FAR Explainer · 91.155

Updated May 17, 2026

14 CFR 91.155 — Basic VFR Weather Minimums (Explained)

Cloud-clearance and visibility minimums by airspace class under 14 CFR 91.155. Why IFR pilots still get tested on this on the instrument oral.

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14 CFR 91.155 — Basic VFR Weather Minimums (Explained)

What does 14 CFR 91.155 require?

14 CFR 91.155(a) prohibits VFR flight unless the pilot maintains at least the minimum flight visibility and distance from clouds specified in the table below for the airspace class being operated in. The rule addresses two distinct elements: flight visibility (how far you can see horizontally) and cloud clearance (how far you must stay from clouds in three dimensions — below, above, and horizontal).

The minimums exist to give pilots enough margin to see and avoid other traffic, and to prevent inadvertent instrument meteorological conditions (IMC) entry. The FAA structured the table so that more complex, higher-traffic airspace (Class B, C, D) carries stricter minimums than uncontrolled Class G, with the notable exception that altitudes at or above 10,000 feet MSL carry the same high-altitude minimums regardless of airspace class.

What are the cloud clearance and visibility requirements by airspace class?

The table below reproduces the requirements from 14 CFR 91.155(a) . All visibility values are in statute miles. Cloud clearance distances are expressed as below / above / horizontal.

Airspace Class	Flight Visibility	Below Clouds	Above Clouds	Horizontal from Clouds
Class A	N/A (IFR only)	N/A	N/A	N/A
Class B	3 sm	Clear of clouds	Clear of clouds	Clear of clouds
Class C	3 sm	500 ft	1,000 ft	2,000 ft
Class D	3 sm	500 ft	1,000 ft	2,000 ft
Class E below 10,000 ft MSL	3 sm	500 ft	1,000 ft	2,000 ft
Class E at/above 10,000 ft MSL	5 sm	1,000 ft	1,000 ft	1 sm
Class G — day, ≤1,200 ft AGL (airplane)	1 sm	Clear of clouds	Clear of clouds	Clear of clouds
Class G — night, ≤1,200 ft AGL (airplane)	3 sm	500 ft	1,000 ft	2,000 ft
Class G — day, >1,200 ft AGL, below 10,000 ft MSL	1 sm	500 ft	1,000 ft	2,000 ft
Class G — night, >1,200 ft AGL, below 10,000 ft MSL	3 sm	500 ft	1,000 ft	2,000 ft
Class G — at/above 10,000 ft MSL	5 sm	1,000 ft	1,000 ft	1 sm

Three patterns are worth memorizing for the oral exam: (1) Class B is always "clear of clouds" regardless of altitude inside the airspace; (2) night minimums in Class G below 1,200 feet AGL match Class C/D controlled airspace requirements; (3) the 10,000-foot MSL threshold triggers the 5 sm / 1,000 / 1,000 / 1 sm standard in every class.

What are the special rules in 91.155(b) through (d)?

14 CFR 91.155(b) contains two traffic-pattern exceptions for Class G airspace below 1,200 feet AGL:

Helicopters may operate clear of clouds within 1/2 sm of a runway or helipad in the traffic pattern with flight visibility of at least 1/2 statute mile.
Airplanes, powered parachutes, and weight-shift-control aircraft may operate clear of clouds (rather than 500/1,000/2,000) in the night traffic pattern if flight visibility is at least 1 statute mile but below 3 statute miles.

14 CFR 91.155(c) prohibits flight beneath a ceiling under VFR within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet, except as provided in 14 CFR 91.157 (Special VFR) .

14 CFR 91.155(d) requires at least 3 statute miles ground visibility (or 3 sm flight visibility if ground visibility is not reported) for any takeoff, landing, or traffic pattern entry at an airport in Class B, C, D, or E surface areas.

Why do IFR pilots get tested on VFR weather minimums?

Three IFR operations require direct compliance with 14 CFR 91.155 , which is why the Instrument Rating ACS includes this regulation as a knowledge element.

VFR-on-top. An IFR pilot cleared for "VFR-on-top" must comply with all VFR cloud-clearance and visibility minimums for the airspace being flown, while simultaneously maintaining IFR altitudes, position reporting, and ATC separation requirements. The two sets of rules run concurrently.

Visual approach. When ATC issues a visual approach clearance, the IFR clearance is cancelled for the approach segment. The pilot must have the airport or preceding traffic in sight and must maintain VFR cloud-clearance appropriate to the airspace. If the airport environment is lost, the pilot must immediately advise ATC and expect a new IFR clearance or instruction.

Special VFR. Under 14 CFR 91.157 , a pilot may request ATC authorization to operate VFR inside a surface-area control zone with less than the standard 3 sm / 1,000-foot ceiling minimums. At night, Special VFR requires an instrument rating and IFR-equipped aircraft under 14 CFR 91.205(d) . Knowing the baseline VFR minimums is a prerequisite to understanding when Special VFR is necessary.

Contrast with IFR equipment. Instrument flight requires the equipment listed in 14 CFR 91.205(d) . VFR flight in IMC conditions does not become legal by carrying extra instruments — 91.155 weather minimums apply to operating authorization, not equipment.

Contrast with IFR descent to minimums. At the end of an instrument approach, the visual reference requirements that allow descent below DA or MDA come from 14 CFR 91.175(c) , not 91.155. Confusing the two regulations is a common oral exam error.

Practice Questions

You are operating VFR at 8,500 feet MSL in Class E airspace. What is the minimum distance you must maintain below clouds?
ATC clears you for "VFR-on-top" at 11,000 feet MSL in Class E airspace. What flight visibility and cloud clearance are required?
You are flying a Cessna 172 in Class G airspace, 800 feet AGL, at night. What are the minimum flight visibility and cloud-clearance requirements?
A DPE asks: "When you receive a visual approach clearance from ATC, does 14 CFR 91.155 apply?" What is your answer?
You are at a towered airport with a reported ceiling of 900 feet overcast and 5 sm visibility. What rule prevents you from departing VFR, and what exception might allow you to depart?

Frequently Asked Questions

Q: What is the minimum flight visibility to operate VFR in Class B airspace?

3 statute miles, and you must remain clear of clouds. Under 14 CFR 91.155(a) , Class B has no numerical cloud-clearance requirement — "clear of clouds" is the standard. The 3 sm visibility floor applies whether you are below or above 10,000 feet MSL inside Class B.

Q: What are the VFR weather minimums in Class G airspace at night below 1,200 feet AGL?

3 statute miles flight visibility and 500 feet below, 1,000 feet above, 2,000 feet horizontal from clouds per 14 CFR 91.155(a) . Night minimums in Class G below 1,200 feet AGL match Class C and D requirements, even though Class G is uncontrolled. The daytime minimum is only 1 sm and clear of clouds.

Q: What changes at 10,000 feet MSL for VFR weather minimums?

Visibility increases to 5 statute miles and cloud clearance expands to 1,000 feet below, 1,000 feet above, and 1 statute mile horizontal under 14 CFR 91.155(a) . These higher minimums apply in both Class E and Class G at or above 10,000 feet MSL, regardless of airspace class.

Q: Can an IFR pilot descend below 1,000 feet AGL on a VFR-on-top clearance?

Only if VFR weather minimums are met at the altitude flown. VFR-on-top requires compliance with 14 CFR 91.155 cloud-clearance and visibility values for the airspace class being transited, plus IFR altitude, ATC separation, and position reporting rules under the IFR clearance.

Q: What is a Special VFR clearance and when is it available?

A Special VFR clearance under 14 CFR 91.157 permits operations in a surface-area control zone with less than 3 sm visibility or below 1,000-foot ceilings. Fixed-wing pilots need an ATC clearance; at night, they must also be instrument-rated and the aircraft must be IFR-equipped per 14 CFR 91.205(d) .

Q: Does 14 CFR 91.155 apply to IFR flight?

Not during active IFR operations in IMC — IFR pilots operate under 14 CFR 91.177 altitude rules and ATC separation. However, 91.155 directly applies during VFR-on-top, visual approaches, and Special VFR. DPEs test it because the line between VFR and IFR operations has direct operational consequences.

Q: What is the minimum visibility for takeoff or landing in Class D airspace under VFR?

3 statute miles ground visibility, or if not reported, 3 statute miles flight visibility during the takeoff or landing, per 14 CFR 91.155(d) . This applies to Class B, C, D, and E surface areas and is separate from the en route cloud-clearance table in 91.155(a).

Q: Can a helicopter operate VFR in Class G airspace with 1/2 statute mile visibility?

Yes, under specific conditions. 14 CFR 91.155(b)(1) permits a helicopter to operate clear of clouds within 1/2 statute mile of the runway or helipad in a traffic pattern with flight visibility of at least 1/2 statute mile, when below 1,200 feet AGL. This exception does not apply to airplanes.

Sources

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Practice questions on VFR weather minimums

This article was researched from FAA primary sources (14 CFR Part 91 via Cornell LII, FAA Instrument Rating ACS, Instrument Flying Handbook) and citing current regulatory text — drafted by MockDPE. Last updated: May 2026. If you spot an inaccuracy, email corrections@mockdpe.org.

Frequently Asked Questions

What is the minimum flight visibility to operate VFR in Class B airspace?

3 statute miles, and you must remain clear of clouds. Under 14 CFR 91.155(a), Class B has no numerical cloud-clearance requirement — 'clear of clouds' is the standard. The 3 sm visibility floor applies whether you are below or above 10,000 feet MSL inside Class B.

What are the VFR weather minimums in Class G airspace at night below 1,200 feet AGL?

3 statute miles flight visibility and 500 feet below, 1,000 feet above, 2,000 feet horizontal from clouds. Night minimums in Class G below 1,200 feet AGL match Class C and D requirements, even though Class G is uncontrolled. The daytime minimum is only 1 sm and clear of clouds.

What changes at 10,000 feet MSL for VFR weather minimums?

Visibility increases to 5 statute miles and cloud clearance expands to 1,000 feet below, 1,000 feet above, and 1 statute mile horizontal — in both Class E and Class G airspace at or above 10,000 feet MSL. The higher minimums apply regardless of airspace class at that altitude band.

Can an IFR pilot descend below 1,000 feet AGL on a VFR-on-top clearance?

What is a Special VFR clearance and when is it available?

A Special VFR clearance under 14 CFR 91.157 permits operations in a surface-area control zone with less than 3 sm visibility or below 1,000-foot ceilings. Fixed-wing pilots need a Special VFR clearance from ATC; at night, they also must be instrument-rated and the aircraft must be IFR-equipped.

Does 14 CFR 91.155 apply to IFR flight?

Not during active IFR operations — IFR pilots operate under 14 CFR 91.177 altitude rules and ATC separation, not VFR minimums. However, 91.155 directly applies when flying VFR-on-top, executing a visual approach, or transitioning from IFR to VFR. DPEs test it because the line between VFR and IFR operations matters operationally.

What is the minimum visibility for takeoff or landing in Class D airspace under VFR?

3 statute miles ground visibility, or if not reported, 3 statute miles flight visibility during the takeoff or landing. This requirement comes from 14 CFR 91.155(d) and applies to Class B, C, D, and E surface areas. It is separate from the en route cloud-clearance table in 91.155(a).

Can a helicopter operate VFR in Class G airspace with 1/2 statute mile visibility?

Authoritative Sources

AI-generated study aid — not an official source. This article was written entirely by AI working from FAA primary sources (Instrument Rating ACS, 14 CFR Part 91, Aeronautical Information Manual, Instrument Flying Handbook, and relevant Advisory Circulars), with sources cited inline so you can verify each claim. It has not been reviewed by a CFI, DPE, or other certificated aviation professional. AI can hallucinate, misstate section numbers, and subtly paraphrase regulations in ways that change their meaning. Treat this page as a study starting point only — always confirm any regulatory, procedural, or operational fact against the linked FAA primary document before relying on it for a checkride, a written exam, or a flight. Last updated May 17, 2026. Spotted an error? Email corrections@mockdpe.org.