Airspace and Air Traffic Control Procedures
Airspace as a planning problem
A balloon drifts and cannot hold, turn or go around, so the exam tests whether you plan the airspace before launch and know the visibility, cloud-clearance and equipment rules for each class.
Classes and requirements
- Class B: an explicit ATC clearance is required, 3 SM visibility, clear of clouds. Radio contact alone is not a clearance.
- Class C: two-way radio established before entry, altitude-encoding transponder, 3 SM, 500 below / 1,000 above / 2,000 ft horizontal.
- Class D: two-way radio established before entry, 3 SM, 500/1,000/2,000. Class D normally tops out at 2,500 ft AGL.
- Class E: no radio requirement; below 10,000 ft MSL, 3 SM, 500/1,000/2,000; at or above 10,000 ft MSL, 5 SM, 1,000/1,000/1 SM.
- Class G: at or below 1,200 ft AGL in daytime, 1 SM and clear of clouds; at night, 3 SM with 500/1,000/2,000. Above 1,200 ft AGL, 1 SM day and 3 SM night until 10,000 ft MSL.
- Special use airspace: prohibited areas are closed; restricted areas require the controlling agency's permission; MOAs and alert areas are legal VFR but expect military traffic; TFRs and national security areas must be checked in NOTAMs the morning of the flight.
Transponder and ADS-B
A balloon certificated without an engine-driven electrical system is excepted from the transponder and ADS-B Out rules, including inside a Mode C veil. The exception is not an airspace clearance: you still need a Class B clearance and radio communications for Class C and D, so the practical answer is usually to stay clear or to carry a battery-powered transponder.
Worked example
Your launch field is 4 NM from a Class D airport whose airspace tops at 2,500 ft AGL, and the forecast track crosses it at 3,000 ft AGL. You will be above the shelf, but if your altitude is uncertain, call the tower before entry and monitor the frequency. With no radio, plan a track that stays clear, because the balloon cannot turn away at the last minute.
Traps
Assuming Class E begins at 1,200 ft AGL everywhere (surface-area Class E exists); treating radio contact as a Class B clearance; and forgetting that 91.119 minimum altitudes still apply inside Class G.