ATC here. One of my favorites is:
11. Planes have radios that can select all ten digits.
Someone's radio broke where they couldn't enter '2' into it, so we had to find frequencies along their path that they could use and where ATC could relay.
11. Planes have radios that can select all ten digits.
Someone's radio broke where they couldn't enter '2' into it, so we had to find frequencies along their path that they could use and where ATC could relay.
plane 1 > assign code 4563
plane 2 > reject
plane 1 > assign code 0827
plane 2 > accept
Also assigning short codes like that isn't something likely to be necessary in an automated protocol like this. Why not just have every message sent between 2 planes include a sender_id: UUID header?
This is not a system where you get to do clean slate greenfield development. Whatever you do must work for the lowest common denominator. ATC is a fairly cheap societal expense compared to developing, certifying, installing, and maintaining systems with the level of integration you want in hundreds of thousands of diverse planes.