Ceilings & Cross Country

Bman.

Bman.

Pre-takeoff checklist
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Bman.
Evening all-

I am PP with around 170 hours, working on my instrument. For most of my flying the weather has always been pretty fair weather, avoiding large storms that I can see with Mark1 eyeball or simply under the hood for training. I have a cross country coming up in a few days and the midwest is pretty solid ceiling from the departure to destination. Usually I have plenty of room to get between cloud and get up to a decent cruising altitude. This pending XC, likely won't have that luxury. I am trying to figure out what is my acceptable ceiling level for a cross country trip. I am not talking scud running here - I will just take a car or push the trip back a few days. Before I do just that, I got to thinking "I wonder what others find an acceptable ceiling height for a 200-300 mile XC trip". 5000'... 6000'.... 4000' ? Knowing you are going to be 500' below the cloud deck (minimum) and heading at VFR altitudes, your altitude (AGL) could be pretty low for a decent portion of the XC trip.

This presents other questions psychologically such as, how much glide distance is comfortable? Maybe that's the fundamental question. If you know your route of flight doesn't have any conflicting obstacles, it really is a question of accepting a reduced glide distance.

This just isn't something I have really confronted as I just opt for postponement or alternate means. Any way, as a VFR working on my instrument, this further reinforces the logic and drive behind instrument training.

Pending the upcoming weather reports, this might be a great trip to ask the CFII to come along for the XC... best idea I've had all nigh.
 
So I do not have an answer to your question...but I do have a story. I am IFR...but I did a 200nm XC trek through some terrain that varied from MSL to 4000 AGL with mostly pretty open valleys to get through. Ceiling was forecast to be 5500 or better all the way so hey, lets go for it VFR.

Most of the way there that 5500' ceiling started closing in FAST especially through one of the passes I needed to get through...lower I sank, higher the terrain rose, the lower the ceiling got...5500' would have been a luxury...I was just BARELY VFR ducking through a small gap in the terrain and clouds and my outs and turn around options were now severely limited...I thought to myself "Oh, THIS is how pilots die". It was a bit of an eye opener for what should have been a non eventful VFR flight according to all the flight planning and forecasts.

Now I was talking to ATC and IFR rated and current and I confirmed he was willing to give me an immediate pop up if necessary, so I did have an "out" but it was a bit of an eye opening experience trying to complete it VFR.

Fo me, anything less than a 5000' AGL ceiling will require some SERIOUS flight planning VFR into unfamiliar airspace.
 
It depends on what you fly? If I fly my J-3 somewhere I am usually at 300-500 AGL, in the 172 anything above 1000 feet and I am fine. Now the V35B Bonanza is a little different, it likes to fly high and fast and is hot inside so I like to get above 3000 in that airplane. Everything I fly gets flown a bit different.
 
Good story - nice to have that out if you needed it. You obviously had that in your front pocket and was ready to play that card at any moment. That makes a significant difference in your ultimate decision making process.

The terrain on this XC is fairly flat - within 800' elevation difference. With that being said, your 5000' AGL or better sounds reasonable for an this XC. Anything less and you can quickly put yourself in a bind with changing weather conditions and VFR altitudes.
 
Depending on your terrain, (and the terrain in your area isn't too extreme) and the distance you want to go, I would suggest ceilings no less than 2000.' Add to that, I'd want to see the ceilings at least 1000' above the highest terrain along the route (2000' if it's really windy).

It really just depends on you're comfortable with as far as flying "close" to the ground. If all your flights are typically 1000 AGL, then what I suggested above shouldn't be an issue for you. If you're more comfortable flying in the 4-5,000 range, things will look different and could cause you some concern during the trip.

You also have to consider your options if the weather doesn't turn out as well as you'd like. Will there be plenty of airports on the way? Can you easily turn around with the terrain on your route? Airspace issues that may compress you?
 
pigpenracing said:
It depends on what you fly? If I fly my J-3 somewhere I am usually at 300-500 AGL, in the 172 anything above 1000 feet and I am fine. Now the V35B Bonanza is a little different, it likes to fly high and fast and is hot inside so I like to get above 3000 in that airplane. Everything I fly gets flown a bit different.
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Archer II (PA-28-181). Most of my flying is done at lower altitudes for training. It's going XC where I like to climb up 1) for glide distance and 2) for cooler temps. Longer XC at 3500 MSL / 2000 AGL +/- just feels low. That's probably where 90% of my time has been logged ironically so not sure why a straight line distance makes a difference. I think it's the changing weather ahead and knowing the lay of the land near my practice area that makes the lower altitudes a non-factor.
 
It really just gets down to what you're comfortable with.

Although I don't suggest this in the least at your experience level, it wasn't uncommon at all to fly all over Alaska VFR with ceiling less than 1000.' 500' and 2 miles was considered good VFR. Keep in mind that obstructions were minimal and we knew the territory like the back of our hands.
 
Anymouse said:
It really just gets down to what you're comfortable with.

Although I don't suggest this in the least at your experience level, it wasn't uncommon at all to fly all over Alaska VFR with ceiling less than 1000.' 500' and 2 miles was considered good VFR. Keep in mind that obstructions were minimal and we knew the territory like the back of our hands.
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... that would be crazy. I could see that in pattern work in a cup/super cub, anything else, forget about it.

I had a trip last year where I ended up getting out of an airport on a return leg that was MVFR. A few minutes after departure the field went IFR. I thought to myself 'yup, it's low clouds, soupy .. and where are the obstacles'. The first 30 miles felt low and fast after that, the sky opened up and I was on the west side of a passing front. It was really nice. It really put me on my flying game to scan for obstacles, traffic, clouds.
 
My real world answer is it depends.

Suppose it’s overcast 4000’ across the whole route. With the 800’ avg elevation that puts the clouds at around 4800’. So you can cruise the whole thing at 3500’ and maintain your cloud clearances with over 1000’ margin. Id be absolutely fine with flying under those conditions. I’d have margin, I’d be at a safe altitude, I’d still have room to descend if I had to as well.

But we’re assuming a stable ceiling that’s consistent across the route and that out weather reports are accurate. You need to take into account the whole picture- what’s it forecast to do, what has it been doing for the past couple of hours, what are nearby fields reporting? Forecasts can be wrong. METARs reports can be wrong too, I’ve seen situations where it’s really broken 3-4000’ but METARS is reporting sky clear because there’s a little hole hovering right over the field.

Now a more real world situation.... conditions at your departure point are overcast 2000 forecast to be broken 3500 and improving. 30nm out its at scattered 2500. Just past that everything says few or sky clear with a forecast of scattered 5,000. Now do you go? My answer is wait until I see at least a 2500’ ceiling then go. I wouldn’t do that if it was like that across the route but a brief duck under to get out isn’t so bad.

Now what if you have sky clear everywhere else but your destination and surrounding fields are at overcast 2000 but forecast to be scattered 4000’ by the time you would get there. Do you go? This is a little harder. My answer is that if there’s a field I can land at short of my destination if things don’t work out and I’m ok with being stranded there for a while then I’d probably try it.

There’s a lot more to a weather situation than I included in my little scenarios. Always look at he the overall situation and leave margin for error in the current condition reports and forecasts. Sometimes those supposed 3000’ broken layers look at lot lower when you have to go under them.
 
What you're comfortable with, really your call. You sound hesitant so maybe you're right, have a CFI go along. I'd go if say there was at least a 3500' ceiling and good visibility, and plenty of outs like airports close by. Even a zig zag course might be a solution in case you feel threaten or overwhelmed by the weather, which would take you to from airport to airport or close enough to land at one if needed.
 
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Can you tell us your planned route? The minimum altitude I'd use will vary quite a bit depending on, well, everything: weather, winds, terrain, obstacles, pilot workload, landmarks, etc.

You also have to keep in mind how much time you have flying and navigating at lower altitudes. I have a fair amount (mostly through flying CAP searches) so, like Anymouse, I'm comfortable in conditions and situations that most pilots are trained to stay away from. I've trained for them and practiced doing them safely, and am also willing to accept a little more risk than most pilots. If you've never flown XC below 3500', marginal weather on an unfamiliar route are not the time to start practicing.
 
I have to agree with what many here said: it depends. For most of my flying, where I'm a flat-lander, flying over mostly farm land of the mid-west, I don't even worry about 1000 foot ceilings...as long as they are forecasted to improve, I've never had a problem flying my 100 knot Cherokee in such conditions...now I should add, that I am VERY fortunate in that I NEVER have to get somewhere, as I have a job that I can take extra days off on a whim. I should also add that I've never flown in less than 6 miles visibility under such low ceilings either. I've spent many an hour waiting out an un-forecasted drop in the ceiling to 500 feet, and one time, I waited out a low ceiling for 5 days...
 
Since I’m flying in mostly flat terrain, I’m usually comfortable with about 2000ft ceilings. I’m also instrument rated so I know I always have an “out” and can just get a pop up clearance if the visibility and ceiling deteriorate.
 
Also, what plane are you using, and how good are the instruments? How the plane will handle and perform would be part of my mental math, as would things like a lazy AI or HI.

I'd also consider the goal of the flight. You have to be able to answer this question: Are the possible outcomes of the flight worth any extra risk or uncomfortable conditions? I'm not working hard in an aeroplane for a hamburger run. For Grandma's 90th birthday party, absolutely, but I was very close with her :)
 
The day I need strangers on the internet to make PIC decisions is the day I hang it up. As far as the OP's dilemma, it is sort of like Donald Trump's underpants. It depends. What kind terrain are you flying over? Hostile or not? What kind of MEAs are you looking at?
 
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Necessary ceiling depends on visibility. If viz is poop, you better be high enough to miss all the towers. If viz is good, towers are easier to spot against the sky than they are against the ground anyhow. Consider your route: Long water crossing? Trackless Forest? Iowa? Then you factor in the potential of ceilings being too low somewhere along the way - are things generally getting better, staying the same, or (have been, forcast) getting worse. Go, think carefully, don't go - in that order.

A couple thousand agl with good viz ain't all bad. Stick to things like roads so you don't end up in the middle of a swamp if the fan quits. Also, towers are never built on the center-line of the pavement.

Be prepared to spend the night somewhere when (not if) the weather does not go as planned.
 
Just so everyone is clear - there is no dilemma as others have implied. That ship has sailed and I am adjusting my schedule for better weather. That was easy. I was simply curious to know what folks consider for their ceiling limits on a XC. From what I am reading, it’s across the board. Too many variables based on folks experience, plane, terrain, ratings and mission to pin down when people make their go / no go decision.

Time to spare, go by air!


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Bman. said:
... that would be crazy. I could see that in pattern work in a cup/super cub, anything else, forget about it.

I had a trip last year where I ended up getting out of an airport on a return leg that was MVFR. A few minutes after departure the field went IFR. I thought to myself 'yup, it's low clouds, soupy .. and where are the obstacles'. The first 30 miles felt low and fast after that, the sky opened up and I was on the west side of a passing front. It was really nice. It really put me on my flying game to scan for obstacles, traffic, clouds.
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Don't take this the wrong way, but just because it may be out of your comfort zone right now, doesn't make it crazy. I would not have flown in those conditions when I had your experience, but as you build experience and become more comfortable with flying and decision making in a variety of circumstances, you can expand your limits.

The key is you must ALWAYS have a plan with alternates/backups and you must continuously be re-evaluting/adjusting your plan as you fly and keep options open. It's when you commit to one course of action with no escape that things can go south in a hurry.
 
I had a very similar situation earlier this year. I had about 150-180 hours, not sure exactly. I was not quite done with my instrument rating. And I wanted to go to a college hockey tournament 450nm away without having to lose two days of my life on the road there and back.

The ceilings were overcast at 1500 along the entire route, except for being scattered at 1500 at both ends of the trip. The visibility was good, at least 6 miles all the way. I could have gone over the layer, and it would have been a smoother and more relaxing ride, but I opted to stay underneath the layer because I didn't want to be "trapped on top" with inadequate fuel to find a hole when I got to the end of the trip. (While I was perfectly proficient to declare an emergency and shoot an approach, I don't believe in taking a flight where Plan B is to declare an emergency. Plan C, sure, but not Plan B. You need to have a good Plan B.)

My definition of scud running is continuing VFR flight into lowering ceilings or visibilities. On that trip, I committed to divert if the ceilings lowered even a little bit from the constant 1500 AGL that they were reported at takeoff, because continuing with even a little drop in the ceiling is the first step onto the slippery slope of scud running and I wanted to cut myself off immediately without taking even one step in that direction. (I did have to descend as I went along because the ground got lower and the ceilings followed the ground a bit.) I put my GPS on the nearest airports page and kept strict awareness of which airports were closest in front, behind, and to each side of my flight path. It worked out fine. And on the return trip, I flew at about the same altitude because there was a stiff headwind aloft.

The terrain I was over is almost perfectly flat, the northern Great Plains. Glide range was moot. If I lost the engine, I was going down on the nearest section line road or field, of which there were plenty beneath me. If I were flying over any significant terrain or at night, this trip would have been less advisable. Make your own decisions based on your comfort level and what your Plan B will be if things don't go according to plan. Flying gives you a lot of personal choice in which risks you will encounter. That's a good thing in general but it does require you to make those choices on your own.
 
Bman. said:
Before I do just that, I got to thinking "I wonder what others find an acceptable ceiling height for a 200-300 mile XC trip". 5000'... 6000'.... 4000' ? Knowing you are going to be 500' below the cloud deck (minimum) and heading at VFR altitudes, your altitude (AGL) could be pretty low for a decent portion of the XC trip.
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Well, a couple of things:
- VFR altitudes do not apply below 3000 AGL.
- You only need to be clear of clouds if you're 1200 and below, 700 near an airport.

Don't get too hung up on the ceiling number. The visibility is an important factor, too, because you need it to see weather changes. Synthetic radar can be deceptive and out of date, especially low and between the radar sites. A low overcast with a crisp edge is preferable to ragged, foggy overcast higher.

This is okay (well, proviso congested area etc. etc.):

a1.jpg

This is not okay:

a2.jpg
Good luck and keep studying the weather, you need it for the landing phase even when on IFR plan.
 
zaitcev said:
- You only need to be clear of clouds if you're 1200 and below, 700 near an airport.
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Gotta throw a clarification here. The 1200/700 thing applies in most cases, however there some now very rare instances where Class G goes up to 14,500 MSL. Also, the 1200/700 thing does not apply in Class D or Class E/C to the surface. Class B has lower weather minimums, but I won't expand on that here. Regardless, if wx is less than the prescribed minimums for those areas, then a special VFR clearance would be required to fly in them. I'll let others argue about SVFR.
 
Bman. said:
I was simply curious to know what folks consider for their ceiling limits on a XC.
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Depends on where I am at as well. I will go VFR with a lot lower ceiling and visibility in Alaska than I would in New Mexico. I have left airports VFR with 500 ft and 2 mile vis in Alaska. I would not do that in New Mexico.

Fortunately wx in New Mexico is usually greater than 10,000 ceiling and 99+ vis. Or I can't see anything just walking to my garage....
 
From a student pilot's perspective:

I would think you'd want the clouds more than 500ft above you, especially up here in the northern plains. The air is cold now and when you are within 500ft of the clouds you are getting pretty close to visible moisture.....biggest worry being carb ice right now.

And lets say you are only 1000agl, that's only 1.5 miles of glide distance and 70sec of glide time (in our 182)- not much!! Plus there are towers, wires and windfarms easily taking up the first half. And in just a few weeks the lakes will freeze and with one snowfall you won't be able to tell a lake from solid ground.

So, for myself I would want ceilings of 3000 or better up here in Minnesota, especially if I were flying a longer cross country during late fall thru spring. Any lower and it seems like options vanish even quicker then you can check them off your list.
 
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