"C.P.I."---A Crash Position Indicator for Aircraft

A novel, light, simple and inexpensive position indicator for crashed aircraft has been developed and subjected to severe tests. A special pulsed transmitter with trickle-charged batteries and an internal antenna is potted in shock-absorbing foam transparent to radio waves and placed inside a special aerofoil. This device, held on the tail of the aircraft, is released automatically upon detection of any abnormal structural disturbance. Then it tumbles away from the aircraft in time to clear the danger zone, slows down to a safe landing and transmits a distress signal from any position and under wide environmental conditions.