Fears for five onboard missing Titanic submarine as 96-hour oxygen cut-off reached

Based on the timeline given by US Coast Guard officials, rescue teams had until 8am ET (1pm UK time) on Thursday to reach the Titan before the chances of survival greatly diminished

Fears are being raised for the five passengers on board the missing Titanic submersible as their emergency supply of oxygen is believed to have run out.

OceanGate Expeditions’ Titan sub was equipped with enough oxygen to last the five men on board for four days – 96 hours – in the event of an emergency situation.

Follow updates on the missing Titanic sub in our live blog here

Based on the timeline given by US Coast Guard officials, this meant rescue teams had until 8am ET, which is 1pm UK time, on Thursday to reach them before the chances of survival ran out.

The Titan submersible left its mother ship Polar Prince at around 8am ET on Sunday to delve 13,000 feet below the surface to the Titanic wreckage, according to the US Coast Guard.

Just one hour and 45 minutes later the sub made its last contact with its support vessel and then failed to resurface at its scheduled time of 3pm EDT.

The US Coast Guard said it received reports of the missing craft at 5.40pm EDT.

The OceanGate Expeditions submersible vessel named Titan used to visit the wreckage site of the Titanic (PA Media)

A major search and rescue operation was launched, headed up by the US Coast Guard in Boston and involving multiple agencies, sonar technology, military-style aircrafts and rescue vessels with deep ocean remotely operated vehicles.

But four days from the moment the Titan entered the Atlantic Ocean, the clock struck 1pm in the UK (8am EDT) on Thursday, and hopes of finding the five men alive greatly diminished.

The passengers were identified as OceanGate CEO and founder Stockton Rush, British billionaire explorer Hamish Harding, renowned French diver Paul-Henri Nargeolet and Pakistani businessman Shahzada Dawood and his 19-year-old son Suleman Dawood.

Hamish Harding, Stockton Rush, Paul-Henri Nargeolet and Shahzada Dawood (clockwise from top left) (Reuters/Getty/WEF/OceanGate)

It is unclear where exactly the sub went missing but the US Coast Guard said it was searching 900 miles east of Cape Cod – where the famed Titanic shipwreck lies beneath the surface.

The Titanic shipwreck sits approximately 12,500 feet at the bottom of the Atlantic Ocean, about 380 nautical miles south of Newfoundland, Canada and 1,240 nautical miles east of New York City.

US Coast Guard officials offered their latest update on the rescue operation at a press conference on Wednesday afternoon, revealing that the search area had been expanded beyond its original 10,000 square miles.

Officials said the five rescue vessels currently involved in the search would be joined by five more in the next 48 hours - after the time the oxygen was expected to be exhausted.

But Captain Jamie Frederick maintained a positive outlook: “We have to remain optimistic and hopeful.”

Captain Frederick also revealed that Canadian military sonar buoys had detected “banging noises” for a second straight day on Wednesday.

He admitted that the search teams had no idea what the sounds were, and searches around the areas they came from had failed to yield any trace of the missing sub.

The sounds were being analysed by US Navy specialists.

A rescue fleet is seen in the search area on Wednesday (US Coast Guard.EPA)

Captain Frederick said two underwater remote operated vehicle (ROVs) had also been deployed in the search zone.

In addition, two Canadian P-3 aircraft were flying back-to-back missions, and two C-130 aircraft would continue to fly through the day and into the evening.

Captain Frederick did not offer any new update on the oxygen timeline, but stressed that there are “many factors” at play beyond the official estimate that was first presented at a press conference on Tuesday.

During that briefing, he acknowledged that officials did not know if crews would be able to rescue the people onboard even if they did manage to find the sub before the oxygen ran out.