Abstract: A passenger aircraft (10) with a security alarm system includes an aircraft fuselage (11) divided into a cockpit (14) and a passenger cabin (12). One or more portable transmitter units (17) carried by cabin crew members or other authorized personnel are adapted for discrete activation which sends a coded signal in the form of a radio frequency data burst to a receiver unit (19) located at an intermediate location in the passenger cabin (12). The receiver unit (19) activates an alarm unit (20) through hard wiring (22) past the bulkhead wall (15). The alarm unit (20) includes one or more audio or visual alarm devices (38, 40) that alerts the cockpit crew to an emergency situation in the cabin (12). The system includes a mute function that automatically mutes various alarms in the cockpit (14) to prevent distraction of the cockpit crew. During the mute on condition, the alarm assembly stores any received signals until the mute on condition is ended.