ADM sanity check (VFR over the top)

cowman

Final Approach
PoA Supporter
Joined
Aug 12, 2012
Messages
5,384
Location
Danger Zone
Display Name

Display name:
Cowman
So I'm not looking for an "is this legal" analysis. I am certain it is, student pilots take note, there's a reason why "1,000 ft above" is part of your cloud clearance rules.

I've found myself playing the VFR over the top card more and more on long cross countries and the results have been consistently the same- a very nice and smooth flight with absolutely no problems whatsoever and pretty scenery to boot. The first few times I did it, it was an "ok normally I wouldn't want to do this but in this scenario it makes sense..... " reasoning. Now it's becoming more along the lines of "Ok, we've done this before. scattered is not a ceiling, forecasts are for clear or few at the destination. These are VFR conditions, stop worrying."

I do not posses an instrument rating, although I have taken some training and intend to get it if I can find another instructor I can easily work with.

As the title says I'm looking for a sanity check from other pilots to get an idea if I'm just doing what one does to make cross country flights and exercising due caution or if I'm playing with fire.


So here's the flight I made yesterday, Jun 6.
KBUY -> KIOB. KIOB was just a fuel/rest stop. Final destination was 2I0, but that field was still reporting a low cloud deck early that morning and it exceeded my usual max leg distance of 3hours so I needed a fuel stop. Originally I had planned one closer to a direct course but VFR conditions seemed more solid further north so I changed the plan.

Weather when I woke up that morning around 7am looked good. Sky clear at our departure point with some IFR conditions from fog(I thought) across the flight path that were forecast to lift between 10am and 1pm. Forecasts at our departure point/destinations mostly said things like "clear below 12,000" "broken 18,000" with a few saying "scattered 4-6,000". Awesome. We'd had to stay an extra day due to some showers/thunderstorms that passed through the previous day. This looked like we were going to good to go. My wife and I had enjoyed our trip but we were ready to go home.... or at least her parent's house which was the final stop before home.

We didn't get to the airport until around 11 - noonish. The "fog" still hadn't completely lifted but I was sure it would, just taking too long. I had to turn in the rental car before incurring another day's charges and I still had to pre-flight and fuel the plane as well as load the baggage. I expected I'd have to wait a little bit at the FBO until the weather had cleared up for sure before leaving and I was OK with this. Sundown isn't until 9pm or so this time of year, we had one 2-2.5hr flight and one ~1.5hr flight to make and 8-9 hours to do it in. I wasn't even adverse to landing a the final destination after dark if need be. No worries.

So by around 12:30 I was checking the weather again. I started to become slightly worried as it was becoming clear the "fog" wasn't lifting and many of the stations were still reporting things like overcast-broken 2,000. The more common sky condition was "scattered-few 5000". My initially planned fuel stop was one of these. I did some re-planning and looking at the satellite views/forecasts/current conditions and decided that I could pick a different fuel stop farther north and avoid most of this. The destination was reporting scattered 5,000 with forecasts for sky clear across that area. Over the next hour most of the stations along the route were giving me similar with the odd holdout "broken 5000".
Now, on most trips the solution would be simple.... fly 4,500 drop lower if needed. However, anyone who plotted this on a chart may have noticed the course takes us over the Appalachians. My only mountain experience was from a week before when I'd cruised over them at 9,500 and looked at the little hills way down below. However, I was not at all comfortable with squeezing between a 5,000' cloud deck and mountainous terrain especially on a summer afternoon. I felt that I needed to go over the top here or not go at all. I'd initially planned on 8,500 but I was already expecting to need to go to 10,500 with 12,500 as an option should that not work.

I ended up sitting in the FBO another hour reloading the weather conditions. I was already 98% certain we could take off and be fine but there was still the odd METAR report of "broken" towards our destination with everything else trending scattered/few/clear. The forecasts were over 5hrs old at that point though so I wanted just a few more positive indications before launching into this. During this time the weather at our departure point had gone from clear to few to scattered... the holes were getting smaller but still clearly there. Forecasts finally updated continuing to predict sky clear or scattered 5,000 along the route and at the destination. Destination area weather was now a little better reporting scattered-few-clear across that area. My certainty was now at 99% that we'd be fine(I don't believe in 100%). I had developed a mental picture of a patchy layer of clouds with large holes and a few dense areas moving slowly.

So we departed from the field and I made a series of climbing turns to remain clear of the clouds and up through the hole we went. The tops were higher than I'd expected, but by around 9,000 or so I was above. Continued on up to 10,500.... there were still some cumulous poofballs sticking up kinda high and I didn't like my sight angle so up we went to 12,500. We were now at the highest altitude I've ever flown at which did give me pause but I'd been to 11,500 before and it was no big deal. This wasn't either. I still pulled out the pulse oximeter I keep in my flight bag a few times to be sure.

So mitigating factors: I had 4.8hrs of fuel for a planned 2.2(expected more like 2.5 with the headwinds). I was on flight following. I had at all times a hole of some sort that I could turn and fly down through. I have a stratus ADS-B receiver which I use to get updates of the weather ahead, including at the destination throughout the flight. I also, as always, got flight following.

The big danger of course would be the clouds closing up and not having a hole back down. The other, always present danger would have been an engine failure and not having a complete view of the ground. However for most of the flight I did have a view of part of the ground and had I been lower I'd have had less glide time so... that didn't seem like a big deal.

I figured worst case if the clouds did close up, I had fuel to search for a hole(and given the weather I surely would have found one further NW). Failing that I could always confess my sins to the controller and get guidance down through the clouds and a nasty letter to deal with. Not exactly plan A or B but a reasonable plan C.

I feel that the most important part of the ADM when going VFR over the top is how sure one is there will be a way down on the other side. This is the first time I headed for a destination that wasn't both reporting currently and forecast to be clear along with the surrounding areas. Still, scattered-few-clear isn't bad. It gave me pause though and the thoughts I had as I made my decision and proceeded through the flight lead to me starting this thread.

The results of the flight? Smooth, comfy... had to close up all the vents cause it was cold up there! As expected cloud cover thinned out the farther we went with occasional thicker patches. Easily found a hole down and landed at my destination as planned. I planned to post this so I took pictures partway through so you all can see what I saw and make judgements :p These were taken all around the same time IIRC so you can see what I was looking at to my left, ahead, and right side. This was the "average" but there were areas of large clear holes and areas of thicker cloud cover.

iphone336.jpg


iphone338.jpg


iphone339.jpg



And just for fun, destination field with sky in the background
iphone341.jpg
 
Oh and this ends with me being a good boy and heading to our final destination getting bounced around by late afternoon thermals at 4,500... below the then few-scattered 6,000 cloud deck.... and then coming today at 10,500 above another scattered 5,000 but with everything reporting/forecast/actually becoming clear by the destination.

Smooth, wonderful, scenic, rough as *$&#&$ when I had to descend for landing.
 
IMHO only - legal or not, rated or not, if you were confident you could let down through a deck if you had to, then yeah; you stayed on top of the weather situation, made your decisions based on logic, vice wishful thinking. And knew it could/could be worse than forecast, and had some ideas about where to divert if that happened.

If you're a good weather guesser, and understand how much spread there is between the factors that could blow the forecast (temps, dew points, speed of fronts, etc.) and have pretty solid "outs", I don't think you're out of line.
 
It's all a personal choice. You thought it through and used logic.

Me?
1- Weather is predictable until it's not.
2- If I got stuck on top, I would be wishing for 10x the turbulent torture in exchange for my predicament.
3- If I had to do all that hand wringing to make a go/no-go, I might ask myself "getheritis"?
Not worth it for this low timer.

But from your pics, if sky was going to broken, looks like I might drop down thru a hole and be totally fine (if not to close to mts)
 
Flying above clouds is a really cool part if flying and always makes the experience feel more "real"

I have the same "concern" (fear, phobia?) of getting stuck on top, but it sounds like we're both OCD about the weather and staying legal, so it a reasonable concern but in that can be mitigated with careful planning.

But, should you get "stuck" my bigger fear beyond the potential "paperwork" is actually getting down through it safely.. flying in clouds is an entirely different kind of flying and until I get my IR I try to do a couple actual instrument flights in real IMC with an instructor so if it ever does happen it won't feel as foreign
 
*edit: "couple actual instrument flights with an instructor *couple times a year*"
 
IMHO only - legal or not, rated or not, if you were confident you could let down through a deck if you had to, then yeah; you stayed on top of the weather situation, made your decisions based on logic, vice wishful thinking. And knew it could/could be worse than forecast, and had some ideas about where to divert if that happened.

If you're a good weather guesser, and understand how much spread there is between the factors that could blow the forecast (temps, dew points, speed of fronts, etc.) and have pretty solid "outs", I don't think you're out of line.

That's a good way to put it.

Eventually though, you will guess wrong. Eventually. BTDT.

Have enough gas to fly to an out.

@OkieFlyer and I were sharing stories of both of our "the weather didn't do what we thought it would" stories over dinner the other night. His was interesting because I hadn't thought much about it over the years -- if you missed something in the weather data that would lead to a stratiform layer turning convective, and unstable, the clouds you're above might CLIMB UP to meet you.
 
Always give yourself an out in case something crappy happens. Seems like you did fine.
 
Looked like good ADM to me. Legal and based on your description/ pics, didn't even appear "over the top."

I've flown over the entire state of Texas with it overcast below and ASOS reports of 300 ft ceilings. Departure is good, destination is good, good to go. Always have a enough fuel to get yourself to an area that allows VMC in the descent.
 
IMO, and looking at the pictures you posted, I wouldn't even consider you "over the top" at that point. Clouds are scattered, there is no ceiling, and if it started to form one you would have no difficulty finding a "hole" to get down through, assuming you stayed situationally aware and willing to exercise that option.

As a VFR pilot I made many, many trips in conditions like the ones in your pics. My "over the top" experiences were limited to 2, maybe 3 occasions when I was 99% sure I could get back down.

As others have said, over the top as a VFR pilot is safe if, and only if, you have outs; the best out being, enough fuel to fly to where you are 100% certain to be able to get down. It sounds like you thought things through very thoroughly and had abundant outs.

Like others have said, I think you did fine. :)
 
At least from those pictures, I wouldn't even consider that "over the top". If the weather is improving, getting above the scattered layer is must! Unless you have some serious convective activity or the temperature is dropping toward the dew point, the clouds are not going to just suddenly change from widely scattered to broken or worse. Keep an eye on them, but go high.

Get out of that rough air!
 
Have lots of gas and cash for your continued IR training. You'll feel better with the rating.
 
Looks like a great flight... I plan all my flights at 9500 to 12,5... just to be out of the heat, and into the smoother air. South West flying makes it important to be high... and those clouds look just perfect. It is a pure joy to be above them, one of the reasons that flying is so great.
 
I'll just echo the guys saying get the rating done. I've done a lot of it VFR but IFR rated. Much less worrisome.

Looked like you handled your situation fine.
 
I'd say marginal ADM. The concern is a bit different than has been pointed out, though.

Over the top above even modest mountains is quite different from overflying coastal stratus. As you found, mountain obscuration can be many thousands of feet thick, and VERY often requires flying near the service ceiling. You did not report density altitude. In summer, it can easily be 3000 higher than pressure altitude. But what you didn't see was that worsening weather doesn't just close holes. It can also, rather easily, go higher. Quickly. And you're already near your service ceiling.

As a rule, I don't overfly mountain obscuration. It's seldom worth it. There are exceptions if the crossing is very short and I can turn around easily (e.g. overflying one standing lenticular -- never fly under those).
 
I ended up sitting in the FBO another hour reloading the weather conditions...

I like to supplement the official weather products with HRRR nowcasts because they update relatively frequently. Aviation flight rules, ceiling, and cloud cover are good ones to look at.
 
Sounds like you did fine looking at the pictures.

One flight I flew on top. Weather was reported scattered at my destination. When I got to the destination is was solid overcast. Turned around and flew 30 minutes found a hole dropped down and flew to my destination under the clouds. The wife was not happy. I had 5 hours fuel on board total flight time was 2.5hours
 
Last edited:
Cowman,

One of the things you missed in your weather analysis was the winds aloft and modification of an air mass over a warmer surface. On the 6th, the winds were NW crossing both a warmer and rising terrain. Had the winds been stronger or the terrain temps been higher, you may not have been able to get on top on that route. That is why the tops were higher that you expected.

If you had considered a route other than a direct line, BLF-PSK, the terrain would have been 1000 ft lower and the tops may have been lower.

Also, if I am taking a 250nm (<2 hour trip with a tail wind) in an Archer, I am not climbing 30 minutes to 12,500 feet unless I have to - just sayin.
 
Last edited:
I (e.g. overflying one standing lenticular -- never fly under those).


Once a lenticular cloud is well downwind of the mountains, it is harmlessly calm. We get them all the time here at M94, downwind of Mt. Rainier. They can drift hundreds of miles from their source. Under/over/around/through........no problem.

Where they are dangerous is in the mountains where they are being formed.
 
Once a lenticular cloud is well downwind of the mountains, it is harmlessly calm. We get them all the time here at M94, downwind of Mt. Rainier. They can drift hundreds of miles from their source. Under/over/around/through........no problem.

Where they are dangerous is in the mountains where they are being formed.

If there is only one, it's quite close to the mountains. And you can get rotors in the flats just downwind of the mountains. You don't have to be IN them.

It's not a lenticular if it drifts.

And the context is mountain obscuration. That doesn't occur hundreds of miles from mountains.
 
This might sound like a silly question, but do you have the ability to call it quits and turn around if you have to? Have you ever had to? I fly most of my VFR flights above scattered clouds, but if things have become even broken when they were not predicted to be, I have "called it quits", even when one time, it meant turning around and flying 100nm back the way I came.
 
I went "over the top" many times prior to my IR. I loved it. But, I always had a way out. For me, it's never been a risk of being forced to descend through a layer that I wasn't legally qualified to descend through, it was taking the risk of, at worst, having to turn around and fly all the way back. Since I always carried enough gas to do so, I was only risking my time, not my ass. And time is abundant. (Well, so's my ass, but that's another problem.)
 
Good stuff, at least I know I wasn't completely nuts and it makes me feel a little better. Also getting some good info on what to look out for in the future.

When I was first turned loose with a PPL and an airplane I used to treat scattered clouds like a ceiling. I also used to be worried to land if winds were going to be much over 10kts. Now I've got more experience and I feel more confident and I'm doing stuff like this flight, yawning at 15G20 winds at destination fields, etc. Outcomes have always been wonderful, I just wanted a bit of a reality check because I don't want to become the guy who pushes it to far.

Turning back is always an option. Landing short of the destination is always an option. So far I have twice landed short of the final destination. Once for marginal VFR conditions not improving as expected, another time for a storm creeping across my path ahead. One thing I love about having an ADS-B receiver is I can get updates on conditions at locations way outside of radio range in flight. It makes these decisions easier and with foreflight I'm able to look up all relevant details of any airport to quickly pick and land at a safe harbor. During any flight I'm always checking ahead and re-evaluating although on flights like this one I'm doing that a lot more frequently than others.

And yes I need the instrument rating. I stopped because my instructor... also the only instructor at our field got a new job and left the area and as far as I know we still don't have a CFII at my home field. Had plans to get stuff together to go do an accelerated course somewhere but I've been wrapped up in other projects and just not been ready to commit to the study time for the written yet. It was a lot easier when I could just pop into the local airport for a couple of hours once or twice a week.
 
IF? They all drift, otherwise they wouldn't form.

These have drifted. What do you call them?

5bf6f2689b82fe2e81edacfbb14f4141.jpg

Those are lenticulars. They are standing wave lenticulars downwind of whatever feature is causing 'em. They probably aren't as powerful as the ones right at the mountain, but they can be nasty.
 
Once a lenticular cloud is well downwind of the mountains, it is harmlessly calm. We get them all the time here at M94, downwind of Mt. Rainier. They can drift hundreds of miles from their source. Under/over/around/through........no problem.

Where they are dangerous is in the mountains where they are being formed.

No. Just no. Numerous errors here especially for the Rockies. There is not a one size fits all for lenticular clouds other than knowing they're a sign of high winds aloft being lifted orographically.

From a flyability standpoint, mountain wave from the Rockies can both be hellaciously strong quite a ways downwind of the rocks and also not form ANY lenticular clouds downrange depending on water content in the airmass. Or alternatively it can form rows of them extending for 200+ miles downwind where the wave can even "bounce" 50-100 miles downrange of the continental divide on the plains.

Quite a different thing than a single bump caused by Rainier.
 
over the top in those clouds is not a problem. Lots of room between them for a descent if necessary and a place to turn around if needed. And under them will be very uncomfortable.

you often see mountain waves hundreds of miles downwind as well. I used to recall seeing +/- 10-15 knots over NC and VA from the Appalachian mountains when flying over the Piedmont or coastal areas of those states between 8 and 11000. VERY long wave in smooth air!

Now, if they start closing up - and you ARE paying attention - then you need to get under them. . . .

If you learn how to read a Skew-T you will then see that often you have caps under you that restrict the clouds from punching through - and that is when you need to worry about the cloud deck spreading under you. Please- get the IR and be done with the issues of having to judge all this - just make sure the tops of those clouds are under the freezing level because otherwise you can turn into a planesickle.
 
If the engine quits how long does a vacuum powered attitude indicator continue to work ? It's actually an honest question because I've flown glass for so long I don't remember.
 
If the engine quits how long does a vacuum powered attitude indicator continue to work ? It's actually an honest question because I've flown glass for so long I don't remember.
Hmmm. I don't know. I do have an electric backup vacuum pump though. Plus, I can fly without an AI, even in clouds. Don't want to, but I can.
 
If the engine quits how long does a vacuum powered attitude indicator continue to work ? It's actually an honest question because I've flown glass for so long I don't remember.

Is the propeller windmilling?
 
Judging by the comments on this thread I get the feeling that everyone here is flying airplanes with enough equipment for basic instrument flying. I would not be real excited about flying a VFR only airplane over the top of a cloud layer for a few reasons, but the main one would be the lack of a vacuum system and related instruments.

Otherwise, if I am in an airplane equipped for instrument flight I would have no problem flying VFR over the top. I've done it many times.
 
Hmmm. I don't know. I do have an electric backup vacuum pump though. Plus, I can fly without an AI, even in clouds. Don't want to, but I can.

And you've done this while running an engine failure checklist and simultaneously managing the fear of how far is the base of this cloud layer from the ground and I wonder what kind of terrain I'm over ?
 
What if it's not ?

Assuming there is an engine driven vacuum pump it will continue to turn with the propeller windmilling as long as nothing in the accessory case is broken. So I'd guess that the vacuum driven instruments would continue to function ok.

If the prop is stopped, no vacuum pump and no vacuum, so the attitude indicator and directional gyro will start to wind down and eventually not be reliable.
 
Assuming there is an engine driven vacuum pump it will continue to turn with the propeller windmilling as long as nothing in the accessory case is broken. So I'd guess that the vacuum driven instruments would continue to function ok.

If the prop is stopped, no vacuum pump and no vacuum, so the attitude indicator and directional gyro will start to wind down and eventually not be reliable.

And that is why partial panel is part of the IR curriculum. You can still keep the shiny side up and the greasy side down without those two instruments. More work, but doable.
 
And that is why partial panel is part of the IR curriculum. You can still keep the shiny side up and the greasy side down without those two instruments. More work, but doable.

I disagree. During instrument training you typically don't practice partial panel work in conjunction with an engine failure, you practice it with the anticipation of having an instrument or vacuum pump problem. Having partial panel training will likely help in the case of an engine failure but I'd bet that the majority of pilots will have a significant performance degradation under those circumstances.
 
And yes I need the instrument rating. I stopped because my instructor... also the only instructor at our field got a new job and left the area and as far as I know we still don't have a CFII at my home field. Had plans to get stuff together to go do an accelerated course somewhere but I've been wrapped up in other projects and just not been ready to commit to the study time for the written yet. It was a lot easier when I could just pop into the local airport for a couple of hours once or twice a week.

Fly down to NC and do an accelerated with @SbestCFII in your plane. Reasonable price and has lots of good reviews here.
 
IF? They all drift, otherwise they wouldn't form.

These have drifted. What do you call them?

5bf6f2689b82fe2e81edacfbb14f4141.jpg

Umm, standing lenticulars can FORM in place downwind, but they don't drift there. Clouds are not balloons. They form where the air cools, usually by rising. In this case, at the top of each wave crest. The wave pattern moves very slowly if at all, far slower than the wind speed.
 
Back
Top