D airspace entry¶

Available now.

What it does¶

A VFR flight nearing a Class B, C or D airport is expected to establish the right kind of contact before entering -- xatc checks for it, independent of flight phase, for as long as the loaded atc.dat has that airspace and its controlling position is staffed. IFR flights are never checked here -- 14 CFR 91.131/130/129 only bind VFR.

Class B: request a clearance¶

Class B needs an explicit request -- say "request Bravo clearance" (or "request clearance into the Class Bravo") to whichever facility owns it. Approved: "cleared into the Class Bravo airspace, maintain VFR at or below four thousand" -- the altitude is the next 500 ft above your current one (minimum 2,500 ft, capped at the Class B's own ceiling). Asking as an IFR flight, or asking a facility that doesn't own a Class B, gets "say again".

A VFR takeoff automatically clears you into your own departure airport's Class B, if it has one -- no separate request needed there.

Entering without a clearance gets an escalating callout: "you are in Class Bravo airspace without a clearance, remain outside Class Bravo airspace", gentle through "possible pilot deviation".

Climbing above your cleared altitude (F10) gets its own callout: "check altitude, maintain VFR at or below four thousand", then "maintain VFR at or below four thousand", then a deviation -- the tolerance scales with conformance strictness the same way every other altitude tolerance does.

Class C and D: two-way contact is enough¶

Class C and D don't need a request at all -- ordinary two-way radio contact satisfies it: any transmission from that facility that uses your callsign. Enter before that's happened and you get an escalating callout naming the airspace: "you entered Class Charlie airspace without establishing communications" (or "Class Delta").

Out of scope¶

Sequencing behind other traffic ("number two, follow the...") doesn't apply to airspace-entry clearances -- whether you're cleared into Class B, or in violation entering C/D without contact, never depends on anyone else's position. Sequencing itself is implemented elsewhere (Approach's landing clearance, the VFR pattern's runway queue) -- see M7-3 in the roadmap.