>If you had a transponder in parallel with each engine, on the ground you could shut down all engines; or for an in-flight fire you could shut down a single eng

>If you had a transponder in parallel with each engine, on the ground you could shut down all engines; or for an in-flight fire you could shut down a single engine; but you could not shut down all engines (transponders) while in flight. Dual transponders linked to engines is not a safe design. You are significantly increasing the chance of an aircraft crash for a slight reduction in uncertainty of the location of crashed/hijacked aircraft. >You've heard of LoJack, right? We track cars worth far less than a jet airliner. People voluntarily deploying tracking systems is different from mandating tracking systems. Cars and buses are at a much higher risk of hijacking per passenger/travel distance than planes.