Cloud Clearance Requirements

[azpilot]

I am a fairly new pilot. I am at about 75 hours now. About 20 of that is cross country. I recently made my farthest journey from home to an airport that is about 150 nm from my home airport. It was a lot of fun. The weather that day was marginal (my marginal, not official marginal), and it made me nervous. Not the bad kind of nervous, but a good kind of nervous.

Anyway, I am trying to figure out how I maintain the proper cloud clearance requirements. Most of the flight was conducted in class G airspace, and it was day, and I was above 1,200' AGL, so the VFR minimums are 1 mile with 500/1,000/2,000. In my particular case visibility was well over 20 miles, so we were good there. I was certainly not above any clouds, and there were no clouds to my sides. But there was a layer above me.

I had planned on making the flight at 7,500 feet. As we climbed up to that altitude, I was getting VERY nervous. I felt like I could nearly reach out and touch the clouds above us. Then, I noticed another plane, that appeared to be about 1,000 feet above us cross going the opposite direction. This perplexed me quite a bit. Here, I thought I was about to but the 500' below rule, and there is another plane that is 1,000' above me going the other way, and I can see him just fine.

So, the question I have is, how in the world am I supposed to know how close I am to clouds? I feel like the only way I could know for sure, it to get close enough that I basically start to enter it, and the quickly descend to get out, but that would be illegal and dangerous. Any thoughts? Is this just something I am going to learn with more experience?

 

[oregonboy109]

It's very hard to judge cloud hights and distances. I would check AWOS/ASOS of the airports you're flying near and see what they're reporting for clouds and use that to make your determination about cruise altitude and cloud distance vertically. Horizontal distance is your best guess really.

 

[Cooter]

Just don't fly though them, and you'll be fine. Level off at an appropriate cruise altitude before you get to them and monitor your altitude. If the clouds get too close for comfort, descend to the next cruise alt. Those are some of the dumbest rules in the book in my opinion.

 

[azpilot]

It's very hard to judge cloud hights and distances. I would check AWOS/ASOS of the airports you're flying near and see what they're reporting for clouds and use that to make your determination about cruise altitude and cloud distance vertically. Horizontal distance is your best guess really.

That's pretty much what I did. The weren't any airports within 50 miles with ATIS or AWOS. All the closest weather reports said the clouds were at 8,000 feet and rising. I planned on going to 7,500 knowing that I may have to go lower.

I guess I'll start to get a better feel for a lot of this as I do it more. I feel like I have a real good sense of distance on the ground. I haven't developed that in the air yet.

 

[oregonboy109]

That's pretty much what I did. The weren't any airports within 50 miles with ATIS or AWOS. All the closest weather reports said the clouds were at 8,000 feet and rising. I planned on going to 7,500 knowing that I may have to go lower.

I guess I'll start to get a better feel for a lot of this as I do it more. I feel like I have a real good sense of distance on the ground. I haven't developed that in the air yet.

That's what I would have done too.

 

[somorris]

I would check AWOS/ASOS of the airports you're flying near and see what they're reporting for clouds and use that to make your determination about cruise altitude and cloud distance vertically. Horizontal distance is your best guess really.

That is the way I like to do it also. Horizontally, I use ground references in our area where the property is set up on a 1 mile grid system. Pretty easy. Over non-definitive areas, not quite as easy. There is a rule of thumb (I don't remember and don't remember exactly where it is) about altitude versus how far out looking over the nose is on the ground. Something like this used with judgment would be about as close as you could get, then compare that distance with ground distance to the cloud(s).

 

[Shepherd]

All cloud regs have the first three words chopped off the front of the sentence.
"Don't get caught......"

It's probably a personal failure on my part. I've been flying my whole life, and I still can't accurately tell my distance from clouds 90% of the time.

 

[Brad Z]

It's not uncommon to inadvertently scrape the edge of a cloud while VFR, but using forecast information and METARs we can get a pretty good idea at what altitude the cloud layers are. And plain and simple, if the altitude you're flying puts you too close to the clouds...change your altitude.

 

[arnoha]

Unbroken layers that have no real definition are basically impossible to determine the distance from visually. By the time you're close enough to make out the sort of detail that would make it obvious, you're way too damn close.

Binocular vision doesn't help. All the regs have clouds far enough where your eyes basically perceive it as "far away" because both eyes are basically straight forward at the same angle. So, the only thing left is to judge based on the scale of the form and experience. Well...clouds have no defined form, so there goes that, too!

The laws are not based on your ability to perceive. They're a rough swag on what is considered safe in a theoretical world of speeds and reaction times. The ability to actually follow the rules did not play into the writing of the rules. And "just don't get too close" is kind of a terrible law.

That said, it gets easier to be comfortable with the ambiguity with practice.

 

[StinkBug]

That's pretty much what I did. The weren't any airports within 50 miles with ATIS or AWOS. All the closest weather reports said the clouds were at 8,000 feet and rising. I planned on going to 7,500 knowing that I may have to go lower.

Just wanna note, cloud heights are given AGL, so depending on the elevation of the reporting station that 8000' ceiling could be well over 8000' altitude.

 

[coloradobluesky]

No AWOS, ASOS or ATIS within 50 miles? Where were you?

 

[midlifeflyer]

No AWOS, ASOS or ATIS within 50 miles? Where were you?

Good point. I'm also trying to understand Where this was:

Most of the flight was conducted in class G airspace, and it was day, and I was above 1,200' AGL,

 

[flyingron]

Of course that plane 1000' above may have been 500' or 1500' above and flying IFR. IFR doesn't necessarily mean in the clouds.

 

[Lachlan]

Didn't you learn all of this stuff when you got trained? Temp minus dewpoint diveded by (2.5 or 4 depending on scale) for approximate base? TAFs, FAs and prog charts? Use the knowledge you learned before you got your certificate and stay safe!

 

[MAKG1]

Didn't you learn all of this stuff when you got trained? Temp minus dewpoint diveded by (2.5 or 4 depending on scale) for approximate base? TAFs, FAs and prog charts? Use the knowledge you learned before you got your certificate and stay safe!

Umm, try that with stratus and you'll be really, really wrong.

What you actually learned was that a single parcel of air will cool by 2.5 C per thousand feet lifted. If there aren't any parcels of air actually being lifted that much, the dew point and temperature can be just anything.

The logical conclusion from overusing that calculation is that clouds don't have tops. Obviously, that's wrong.

Estimating cloud bases above summer thermals from that calculation works OK. That's about it.

The right answer is to make your best estimate visually -- and it's hard -- or to use local AWOS (remember to add field elevation) or PIREPs.

 

[Caramon13]

When I fly VFR, the only clouds I worry about are BKN or OVC. If I have anything less I'm confident I can maneuver around them (and have been successful in doing so).

If there is a BKN/OVC layer at my destination below where I would file altitude-wise, I file IFR.

Also, one of my go/no-go checks (before my instrument rating) was whether or not there was any MVFR weather at my destination at my ETA. If there was, it was PROBABLY a no-go. Especially if the weather was right on the cusp of being IFR.

The only "clouds" I ever flew through when I was VFR were ones where you could see through the other side. Those were more like "heavy mist" or "wisps".

As a VFR pilot using only Flight Following you have a LOT more leeway getting around clouds then someone on a flight plan or IFR.

One other trick I could use for determining if I was close to clouds (particularly since I have a lot of cotton ball looking cumulus where I fly) was to pay attention to the feel of the air and my VSI. If I was close to a cloud above me, within 500 ft, the VSI would start showing a rise due to the updrafts (like the cloud was sucking me in). And, the air would start getting a bit turbulent (more than usual).

 

[James331]

Just don't go into a cloud, the rest is academic.


No one can honestly judge cloud distances with a chit of accuracy.

 

[Palmpilot]

To a large extent, we just have to give it our best shot, and hope for the best.

 

[Kritchlow]

It's not comforting descending through IMC and have VFR traffic called 1,000' below you and you have 2,000' more to go.

Just sayin'

 

[Lindberg]

Just don't go into a cloud, the rest is academic.


No one can honestly judge cloud distances with a chit of accuracy.

But whatever you do, don't post a wide-angle photo or video of you anywhere near clouds, or someone will say you're a law breaker.

 

[acrophile]

Just don't fly though them, and you'll be fine. Level off at an appropriate cruise altitude before you get to them and monitor your altitude. If the clouds get too close for comfort, descend to the next cruise alt. Those are some of the dumbest rules in the book in my opinion.

Seriously? You seem unaware of the reason for the rules (and so you leap to the conclusion that they have no good reason).

Cloud separation rules are primarily for the sake of IFR traffic. If you're flying just below the clouds and an IFR plane descends into you from the clouds without having time to see and avoid you, you (and the other plane's occupants) will most certainly not be "fine".

A decision to violate these "dumb" rules is a callous choice to recklessly endanger not only your own life, but the lives of others who are flying lawfully under IFR. It's analogous to intentionally running a red light without even being able to see around the corner to tell if anyone is about to (lawfully) cross your path.

 

[Kritchlow]

Seriously? You seem unaware of the reason for the rules (and so you leap to the conclusion that they have no good reason).

Cloud separation rules are primarily for the sake of IFR traffic. If you're flying just below the clouds and an IFR plane descends into you from the clouds without having time to see and avoid you, you (and the other plane's occupants) will most certainly not be "fine".

A decision to violate these "dumb" rules is a callous choice to recklessly endanger not only your own life, but the lives of others who are flying lawfully under IFR. It's analogous to intentionally running a red light without even being able to see around the corner to tell if anyone is about to (lawfully) cross your path.

Precisely

 

[alfadog]

If I am below the cloud then I am 500' below the cloud. Just sayin'

 

[Palmpilot]

I don't think saying that cloud distances are difficult to judge equates to a decision to violate the rules, but we do have to TRY to maintain the required separation, and it's better to err on the side of farther than required than too close.

 

[Kritchlow]

If I am below the cloud then I am 500' below the cloud. Just sayin'

Just sayin' what?? You may get a nice hello if an airplane comes out of that cloud.

 

[alfadog]

Just sayin' what?? You may get a nice hello if an airplane comes out of that cloud.

Just sayin' I'm not getting out there with a tape measure. Not saying I'm flying along with the cloud base scraping the windshield.

 

[Matthew]

My biggest excitement was doing some IMC work with my CFI. What we didn't know was we were about to pop out the side of the shelf/layer we were in and come out into very good VMC. Our controller gave us a very quick "Traffic alert!" and told us to turn left immediately. We did, and we ended up popping out into VMC before we got back into IMC. We were there just long enough to see the rivets on the plane we would have t-boned. Other plane was bumbling along VFR. I don't know what his horizontal clearance was, maybe he was legal, but it looked way too close for me.

 

[acrophile]

I don't think saying that cloud distances are difficult to judge equates to a decision to violate the rules

Of course not. No one suggested otherwise. But when pilots call the separation rules "dumb" and say "Just don't fly though them, and you'll be fine", or "All cloud regs have the first three words chopped off the front of the sentence. 'Don't get caught......'", that does imply a decision to violate the rules--apparently without even being aware of the grave risk involved.

 

[Cooter]

Seriously? You seem unaware of the reason for the rules (and so you leap to the conclusion that they have no good reason).

Cloud separation rules are primarily for the sake of IFR traffic. If you're flying just below the clouds and an IFR plane descends into you from the clouds without having time to see and avoid you, you (and the other plane's occupants) will most certainly not be "fine".

A decision to violate these "dumb" rules is a callous choice to recklessly endanger not only your own life, but the lives of others who are flying lawfully under IFR. It's analogous to intentionally running a red light without even being able to see around the corner to tell if anyone is about to (lawfully) cross your path.

If anyone is leaping to conclusions its you. You might want to take a deep breath and slow down a little. I know why the rules are there. But now I guess I need to defend my position on callously running red lights and willfully endangering lives instead of explaining what I initially meant. Holy cow.

 

[Palmpilot]

Of course not. No one suggested otherwise. But when pilots call the separation rules "dumb" and say "Just don't fly though them, and you'll be fine", or "All cloud regs have the first three words chopped off the front of the sentence. 'Don't get caught......'", that does imply a decision to violate the rules--apparently without even being aware of the grave risk involved.

Point taken.

 

[Kritchlow]

Of course not. No one suggested otherwise. But when pilots call the separation rules "dumb" and say "Just don't fly though them, and you'll be fine", or "All cloud regs have the first three words chopped off the front of the sentence. 'Don't get caught......'", that does imply a decision to violate the rules--apparently without even being aware of the grave risk involved.

Yet again, well stated.

 

[brien23]

Big Sky little airplane, just make sure your off the airways. More midair's happen in sever VFR than bad weather. When the weather is bad and clouds all around very few VFR types are out so Big Sky little airplane. On the other hand VFR into IFR average pilot has less than 3 minutes to live before he looses control unless you have a autopilot then you will probably be ok if you turn back.

 

[Kritchlow]

Big Sky little airplane, just make sure your off the airways. More midair's happen in sever VFR than bad weather. When the weather is bad and clouds all around very few VFR types are out so Big Sky little airplane. On the other hand VFR into IFR average pilot has less than 3 minutes to live before he looses control unless you have a autopilot then you will probably be ok if you turn back.

Large airplanes descending at those altitudes are very rarely on an airway.

 

[brien23]

Large airplanes descending at those altitudes are very rarely on an airway.

I doubt your not talking to anyone and that little airplane transponder would show up on your TCAS or ATC telling you about the traffic. If it is a plane without a transponder they probably have no gyro instruments and have already spun in and not a problem for you.

 

[Kritchlow]

I doubt your not talking to anyone and that little airplane transponder would show up on your TCAS or ATC telling you about the traffic. If it is a plane without a transponder they probably have no gyro instruments and have already spun in and not a problem for you.

Ahhh.... Ignore the rules and hope technology catches the problem.

Hmmm... That sounds familiar..??

 

[Lachlan]

Umm, try that with stratus and you'll be really, really wrong.

What you actually learned was that a single parcel of air will cool by 2.5 C per thousand feet lifted. If there aren't any parcels of air actually being lifted that much, the dew point and temperature can be just anything.

The logical conclusion from overusing that calculation is that clouds don't have tops. Obviously, that's wrong.

Estimating cloud bases above summer thermals from that calculation works OK. That's about it.

The right answer is to make your best estimate visually -- and it's hard -- or to use local AWOS (remember to add field elevation) or PIREPs.

First, as stated, the cloud base estimate is only ever an estimate of where the base might be with a normal lapse rate; it is never a guarantee that clouds will be there. It works well as an estimate, though. Here's a current METAR:

DENVER CENTENNIAL AIRPORT, CO, United States - KAPA 151653Z 12006KT 10SM FEW080 SCT095 BKN220 M02/M14 A2973 RMK AO2 SLP098 T10221139

Temp 27F, dp 7F. So, 27-7=20; 20/4=5. So, 5000' agl = scattered clouds at 9500' since the airport is at 5885. 4800' agl if you go Celsius. Even closer to the scattered @ 9500'. Again, it's an ESTIMATE. The original poster seems completely amazed and overwhelmed by clouds, and as a new time pilot should have all sorts of tools in his head for properly thinking about weather, including cloud formation. If he never learned about weather, then I'm gonna hug my CFI this weekend because I've learned a lot from him and never been surprised or unprepared for any weather related situation.

 

[OkieAviator]

In my particular case visibility was well over 20 miles, so we were good there. I was certainly not above any clouds, and there were no clouds to my sides. But there was a layer above me.

You'll be able to tell because if you get too close lasers come out of the clouds and shoot at you. Just happened to a Bonanza in Colorado recently.

 

[paflyer]

So, the question I have is, how in the world am I supposed to know how close I am to clouds?

Ask the FAA's Chief Counsel for an official opinion.



Uh, that's a joke, son.

 

[Palmpilot]

Big Sky little airplane, just make sure your off the airways. More midair's happen in sever VFR than bad weather. When the weather is bad and clouds all around very few VFR types are out so Big Sky little airplane.

Big sky theory has failed often enough that it has been thoroughly discredited by now.

On the other hand VFR into IFR average pilot has less than 3 minutes to live before he looses control unless you have a autopilot...

That's not true.

Even if it were, it would be irrelevant. The purpose of the required cloud clearance distances is not to keep VFR-only pilots from accidentally entering clouds; it's to give the pilots time to see and avoid each other after the IFR aircraft pops out of the cloud.

 

[Matthew]

My first inadvertent encounter: overcast, clg were pretty good for an easy VFR flight underneath without feeling pinched. Clearances between me and cloud bases looked good, and everything matched the TAF and area METARS/ATOS/ASIS/AWOS, everything. But there was that one line of clouds hanging down that blended into the background. I drove right into them and said the two magic words, the first is "Oh". I got my eyes down onto the panel and about that time I popped through.

My lesson learned: There are times when clearance underneath can fool you. In that case, with an overcast, the bases looked determinate but weren't.