📘14 CFR §91.155 - Basic VFR Weather Minimums

✏️ Plain-English Summary:

This reg sets the minimum visibility and cloud clearance required to fly VFR (without a flight plan or ATC clearance). The rules change depending on airspace and altitude, so memorizing the categories is key.

✅ Key PPL Takeaways:

🗂️ Break It Down by Airspace:

Airspace	Visibility	Cloud Clearance
Class A	❌ VFR not allowed	Must be on IFR flight plan
Class B	3 SM	Clear of clouds
Class C/D/E Below 10,000’ MSL	3 SM	500' below, 1,000' above, 2,000' horizontal (💬 “152 rule”)
Class E At or above 10,000’ MSL	5 SM	1,000' below, 1,000' above, 1 SM horizontal
Class G Day, <1,200’ AGL	1 SM	Clear of clouds
Class G Night, <1,200’ AGL	3 SM	500 below, 1,000 above, 2,000 horizontal
Class G Above 1,200’ AGL but <10,000’ MSL	Day: 1 SM Night: 3 SM	500 below, 1,000 above, 2,000 horizontal
Class G Above 10,000’ MSL	5 SM	1,000 below, 1,000 above, 1 SM horizontal

💬 Memory Aids:

• “152 Rule” → 3 SM vis, 500 below, 1000 above, 2000 horizontal (C/D/E below 10,000’)

• “5-111 Rule” → 5 SM vis, 1000 below, 1000 above, 1 SM horizontal (E/G above 10,000’)

• Class B = Big airports = easy → 3 SM, clear of clouds

• Class G = Ground / Uncontrolled → Looser rules, especially below 1,200’ AGL in daytime

✈️ Scenario:

You're flying VFR at 8,500’ MSL in Class E airspace on a clear day. Visibility is 4 SM. ✅ Legal? Yes — you're below 10,000’, so the 3 SM / 152 cloud clearance applies.

Now you're at 10,500’ MSL — still 4 SM vis. ❌ Not legal — you need 5 SM and 1,000’ / 1,000’ / 1 SM clearance above 10,000’.

🎓 CFI Teaching Tip:

Print a VFR Weather Minimums chart and walk students through the table using their local airspace. Tie in §91.155 to Special VFR (91.157) to explain how pilots can sometimes request clearance in marginal weather at towered airports.

📚 References:

• FAR §91.155 – Basic VFR Weather Minimums

• AIM 3-1-4 & 3-3-1 (VFR Weather)

• FAA Airspace Diagram – PHAK Ch. 14

• Pilot’s Handbook of Aeronautical Knowledge (PHAK) Ch. 11