Underwater noises heard in desperate search for submersible missing with 5 aboard near Titanic

A Canadian military surveillance aircraft detected underwater noises as a massive operation searched early Wednesday in a remote part of the North Atlantic for a submersible that vanished while taking five people down to the wreck of the Titanic.

A statement from the U.S. Coast Guard did not elaborate on what rescuers believed the noises could be, though it offered a glimmer of hope for those lost aboard the Titan as estimates suggest as little as a day’s worth of oxygen could be left if the vessel is still functioning.

Three vessels arrived on scene Wednesday morning, including The John Cabot, which has side-scanning sonar capabilities and is conducting search patterns alongside two other vessels, the Skandi Vinland and the Atlantic Merlin, the Coast Guard tweeted.

Meanwhile, questions remain about how teams could reach the lost submersible, which could be as deep as about 12,500 feet (3,800 meters) below the surface near the watery tomb of the historic ocean liner. Newly uncovered allegations also suggest there had been significant warnings made about vessel safety during its development.

Lost aboard the vessel are pilot Stockton Rush, the CEO of the company leading the expedition. His passengers are a British adventurer, two members of a Pakistani business family and a Titanic expert.