FAR 71.31 — Class A Airspace
FAR 71.31 designates Class A airspace and subjects all pilots and aircraft within it to Part 91 rating, operating, and equipment requirements.
FAR 71.31 is the rule that formally designates Class A airspace in the United States. It does this by pointing to two sources:
- The airspace descriptions in § 71.33
- The routes contained in subpart A of FAA Order JO 7400.11K (incorporated by reference under § 71.1)
Whatever those documents describe is, by regulation, Class A airspace.
Once you're operating inside Class A, every pilot and aircraft is subject to the rating requirements, operating rules, and equipment requirements of Part 91. In practical terms, this is what locks in the familiar Class A rules students learn elsewhere — instrument rating required, IFR flight plan and ATC clearance required, and the equipment (transponder, altitude reporting, etc.) called out in Part 91.
Why it matters: § 71.31 is the legal hook that takes Class A from a chart depiction to an enforceable regulation. If you fly into Class A without meeting Part 91, you're not just busting a procedure — you're violating the airspace designation itself.