Abstract: An alarm system to keep an aircraft pilot or a vehicle operator alert utilizes a first timer to activate visual alarm. The first timer is reset by actuation of the aircraft communications press-to-talk button. If the pilot fails to reset the first timer within a predetermined time, a second timer triggers an audio alarm. Once the audio alarm is triggered, it remains triggered and not resettable for a predetermined period of time. During normal operation of an aircraft during landings and takeoffs, the communications press-to-talk button is actuated as part of normal cockpit operations at intervals shorter than the time for the first timer to complete its timing cycle. Accordingly, an alarm is not generated during such landings and takeoffs, but is effective during cruise flight when the danger of drowsiness is greatest.