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Class A airspace generally begins at which altitude?

Choices

  • 10,000 feet MSL

    10,000 MSL is a common transponder/speed threshold, not the base of Class A.

  • 14,500 feet MSL

    14,500 MSL relates to some Class E floors, not Class A.

  • ✓ 18,000 feet MSLcorrect

    Class A runs from 18,000 MSL up to and including FL600.

  • Flight level 600

    FL600 is the top of Class A, not its base.

Why

Class A extends from 18,000 feet MSL up to and including FL600 and is flown under IFR only.

FAA source: 14 CFR 71 / AIM 3-2-2browse the reference library →

This is taught in The Airspace System at a Glance — study the lessons free, then practice with grading and mastery tracking.

Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.

Class A airspace generally begins at which altitude? · PPL Free Ground School