Advice on flying 180hp in Sierra Nevada mtns

[piperboy84]

I am planing flights from Carson City Nevada out of the Tahoe area over the mountains and down into the Bay Area and also down to Socal on a somewhat regular basis. It appears from the charts the best route would be when leaving Carson City to fly south past Minden then follow the highway out to Placerville. Is it realistic to attempt to do this journey (in regards to both the climb out and mountain crossing ) in a lightly loaded 180hp aircraft during the summer months. I am aware of the mountain wave and rotor reputation of the area,however assuming I'm flying in light winds is it reasonable to expect to make this journey with all the density attitude issues?

The POH says it's doable, but I was hoping someone on here who has done this trip in a similar type machine and could share their opinion on "real life" issues to be considered.

[Madbob]

Just remember Density Altitude and Steve Fossett. He hit the side of a rather high hill in a Super Decathalon in the same area.

I'm, no expert of flying in mountains in a light single but the fact that you ask the question shows good awareness of the issues.

I am sure that you will get lots of advice on this thread. All I can say is good luck, plan carefully and watch the weather. I am sure it will be a lot of fun.

MB

[ChickenHouse]

When I was living in SF Bay Area, I did the trip to Lake Tahoe several times in an old 145hp light single, so yes, it is doable. Be careful with weather on that route and calculate +50% on top of your personal risk capability.

Due to the mountains, you will face good weather on one side and very bad on the other - many times - so do not rely on taking the plane.

Good alternate routes are crossing Crystal Bay and join 80 overhead Truckee, or go South and follow Mokelumne River (only and only if in very! good weather, it's spectacular but tricky).

Depending on the plane going direct on top might be a bit on the edge.

[Desert185]

The highest terrain is Luther Pass @ 7735', just south of Tahoe. If you go in the morning and watch the winds at 9,000' and 12,000' you'll be fine. Stay over Hwy 50 to Placerville.

[Mark 1]

I've done this several times, latest being two days ago, coming over Mammoth Lake at 14500' towards Modesto.
if you're going further South, you can go down Owen's valley and over Mojave to SoCal, but it can get very turbulent as the day progresses.
Around 12000' is good for the Tahoe area although the emergency landing options are very few.

[piperboy84]

I did a few flights years ago up the Owens Valley from LA to Mammoth the turbulence was horrendous, I think desert185 idea of getting thru the mountain pass and out into the San Joaquin valley rather quickly is the way to go,

Attached is a rather sad story about flying the Owens Valley
http://www.flyingmag.com/pilots-plac...alley?page=0,0

[Desert185]

This is my neighborhood (one of them, anyway) and that is what I would do. It minimizes the time crossing the rocks. Once you intercept 50 westbound, its all downhill fairly rapidly to Placerville. Stay on the updraft side of the passes if there is enough wind to promote updraft/downdraft.

If the winds aloft in the KTVL area are more than 20-30 at 9,000-12,000', I would wait for another day.

[AdamFrisch]

Done that trip quite a few times. Owens Valley can be brutal with the rotors and turbulence at times, but the views are spectacular. Central Valley is less hard work as then you're on the updraft side mainly, but is very boring visually. I personally would rather deal with turbulence in Owens than cross the Sierras in a single, but that's just me. That's why I fly a twin I suppose - I'm a nervous flier.

Last time I came down Owens Valley I tuned in Mojave Airport and the AWOS was reporting 60kts winds! You could see the dust clouds racing across the desert floor. But at 13500ft it was smooth.

[piperboy84]

I personally would rather deal with turbulence in Owens than cross the Sierras in a single, b

But the Owens valley route still involves crossing significant mountain ranges from Mammoth up to Carson city

[India Four Two]

pb84,

Thanks for the link to that story.

I have extensive experience of wave and rotor in gliders and towplanes in the lee of the Canadian Rockies, but I've never flown in the Owens Valley, although I've been there on the ground (on a good day).

So my question might be naive, but if encountering rotor turbulence, why wouldn't you fly higher to try to get above it, into the wave?

[Desert185]

If you have O2 onboard. If not, descending to fly low near the valley floor is your best bet if you didn't see the weather forecast and didn't consider flying on the west side of the Sierra. That valley can get nasty.

[India Four Two]

Desert 185,

Thanks for your reply. I suspected that might be the case.

In the Front Ranges of the Canadian Rockies where I flew, the peaks are below 9000', so it is feasible to climb above the rotor.

Also, we don't have another set of mountains downwind to complicate the wind patterns.

The elevation difference from the valley to the peaks is only 5000', so altogether a much smaller scale than the Sierra - Owens Valley situation. In spite of that, we regularly get waves to over 40,000', particularly in the Fall.

[FullWings]

A friend of mine hired a 172 and had to thermal it to get out of the valley as the performance was pretty badly affected by the summer density altitude.

Airmass movements of +/-1,500fpm over quite large areas are not uncommon during the hot months and can easily overwhelm the available rate-of-climb of small to medium sized aircraft. You're going down, down, down as Johnny Cash would have said...

[RatherBeFlying]

At the Cowley Alberta (3876 ASL) wave camps we regularly tow 2-seat gliders behind a 180 hp Scout through rotor.

If you hit heavy sink, get out of it - - or pick out a landing spot.

[India Four Two]

Hey RBF,

Maybe we know each other! I'm ex-Cu Nim. Many tows at YYM.

Barry Bradley used to say "The rotor is not rough unless you get rolled inverted!"

[Desert185]

Desert 185,

Thanks for your reply. I suspected that might be the case.

In the Front Ranges of the Canadian Rockies where I flew, the peaks are below 9000', so it is feasible to climb above the rotor.

Also, we don't have another set of mountains downwind to complicate the wind patterns.

The elevation difference from the valley to the peaks is only 5000', so altogether a much smaller scale than the Sierra - Owens Valley situation. In spite of that, we regularly get waves to over 40,000', particularly in the Fall.

Here's one that I'm still not sure I understand. I once flew VFR from the Minden, NV (MEV) area direct course to Ely, NV (ELY) with 50 kts on the tail at 11,500' in my 185 WITH NOT A HINT OF TURBULENCE until descending into Ely. If you know the mountain and valley structure in NV, that is hard to comprehend. Not that I'm complaining. Any other time and we would have been beat to heck with the mechanical turbulence.

[India Four Two]

Desert185,

I knew where Minden was, but I had to look for Ely on GE. I see that the maximum elevations on that route are about 7000'.

I have often found in good wave conditions in southern Alberta, or when arriving or departing from Salt Lake in commercial jets, that it can be very smooth with little or no turbulence above the local ridge lines, but very rough below them.

I'm not sufficiently up on the physics of waves to know what causes those conditions, but you must have had the right conditions on that trip. Did the turbulence start below the ridge top elevations?

[Desert185]

Did the turbulence start below the ridge top elevations?

Yes. On descent into Ely. I was very close to some ridge tops enroute and could see blowing snow. Actually, there are four ridge lines that exceed 10,000' on that route.