While searching for the missing submersible on Tuesday, a Canadian aircraft detected "banging" noises in the area where the explorers had been, according to internal email sent by Homeland Security's National Operations Center, which Rolling Stone obtained. The sounds came every 30 minutes, and after four hours, "additional sonar was deployed and banging was still heard."
The president of the Explorers Club in New York posted on Twitter that "likely signs of life have been detected at the site" and that there is "cause for hope." (See tweet below.)
From The New York Times:
The Coast Guard said in a brief statement on Twitter that some of the remote-operated vehicles involved in the search had been relocated in an attempt to determine the origin of the sounds. Those searches had so far "yielded negative results" but were continuing, the statement said. …
On Tuesday, the president of the Explorers Club, a New York-based organization, sent club members a letter that said sonar in the search area had "detected potential 'tapping sounds' implying that the crew may be alive and signaling" at 2 a.m. local time. The club's president, Richard Garriott de Cayeux, did not elaborate.
In a statement posted to Twitter later on Tuesday, he said that "likely signs of life have been detected at the site." He added that the club was working for approval to deploy a remote-operated vehicle in the search area that was capable of descending to depths of 6,000 meters, or nearly 20,000 feet.