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VFR Mountain flying

My hard copy of Sparky Imeson’s book Mountain Flying Bible is not with me, but this recent handbook is available as an ebook.

https://www.kobo.com/gb/en/ebook/mountain-canyon-and-backcountry-flying

All my VFR mountain flying has been in benign VMC, so while have logged a fair amount of mountain flying it has not involved careful weather decision making. Also the flights have been from tarmac to tarmac, so no ‘backcountry’ techniques.

Will read the eBook and provide a review.

Enstone (EGTN), Oxford (EGTK)

Here is a link to a couple of canyon meteorology articles by Amy Hoover

http://pilotgetaways.com/mag/spr04/canyon-flying-part1

http://pilotgetaways.com/mag/sum04/canyon-flying-part2

They are good articles which give some feel for judging the effect of prevailing winds, thermal, orographic lift and turbulence at different times of the day.

Enstone (EGTN), Oxford (EGTK)

Flying up a narrow canyon is different; it should be accomplished by flying on the downwind side. This way, if you get into trouble and need to reverse course, you are not turning into a worse situation,. Flying in a narrow canyon along the updraft side will cause the airplane to penetrate into the downdraft side during a turnaround maneuver.

This is from the late Sparky Imeson’s site, and the quote can be found on this page

https://www.mountainflying.com/Pages/articles/canyon_and_ridge_flying.html

The AIPM (Association of Italian Mountain Pilots), also points out that in typical hazy, summer conditions in the Alps visibility is much, much better, in the shady side of the canyon. Making a turnaround in a canyon from the sunny side means you are turning blind from going from hazy sunlight to the shady side, however turning towards sunlight you have good visibility.

Enstone (EGTN), Oxford (EGTK)

A good place to start and a lot of information it is here and here.

Nice videos articles and resources, most of them are about Alaska. I wish it should be a similar site about Alps or other European places

ES?? - Sweden

I am sure mountain flying can be made into an art, science or something more in the “athletic” (outback) department. But, I have been flying in the mountains since I got my PPL, and even though Norway has the same climate and terrain as Alaska, there is no mountain flying courses here. There is ski and water ratings, and that’s it. “Alaska style” flying (landing on riverbanks and so on) is not allowed anyway, due to the law against motorized activity in “the wild”. The pure outback experience is impossible, but lots of places to land if you ask the owner of the land (the land cannot be outback country though). There is also lots of tiny private strips where you would think landing is impossible (and it is, without the right equipment). In Norway we live very spread out, so there is no shortage of places to go for the adventurous.

The hard core “riverbank” Alaska stuff, I guess requires some more adaptation. It’s not something you just set out to do on your own the first time, not if you hope to get away with it without wrecking the plane or worse. At least I would never do that, because the need for local knowledge alone is too high. That particular kind of flying cannot be done in Europe in any case.

Commercial and “high end” GA is almost exclusively helicopter (VFR and IFR for ambulance/offshore) and twin TP, King Air mostly. This is what you need to go places with a reasonable expectation of getting to the destination when you want. You either fly high and fast, or fly something that can flown real slow and low, and can land everywhere. There are public airports all around the coast, capable of taking moderately sized TP aircraft, and the larger airports (about 8-10) can take aircraft of any size. They are open to all GA as well. In addition there are these private strips all around.

Private GA (SEP) will be very limited by weather, so it tends to be recreational more or less exclusively.

IMO, the main thing about mountain flying: it’s a 3D experience. The ground is all around you, there is no horizon, and the sky is up, straight up almost exclusively at times. The winds are also 3D. They can blow you up and down with the same magnitude as horizontal winds. However, what exactly is supposed to be so difficult or special about this, I don’t know. Seriously I don’t. I hear and read about people terrified by “mountain rotors”, and it makes me shake my head. You just have to ride along. You cannot fight a rotor in a SEP, but unless you do something really stupid, like letting the airspeed fall below the stall limit, a rotor will never push you into the ground. It’s physically impossible. Occasionally today, but routinely before, I often tow gliders straight through rotors and up into the waves above. No problems whatsoever, but the ride is not what anyone would call pleasant. It’s the same with downdraft or waves. On occasions I have lost at least 2000 feet in no time. Pretty dramatic, but harmless. No wind will push you into the ground. Flying over ridges or peeks requires attention, but again, the wind will never push you into the ground, it’s your forward motion that will. You have to be able to turn back when you see you won’t make it, there is nothing else to it.

The real danger is weather, loss of visibility. You need eyes on the outside to fly in the mountain, there is no substitute. Newer aircraft also has EFIS with AH, which I find rather helpful when there are clouds around or in rain (poor vis) and over water/snow. ASI is the most important instrument, then AH, alt is secondary, I hardly look at it. No moving map will ever beat a thorough study of a good map up front, or local knowledge. In the Alps I guess altitude is important also, because the mountains are so high 10k+, and then other alt related things becomes important factors. But for navigating?

In clear blue sky you can fly above it all, or most of it, and that is what you do. Flying above it has very little to do with mountain flying as such, but you certainly feel it and see it on the altimeter when heading into some waves

Last Edited by LeSving at 09 Sep 10:57

RobertL18C wrote:

Flying up a narrow canyon is different; it should be accomplished by flying on the downwind side. This way, if you get into trouble and need to reverse course, you are not turning into a worse situation,. Flying in a narrow canyon along the updraft side will cause the airplane to penetrate into the downdraft side during a turnaround maneuver.

This is from the late Sparky Imeson’s site, and the quote can be found on this page

https://www.mountainflying.com/Pages/articles/canyon_and_ridge_flying.html

Robert, I have to come back to that again. To me it really does not make sense at all to fly on the downwind side.

Your rationale seems correct when you are in the need to turn around. But flying on the downwind side might be the reason for you being in that situation in the first place!

Also I could not find any quote supporting this statement on the site you linked. Instead the graphic suggests the opposite.

EDNG, EDST, Germany

It is the last paragraph on the section about Narrow Canyons.

As @LeSving points out, the potential downdraft on the lee side will not force you into the ground, but may result in not being able to out-climb rising terrain – although you should have planned to be above the highest point in the canyon pass in the first place. However a turn towards strong downdrafts can result in an accelerated gust stall and loss of control.

I disagree about rotors being small potatoes-in the alps and rockies a 40 knot plus mountain wave with lenticular clouds will dismember a bush plane with ease – even high wing strut Cessnas which enjoy a reputation of surviving severe turbulence.

A lot of the books on mountain flying are devoted to reading terrain/micro climate, and calculating carefully density altitude calibrated performance. This may be less of a factor in Alaska in a predominantly ISA minus atmosphere, but very relevant in say Leadville Colorado in mid summer.

Enstone (EGTN), Oxford (EGTK)

RobertL18C wrote:

It is the last paragraph on the section about Narrow Canyons.

As @LeSving points out, the potential downdraft on the lee side will not force you into the ground, but may result in not being able to out-climb rising terrain – although you should have planned to be above the highest point in the canyon pass in the first place. However a turn towards strong downdrafts can result in an accelerated gust stall and loss of control.

Thx for pointing this out. For the scenarios described – i.e. turn radius larger than half of the canyon width – that strategy makes sense.
I disagree about rotors being small potatoes-in the alps and rockies a 40 knot plus mountain wave with lenticular clouds will dismember a bush plane with ease – even high wing strut Cessnas which enjoy a reputation of surviving severe turbulence.
Agreed.

Edit: quotation corrected.

Last Edited by Supersonic at 09 Sep 15:52
EDNG, EDST, Germany

Spot on description @LeSving
Here it is a pretty clear statement and is opposite what @RobertL18C claims:
FLY THE SIDE OF A CANYON
If you have a choice when flying through a canyon, fly the upwind side. It provides a better ride and there is no compromise with aircraft performance degradation due to downdrafts and turbulence.
Generally speaking the best path to fly through a canyon will be on the updraft side (a narrow canyon is the exception).
Normally we associate updrafts with the sunny side of a mountain, but in canyons it depends on the airflow down a slope more than whether or not the sun is shining on the surface.
About NARROW CANYONS – “Until you become experienced by receiving flight instruction from a knowledgeable mountain instructor, stay out of these areas.” …
and then goes further: “For normal flight through a canyon, even one with upslope terrain, the flight is generally made on the side of the updraft”
@Supersonic is right.

ES?? - Sweden

Perhaps something was lost in reading up/downwind vs up/downdraft sides of the valley?

Antonio
LESB, Spain
24 Posts
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