Distress beacon - e.g. for crashed aircraft has automatically inflatable balloon to lift it clear of craft in case of fire

摘要

The balloon remains fixed to the craft by being connected to it by an axial cable. The balloon carries a signal emitter and the cable connector is a conductor so that the emitter can be supplied. The ballon can also have its own current supply e.g. solar collectors, and the signal given out by the emitter can be radio, sound or light waves. - At rest the balloon is held in a covered envelope which also contains the emitter, the cable and a compressed air supply.