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Picking up VFR mountain flying

Gliders avoid downdrafts, and seek updrafts. You do the same in a powered aircraft. You plan your flying ahead – as you fly – in the mountains. Not all before T.O. As regards “rotor” are we all meaning the same thing? The bit under a wave crest. About the same time as a glider crash (one injured, one fatal) near Tomintould, north of the Cairngorms, a C172 from Inverness, in the same area, was turned upside down and lost several thousand feet.

EGPE, United Kingdom

I did quite a few hours (when I lived in the US) flying a Cessna 140 with a C85 engine and a cruise prop in the mountains. I flew routes in the mountains as if I were flying a glider, taking advantage of ridge lift and any thermals and staying away from areas I’d know to have sink based on gliding experience.

Andreas IOM

Can someone define a rotor. During my recent trip through Africa we flew over Namibia and in a rotor on the lee side of a mountain crest. It turned our plane over in a matter of seconds. What is so funny about this? Do I miss something here?

EHRD, Netherlands

AeroP checking met texts it is the turbulence associated with mountain waves and lies below the lenticular formations on the lee side of ridges. Reverse flow can occur, and also ragged circulating cumulus or rotor clouds can occur. Lenticular or rotor clouds may not develop, but associated turbulence can still occur.

Turbulence in the order of 2 to 4g, although 7 g is possible. Gliders and aircraft have broken up in rotor so need to be treated with extreme caution.

Typically if free stream wave is above 25-30 knots, you would want to avoid the areas below the wave on the lee side.

The rotor area can be quite deep so the other rule, in addition to wave speed, is to fly above the ridges by half the mountain elevation.

Enstone (EGTN), Oxford (EGTK)

fly above the ridges by half the mountain elevation.

That’s an interesting way to put it, and I wonder what the physical rationale is. The altitude alone of the summit cannot be the sole factor because the terrain before and after could be almost as high.

The sort of rule I have read about is to fly at 2000ft above the peaks for every 10kt of wind above them, to ensure that downdraughts are below -500fpm. Such a rule “must” make sense, I would think. Normally I cross the Alps about FL180 and this is some 6000-8000ft above the general terrain.

A good leaflet on mountain flying appears to be this one which was given to me by a Swiss pilot.

Shoreham EGKA, United Kingdom

I collated this information ove a year ago, on accidents involving U.K. hills.. I don’t think there are any more recent accidents. Very few (2?) are in good VFR. None involve what I regard as mountain flying – deliberately flying in the mountains below their summits.. Entering cloud below near-by terrain, (unless on a documented IFR procedure), is dangerous. A precautionary landing seems more survivable. I’ve ommited to links to accidents where this was the successful choice.Surprisingly few are in the Highlands. There’s one I think I’ve missed from thr 1990’s.

G-JMTT IFR A/H failure
G-BNGD Vacuum failure with t/s u/s in night imc
G-BPAD Navigation?
N92562 IFR Approach
G-PICS Fatigue?
G-BXLJ Entered cloud in good weather??
N8174V Wave/Turb/Downdraft
G-BMPO Wave/Turb/Downdraft
G-AVWG Wave/Turb/Downdraft
N8174V Wave/Turb/Downdraft
G-BMVJ Wave/Turb/Downdraft
G-AWLY Wave/Turb/Downdraft
G-BILR Wave/Turb/Downdraft
G-BWFW Wave/Turb/Downdraft

G-BPKG Grob – Ice?
G-BXLJ Entered cloud in good weather? Cloud formed around them??
G-BHHR ?? problem in cloud over hills?
G-BHPX Downdraft? Not flying low in valley.
G-AVXX trying to climb through cloud
G-BSKJ descend below hills in cloud
G-TDAD flying below hills
G-SACV Flying low enter cloud?
G-BIIJ imc below hills
N700S Poor viz descent to land.
G-ASKS descent/approach in poor vis
G-BNJS cloud cfit??
G-BSYC Descend into hills,%20G-BSYC%2011-09.pdf
G-IPJC descend below hills

EGPE, United Kingdom

I recall speaking to the pilot of TB20 N700S (N700S later became a TBM700).

He flew a DIY IAP, didn’t get visual at the “MDH”, went around, but his DIY IAP did not include a missed approach segment and he hit a hill.

That is one of the extremely few accidents on DIY IAPs.

The UK CFITs are nearly all people flying into terrain via nav errors (at night or in IMC), or loss of control in IMC.

Shoreham EGKA, United Kingdom

@Commander wrote:

One of my dreams is to be able to say.. lets go to Courchevel .. or .. St Tropez .. or ..

Should I start pursue a mountain rating and if so where or should I go for a local rating?


You don’t say where “local” is, but I recommend Megève LFHM. The DGAC will give you a “qualification montagne” for wheels or skis. If you have a foreign EASA license you’ll have to wait until 2018 to convert the qualification into a rating – if you can be bothered.

It helps to do some tail wheel landings before you go. You can get a TW endorsement in the mountains but they probably won’t teach or demonstrate wheel landings; however, that’s something you can teach yourself when you’re ready.

Glenswinton, SW Scotland, United Kingdom

Jacko wrote:

wheel landings; however, that’s something you can teach yourself when you’re ready.

If I recall Correctly, Stick and Rudder has a good explanation of those (and I think that’s how I learned mine!)

Yes, me too. There’s not much about flying that can’t be learned from Langeweische senior. Mind you, I was glad to have nobody watching my first attempt, and equally glad to have a good 30 inches of prop clearance

Correction: always glad to have nobody watching…

Glenswinton, SW Scotland, United Kingdom
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