Grand Canyon Flight

[In God We Trust]

As for your question about downdrafts the best I give you is the textbook answer. Beware downwind of ridges and peaks, especially with a wind in excess of 15kts and intersect at 30 degrees or better. From the leeward side give yourself extra altitude (like at least 1000’) because downdrafts can exceed your climb capability. Approach from a 45 degree angle so you can turn away if you need to. Turbulence may also be a concern.

Safe travels,

blave

 

Thanks for that advice Blave! That makes sense, if your able turn into the upwind, a 45 degree approach makes you more able to do so. I would imagine once you get turned around your not out of harms way until you get to the crest of the ridge or peak, is that the case?

[blave!]

Thanks for that advice Blave! That makes sense, if your able turn into the upwind, a 45 degree approach makes you more able to do so. I would imagine once you get turned around your not out of harms way until you get to the crest of the ridge or peak, is that the case?

Again, speaking in terms of theory here rather than practical experience (someone with practical experience please feel free to jump in) the idea is if you are approaching (a ridge or rising terrain) into the wind a small angle is good because then it's easier to turn away towards descending terrain instead of having to do a full 180.

From the windward side yes you would be able to turn upwind as well as towards descending terrain. Another consideration is that the downdraft is adding to your induced flow, reducing your angle of attack and making a climb even tougher. If you are at high altitude and close to or at full throttle RPM is a concern too.

One more bit of theory on recognizing downdrafts. In drier climates the appearance of virga at the cloud base and a dust ring at the surface is indicative of their presence.