Title: FlightPerformanceCalc Aviation / Airspace
Tags: airspace

Tag: Class A
Question: Class A airspace — altitudes and rules?
Answer: 18,000 ft MSL up to and including FL600. IFR only — an instrument rating and an ATC clearance are required. No VFR flight.
Ref: AIRSPACE · 01

Tag: Class B
Question: Class B — shape, altitudes, and how you enter.
Answer: Surrounds the nation's busiest airports; surface to about 10,000 ft MSL, shaped like an upside-down wedding cake. You must receive a specific clearance — "cleared into the Bravo" — before entering.
Ref: AIRSPACE · 02

Tag: Class B
Question: Equipment and pilot requirements for Class B?
Answer: Two-way radio, a Mode C transponder, and ADS-B Out. At least a private certificate — or a student/sport/recreational pilot with the required endorsement (student solo is prohibited at ~12 of the busiest Class B airports).
Ref: AIRSPACE · 03

Tag: Class C
Question: Class C — dimensions and entry requirement?
Answer: Around airports with a tower, radar approach control, and moderate traffic. Typically surface–4,000 ft AGL: a 5 NM inner core and a 10 NM outer shelf (1,200–4,000 AGL). Two-way radio communication must be ESTABLISHED before entry.
Ref: AIRSPACE · 04

Tag: Class C
Question: When is two-way radio communication "established"?
Answer: When ATC replies using your call sign. "N123, standby" = established (you may enter). "Aircraft calling, standby" without your call sign = NOT established — remain clear.
Ref: AIRSPACE · 05

Tag: Class D
Question: Class D — dimensions and entry?
Answer: Surrounds a towered airport (no radar service by the tower). Roughly surface to 2,500 ft AGL and about 4 NM radius, tailored to the instrument approaches. Two-way radio communication must be established.
Ref: AIRSPACE · 06

Tag: Class E
Question: What is Class E airspace?
Answer: Controlled airspace that isn't A, B, C, or D. Floors are commonly 700 ft AGL (magenta shading), 1,200 ft AGL (blue shading), or the surface; it extends up to but not including 18,000 ft MSL. No clearance is needed for VFR.
Ref: AIRSPACE · 07

Tag: Class G
Question: What is Class G airspace?
Answer: Uncontrolled airspace — from the surface up to the overlying Class E floor. ATC has no authority there, and VFR weather minimums are the lowest. Common in remote and low-altitude areas.
Ref: AIRSPACE · 08

Tag: Special Use
Question: Prohibited vs Restricted areas?
Answer: Prohibited (P-): flight is banned entirely (e.g., P-56 over the U.S. Capitol/White House). Restricted (R-): invisible hazards such as artillery or missiles — you may transit only with the controlling agency's permission, and only when it is not "hot."
Ref: AIRSPACE · 09

Tag: Special Use
Question: What is an MOA (Military Operations Area)?
Answer: Airspace that separates military training from IFR traffic. VFR flight through an active MOA is legal without a clearance, but use extreme caution and request advisories; verify whether it is active.
Ref: AIRSPACE · 10

Tag: Special Use
Question: Warning Area vs Alert Area?
Answer: Warning Area (W-): hazardous activity starting 3 NM or more offshore over international waters. Alert Area (A-): high volume of pilot training or unusual activity — every pilot shares equal responsibility for see-and-avoid.
Ref: AIRSPACE · 11

Tag: Equipment
Question: Where are a transponder and ADS-B Out required (91.215 / 91.225)?
Answer: In Class A, B, and C; above the lateral limits of Class B or C up to 10,000 ft MSL; within the Mode C Veil (30 NM of a Class B primary airport); and generally at and above 10,000 ft MSL (except at or below 2,500 ft AGL).
Ref: AIRSPACE · 12

Tag: Equipment
Question: What is the Mode C Veil?
Answer: A 30 NM radius ring around a Class B primary airport, within which a Mode C transponder and ADS-B Out are required from the surface upward.
Ref: AIRSPACE · 13

Tag: Speed
Question: Maximum speed below 10,000 ft MSL?
Answer: 250 knots indicated airspeed (KIAS).
Ref: AIRSPACE · 14

Tag: Speed
Question: Speed limit beneath a Class B shelf or in a VFR corridor through Class B?
Answer: 200 knots indicated airspeed (KIAS).
Ref: AIRSPACE · 15

Tag: Speed
Question: Speed limit within 4 NM of a Class C or D primary airport at or below 2,500 ft AGL?
Answer: 200 knots indicated airspeed (KIAS).
Ref: AIRSPACE · 16

Tag: Charts
Question: How are Class B, C, D, and surface Class E drawn on a sectional?
Answer: Class B = solid blue lines. Class C = solid magenta lines. Class D = dashed blue lines. Class E to the surface = dashed magenta lines.
Ref: AIRSPACE · 17

Tag: Charts
Question: What do the fuzzy magenta and fuzzy blue vignettes mean?
Answer: Fuzzy magenta shading = Class E floor begins at 700 ft AGL. Fuzzy blue shading = Class E floor begins at 1,200 ft AGL. The airspace is on the shaded side of the line.
Ref: AIRSPACE · 18

Tag: Charts
Question: What is a TRSA?
Answer: Terminal Radar Service Area — overlays certain Class D/E airports and offers radar sequencing and separation. Participation is voluntary but recommended; depicted with solid gray lines.
Ref: AIRSPACE · 19

Tag: SVFR
Question: What is Special VFR and where can you get it?
Answer: An ATC clearance to fly VFR in controlled airspace to the surface below normal VFR minimums (at least 1 SM visibility, clear of clouds), within the lateral limits at/below the airspace. Not offered at some busy airports; night SVFR requires an instrument rating and a properly equipped aircraft.
Ref: AIRSPACE · 20

Tag: TFR
Question: What is a TFR and why check for them?
Answer: A Temporary Flight Restriction — published by NOTAM around hazards, VIP movement, major sporting events, or disasters. Check NOTAMs before every flight; busting a TFR risks interception and enforcement action.
Ref: AIRSPACE · 21

Tag: Minimums
Question: What airspace does the "3-152" cloud-clearance rule cover?
Answer: Class C, D, and E below 10,000 ft MSL: 3 SM visibility, 500 ft below, 1,000 ft above, and 2,000 ft horizontal from clouds.
Ref: AIRSPACE · 22

Tag: Services
Question: What service does Class C provide that Class D does not?
Answer: Class C has radar approach control providing sequencing and separation from IFR traffic plus traffic advisories to VFR aircraft. A Class D tower sequences runway traffic but does not provide radar separation itself.
Ref: AIRSPACE · 23

Tag: Class B
Question: What certificate does a student pilot need to enter certain Class B airports?
Answer: A logbook endorsement for that specific Class B airspace after ground and flight training. At about a dozen of the busiest Class B airports (listed in 91.131), student solo operations are prohibited entirely.
Ref: AIRSPACE · 24