Clearly an exception could be made in this case. Systems that are part of a passenger jet could hardly be called consumer grade. Incidentally, my GPS watch (Ga

Clearly an exception could be made in this case. Systems that are part of a passenger jet could hardly be called consumer grade. Incidentally, my GPS watch (Garmin) was working last time I was on a plane. It was bang on 700kph the whole time IIRC.