Airspace and Air Traffic Control Procedures
Three questions for any airspace
For every airspace question ask: what communication is required, what equipment is required, and what weather minimums apply? Class A is IFR only. Class B requires an explicit clearance plus a transponder and Mode C, and the Mode C veil extends 30 nm around the primary Class B airport. Class C and Class D require established two-way radio communications before entry; Class C also requires a transponder and Mode C. Class E is controlled airspace with no VFR communication requirement, and it can exist as a surface area, an extension, or above 14,500 MSL. Class G is uncontrolled, with minimums that change with altitude and day/night.
Special use airspace
Prohibited areas are off limits. Restricted areas are hazardous when active; check with flight service or ATIS. MOAs and alert areas contain military activity but VFR flight is legal. Warning areas lie over international waters. TFRs may be regulatory or issued by NOTAM.
Traps
- Class B is a clearance; Class C and D are communications. A radio call does not authorize Class B entry.
- Speed limits: 250 kt below 10,000 MSL, 200 kt under Class B or within 4 nm of a Class C or D airport at or below 2,500 ft AGL.
- Oxygen: 12,500 to 14,000 MSL for more than 30 minutes, and continuously above 14,000.
- Class G minimums tighten above 1,200 ft AGL and again at 10,000 MSL.
Rule of thumb
Memorize the cloud-clearance pattern of 500 below, 1,000 above, 2,000 horizontal with 3 SM visibility, then adjust only for Class B (clear of clouds) and Class G at 1,200 ft AGL or below by day (clear of clouds, 1 SM).