This question: Do commercial aircraft carry personal weapons? until yesterday contained an answer that began with words to the effect that arming pilots was “a recipe for disaster” due to the presumed ease with which an attacker might disarm a pilot and turn the weapon on them. It was stated that...
@ymb1: It doesn't say it applies to Part 139 only, but for airport certification for Part 139 activities it would be an acceptable mean of compliance. So you may be wrong or right, but this information is not sufficient to decide. — mins5 mins ago
@mins: An AC to meet the regs of Part 139, is for Part 139 airports. How can it not be? Why would a non-Part 139 airport want to meet the regs of this AC, including the beacon?
this should address 757toga's first comment
and IMO worth stating in the answer, because right now it reads like all U.S. airports need a beacon
@Jamiec I found the answer to your now-deleted question, from the UK AIP:
> 5.3.3 Pilots landing at aerodromes beneath Terminal Control Areas and Control Areas should use aerodrome QNH when flying below the Transition Altitude and beneath these Areas, except that the aerodrome QFE may be used when flying within the circuit. It may be assumed that for aerodromes within the boundary of the same TMA or CTA, differences in their QNH values are insignificant.
i.e. in the UK ATC needs to know if you'll be on QNH or QFE
