What’s YOUR experience with crossing the Alps in high wind conditions?
Tomorrows forcast is a wind of 35 kts from 230 in FL140 and “moderate turblulence” up to 140. I plan to fly in 150, or maybe 160 …
25 knots is the rule of thumb for light GA, or climbing in smooth air to a height which is half the height of the mountain range (AGL) above the range – which in the case of the Alps would be at least FL160? In theory this height gives a margin of safety for the effect of turbulence, in particular of the rotor type.
My only experience of cracking my head on the ceiling (just a head bump), despite being strapped in, was in a Cessna 140 over relatively puny hills (3,000 feet) and a brisk mid level wind. 35 knot plus across the ridges in the Alps might be more interesting.
The highest peak should be around FL110 if you fly a little bit east (LOWZ LOWK) so I think at FL150 you should be fine. I never had any problems at that altitude, obviously I don’t fly in föhn conditions and not in IMC for long time.
What is the route and the terrain height, and the wind angle relative to the ridges? That’s crucial.
The route across the Alps is straight from Salzburg to Klagenfurt and then South, I have planned FL150 … and I also can ask for a more Eastern route where the mountains are a bit lower and the wind is less … The track is about 140-150, the wind will probably be 230
It’s going to shake big time. Today was v shaky on this side of the Alps.
Where was that, and what altitude?
Shouldn’t really shake so much in FL160
Ok, checked, Geneve, …. that’s a different story than the EASTERN part of the Alps
One rule of thumb is to maintain 1000ft above the ridge(s) for every 10kt of wind blowing across them, to keep any downdraughts below 500fpm.
Somebody will no doubt get some program and plot that route on it but a non-T SR22 will maintain 500fpm only to about FL110. At FL150 it will be about 300fpm. Very similar to a TB20.
If the peaks are at FL100, I would fly it at FL180 to keep it smooth and safe.
a non-T SR22 will maintain 500fpm only to about FL110. At FL150 it will be about 300fpm. Very similar to a TB20.
I think there is a difference between 310HP and 250HP…
Flyer59, may I direct you to the Austrocontrol VFR WX website, alas only in German. Looks like you’ll have some Föhn, I’d go further east in your case and cross somewhere east of the Linz-Graz line.
Northern side of the Alps @ 14local tomorrow:
5000ft amsl 140-190/10-15kt im W 12 Grad C und im E 14 Grad C.
10000ft amsl 220-240/15-25kt um +3 Grad C.
Nullgradgrenze: 11500ft amsl im W und 12500ft amsl im E. (freezing level)
Southern side @ 14:00 local:
5000ft amsl 180-240/10-15kt 11 Grad C im W und 13 Grad im E.
10000ft amsl 230-260/20-25kt +3 Grad C im W und +5 Grad im E.
Nullgradgrenze: 12000ft amsl im W und 13000ft amsl im E.