Bluefin-21 robotic mini submarine deployed to search for the missing Malaysia Airlines plane in the southern Indian Ocean has had its first mission cut short.
The drone was sent to search the sea floor for wreckage after signals believed to be consistent with “black box” flight recorders were detected.
The Bluefin-21 exceeded its operating limit of 15,000ft and was brought back to the surface.
It was due to return later on Tuesday if weather conditions permitted.
“To account for inconsistencies with the sea floor, the search profile is being adjusted to extend the sonar search for as long as possible,” an update from the US Navy – which operates the Bluefin-21 – said.
The US Navy said in a later update that no objects of interest were found when the six hours of data were downloaded and analyzed.
Flight MH370 went missing on March 8 with 239 people on board. It was flying from Kuala Lumpur to Beijing when it lost contact with air traffic controllers over the South China Sea.
Malaysian officials believe, based on satellite data, that it ended its flight thousands of miles off course, in seas west of the Australian city of Perth.
Amid a major international search, an Australian navy vessel last week detected four acoustic signals using a US Navy towed pinger locator. Officials believe these could come from the missing plane’s flight recorders.
No signals have been detected since 8 April, however, leading to fears that the recorders’ batteries – which last about a month – have run out.
Bluefin-21 is an almost 5m-long vehicle that can create a sonar map of the sea floor. On Monday officials said each mission was expected to last 24 hours, with 16 hours spent on the ocean floor, four hours’ diving and resurfacing time, and four hours to download data.
The submersible has a safety feature that brings it to the surface if it exceeds its performance capabilities, however.
The sea where the Bluefin-21 is searching is estimated to be about 4,500m deep, but experts say there could be variations on the sea floor.
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