<human>:  When en route from China to France, must pilots know their altitude in the imperial foot?
<bot>: Yes, pilots must know their altitude in the imperial foot when en route from China to France. Most international airports and aviators use the foot to measure altitude and China and North Korea require pilots to use meters for altitude and pilots must communicate their altitude with local air traffic control, so pilots must know their altitude in the imperial foot when en route from China to France.