§ 91.157 Special VFR weather minimums.
(a) Except as provided in appendix D, section 3, of this part, special VFR operations may be conducted under the weather minimums and requirements of this section, instead of those contained in §91.155, below 10,000 feet MSL within the airspace contained by the upward extension of the lateral boundaries of the controlled airspace designated to the surface for an airport.
(b) Special VFR operations may only be conducted—
(1) With an ATC clearance;
(2) Clear of clouds;
(3) Except for helicopters, when flight visibility is at least 1 statute mile; and
(4) Except for helicopters, between sunrise and sunset (or in Alaska, when the sun is 6 degrees or more below the horizon) unless—
(i) The person being granted the ATC clearance meets the applicable requirements for instrument flight under part 61 of this chapter; and
(ii) The aircraft is equipped as required in §91.205(d).
(c) No person may take off or land an aircraft (other than a helicopter) under special VFR—
(1) Unless ground visibility is at least 1 statute mile; or
(2) If ground visibility is not reported, unless flight visibility is at least 1 statute mile. For the purposes of this paragraph, the term flight visibility includes the visibility from the cockpit of an aircraft in takeoff position if:
(i) The flight is conducted under this part 91; and
(ii) The airport at which the aircraft is located is a satellite airport that does not have weather reporting capabilities.
(d) The determination of visibility by a pilot in accordance with paragraph (c)(2) of this section is not an official weather report or an official ground visibility report.
Notes from the AIM 4-4-6
An ATC clearance must be obtained prior to operating within a Class B, Class C, Class D, or Class E surface area when the weather is less than that required for VFR flight. When a control tower is located within the Class B, Class C, or Class D surface area, requests for clearances should be to the tower. In a Class E surface area, a clearance may be obtained from the nearest tower, FSS, or center.
To the left is the view if taking off on Rwy 29 and to the right is Rwy 11. The airport was conducting GPS approaches on Rwy 29 when these pictures were taken but was still VFR. It changed to IFR shortly thereafter.
Special VFR is designed to allow pilots to takeoff and land at airports that do not technically have VFR conditions but the flight can be operated in visual conditions. Note that the pilot must request a SVFR clearance because ATC is not permitted to offer or even suggest the clearance. Examples include:
- a huge cloud directly over the airport that limits reported vertical visibility to less than 1,000′
- high fog approaching the airport that limits vertical visibility to less than 1,000′ over the airport, but blue skies are visible in the opposite direction
- low fog is moving over the airport and the weather station is reporting horizontal visibility of less than 3 miles, but the departure/arrival end of the runway is still clear
- scattered clouds in the direction you want to go are too close for distance from cloud minimums, but if you could get through them you could be VFR On Top
- flight and ground visibility are less than 3 miles, but the airport lights, VASI, or lighting system are on and there is no doubt that you can find the airport and land
Note that Special VFR is not allowed in most Class B areas—the “appendix D, section 3” part of the regulation. Also note the words, “surface area”. SVFR applies to the surface area of the airspace, so Class E extensions to an airport, that go to the surface, are covered by the regulation. Once you are clear of the airport surface airspace, you must comply with the VFR requirements of the airspace you are in—most likely, Class E or G. Visibility and cloud clearance requirements of that airspace apply.
Night clearance (acutually not night, but between sunset and sunrise) for Special VFR requires that the pilot meets the applicable requirements for instrument flight under part 61 of this chapter. This refers to § 61.57 Recent flight experience: Pilot in command. The pilot must be night current if carrying passengers and instrument current in order to accept a Special VFR clearance.
IFR traffic takes precedence over Special VFR. Special VFR traffic needs to fit into the IFR traffic flow with full IFR separations. On a recent flight, visibility was similar to the pictures above. The ceiling was 400′ with a big hole about a mile from the runway. I asked for SVFR and a while later a helicopter also requested SVFR. We had to wait until landing traffic was on the runway, which took about a half hour. By then the field was VFR and we were given VFR clearances. We still couldn’t fly VFR to the Southwest, but Southeast was fine.
You can’t get a Special VFR clearance if reported visibility (from the ground) is less than 1 mile, but flight visibility is good and the airport is in sight. Not too likely to happen, but you should be aware that conditions like that could exist. If there are no other options, you could declare an emergency and land.