
The Bluefin can create a three-dimensional sonar map of any debris on the ocean floor. But the search in this area is more challenging because the seabed is covered in silt that could potentially cover part of the plane. ‘What they’re going to have to be looking for is contrast between hard objects, like bits of a fuselage, and that silty bottom,’ Mr Williams said. ‘With the types of sonars they are using, if stuff is sitting up on top of the silt, say a wing was there, you could likely see that … but small items might sink down into the silt and be covered and then it’s going to be a lot more challenging.’
The search moved below the surface after crews picked up a series of underwater sounds over the past two weeks that were consistent with signals from an aircraft’s black boxes, which record flight data and cockpit conversations. The devices emit ‘pings’ so they can be more easily found, but their batteries only last about a month and are now believed to be dead.
Australian Prime Minister Tony Abbott raised hopes last week when he said authorities were ‘very confident’ the four strong underwater signals that were detected were from the black boxes on Flight 370, which disappeared March 8 during a flight from Kuala Lumpur, Malaysia, to Beijing with 239 people on board, mostly Chinese.
But Houston warned that while the signals are a promising lead, the public needs to be realistic about the challenges facing search crews in the extremely remote, deep patch of ocean. ‘I would caution you against raising hopes that the deployment of the autonomous underwater vehicle will result in the detection of the aircraft wreckage,’ Houston said Monday. ‘It may not.’
The submarine takes 24 hours to complete each mission: two hours to dive to the bottom, 16 hours to search the sea-floor, two hours to return to the surface, and four hours to download the data.
The black boxes could contain the key to unravelling the mystery of what happened to Flight 370. Investigators believe the plane went down in the southern Indian Ocean based on a flight path calculated from its contacts with a satellite and an analysis of its speed and fuel capacity. But they still don’t know why.
On Tuesday, Malaysia’s defence minister, Hishamuddin Hussein, pledged to reveal the full contents of the black boxes, if they are ever found. ‘It’s about finding out the truth,’ he told reporters in Kuala Lumpur. ‘There is no question of it not being released.’
Up to 11 planes and as many ships were on Tuesday scouring a 62,000 square kilometre patch of ocean about 2,200km north-west of Perth, hunting for any floating debris.
But the weeks-long surface search was expected to end in the next two days. Officials haven’t found a single piece of debris confirmed to be from the plane, and Houston said the chances that any would be found have ‘greatly diminished.’ – DM