The RC-12H Guardrail Common Sensor system is a U.S. Special Electronic Mission Aircraft used as an airborne signal intercept and emitter location system that provides real-time tactical battlefield signal intelligence information. This aircraft was assigned to the 3rd Military Intelligence BN (AEB) Korea. Its crew was 2, its speed was 200 KT, its range was 1200NM, and it had 2 PW PT6A-42 850SHP engines.