Flying in the high mountains

Discussion in 'Flight Following' started by Snowmass, Jul 19, 2021.

  1. Snowmass

    Snowmass Line Up and Wait

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    Two were killed a few days ago in a 2007 Bonanza leaving Aspen. One was low time but the other pilot an ATP! It's always the same old sad story. The climbed up a canyon in trying to clear the high ridges to the east. The lowest possible pass is 12,000'. The rule is very simple: always circle climb well above the highest terrain any where near your route BEFORE starting to cross. Never try to out climb the terrain.
     
  2. murphey

    murphey Touchdown! Greaser! PoA Supporter

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  3. sourdough44

    sourdough44 Pattern Altitude

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    I know it’s on the other accident thread. Another thingy, much of the time around here, GPS direct works. In the higher terrain, one may well have to take the longer way for the more forgiving route.

    I went to the Grand Canyon a few years ago, GPS direct from WI wasn’t going to work.
     
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  4. Snowmass

    Snowmass Line Up and Wait

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    Yes, but the FAA, in its infinite stupidity, no longer publishes World scale charts just Sectional and flying in a fast plane long distances with Sectionals is impractical. I am willing to bet they did not have paper chart on board. Colorado does give out World scale charts if you can get one. I can't imagine planning a route through passes on glass. But, in any case, at 15,000 feet you are above all Colorado terrain. Surely a Bonanza can reach 15,000 feet with two persons. My 1964 C-210 would get to 21,000 feet or more.

    The key point is climb above terrain BEFORE attempting to cross, not enroute.
     
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  5. Racerx

    Racerx Line Up and Wait

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    I'm a flatlander and contemplating flying to northern New Mexico via La Veta pass this fall. I thought someone mentioned a seminar at OshKosh for mountain flying...by Colorado pilots? I might be imagining that though
     
  6. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    Nope, not imagining it....Bill Standerfer will be giving at least one, possibly more 1 hr talks at OSH. Bill is lead instructor of the Colorado Pilots Assoc Mountain class.
     
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  7. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    What are you going to be flying?

    There's an AWOS on top of LaVeta, KVTP 119.925 or call 719-587-3120

    If the winds are > 20, take the long way south TAD-RTN and you're in NM. Watch out for the R west of I-25 between PUB and TAD. Careful because I-25 cuts thru the eastern edge of the Restricted area.

    Altho the road and pass is over 9000 ft msl, you'll have mountain peaks above you on either side of you. Recommend being at 11.5K going over, or higher if you can. The road below is not suitable for an emergency landing because it's twisty.

    Here's the list of all the mountain passes with AWOS. There's a push to get cameras on them, but it takes a while.

    https://www.codot.gov/programs/aeronautics/mtnawos
     
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  8. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    If you can see the mountains on the other side of the mountain you're crossing, you're high enough. Maybe not for the next line of mountains, but for the one you're crossing now. Welcome to geometry.
     
  9. Racerx

    Racerx Line Up and Wait

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    Awesome info. Any idea on dates?

    As for the trip it'd be in the Cherokee Six 300 into Taos. Got an elk hunt planned and have always driven the 22 hours just because of all the gear we bring for 2 weeks.
     
  10. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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  11. Snowmass

    Snowmass Line Up and Wait

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    Agree but dozens of airplanes have crashed trying to fly east from Aspen. The key is to climb higher BEFORE approaching the high country and not trying to outclimb the terrain. They fly up a valley that is too narrow for a 180 and can't climb above the end so they crash. If you are over 15,000 feet than it does not matter which route you take as you are over everything. So circle well above terrain any close to your route and then cross; it's that simple.

    This is not a supposition. This very scenario has happened many times. Ask Aspen Search and Rescue.
     
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  12. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    Bill’s sessions at OSH should be in the catalog. If you want the full day ground followed by the 4-5 hour the next day, that’s in Denver at KBJC in late August. Check the Colorado Pilots Assoc web site. New Mexico Pilot Assoc has a similar program which might be better for you, since it’s geared to northern NM and southern CO.
     
  13. MajorTurbulence

    MajorTurbulence Pre-takeoff checklist

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    Flying a Cherokee Archer or other similar NA Single can be thought of as a safety feature in that most would realize that you are not out climbing terrain that high up. An ATP should be in the “most” category. There is that smaller group that have limited experience and have failed to recognize what they don’t know, and have not taken the requisite steps to learn, and I realize the statistics include them. Circling to altitude is certainly the ticket.

    Having unrealistic expectations seem to go along with Bonanzas. This accident sounds very similar to the airline pilot flying his just married bride within the last 2 years in his Bo in Colorado. The breed has certainly been hyped up over the decades, but is not superplane, although I’d still like to have one.;)
     
  14. sarangan

    sarangan Cleared for Takeoff

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    La Veta was the first pass I flew across, as a newly minted pilot and also new to the mountain areas. It is a very easy pass because the terrain on either side is flat and low unlike the ones near Aspen.
     
  15. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    I have no interest flying east out of Aspen at any altitude in a single piston engine airplane. Just because you're over 15K doesn't mean it's a no-brainer flight.

    "Snowmass" name indicates you're familiar with the area. If not, look at a map. There's no place if something goes wrong until you're in the Leadville/Salida valley.
     
  16. Wagondriver

    Wagondriver Pre-takeoff checklist

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    I would have no qualms about flying east out of Aspen. But then I don't load 80 gallons, 2 guys with bags, in an already heavy plane with mediocre performance, and then take off during the hottest part of the day in the middle of summer. I do believe that Bonanza was at service ceiling based on the performance data. Whats the gross on that thing, like 3600lbs? With 300hp? NOT impressive with a DA about 11,000.
    Yes, its high unforgiving country, but then so is ALL the high country. If I did not fly over the inhospitable areas, I wouldn't fly much. Know your performance, give yourself an out. That alone will most likely keep you alive!
     
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  17. texasclouds

    texasclouds Pattern Altitude

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    A guy in our Cessna 170 club claims his son landed (and departed) at Leadville in their 170. It was done smartly though.
     
  18. bluesideup

    bluesideup Pre-takeoff checklist

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    Hi.
    That is only part of the equation. If the mountains you see on the other side get smaller / shorter you will likely hit the ones right in the front of you, you need to make sure that they get bigger / taller to confirm that you will make it above the ones near you.
     
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  19. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    I don’t care how fast your plane is, you shouldn’t be flying in the mountains with a WAC.
     
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  20. Racerx

    Racerx Line Up and Wait

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    Unfortunately I'll be in Alaska last week of August. Had already looked at that.
     
  21. Jdm

    Jdm Pre-takeoff checklist

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    Well ya got me thinking. Thanks for that. Just made a flight over the high mountains in a Bonanza that I was delivering a few days ago. Also recently purchased an A36 of my own. Airline type as well. Luckily I’m active in GA and fly other HP aircraft that are also commonly associated with unrealistic expectations. Good discussion here, excellent points about the circling climb. We were prepared to fly the ODP, which basically climbs in a circle, but ended up in the clear with good climb options for a visual departure. Also planned the flight close to daylight to take advantage of reduced DA.
     
  22. MauleSkinner

    MauleSkinner Final Approach

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    I disagree…becoming an ATP requires no direct knowledge of mountain flying, Cherokee or otherwise.

    well, let me clarify…an ATP “should” realize that, but not by virtue of being an ATP.
     
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  23. Captain Sweet T

    Captain Sweet T Pre-Flight

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    Question for the experienced...

    So there is less air for the wing and prop to grab onto and engine to breath. If you have a turbo, your engine will still perform. What percentage of the total performance loss is the prop and wing if you still have 100% engine power from a turbo?
     
  24. Snowmass

    Snowmass Line Up and Wait

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    I have been flying the Rockies for almost 70 years with a WAC. But I know how to fly, how about you? What you shouldn't do is fly without paper charts.
     
  25. Snowmass

    Snowmass Line Up and Wait

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    My 1964 C-210 has a service ceiling at gross of 21,000 feet. I have been to 23,000 feet at partial load. I can't believe a Bonanza is such a sick airplane that it can't clear 15,000 feet but maybe it is. I any case I have been flying the high Rockies for almost 70 years no problem. In fact I even crossed the divide in an 85 HP Aeronca Chief in summer at 13,500 feet at gross by soaring over Berthoud Pass.
     
  26. sarangan

    sarangan Cleared for Takeoff

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    The wing will produce the same lift (which is the same as the weight of the airplane), except your true airspeed will be greater. This increase in TAS is the concern when it comes to making tight radius turns inside a valley.
    The thrust from the propeller will decline with decreasing density unless the prop speed increases proportionally.
     
  27. Racerx

    Racerx Line Up and Wait

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    Couldnt find anything about the session so emailed Bill directly. "My forum was to have been in the FAA building, but FAA management decided to cancel all their forums. Sorry, but nothing from me this year at OSH." Damn
     
  28. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    Rats! I'm surprised they couldn't/wouldn't move it to one of the tents. Bill's sessions are always packed.
     
  29. DoubleD

    DoubleD Pre-takeoff checklist

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    Sure about this? It seems to me a CS prop will just run at higher pitch to maintain RPMs at a given engine power output. So, it seems to me, talk about wings and propellers losing efficiency with altitude is not correct.
     
  30. DogoPilot

    DogoPilot Pre-Flight

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    Same RPM but less air to bite, therefore less thrust produced is my understanding.
     
  31. texasclouds

    texasclouds Pattern Altitude

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    Less dense air has fewer air molecules. That means less power on engine output, less thrust from propeller biting lower density air, and less lift from wing. Often also higher AOA is required.
     
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  32. SloRoam

    SloRoam Pre-Flight

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    I find it easy to think of density if I think of air as a series of golf balls, each golf ball representing an air molecule. As density of air goes down because of temperature or pressure or whatever, the golf balls get farther apart. The golf balls are what cools down the engine, lifts the plane and for the propeller to bite into. Visualizing that helps make the physics easy.
     
  33. sarangan

    sarangan Cleared for Takeoff

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    Its constant speed, not constant thrust. Assuming constant speed, the thrust will decline linearly with density.
    https://www.grc.nasa.gov/www/k-12/airplane/propth.html

    One could increase the rpm to increase thrust, but eventually you will run into the mach speed limit for the prop.
     
  34. DoubleD

    DoubleD Pre-takeoff checklist

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    But it's not constant pitch, so at the same RPM pitch is higher in thinner air, at constant power. Of course, engine output is lower in thinner air (normally aspirated), but that's a different matter and we all agree on its effect on performance. As for the wing, it's not "less efficient", it's traveling faster at any IAS and therefore hitting more air molecules (golf balls) at the higher TAS.
     
    Last edited: Jul 24, 2021
  35. Racerx

    Racerx Line Up and Wait

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    Going faster at high altitude doesn't mean a wing is "efficient". It means the air is less dense which means there's less drag. A wings main purpose is to produce lift, not go fast. Why is your ground roll longer and speed increased at high DA Your wing isn't producing enough lift, so it's less efficient. Think of your prop the same way as a wing. They're both airfoils after all. If your wing isn't producing as much lift, your prop isn't producing as much thrust. When your TAS increases, it means the aerodynamic drag has decreased because the air is thinner. Your

    Another example. Think of a boat prop. Water is low da. Pushes like an sob. Take that same prop out of the water and into the air, I don't care what pitch the blades are, there's less thrust produced. Your indicated airspeed will read slower at higher altitude than true airspeed because indicated airspeed works off pressure. There's less pressure. Going faster does not mean you're hitting more molecules. Just means you're going faster.
     
  36. DoubleD

    DoubleD Pre-takeoff checklist

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    Seems like we're stuck over the definition of "efficient". I'm not an aeronautical engineer, but I've been reading about airplanes and flying for 60 years and I've never heard of a wing or propeller being less efficient at higher altitudes. If they were, we'd fly as low as practical.
     
  37. Southpaw

    Southpaw Pre-takeoff checklist

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    perhaps " effective " VS "efficient"
     
  38. sarangan

    sarangan Cleared for Takeoff

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    Just like a wing, when density decreases you have to increase your true airspeed (which in this case is RPM), or angle of attack (which is propeller pitch) to maintain the same lift (which is thrust). But the tips of an 80-inch prop at 2500rpm will be close to mach 0.8, so there is not much room to increase RPM. You can increase pitch, but just like a wing, at high angles of attack the induced drag goes up, so the propeller efficiency will decline. Efficiency is thrust * forward speed / crankshaft power.
     
    Last edited: Jul 25, 2021