Underwater noises detected by Canadian aircraft, as oxygen levels reduce to around 30 hours of breathable air
The Titan could be in extremely deep water: the wreck of the Titanic, where the submersible with its five passengers was heading, lies at a depth of 3,800 metres.
Search teams have detected underwater sounds, the US Coast Guard has said, as the clock ticked down to the last 24 hours of the craft’s presumed oxygen supply.