VFR flying and fog

[warthog1984]

Anybody know what the official view on VFR flying in widespread heavy fog / mist [vs clouds or "thick air"] is? I cancelled a flight recently due to possible fog on the way back, and was wondering.

For example, if the ATIS was reporting 1500ft and 5 miles with fog, as you ascend/descend you would presumably maintain +500/-1000ft clearance from the "thick" areas and you'd have legal straightforward visibility.

Granted, it'd still be like flying in a milk bottle; but is it a legal milk bottle?

 

[flyingron]

5 miles in fog is VFR. 3 miles in fog is VFR. You'll have to assess what your comfort level is. Note that the whole point of the visibility / cloud clearance rules is not to protect the idiot VFR pilot from flying in bad weather but rather to give see-and-avoid a chance to work (which is why it varies with airspace and altitude).

Actually, you'll never see an official weather forcast that mentions FOG and VFR-legal visibilities. Anything over 5/8 mile is MIST not FOG.

 

[Geico266]

Experience is the only governing factor here. Set your minimums for flying and stick to them until you feel comfortable lowering them. Check visibility reports at airports ahead of you and monitor them for improving or degrading VFR conditions.

I find this link very helpful in looking for trends.

http://www.wrh.noaa.gov/zoa/mwmap3.php?map=usa

 

[jsstevens]

5 miles in fog is VFR. 3 miles in fog is VFR. snip

And I'll add from personal experience your horizon gets iffy in 5 miles before you get very high up (even 2500'). In 3? No thanks. Doesn't mean I think you shouldn't fly, just be aware that you're relying more on instruments and you still need to look outside to see and avoid.

The attached picture was taken in level flight at 2500 on a 5 mile visibility day. (It's my younger daughter when she was 6. Yes, she is cute, thank you.) See the ground? See the horizon?

For me, 5 miles is pretty much my lower bound for VFR.

John

 

[Sac Arrow]

And I'll add from personal experience your horizon gets iffy in 5 miles before you get very high up (even 2500'). In 3? No thanks. Doesn't mean I think you shouldn't fly, just be aware that you're relying more on instruments and you still need to look outside to see and avoid.

The attached picture was taken in level flight at 2500 on a 5 mile visibility day. (It's my younger daughter when she was 6. Yes, she is cute, thank you.) See the ground? See the horizon?

For me, 5 miles is pretty much my lower bound for VFR.

John

For that matter, it doesn't even have to be fog or mist. A 5 mile vis haze at 5,000+ feet will make the horizon disappear, and terrain as well. Best to be above it so you don't have to guess which way to turn when you do see it.

 

[poadeleted20]

You won't see the vis reported 5FG in a METAR -- fog (FG) is reported only with visibility of 5/8 sm or less. If it's 5 miles, the restriction would be reported as mist (BR). See http://aviationweather.gov/static/help/taf-decode.php for more. Also, if the visibility in the mist five miles, that means you have more than the required 3 sm visibility for VFR in controlled airspace, and it's not a "cloud" from which you must maintain the 91.155 cloud clearance distances.

 

[steingar]

For me, 5 miles is pretty much my lower bound for VFR.

John

Here that's visibility on a clear summer day.

You can go over fog, but you really shouldn't if the stuff is IFR. While you can go over it in clear conditions, should anything untoward happen you'll have to land in IMC, a big no no for VFR pilots. Should you survive, the FAA will have some rather pointed questions for you.

 

[jordane93]

Anything below 5 and I'll just file. Makes it easier. Why chance it going VFR?

 

[warthog1984]

Anything below 5 and I'll just file. Makes it easier. Why chance it going VFR?

No instrument rating yet, that's why!

So it sounds like even with soupy conditions, it'd still be legal in fog/mist.

My big question was the ceiling- I knew a fog bank wasn't a hard ceiling/cloud, but wasn't sure how the feds would take it since the ground-bound ASOS would be reporting a ceiling value.

And before anyone asks- I have gone over a similar situation (moonless night VFR) with my CFIs and they've been supportive of my decision-making.

 

[flyingron]

Five miles in haze is pretty typical summer conditions here in the DC area. Margy and I had a different idea about weather for a long time. She learned here so she was attuned to hazy days but couldn't tolerate windy conditions. I learned in Colorado where 20G33 is good student solo weather but unless you were lfying into a thunderstorm, you had unlimited visibility.

Oddly, my tolerance for VFR in low visibilities went away when I got my instrument rating. If it's less than 5 I punt and file.

 

[poadeleted20]

My big question was the ceiling- I knew a fog bank wasn't a hard ceiling/cloud, but wasn't sure how the feds would take it since the ground-bound ASOS would be reporting a ceiling value.

If the ASOS is reporting 1500-5, then the base of the clouds is at 1500 AGL, and the visibility is 5 miles at the surface. From a 91.155 perspective, it would be legal to operate VFR in those conditions as long as you stay 500 below the deck, i.e., 1000 AGL or below, since you meet the 91.155 criteria for VFR in controlled airspace below 10,000 MSL/2500 AGL. Whether or not you could also comply with 91.119 regarding minimum altitude is another story, because if you're over a congested area, you would not be staying 1000 above the highest obstruction within 2000 feet horizontally (one assumes that there's no such thing as a congested area which has nothing sticking up above the surface). Whether or not it's safe/smart to operate VFR below that 1500 AGL deck is still a third issue to consider even if you're legal by both 91.155 and 91.119, and depends on a whole host of other factors. Note that JFK Jr was operating VFR quite legally with about 5 miles in haze below a higher overcast off Martha's Vineyard that night 15 years ago, and that did not end well.

 

[flyingron]

As I stated originally, VFR weather minimums are for collision avoidance, not to keep pilots upright.

 

[acrophile]

As I stated originally, VFR weather minimums are for collision avoidance, not to keep pilots upright.

VFR minimums are indeed primarily for collision avoidance. That's why a non-instrument pilot can fly VFR at night with no visible ground or horizon, even though keeping the plane upright is just as hard then as when in a cloud.

But VFR minimums are not solely for collision avoidance. In Class G, for example, there are cloud-distance and visibility minimums for VFR flight. But you can fly IFR in clouds in Class G with no clearance or flight plan--and therefore with no collision avoidance. So the VFR minimums in Class G can't plausibly be intended just for collision avoidance. Otherwise, why allow blind IFR in the same airspace?

 

[flyingron]

No, it just means that IFR to IFR separation in class G is just big sky. It doesn't mean that once someone pops out of the cloud (or is VFR to begin with) they VFR rules aren't helping separation.

 

[acrophile]

No, it just means that IFR to IFR separation in class G is just big sky. It doesn't mean that once someone pops out of the cloud (or is VFR to begin with) they VFR rules aren't helping separation.

But since big-sky separation is good enough for flying inside a cloud if you're IFR in Class G, why wouldn't it also be good enough if you're VFR?

 

[flyingron]

Because they figure there are more VFRs cruising around in uncontrolled airspace than IFRs.
And if you believe the FAA/NTSB interpretations on this, it's careless and reckless to fly through uncontrolled airspace IFR unless you've got a clearance for the adjoining controlled airspace anyhow.

 

[acrophile]

Because they figure there are more VFRs cruising around in uncontrolled airspace than IFRs.

And they figure 1sm visibility is enough for VFR see-and-avoid separation?

 

[Datadriver]

Anybody know what the official view on VFR flying in widespread heavy fog

There's an oxymoron

 

[AdamZ]

Here is the thing about Fog and I'll add Haze. I've seen fog that looked "wispy" and you could easily see through it when you were on the ground and when you looked up you could see blue sky. Then after take off when you look down the field is totally obscured.

Likewise I've taken off in to haze where the viz was 3 but when I got up in it, well lets just say that I was very happy I had my IR.

 

[BillTIZ]

Anybody know what the official view on VFR flying in widespread heavy fog

I've been in heavy fog, I could not see more than one car length. Even worse at night with headlights. Turned them off and used the "fog" (driving) lights. Ok, now I can see two car lengths.

5 miles in mist is no problem, as long as you know the temp dew point spread will not change.

I've seen fog banks rolling in off the ocean and I was racing the fog wall to the airport.

Summer ugly pollution haze. It was late in the day headed from Shreveport to Monroe at about 5500MSL, no real VIS problems just crappy 10-15 miles in haze. Turned around to head back. Low sun, I had pretty much zero forward VIS, but had a good 10 miles off each wing tip looking north and south.

 

[W. Stewart]

You can go over fog, but you really shouldn't if the stuff is IFR. While you can go over it in clear conditions, should anything untoward happen you'll have to land in IMC, a big no no for VFR pilots. Should you survive, the FAA will have some rather pointed questions for you.

Taking off in a foggy area or flying over an area of widespread fog sure bothers this single-engine IFR pilot, too. With me, it is not a question of maintaining control, as you are only in true "fog" a very brief while. It is a matter of not being able to see what you are about to hit.

It sure is neat, though, seeing all the antennae and water towers poking up through a solid fog.

Wells