WrightFlyer Posted April 17, 2022 Report Posted April 17, 2022 I'm an East Coast/flat land pilot heading to Colorado for a conference for work next week. Specifically I'll be at KCFO near Denver. Been awhile since I've done high altitude training - and that was in a helicopter about 20 years ago. Thought I'd reach out to the hive mind and locals for tips/techniques for operating out of high DA airports in a piston aircraft. I have a 252 Rocket, I'll be the only passenger with minimal bags. CFO field elevation is 5500' and runways are 8,000'. I've been calculating take off and landing distances using the POH using the current METARs at CFO to get a feeling for what right will look like. (current winds 300 at 19G29 - yikes!) What should I expect for starting, mixture settings, aircraft "feel" and any other high altitude anomalies? I've been reading articles on operating in high DA areas and talking to a few other smart folks I know. Appreciate thoughts from the group. Travis 1 Quote
Mooney Dog Posted April 17, 2022 Report Posted April 17, 2022 Dont be surprised if the take off takes longer than you're used too. Thats what got me my first high DA high alt airport! If you did your calculations and you have enough runway, you're good! just have an abort spot in mind. Mixture settings can be a pain but not impossible. Im assuming you have an engine monitor so that should make it all easier too. The rocket is turbo'd i believe, so doubt you'll have a problem with MP. Other than that i hope its a good trip. 2 Quote
philip_g Posted April 17, 2022 Report Posted April 17, 2022 (edited) You have a rocket. You will notice basically zero difference. Lean aggressively for taxi and go full rich for runup and take off. Nothing changes really. Cfo isn't even that high. Edited April 17, 2022 by philip_g 2 Quote
kortopates Posted April 17, 2022 Report Posted April 17, 2022 Mixture settings are unaffected with the Turbo, except for idling at high DA. But if you lean aggressively at sea level you'll be fine at altitude. Although it take a lot of prime fuel to start a Continental, a bit less at altitude and I'd startup with the mixture set less than full rich. Compared to Sea level, it might seem to take for ever to accelerate to Vy after liftoff because of the much faster TAS required at altitude (basically about 2 kts for every 1000' of DA) so just be patient and keep the nose down till you get to Vy where you can really climb like a rocket! With gusty winds expect turbulence right after liftoff as well which will further slow down your ability to accelerate and climb, so give your self plenty of room to get to altitude away from terrain the best you can. But without turbulence, once your at Vy and above you'll be back to your familiar climb rate. The biggest hazards in mountain flying for us are turbulence and mountain wave activity that can create strong downdrafts; especially the rotors that can cause significant structural damage to a plane in seconds that set up on the leeward side near the ridge height altitude. All its takes is 15-20 kts of wind directly perpendicular to the range to form mountain wave activity. If there is enough moisture , rotor clouds will be visible to you but more often they are invisible but just as turbulent. Above all, if mountain wave activity is possible or likely, don't let the AP fly the aircraft in altitude hold mode. If you're going to use the AP at all, just keep it in pitch mode (along with whatever lateral mode you want) so you are aware of any downdrafts. Keep in mind the downdrafts are always stronger than the updrafts. If caught in a downdraft never make a 90 degree turn that has you paralleling the ridgeline and wave. That will just keep you in the down draft. Instead either make a 180 if your too close to terrain in a threatening downdraft or continue perpendicular to the ridge line. Also rather than fight a downdraft pulling up the nose, like your AP would do in altitude hold, instead lower the nose to get out of it as soon as possible and catch the updraft further down wind to help recover altitude. The period size of the wave though will vary with the strength of the winds and height of an inversion layer that caps the wave where the lenticulars will hang out if there is enough moisture. To avoid threatening downdrafts too close to terrain, clear the mountain peaks by an altitude of at least 50% of the range height above the lower flat terrain. Lastly try to avoid descending into the mountain airport at great speeds and get slowed down before you descend into where turbulence is likely to exist. One of my favorite destinations is Mammoth Airport for skiing and climbing where I keep an airport car and I once saw a King Air pilot make that mistake, After he descended way too fast into turbulence he discovered after landing his wing skins where very obviously wrinkled throughout the span of the wings. To get slowed down in unexpected turbulence, in addition to pulling back power, I'll pop the speed brakes instantly in level flight and then drop the gear below gear speed and ride out the really bad turbulence at Va that way. The gear down not only helps slow down but helps with stability. Most of the time with the Turbo we can simply climb above the turbulence to smooth air in the upper teens. But sometimes, particularly in winter, we're capped below an icing layer and am forced to endue it. XM music really helps with the comfort level till you get out of it. 6 Quote
ilovecornfields Posted April 17, 2022 Report Posted April 17, 2022 @kortopates for the win! This book is good as well if you haven’t read it yet: Mountain Flying Bible Revised https://www.amazon.com/dp/1880568179/ref=cm_sw_r_cp_api_i_BF0RPCXAE2GJ3SW7S6XV Gear down really helps in turbulence. 2 1 Quote
philip_g Posted April 18, 2022 Report Posted April 18, 2022 Guys.... Cfo is in Denver. East of the rocks. He will not be doing any mountain flying nor crossing any passes or ridges. The mountain wave may be an issue however. 3 Quote
carusoam Posted April 18, 2022 Report Posted April 18, 2022 Hmmmm…. What if… The OP wants to know everything there is to know about landing and taking off at places in and around Denver…. In his Rocket? He got great insight from a CFII that flys in the neighborhood… Followed by a really sharp guy who knows a good book… MSers don’t usually run with partial information… this far out from a trip…. Get as much info as you can tolerate… The cool thing about mountain flying training… You get to see ground speed vs. airspeed causes some funky visual cues… The turbo solves the power issue, but the wings are not TC’d… the T/O and landing distances grow… Use the ASI, be cautious of what you are seeing… the ground speed will be faster at the same airspeed… https://www.airnav.com/airport/KCFO PP thoughts only, not a CFI… Best regards, -a- 2 Quote
philip_g Posted April 18, 2022 Report Posted April 18, 2022 (edited) 1 hour ago, carusoam said: Hmmmm…. What if… The OP wants to know everything there is to know about landing and taking off at places in and around Denver…. In his Rocket? He got great insight from a CFII that flys in the neighborhood… Followed by a really sharp guy who knows a good book… MSers don’t usually run with partial information… this far out from a trip…. Get as much info as you can tolerate… The cool thing about mountain flying training… You get to see ground speed vs. airspeed causes some funky visual cues… The turbo solves the power issue, but the wings are not TC’d… the T/O and landing distances grow… Use the ASI, be cautious of what you are seeing… the ground speed will be faster at the same airspeed… https://www.airnav.com/airport/KCFO PP thoughts only, not a CFI… Best regards, -a- I happen to also be a cfii. I also happened to have owned a rocket. I also happened to base that rocket at bjc about 20nm from CFO. If the original poster is flying a rocket I'm probably not going to insult them with "watch your airspeed on final" like a new student.... I will add that of his fuel setup sucks there's a chance the engine could quit on rollout. The rockets are finiky. Edited April 18, 2022 by philip_g 1 Quote
carusoam Posted April 18, 2022 Report Posted April 18, 2022 10 minutes ago, philip_g said: I happen to also be a cfii. I also happened to have owned a rocket. I also happened to base that rocket at bjc about 20nm from CFO. Do you have anything else you want me to clear up before you tell me I don't know what I'm talking about again? I will add that of his fuel setup sucks there's a chance the engine could quit on rollout. The rockets are finiky. Hmmmm… What if my memory was that of an older gentleman, and couldn’t remember your skill level… I may have confused you with a guy that flys an M20J around Hawaii… I would gladly erase the part where I wrote you “don't know what I'm talking about”… But, I don’t think I can find that… you must have confused my input with somebody else’s… Wait a sec… Why are we discussing your awesome flying skills…? Weren’t we discussing flying in and around Colorado? Why didn’t you add what you know about the differences flying there vs. what the OP was requesting…? Knowledgeable people have great input… Always adding to the conversation… Hey… there is a great thread for Mooney pilots that are CFIs… Many have posted their credentials there… unfortunately, my memory skills aren’t strong enough to know what you put there without looking you up… Enough about my challenges… Back to the OP’s question… Best regards, -a- 1 Quote
ArtVandelay Posted April 18, 2022 Report Posted April 18, 2022 Coming from the east, the OP doesn’t need to deal with the mountains. Executive summary:Fly in the morning when air is cool and stable, be aware of density altitude, ground speed is higher but IAS is the same.Enjoy the trip. 2 Quote
Schllc Posted April 18, 2022 Report Posted April 18, 2022 I am also predominantly a flat lander, and year before last I flew my turbo all over the northwest. Most places that are paved, take into account the elevation, and have longer runways. what was a challenge for me was remembering to check the elevation of the airport to adjust my pattern altitude. I got very accustomed to the field elevation being irrelevant in planning. When I checked my atis and frequencies for landing I would write down what my 1000’ above field elevation would be so I didn’t have to look, or think about it on approach. The highest field I landed at was just below 8000 and while things “feel” a little different, in a turbo, all your critical numbers are the same so it didn’t affect me as much as I thought it would. the year before that we did much of the same trip in a NA 180 tail dragger, that was night and day different. 2 Quote
BobbyH Posted April 18, 2022 Report Posted April 18, 2022 17 hours ago, WrightFlyer said: (current winds 300 at 19G29 - yikes!) Looks like you are asking all the right questions. I thoroughly love flying at the higher altitudes (grew up in Northern CO). At a higher DA you will find not only your ground speeds are higher but also the affects of crosswinds on landing have less affect than at sea level. Again this is due to the lower air density. A couple fun things I noticed coming in from Eastern CO to the Front Range is that you can start your descent while maintaining the same altitude. (The ground will come up and smite you . . . ), and it seemed to take way too much runway to both land and take-off. Hope you have a fantastic trip out and fully enjoy the amazing beauty of this country on route. Bob 2 Quote
aviatoreb Posted April 18, 2022 Report Posted April 18, 2022 (edited) I've flown west in my rocket from the lowlands of the east. To Colorado and also to Montana on a few occasions. Engine operations are identical to usual. The only thing that I knew but still it is striking to see - is you need a longer runway since you take off and fly (stall speed) based on indicated airspeed, but when at say 5500 ft as we know the true airspeed is higher with the given IAS - meaning you are going faster across the ground meaning you eat up more runway quickly. So you might land on a 4000 ft runway ( say like in Boulder) but while that is quite fine in the rocket, its not as long as it seems. Oh - same story with landing. Oh you can end up with more gusty turbulent conditions on the front range than you might be used to. Edited April 18, 2022 by aviatoreb 3 Quote
FoxMike Posted April 18, 2022 Report Posted April 18, 2022 My Bravo lives at CFO. A couple of items you did not ask about but may help you out. Lately we have been having a lot of windy days so you might find the approach and landing challenging. If you are VFR approaching Denver Class B we have a 1995' tower just east of the Class B. If your IFR controller will keep you clear. CFO has become a favorite for training. You may be mixing it up for 4 or 5 Skyhawks. Highest activity is 7AM till 2PM. Often the tower is training controllers so the traffic pattern gets really large. The tower chief wants his trainees to be comfortable so he allows them to put miles between aircraft. This is less of a problem now than it was a month ago. If you can get hangar space it is usually a good idea. It is a little early for hail season but a late snowstorm could delay your departure if you are outside. 2 Quote
PeteMc Posted April 18, 2022 Report Posted April 18, 2022 13 hours ago, philip_g said: I will add that of his fuel setup sucks there's a chance the engine could quit on rollout. I'll 2nd to give the mixture a few twists to lean on the rollout. My first time into the Albuquerque area I landed at Coronado, NM (4AC) and it didn't seem like any other landing until I slowed down and pulled off the runway.... Engine quite. Learned to lean on the rollout after that. (Long before it was a big thing to lean aggressively for taxi. ). 1 Quote
WrightFlyer Posted April 18, 2022 Author Report Posted April 18, 2022 Appreciate the insights from the group. True that I'm not crossing the Rockies or heading to Leadville and more than likely won't experience true high DA. All of my high DA training was in turbine aircraft which is a different set of issues. The purpose of my post was to find out the little things that can make a big difference in a piston airplane. What may be common sense to some is new knowledge to others. That's what MS is about right? My take aways: Aim for Vy, be patient on a longer than expected takeoff roll Be prepared for turbulence and stay ahead of the plane more than usual Write down traffic pattern altitude when getting ATIS/ASOS Lean on rollout instead of on the taxiway Order a copy of the Mountain Flying Bible Keep a lookout for training ops at CFO on arrival - hit up @FoxMike for the best local watering holes Fly early - which is already my SOP! I know more than when I posted my question, which was my goal. Thanks all! - 3 Quote
Utah20Gflyer Posted April 18, 2022 Report Posted April 18, 2022 Maybe I feel this way because I'm in Utah so the thought of flying in Denver seems like a rather routine matter, but based on the time of year and the length of the runaways I would say just fly the plane like normal, it really shouldn't be a big deal. If it were august and the runway was 3000 feet then we might have something to talk about. 1 Quote
Matt Ward Posted April 19, 2022 Report Posted April 19, 2022 It was alluded to above, but be ahead of the airspace around Front Range. The Bravo sneaks up on you really fast - as in departing the pattern fast. Not a huge deal but be on your toes. 1 Quote
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