You may remember reading about my mountain flying training earlier this year. Well, October 15, the “end” of Colorado’s best mountain flying season, is approaching so I had to take advantage of another beautiful morning to fly before hibernating my “newly” learned skills until next year. This time, the route was not well defined as the forecast for high winds and turbulence was very present for the early afternoon. Instead, we decided to be flexible and just go “check it out,” with the mindset that we would turn around at the first sight of bad turbulence.
We ended up flying a loop from Front Range (or FTG, shown above with the Rockies and Denver International Airport in the background) to Gunnison and back around. From FTG, we flew by Devil’s Head Fire Tower southwest of Castle Rock, over Cheesman Lake, right over Harriet Alexander Field Airport (KANK) in Salida, south of Monarch Pass, and around towards Gunnison. From there, we flew over Taylor Park Reservoir, up Cottonwood Pass and down towards Buena Vista before starting to head back directly towards FTG.
This flight was intended more for sightseeing than training so no landings were made along the route to ensure we got back to lower ground before the winds picked up causing moderate turbulence.
Even though the flight was not necessarily meant as a training flight, we, GA pilots, always have room for improvement and learning or experiencing something new. This flight was no different. Two pressure fronts, a cold and a warm, came close to each other at about the mid-point of our flight (the picture below shows that day’s current surface analysis chart right after the flight). In meteorology classes, we learn that cold fronts and warm fronts cannot mix or collide because of the difference in temperatures and densities. Warm air, being lighter, will usually be pushed atop the colder air. The air cools as it rises and the water vapor in it condenses. Precipitation, clouds and storms can be found in these scenarios. Fortunately, the formation of any type of visible moisture was not forecasted for the duration of our flight; however, the next day, on October 9th, almost the entire state of Colorado welcomed snow - the first snow of the season for Denver.
But, what we did experience was quite interesting! Upon reaching the mid-point of our flight, our altimeter setting went from 29.77” to 30.21” of Hg in a matter of seconds (ok, maybe a few short minutes) between two nearby weather stations. Do you know what that meant? A 400’+ difference in altitude! Wow!
I had noticed a big altitude discrepancy between my indicated altitude and ForeFlight’s (my iPad’s) altitude but which one was accurate?. I know the source of an altimeter’s information and how it works. An altimeter measures Outside Air Pressure (OAP) from the static source which gets converted to an altitude and the setting obtained from ATC or weather stations corrects it for changing air pressure. After manually adjusting the altimeter with the setting from the next weather station, it read correctly and ForeFlight was dead on, accurate, the entire time. Good to know! I assume ForeFlight must be automatically inserting the latest altimeter setting into the application since I had an ADS-B In unit connected to it.
In the mountains, when you already don’t have too much clearance from the ground as it is, a 400'-500’ difference in altitude is a huge difference. It did not present a safety concern for us because we were flying VFR in VMC conditions and we judged our altitude based on charts and looking out the window. But, can you imagine if we would have been flying IFR in IMC conditions? Would we have noticed or picked up (from a weather station) the large change in pressure before it was too late (causing a Controlled Flight Into Terrain or CFIT accident)? I, once again, want to thank the Colorado DOT and, in particular, the Division of Aeronautics for installing and maintaining wonderful AWOS stations on top of critical mountain tops/passes throughout the state. They are not only convenient and “nice to have” but can be lifesaving as well.
One other thing that is quite interesting and that we need to pay attention to when flying at high altitudes is the difference between true airspeed and indicated airspeed. Early on in our flight training, we learn that True Airspeed (TAS) is Indicated Airspeed (or IAS, what the airspeed indicator in the airplane shows us) corrected for altitude and temperature. At sea level on a 15°C day, IAS will be the same as TAS. However, as the temperature or altitude increases, the air density will decrease, causing the IAS to read lower than TAS. A good rule of thumb to approximate the difference between IAS and TAS without looking at specific temperatures, a chart, or a calculator is to increase IAS by 2% per 1,000’ increase in altitude.
At one point in the flight, when going over Cottonwood Pass (the one between Taylor Park Reservoir and Buena Vista as I’m told Colorado has different passes with the same name), we reached 14,000’ to clear it. Our indicated airspeed was showing 110 kts while our true airspeed was 28% more or 140 kts and our ground speed reached 173 kts.
Yes, I had to take a picture of the speed and altitude. I mean, c'mon, how often we do see that!? Hardly never for the speed and, this time, I climbed a 14er without sweating. And don't mind the helicopter symbol although it would be pretty sweet to see that speed (even if ground speed) in the R-22 I normally fly.
As for the rest of the flight, it was beautiful as always and surprisingly very smooth. Those Rocky Mountains sure are beautiful, especially now that they have already received some snow and the fall colors are still very much at play.
Pikes Peak on the back, left and Devil's Head area on the front, right.
The Devil's Head Fire Tower and the stairs to it can be seen above.
I was told this landscape was formed by glaciers. Quite interesting and different, huh?
The Moon delighted us with its presence throughout the flight and made for some nice sights
Harriet Alexander Field Airport (KANK) in Salida. It's on a good looking mesa, reminding me of Sedona a bit (except for the red rocks all around).
Colorado's popular Aspens are very pretty this time of the year and sand getting blown towards the Great Sand Dunes National Park in the San Luis Valley is seen in the distance.
Heading up Cottonwood Pass. The dirt road going up it can be seen in the right picture. Great fun with a Jeep.
This was my favorite part of the flight... so close to the mountains!
We flew a C182RG instead of a C172 and, boy, did it make a difference! The 182 could climb without constraints. No need for S-turns or circles to gain altitude. Not as much need for multiple alternate or escape plans, either.
Devil’s Head Fire Tower really caught my attention during flight so, after lunch, I drove the dirt road to the trailhead and hiked up to it to admire the views from a different angle. It was actually pretty cool to see an area from two different points of view in the same day, with similar weather conditions. I say similar because, by the time I made it up, the wind was, as expected, blowing quite a bit. I tell you… I’m not afraid of heights but walking up those stairs without backing (pictured below) made me a little nervous with that strong wind blowing us everywhere. Someone did lose a hat, haha.
And its history is worth reading as well...
- In 1907, a 10'x12' tower was constructed on top of the highest rock at Devil's Head. That same year, a small but comfortable cabin was built at the base of the rock (200 ft down from the tower).
- The fire lookout/tower was situated strategically to spot forest fires. The tower provides 360-degree views of more than 100 miles in every direction.
- From 1919 to 1921, Helen Dowe worked as a fire lookout for the newly formed U.S. Forest Service.
- In 1951, the original tower and cabin were replaced by the Army Corps of Engineers using 72 pack mules to haul equipment and supplies up the mountain. The fire lookout still lives in the cabin. It doesn't have running water but it has electricity for cooking and heating.
As always, fly safe and fly often! Life is short and we have to enjoy every minute of it! :)
A summary of this blog appeared in the Dec 2017/Jan 2018 edition of Midwest Flyer Magazine: