DiputadoVolador

I work for a 135 canyon tour operator. This morning while enroute to GCN VFR ATIS reported runway visibility at 1/4 mile due to smoke from forest fires in the area. It was a thin layer of smoke, tower visibility was reported at +10 miles. The Captain and I discussed what our options were. Special VFR or analternate? Just after that a new atis came out with the vis at 3 miles. I looked it up after the flight and I jut want to make sure I have interpreted everything right.

Standard VFR flight visibility requirement in class D is 3 miles. Special VFR requires 1 mile. 91.205 states that for special VFR the ground visibility must be atleast 1 mile. If the ground visibility is not reported then flight visibility may be substituted.

So my conclusion is; that when ground visibility is reported at less than 1 mile and everywhere above 50 feet it's clear and a million, even if you have the runway in sight and determine that flight visibility is atleast 1 mile you can not land VFR.

Is that correct?

socal swede

Thats how I would interpret it.

DiputadoVolador

Thanks Socal,

Sometimes I'm not sure how I interpret FARs is the same way the FAA does.

Twin Wasp

I'm guessing this is when you got there?

KGCN 231254Z 00000KT 1/4SM FU FEW100 03/M05 A3008 RMK AO2 TWR VIS 10 SLP108 FU LAYER UP TO 60FT AGL T00331050

This is what happens when you get two branches of government 'working together.' The 1/4 mile in smoke is the Surface Visibility since it's from a AO2 box. There isn't any RVV anymore so the only thing that trumps the surface vis is RVR for a particular runway. That's all NWS stuff. Then the FAA comes in and says you need 1 mile Ground Visibility for SVFR (in 91.157, not .205.) And ground visibility is defined in 1.1 -

Ground visibility means prevailing horizontal visibility near the earth's surface as reported by the United States National Weather Service or an accredited observer.

Prevailing vis comes from a manual observer scanning the horizon so if you get really picky there is no prevailing vis in the above report which means there is no ground visibility. But the NWS says they'll call the reported vis, manual or automated, prevailing visibility.

The end result is whatever is reported in the main body of the report is controlling unless you have RVR for a particular runway. Other remarks are just nice to know.