For some reason that reminds me of this:
http://web.archive.org/web/20080104161307/http://www.nasm.si.edu/research/aero/aircraft/focke_achgelis.htm
'Should the U-boat came under attack and need to 'crash' dive, the pilot pulled a large red lever above the seat. This started a chain of events designed to save the submarine without sacrificing the pilot. The towline disconnected from the aircraft, freeing the submarine to dive immediately, and the spinning rotor simultaneously departed from the airframe rotor mast. As the rotors flew up and away, they pulled a cable that deployed the pilot's parachute. When parachute blossomed, the pilot popped his seat harness and the remainder of the gyrocopter fell into the sea. After the submarine evaded the threat, it could return to the surface to pick up the pilot. If time and circumstances permitted, the pilot could release the towline without triggering the entire emergency sequence. The flyer could then ditch his Fa 330 near the submarine, or attempt to land back aboard the ship. The type of threat and the speed of its approach dictated the pilot's actions.'