It is interesting – and instructive – to read different pilots (all well qualified) comments on this forum explaining which side of a Canyon one should fly in the mountains.
Each speaks with authority & experience – although often advocating different methods!
The conversation has made me ‘review’ my Mountain training course – which I did many years ago – via (US) AOPA and, interestingly, they confirm what I was originally taught:
“Upslope Winds
In the mountains, it’s often best to stay on the windward (i.e., upwind) side of ridges. You’re less likely to encounter performance-robbing downdrafts, and if you need to turn away from the ridgeline you’ll be turning into the wind—which will decrease your groundspeed and improve your climb gradient.
Yet, posters with good local knowledge and experience advocate “flying down the righthand side”.
Is there a European standard/method which I should readjust to?
US canyons (valleys?) that people fly through tend to be much wider than European ones. In the Simplon case, is particularly narrow, but many others aroung here are, too.
it’s often best to stay on the windward (i.e., upwind) side of ridges
Is also not nearly as absolute as people want to make it (“often”, “best”).
Why can’t people accept that there is no right or wrong and that they have to decide for themselves, case by case?
Further points are: airspace. Take the Großglockner route as an extreme example. Due to the national park, there is no choice wahtsoever. Pilots are forced to fly a 400-metres wide corridor, with many prescribed turns. Risk of collision is at a max and no chance to chose the “windward” side.
On this you will get random answers depending on many factors: hight, width, traffic, turn, sink, sun, wind, clouds, glider/power…as long as you know what you are getting? what you are missing? why you are doing it? there is no left or right…in touring pistons, you should not fly narrow valley at very low height in conditions where left vs right matter
In Cubs/Maules or Gliders, we can debate this more in details 
In Cubs/Maules or Gliders, we can debate this more in details
Forgetting adequately powered RVs here
My lengthy experience with the Alps is that because the valleys are relatively narrow, eg the height of the ridge line is around or greater than the width of the valley floor, the wind blows along the valley, one way or the other, 99% of the time. Thus the “upwind” side of the valley is meaningless. For example take Sion – 95% of the time the wind flows from west to east, 5% the other way. There are very good reasons for this, the high peaks heat up during the morning from the sun, therising air from these peaks draws air along and up the valley.
Given this the right hand side convention is almost always the right way. Safe traffic flow trumps any possible consideration of “upwind side”.
Note though that in the deep Alpine valleys, such as at Sion, at a certain altitude, often 8 to 10 thousand feet you will encounter sudden wind shear. This is where the prevailing wind spills over the mountain ranges on its way across the continent. This wind direction will be completely disconnected to whats happening to the ‘of river’ wind in the valley below which will be following the valley mostly towards the higher end of the valley, sometime the other way.
Peter_G wrote:
Each speaks with authority & experience – although often advocating different methods!
Different methods may work for different places. In the Alps, the fly to the right side of the valley whenever possible is taught everywhere I know of, certainly in Switzerland it is the reckognized way people expect others to fly. In high wind conditions, it may be necessary to go away from that, but this was not the case here and with high winds, I would not fly in the Alps anyway. Other than that, flying on the right side has huge advantages: Your visibility from the LH seat is much better, you are in the traffic flow rather than going opposite. And, not least, it is what people from the continent do instinctively as they also drive on the right. which is why I am wondering whether that was the reason this pilot ended up flying on the left….
In the Alps, the fly to the right side of the valley whenever possible is taught everywhere I know of,
Thank you Mooney_Driver for this information.
In the future, I will ”fly on the right”.
Never too old to learn . . .
Mooney_Driver wrote:
I would not fly in the Alps anyway
Flying in the Alps is one of the greatest flying experiences you will ever have. Just take it step by step. Nothing to be intimidated by.
The downside of learning to fly in the Alps is that when I finally flew to England I had absolutely no idea how to do a cross wind landing! Had to get someone to teach me. All alpine valley airports are aligned with the direction of the valley floor (and parallel to the adjacent river) and the wind blows directly one way or the other along the runway – easy.
@Buckerfan
Interesting stuff, thank you!
Mooney_Driver wrote:
And, not least, it is what people from the continent do instinctively as they also drive on the right.
Not in my experience. I usually do a couple of introductory flights to the alps per year (“Alpeneinweisung” in German), and people tend to fly as far away from the mountains as possible. I.e. right in the middle of valleys. I’ll probably say “more to the right please” about 400 times during two or three hours of flight ;-)
