Originally Posted by HighFlight

Is there anything in the FARs or AIM that specifies altitude for sterile cockpit? Other than our manuals, I mean? 121.542 just says 10,000 feet, and doesn’t specify what measurement is being used. OAL use 10,000 MSL, just curious why we choose “approximately 10,000’ AFE”, when there is an easier number to see on our instruments?