How Safe Arm Devices Work
The Safe Arm Device (SAD) is an electro-mechanical device used to provide a reliable initiation of an explosive train when it is commanded in the ARM state and provided with the correct firing stimulus. The SAD utilizes an Electro-Explosive Device (EED) for energetic output to initiate the explosive train. When the SAD is in the SAFE position the device is intrinsically safe from Safe Arm Device iiinadvertently initiating the connected explosive train. In the SAFE position, the detonator is both electrically and mechanically isolated (rotated out-of-line with the output port) from any electrical inputs and explosive train outputs providing the needed intrinsic safety. The SAD is commanded to the ARM state when the arming circuit is energized with the required input voltage pulse. In the ARM state, the EED is rotated to the SAD output port putting it in line with the explosive ordnance train. Once in the ARM state, the SAD can be initiated when the required electrical input stimulus is provided to the EED firing circuit. The SAD contains both local visual (window) and remote electrical redundant safe and arm position monitor circuits. The SAD includes a safing mechanism for manual safing.