The full 14 CFR 91.155 table — visibility and cloud clearance for every class of airspace — plus the memory aids that make it stick.
Visual Flight Rules depend on one thing: see and avoid. The minimum visibility gives you the range to spot other traffic in time, and the cloud-clearance buffer keeps you from emerging from a cloud right next to an aircraft flying on instruments. 14 CFR 91.155 sets the exact numbers, and they tighten as airspace gets busier or faster.
No VFR. 18,000 ft MSL and above.
ATC keeps you separated, so you only need to stay out of the clouds.
The “3-152” minimums.
Same as Class C.
The “3-152” minimums.
The “5-111” minimums — faster traffic, more room needed.
The lowest minimums in the system.
Night raises the bar.
The “5-111” minimums.
Class B*, C, D, and E below 10,000 ft
3 SM visibility · 1,000 ft above · 500 ft below · 2,000 ft horizontal.*Class B is the exception: 3 SM but only “clear of clouds.”
At or above 10,000 ft MSL
5 SM visibility · 1,000 ft above · 1,000 ft below · 1 SM horizontal. More room for faster, higher traffic.
When conditions are below basic VFR, an ATC Special VFR clearance can let you operate in controlled airspace at an airport with at least 1 SM visibility and clear of clouds. You must request it and ATC must approve it — and at night it generally requires an instrument rating and an IFR-capable aircraft.
FlightKit’s airspace module pairs the FAA airspace diagram with quizzes and flashcards, so the classes, altitudes, and minimums actually stick before your checkride.
They are the minimum flight visibility and distance-from-clouds required to fly under Visual Flight Rules, set by 14 CFR 91.155. They exist so VFR pilots can see and avoid other traffic and stay clear of clouds where IFR traffic may emerge. The exact numbers depend on the airspace class, your altitude, and whether it is day or night.
In Class C, D, and Class E below 10,000 ft MSL you need 3 statute miles visibility and to stay 500 feet below, 1,000 feet above, and 2,000 feet horizontally from clouds. Pilots remember it as “3-152”: 3 miles, 1,000 above, 500 below, 2,000 horizontal.
Above 10,000 ft MSL (in Class E and Class G) the minimums increase to “5-111”: 5 statute miles visibility, 1,000 feet below, 1,000 feet above, and 1 statute mile horizontal from clouds. Traffic moves faster up high, so you need more room and range to see and avoid.
Special VFR (SVFR) is an ATC clearance that lets you operate in controlled airspace at an airport with less than basic VFR minimums — at least 1 statute mile visibility and clear of clouds — when conditions are below the normal numbers. You must request it, ATC must approve it, and at night you generally need an instrument rating and an IFR-capable aircraft.
It is harder to see and avoid traffic and terrain in the dark, so Class G night minimums rise to 3 SM and 500/1,000/2,000 cloud clearance — matching the daytime controlled-airspace numbers. There is a limited exception within half a mile of a runway in the traffic pattern.
That is exactly the point. The visibility minimum gives you range to spot traffic, and the cloud-clearance buffer keeps you from popping out of (or into) a cloud right next to an aircraft on instruments. They are see-and-avoid margins, not just bureaucratic numbers.