Tobzalp and Chris Higgins
You are both right…. and both wrong.
FAA AIM states that:
Two-way radio communication must be established with the ATC facility providing ATC services prior to entry and thereafter maintain those communications while in the Class D airspace. Pilots of arriving aircraft should contact the control tower on the publicized frequency and give their position, altitude, destination, and any request(s). Radio contact should be initiated far enough from the Class D airspace boundary to preclude entering the Class D airspace before two-way radio communications are established.
And also…..
2. If workload or traffic conditions prevent immediate entry into Class D airspace, the controller will inform the pilot to remain outside the Class D airspace until conditions permit entry.
Effectively, establishment of two-way communications is an
implied clearance, but a clearance
can be denied for reasons which are not limited to IMC.