Wednesday, July 15, 2009

Some Mountain Flying Thoughts

Winter Park Aerial Panorama
Recently, a reader asked me for some of my thoughts on flying in the Rocky Mountains with a small plane such as the Cessna 182. The best thing you can do is fly near one of these areas and get some specialized instruction. Most airports around Denver have flight instructors available for mountain instruction. I am not an instructor (at least not yet), but I have some experience of the mountains. Here are some of the big things I can think of from lessons I have had and some of the books I have read. Once again, the best thing is to find an instructor in one of these areas for the specialized instruction.

Before taking instruction or the next best thing to instruction is to read a book about Mountain flying. Here is a link to some books on Mountain flying. Sparky Imeson's mountain flying book is a standard for reading on the subject. There are also good tips on Sparky's web site. Some of those web pages are more focused for backcountry mountain strips. Here is a minimum mountain flying knowledge page. If you become interested in backcountry strips, I would recommend taking a class such as the ones offered by McCall Mountain/Canyon Flying Seminars. I took the basic course and wrote about this great mountain/canyon flying seminar in the past.

  • Make sure you richen your mixture somewhat before landing. I do 5 half turns rich of my cruise mixture, but not full rich. Full rich and too lean is not good at high altitude. This method gives you appropriate power for a go-around if needed.
  • Land with short field techniques with smooth stabilized approach/descent. Don't chop the power on short final if you would land too long. Go around and try again.
  • Ground speed is faster landing at high altitude, it looks different, but keep same airspeed. This is due to larger indicated vs true airspeed difference at altitude.
  • Do not land too fast. Fly the speeds in the POH. Very important at high altitude. Landing fast will cause you to float and use a lot of runway distance.
  • Don't land two slow either; you do not want to stall.
  • Colorado airport information is available on-line on the CDOT web site.

  • Lean during runup. Find where leaning mixture drops RPM. Then richen 5 half turns
  • Takeoff with short field techniques
  • On takeoff reach 70% of take off speed 1/2 way down the runway, if not abort. Wind, weight, temperature, pressure altitude or something is causing problems.
  • Be 10% or more under gross weight. Reduced weight greatly helps your takeoff distance. Don't fill tanks all the way if at a high altitude airport
  • Your manifold pressure at takeoff will be much lower and the wings/prop develop much less lift. You can simulate the manifold pressure difference at your airport. A 29.92 day at 10,000 feet, I think would be about 19" Manifold pressure at takeoff
  • Likely the temperature will be much higher than standard as well which will greatly affect things and cause a very high density altitude. Taking off from Leadville in the middle of the day in the summer is a bad idea.
  • Check your takeoff distance in your POH, but realize your distance will possibly be much longer due to not being a new plane and not being a professional test pilot.


  • Climb out after take off, fly the POH airspeeds. Your pitch and climb rate will be much slower, but this is normal.
  • Watch your rudder control; step on the ball during the climb. Coordinated flight will help increase your vertical climb rate and is safer.
  • Don't let your speed drop too low trying to maintain a positive climb rate and stall
  • Watch for clearing obstacles when climbing out. Circle if you need to.
  • Lean your mixture appropriately. The 5 half turns rich works pretty well for me to start. Then afterwards I do it according to fuel flow mentioned in POH. I have a Fuel Flow meter. The fuel flow is about right for the EGT to be about 250+ rich of peak. Too lean is not good too. Detonation can happen and cylinder temps can get too high.
  • Keep cylinder temps 390 degrees or lower. Level off, gain speed, and richen mixture to lower cylinder temps
Crossing Ridges

  • Be careful crossing ridges. Approach at 45 degrees when close. Maybe within 1 mile. If you approach at 45 degrees, you will have only 90 degree turn to go back to lower terrain If you are further away from the ridge, you can probably afford a full 180 degree for lower terrain.
  • Downdrafts can be subtle or severe in the mountains. I have usually seen subtle ones which are still a problem. You get down to Vy and you still can't have positive climb rate. Make sure you are at max RPM max throttle. 2600 RPM in my C182P.
  • If in a severe downdraft, turn around in the direction of lower terrain.
  • If in slight downdraft, try near opposite side of the valley, if one side is in down draft, sometimes other is in slight updraft. Otherwise, go further away from pass and try climbing before approaching pass.
  • If having difficulties climbing, but not in a downdraft, you can step climb. Level, gain speed, then climb a bit, level, gain speed, then climb, repeat.
  • Always plan an alternate to crossing your intended pass. A different pass or another day. Or possibly stop and rent a car for the last portion of the trip.
  • Turbulence as you get closer to ridge is probably a sign to not cross the ridge here or today. Some is expected, but severe turbulence is definitely a warning. Likely bad downdrafts as you get closer. Flying higher can help.
  • 20+ knots predicted winds aloft at 12,000 is a concern. 30+ is probably a no go. Sometimes the Mountain AWOS will be indicating 30+, but it can be ok if it is not too near you. But be careful.
  • One side of the valley or ridge is usually smoother than the other due to winds. Sometimes it is dramatic.
  • I usually cross 1000-2000' over the passes. Especially when my wife is with me and when I was new. That will put me 12,500+ over many of the passes and then I drop down after the pass to under 12,500.
  • My 7-year old son gets airsick easier at higher altitudes, so I try to descend when possible.
  • If you have Garmin 430 Waas, the altitude reported on the Terrain page is accurate. I have found this is better than using the Altimeter setting from the airport. Usually you are higher than what the airport altimeter setting would tell you. The altimeter setting will vary around the pass and a mountain AWOS will tell you a pretty high setting which is valid only for the pass.
  • Mountain AWOS are good for wind and cloud reports. But it can be reasonably clear at the pass with clouds backed up on the other side.
  • Also watch that you can see more and more terrain on the other side as you approach a pass. This ensures you are currently higher than the pass.
  • Fly the main passes and then down the valleys. See my other blog entry for some suggestions on VFR Paths over the Rockies. It won't be a GPS direct course, but you usually can make some GPS waypoints that are relatively close to what you want to fly. Fly it with a Sectional Map and watch very carefully where you are and where the nearest airport is. There is a sectional of Colorado with passes marked at the CDOT website.

Other General Items

  • Portable oxygen is good at altitude if possible especially for a flatlander. Maybe borrow one? I use it if I am going to be at 12,500 or higher for a long trip, and I live at 5,000. It keeps you thinking clearly and prevents headaches. Remember to refresh your memory on the oxygen altitude requirements.
  • Manifold pressure goes up as you descend. This can be strange when you are reducing power and trying to lose altitude. You set it at 15", descend 2000' and MP is now at 17" without moving the throttle. You need to keep reducing the throttle a little as you go lower in altitude to maintain 15". Make sure cowl flaps are closed as you descend.
  • Always have an out. Know where lower terrain is. Plan so that you don't have to go over the pass. Stay a night somewhere and wait for a better day. Plan for a different way around even if it adds 2 hours. Always be able to turn to lower terrain. Land and rent a car for the last portion of the trip.
  • Avoid IFR in the mountains
  • Avoid night flying in the mountains
  • Carry survival equipment in the case of emergency. Sleeping bags or lots of space blankets, first aid, etc.
  • I use a SPOT Satellite Messenger for emergency notification and tracking as indicated in a past blog. A Personal Locator Beacon is another good way to go.
  • File a flight plan and get flight following if possible. Flight following is not possible in most mountainous areas though.
Instructors or others out there... Did I miss any big items?


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