Possible signs of life have been detected in the same area where a Titan submersible went missing in the Atlantic Ocean with five people on board, it has been reported.

An internal US government email obtained by Rolling Stone magazine revealed on Wednesday (AEST) that a Canadian aircraft helping with the search reported “contact” in a location “close to the distress position”.

This “contact” was described as “banging” occurring at half-hour intervals and coming from the same location where the deepwater craft vanished.

The information was sent in an internal email update to US Department of Homeland Security leadership.

“RCC Halifax launched a P8, Poseidon, which has underwater detection capabilities from the air,” the DHS emails read, according to Rolling Stone.

“The P8 deployed sonobuoys, which reported a contact in a position close to the distress position.

“The P8 heard banging sounds in the area every 30 minutes. Four hours later additional sonar was deployed and banging was still heard.”

The email did not state when the banging was heard, or what was thought to have caused it.

Later, the US Coast Guard confirmed the report on Twitter, saying the Canadian aircraft had detected “underwater noises” in the search area.

As a result, a remotely operated vehicle (ROV) was relocated there in an attempt to explore the origin of the noises.

“Those ROV searches have yielded negative results but continue,” said the Twitter post.
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“Additionally, the data from the P-3 aircraft has been shared with our U.S. Navy experts for further analysis which will be considered in future search plans.”

Tweet from @USCGNortheast

Rolling Stone also quoted an email from the president of the Explorers Society to its members.

“It is being reported that at 2am local time on site that sonar detected potential ‘tapping sounds’ at the location, implying crew may be alive and signalling,” it said.

The Canadian military has dropped sonar buoys to listen for any sounds that might come from the Titan.

A commercial vessel with a remote-controlled deepwater submersible is also searching near the mid-ocean site.

One pilot and four passengers were inside the miniature sub early on Sunday (local time) when it lost communication with a parent ship on the surface about an hour and 45 minutes into its two-hour dive.

Those on board are OceanGate founder and chief executive Stockton Rush, British billionaire Hamish Harding, Pakistani-British businessman Shahzada Dawood with his son 19-year-old Suleman, and French explorer and Titanic expert Paul-Henri Nargeolet.

The sub was equipped with four days of emergency air when it went missing on Sunday, but that supply is now believed to be running out.

As Canadian and US authorities stepped up the search, previous questions about the safety design and development of the submersible by its owner, US-based OceanGate Expeditions, came to light.

The sub hull design’s ability to withstand such depths was questioned in a 2018 lawsuit filed by OceanGate’s former director of marine operations David Lochridge, who said he was fired after he raised safety concerns.

OceanGate said in its breach-of-contract suit against Mr Lochridge, who is not an engineer, that he refused to accept the lead engineer’s assurances and accused him of improperly sharing confidential information.

The two sides settled the case in November 2018.

The company did not respond to requests for comment from Reuters and its lawyer in the Lochridge case, Thomas Gilman, declined to comment.

A lawyer for Mr Lochridge said only: “We pray for everyone’s safe return”.

OceanGate said it was “mobilising all options” and US Coast Guard Rear Admiral John Mauger told NBC News the company was helping to guide the search efforts.

“They know that site better than anybody else,” Rear Admiral Mauger said.

“We’re working very closely with them to prioritise our underwater search efforts and get equipment there.”

The Titanic site is about 1450 kilometres east of Cape Cod and 644 kilometres south of St John’s, Newfoundland.

US and Canadian aircraft have searched almost 20,000 square kilometres, larger than the state of Connecticut, Frederick said.

A French research ship carrying an autonomous deep-sea diving vessel has been dispatched at the request of the US Navy and was expected to arrive at the search area Wednesday night local time, the Ifremer research institute said.

Those aboard the submersible, the highlight of a tourist expedition that costs $US250,000 ($370,000) per person, included British billionaire Hamish Harding, 58, and Pakistani-born businessman Shahzada Dawood, 48, with his 19-year-old son Suleman, both British citizens.

The 77-year-old French explorer Paul-Henri Nargeolet and Stockton Rush, founder and CEO of the vessel’s US-based operating company OceanGate, were also reported to be on board.

-with AAP