Navigation in Controlled and Uncontrolled Airspace
Airspace classes and clearances
Navigation in Controlled and Uncontrolled Airspace tests whether you can plan a flight through different airspace types without breaking rules. Under ICAO, controlled airspace includes Classes A to E; Class G is uncontrolled. Class A normally allows IFR only; Class D requires an ATC clearance for both IFR and VFR. Class E is controlled for IFR, while VFR participation rules vary by state, so check the AIP. Before entering controlled airspace, confirm the boundary, altitude, radio frequency and transponder requirements. In uncontrolled airspace, use correct position reports, maintain look-out and avoid known traffic areas. RMZ and TMZ require radio or transponder equipment as published.
Worked example
You are 10 nm south of a Class D boundary at 2,500 ft and request entry. Call: “Tower, G-ABCD, 10 nm south, 2,500 ft, request entry.” Do not cross the boundary until cleared. If the controller says, “G-ABCD, cleared to enter, maintain 2,500 ft, squawk 7000,” read back the clearance, altitude and squawk. If the clearance is not understood, request clarification and remain outside.
Traps
Do not assume that a radio call is a clearance. Do not enter Class D without an explicit clearance. Do not confuse Class E with uncontrolled Class G. Check whether the transponder or radio is mandatory in an RMZ/TMZ. Do not use a clearance for one aircraft as authority for another. Monitor the correct frequency and keep position reports accurate.