Titan sub: How do surveillance planes spot ocean submersibles?

What hasn't changed, for even the most cutting-edge aircraft, is reliance on old-fashioned intelligence. "To be most effective, the P-8 needs first to have a rough sense of the location and direction of the submarine to find it," says Dr Sidharth Kaushal, a research fellow at the UK defence and security think tank, the Royal United Services Institute (RUSI).