Editorials Dead man November 02, 2009 Share 1 -- As every schoolboy used to know, a dead man's switch is a device in a locomotive that the engineer must hold on to, or periodically activate, to keep the train running. The intent is to prevent the train from becoming a runaway if the engineer dies or falls asleep. The dead man's switch seems to have originated on trains, but similar devices are now common on lawn mowers, chain saws and personal watercraft -- but not airplanes. And that brings us to Northwest Flight 188, the San Diego-Minneapolis flight that infamously overshot its destination on Oct. 21. The incident triggered a national debate about the two pilots and pilots in general: Were these guys napping? Are pilots overworked? Should pilots in general be allowed to take controlled naps during long flights? The Northwest pilots initially claimed they were merely involved in a "heated discussion" about airline policy. They later admitted they were going over Delta's new scheduling system on their personal laptops, a violation of company policy and of FAA regulations, for which they have lost their licenses. That clears the air about what happened to Flight 188, but it hardly ends the debate about distracted pilots, tired pilots or napping pilots, all of which are unacceptable. If the industry and its regulators decide that we need new procedures to keep pilots awake and alert, we would suggest a device in the cockpit that sounds an alarm if there is no human input for a certain interval. The interval can be varied depending on the flight plan: short in busy urban corridors, longer on overnight transoceanic flights. The device could be set up to sound a cockpit warning, alert the cabin crew or contact ground control. We are not aeronautical engineers, but if it's good enough for trains that haul coal on rails, it should work in planes that carry people up in the air.