Module MOD-08 · 7 min · ACS PA.I.E

Busy Airports: Class B, C and D

← Airspace and Operating Requirementsdraft — pending CFI review

Why this matters in flight: Each of these classes has a different rule for what you must do BEFORE you enter. Mixing them up is a common checkride and written-test error, and in the air it can mean an airspace violation.
Standard left-hand traffic patternA rectangular traffic pattern around a runway with left turns. The legs, in sequence, are departure and upwind, crosswind, downwind flown opposite the landing direction, base, and final approach aligned with the runway.RWY 36UpwindCrosswindDownwindBaseFinalWind
DRAFT schematic — pending CFI review. Standard left traffic; some runways use right traffic. Not to scale; not an FAA-approved figure.

Class B, C, and D all surround airports with control towers, but the entry rule is different for each. Class D only requires that you establish two-way radio communication with the tower before entering. Class C requires the same two-way communication PLUS a Mode C transponder and ADS-B Out. Class B is the strictest: you need an explicit clearance — the controller must say the words "cleared into the Class Bravo" — and you also need the transponder and ADS-B Out. A helpful memory aid: for D you must be heard, for C you must be heard and seen (transponder), and for B you must be heard, seen, and cleared. Class B is drawn like an upside-down wedding cake with shelves that step outward as you go up.

Key terms

Two-way communication
ATC using your call sign counts as establishing communication.
Clearance
An explicit ATC authorization; required to enter Class B.
ADS-B Out
Automatic Dependent Surveillance–Broadcast; broadcasts your position.

Summary

D = be heard; C = be heard and seen (transponder + ADS-B); B = be heard, seen, and explicitly cleared.

Quick check ▾

One question on what you just read.

Question 1 of 1

Objective mastery: 15%

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What is required before entering Class B airspace?

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Sources

Every claim traces to a source — paraphrased knowledge elements pointing at the governing FAA publication; not yet verified against a retrieved source.

  • AIM 3-2-5 / 14 CFR 91.129 — Aeronautical Information Manual unverified
  • AIM 3-2-4 / 14 CFR 91.130 — Aeronautical Information Manual unverified
  • 14 CFR 91.215 / 91.225 — 14 CFR Part 91 — General Operating and Flight Rules unverified
  • AIM 3-2-3 / 14 CFR 91.131 — Aeronautical Information Manual unverified

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