The invention provides a sensor for determining when a latch for securing an engine cowl on an aircraft is secured by detecting the proximity of a latch hook and a latch pin. The sensor includes a resonant circuit configured and adapted to transmit a status signal when the latch is in a secured state....http://www.google.com/patents/US7994940?utm_source=gb-gplus-sharePatent US7994940 - Mechanical latch locking detection sensors
