Leaning the Mixture for a High Density Altitude Takeoff

Here's a short video showing you several ways to lean your airplane's mixture for a high density altitude takeoff. This piece covers leaning for normally aspirated engines having fixed pitch and constant speed propellers. (www.becomeapilot.com)

[@gunlovingliberal1706]

"If you're like me, and I know I am ..." That is a great line. I am going to steal it.

[@Flight-Instructor]

Ha, I promise I won't press charges. :) Best, Rod

[@howardflies]

I love the use of humor in imparting knowledge, being an aspiring instructor I seek to have elements of such humor to allow students to feel more at home and at ease. Well done

[@Flight-Instructor]

Thank you, Howard. That's very nice of you to say. Rod

[@tonyperez2467]

Your comment ref boarder patrol at a cinco de mayo event can be misunderstood as insensitive. I know your last name is Machado but that’s no excuse to use your description in your video. You seem like an educated person. Pls be aware that your comments are not appropriate. I hope you understand. Thks sir

[@CristiNeagu]

@@Flight-Instructor That's what made Flight Simulator 9 so great for me.

[@mikehammer5380]

@@RS-uo2nd pretty poor humor… especially given that around 40% of America celebrates cinco de mayo regularly and less than 0.04% of us are illegal aliens. It tries to slap a label of illegal freeloader on a massive portion of our American citizens of hispanic and Latin descent. He could have used any number of aviation related terms for being nervous, like a 16 year old on their first solo.. or maybe a new IFR pilot on their first IMC approach. Casually concealed racism is still racism. Also of note since you’re accusing Mr. Perez without knowing, I’m not Caucasian but I want my hombres from another madre to feel welcome as we share a wonderful tradition together.

[@CristiNeagu]

Every time i hear Rod it reminds me of all the flying lessons i took in FS9. Really good training.

[@johnpro2847]

yep Rod use to make me apprehensive whenever he said "I don;t thing this lesson is going too well "..then dump me out of the lesson or he just disappeared somewhere until I restarted the lesson.

[@tomasnokechtesledger1786]

Then, 2001 ate that great side of FS

[@CristiNeagu]

@@tomasnokechtesledger1786 FS9 was released in 2003...

[@tomasnokechtesledger1786]

@@CristiNeagu 9 Lessons Tutorials were great.

[@olavpettersen9465]

I wish he was in MSFS 2020.

[@All.american.timepieces]

I miss this voice on fs 2004. Wish the newest version also had the lesson he would give. Very valuable.

[@Flight-Instructor]

Thank you! I do appreciate the comment. Best, Rod

[@Hedgeflexlfz]

Wow! I didn't even realize they didn't lean the mixture in that famous accident. Incredible

[@deadwood97]

I found this video on leaning since I have a "75 C-182 and am in the process of installing a engine monitor, and oh my gosh, that -150, N18716 is the airplane I soloed in back in 1983 out of a 1800" gravel strip in WA state when I was 16! It looks great! Great videos as well Rod. Cheers!

[@Flight-Instructor]

Thank you! And 18716 is a wonderful airplane to fly.

[@gmcjetpilot]

I've heard Rod Machado speak live at least 10 times at aviation conventions and Oshkosh. I never "tire" of his stories. I'm a CFI and teach mixture use. Most POH's discuss this topic.

[@flycow69]

Thanks for the videos. Keep them coming.

[@Flight-Instructor]

Thank you!

[@remf4519]

Excellent as always, thank you Rod.

[@Flight-Instructor]

Thank you, REMF.

[@michaeljohn8905]

Rob you are a legend in the GA community. Would love to meet and have a beer. Thanks Michael.

[@Flight-Instructor]

Thank you, Michael. I would love to have a beer with you, sometime. Best, Rod

[@newmanlord7130]

100% lntuitive lnstruction Training Sir,How l wish You Are Always Here Sir, God Bless You . From Ghana.

[@peregrinussolutionsllc6010]

You rock Rod! Thank you for sharing your knowledge and experience. I greatly enjoy your positive sense of humor :-D It makes your already informative books & videos even more enjoyable!!!

[@gunsaway1]

Excellent. Thanks

[@jefar53]

I’ve been a CFI since 2013 and would love to have him as my CFI

[@TheJaguar7777]

Great video - thanks!

[@Flight-Instructor]

Thank you!

[@Warbird-Aviation]

Very good video!!! Thanks very much

[@kakai7640]

Rod is very smart guy.

[@maritestaylor8458]

Awesome video thank you

[@lowifrles9813]

Yes! I saw that video a few weeks back and said the same thing!

[@kyleiriarte4434]

So good!

[@Flight-Instructor]

Thank you!

[@OneJoshParker]

PINE AIR FRESHENER 😂😂😂😂 You wild

[@spoiler5oo]

you're still #1 in mt book

[@k7ylan07]

Rod thank you so much you are the greatest on KZbin in addition to the fact that you have the coolest last name.

[@Flight-Instructor]

Thank you Ahmed. That's very kind of you to say.

[@gregshonle2072]

Having learned to fly in high density altitude (base elevation about 5300 feet -- on hot summer days, the density altitude would often get close to 9000 feet...), I always thought leaning for max power was a normal part of run-up!

[@josesbox9555]

I did the same as a riddle rat

[@mikearakelian6368]

This brings me back to my 135 days and flying out if RNO, or tahoe... And soaring ridges east to get altitude to cross over west bound... And my pax had to take s bus back to Salinas... Helps my cognitive decline

[@ViceCityMasta]

Love your vids! wish you were my instructor haha

[@Flight-Instructor]

Thank you! VCM. I sure do appreciate that comment. Glad you found this video useful. Best, Rod

[@Flight-Instructor]

Thank you!

[@mikelong9638]

It still amazes me how many pilots I fly with that never touch the mixture during flight (even instructors). As Rod points out in this video leaning isn't about just about saving gas.

[@russiandrivers9986]

Thanks. I was wondering what that red lever was for.

[@MsTatli]

it would be so great if there was a similar fun e-learning course for CARS ( Canadian Air Regulations ).

[@robbierockin939]

oh your good man .. thankyou

[@Flight-Instructor]

Thank you!

[@JimForeman]

Lots of good information but you missed one point about high density altitude flying, that is starting the engine. I used to be with Black Forest Gliderport in Colorado (elevation 7200 feet) and we'd often have pilots fly in to fly gliders. They would try to start their engines only to have them start, belch black smoke and die from flooding. One of the instructors would usually go help them get their engine running. One day this guy in a Baron got one engine running and was having the other one refusing to run after starting. I went out to help him but he informed me that he didn't need some Cub pilot to tell him how to fly. He cranked on it until he finally burned up his starter.

[@oldfangle2207]

Hi Rod- I've heard that you don't do this procedure with a fuel-injected engine, as there is no enrichment valve and the fuel meters for best power considering airflow?

[@TheDesperado46]

No stereo on this video...?

[@larryehrlich8702]

On KZbin lookup "Leaning The Advanced Class" by Savvy Aviation. This guy is an expert on the subject. Go there now!

[@johnny5039]

Nice video, I got a question. Most Cessna takeoff charts show pressure altitude for distance over 50ft obstacle. How much percent should you add to this for high density altitude days?

[@Flight-Instructor]

Thanks, JS: It's true that most Cessna takeoff charts show takeoffs at different pressure altitudes, but they also show four to five temperature ranges for each pressure altitude, too. So you wouldn't need to calculate DA directly since variable temps above standard are part of the chart. Does that help? If not, then send me a copy of the chart you're using to: [e-mail] and I'll have a look. Best, Rod

[@johnpro2847]

Our Rotax powered light sport aircraft does not have mixture control...

[@PointyTailofSatan]

I just strap some RATO bottles to the side of my plane, and light them up on takeoff. 5 G's of acceleration at takeoff should be good enough. And an accelerating vertical climb in a Cessna is pretty cool.

[@karlsandin4515]

Classic

[@johnpro2847]

yep @ 7:45 Our prop with 500 hours has just been repaired on our Vixxen A32 . Any more stone chips and a $6000(AUD) replacement is required. Gravel everywhere at YCAB and $300,000 sitting in the airfield committee bank account. Figure that out..?

[@ravenmusic932]

I saw the crash a couple of months ago...really painful, especially because the pilot didn't get the plane back on the ground before the trees came.

[@madmoneymike5]

Rod, quick question. Doing this (full throttle) run up, are you suggesting we do this in place of the usual 1700-1800 RPM run-up where we check the mags, or is this in addition to? If in addition to, would you do this before or after the mag check? Thank you!

[@Flight-Instructor]

Greetings Michael: I think you are confusing the phrases, "full throttle runup" with "using full throttle in the runup area to set the mixture for a high altitude takeoff." You only need to use full throttle to set the mixture for best power before takeoff. The typical runup where you check the mags, etc., is still done at the recommended RPM in the POH. Please go back and watch the video again to get the nuance in the narration. Best, Rod Machado

[@madmoneymike5]

@@Flight-Instructor Thank you! Based on your response, I think the answer to my question is "in addition to." So my follow up question was, which should happen first? Logically, I think it would be the mag check at the recommended RPM in the POH that is done first with mixture rich, and then full throttle to get the right mixture for density altitude. Is that right?

[@Flight-Instructor]

Greetings Michael: Yes, do the runup first and do it at the appropriate mixture settings which typically involves a little learning to prevent plugs fouling (if appropriate). The use of full power in the runup area is done after the lower RPM runup to "approximately" set the mixture for best power on takeoff. Rod

[@madmoneymike5]

@@Flight-Instructor Thank you very much! The 15 year old version of me flying Flight Simulator never would have thought I'd get the opportunity to ask you questions like this. You're a celebrity in my house! Thanks for being a part of this guy's dream of being a pilot. 🙏🤝🏻

[@Flight-Instructor]

Greetings Michael: It's absolutely my pleasure! I'm happy you found this information useful. And kudos to you for asking these types of questions, too. Best, Rod Machado

[@jjohnston94]

How do you lean for a go-around when arriving at a high DA airport? You don't have the luxury of being able to do a full throttle runup first. Just leave it at the cruise mixture setting? Or maybe get down to pattern altitude and do a full throttle run when you're 10 minutes out?

[@Flight-Instructor]

Greetings JJ94: That's an excellent question. If you have the mixture set for a cruise at a high-density altitude (say, 10,500 feet) and descend for landing at an airport having a lower density altitude (say 5,000 feet for this example), then you certainly should reset the mixture before landing. It's entirely possible (depending on the difference in these density altitudes) to be on final, attempt a go around and have the engine sputter or fail with the application of full throttle (once again, depending on the difference between the two altitudes above). So here's a general rule to follow. When leaving a cruise altitude and before entering the traffic pattern at your destination airport, move the mixture control forward one-half of its "present" aft travel. On the downwind leg, you can test this mixture setting by smoothly applying full power then reducing power to the pattern setting again. If the engine doesn't sputter or cough, you've got the assurance needed to know that a go-around is possible with that mixture setting. If the engine sputters or coughs, then move the mixture control forward one-half of its "present" aft travel again. And, of course, upon going around, you can readjust the mixture for maximum power at the appropriate time. As an addendum regarding the go around, it's very very rare to have a normally aspirated engine (that's not being fed by an electric "boost pump") quit because it received too much fuel. Engines can handle a lot of extra fuel when operating at full "throttle" settings. On the other hand, an engine can easily sputter or quit if it doesn't have enough fuel regardless of the throttle position.

[@deani2431]

One cannot do a full throttle runup in many high performance taildraggers.

[@zakizakizaki9186]

Why we would enrich the mixture to the best power not lean it when we have" hight density altidue"= low air density ?

[@Flight-Instructor]

Zaki, please ask that question again. I don't understand the question. Best, Rod

[@craigwall9536]

Well, you _almost_ covered the case where you've got more thrust than brakes during the run-up; those of you with 1947 Ercoupes and factory brakes know what I mean... Since I've got full time EGT and CHT for each cylinder and they all run pretty close, I just 1) lean during taxi to the point that when I apply full throttle for takeoff it sags noticeably; then I know I need to enrichen but that I'm already on the lean side of peak. 2) I richen to get max power for takeoff by feel and sound, but 3) I've got EGT and CHT to watch during initial climb out so I don't get into the dangerously hot part of the engine operating envelope. That 15% automatic enrichment is great if you aren't monitoring temps, but if you are it's just throwing fuel away if you know you for sure you can stay out of the hot zone. You can do this all by feel if you KNOW the mixture distribution is even, and you can't know that unless you have temps for each cylinder. As an extra bonus, I go wide open throttle on takeoff and for the rest of the flight I manage power with mixture and carb heat- that is to say, I lean to drop the RPM to the bottom of the green in cruise climb and keep coming back after leveling off. Then if I want to climb after that, I richen NOT with mixture, but by pulling carb heat. This is a safe technique but not one most people would use because in cruise I'm running "acceptably rough"- which is a state where shutting off one mag gives a 200 or 300 RPM drop. Then pulling some carb heat jumps the RPM up about 200 RPM and without changing anything else, you get a nice cruise climb. In cruise I'm shooting for 1.316 times the max L/D IAS (best range speed) because THAT speed- the Carsten Speed- is where you get the most _speed_ for the _least drag._ It's NOT max range speed but it gets you there while you've still got daylight. In fact you can make up for lost time by going high to get the TAS up and by skipping an intermediate fuel stop since the fuel burn is so far down. . Some will object that leaned that much takes you out of the MAX ECONOMY mixture region, and it does- but I'm burning less than 4 gallons an hour with a C-85 and contrary to the old conventional wisdom, it doesn't "oxidize" the valves. CHT is the only temp that actually matters. I find that the power adjustment using carb heat is much easier than using a sensitive mixture knob since it takes much more travel with carb heat to get the same change. (All this should take into account the winds aloft- I lean much farther going downwind since a really puny power setting keeps you in the air longer so you take advantage of the favorable wind. Going upwind, I don't get quite as stingy with the fuel burn... you want to speed up a bit since it decreases the time you're penalized by an adverse wind.) One last thing: if you want to start leaning below 4000 ft, note the density altitude given by the airport weather recording and just climb however many feet are required to make 4000 (which in Texas is often pattern altitude)...OR, you can add carb heat as soon as you clear the terrain to give the ENGINE a 4000 ft density altitude BEFORE the airplane sees 4000 ft of density altitude. If that's not clear, I'm saying that carb heat lets you operate the airframe and the engine at two _different_ density altitudes simultaneously...which is _sometimes_ useful. Bottom line is, I go wide open throttle at the start of the takeoff roll and never retard it until I'm on downwind. That reduces "pumping losses" against a tilted throttle butterfly plate. Every other power change is done by mixture or carb heat. You might find my engine roughness a bit disconcerting, but if Peter Garrison could regularly cross the Atlantic in a homebuilt using the "acceptable roughness" rubric, it's good enough for me. And my engine loves it- operated this way, my CHTs stay down around 350F and there's not a spec of carbon fouling to be seen- you can easily double your TBO this way.

[@chester8420]

Interesting that you are controlling engine power output with fuel, not throttle. Like a diesel engine. I have never tried that. Also since it is full throttle and not pulling vacuum, there's no loss of energy there either.

[@clarkstonguy1065]

Very interesting dissertation. If we were talking about modern engines, I would probably frown upon the concept of using carb heat as a substitute for throttle. However, given the fixed ignition timing in our Lycosaurs, you may be on to something. I am really wondering here if leaned to the point of roughness on one cylinder if carb heat actually may be more effective for smoothing out the combustion in the worst cylinder than actually richening with the mixture knob. Obviously it results in less power at full throttle than using the red knob would provide. And, don't try this at high power as a hot mixture is much more prone to detonation - so be on your game if using this trick as a substitute for altitude in order to get below 75% power for "safe" aggressive leaning!

[@antoniomorales9143]

Is Rod the Bob Ross of aviation?

[@andrewmorris3479]

Awesome video! But it’s simple, buy a Rotax 915 iS and you’ll never have to worry about density altitude again. 😋

[@janetreed223]

Or, better yet, if you have a engine monitor, pick a cylinder and note the EGT when taking off at sea level, probably somewhere between 1200 and 1300 degreees. On your next high density take off, lean the mixture and match the EGT on your chosen cylinder and lean in the climb. You will have max HP from take off to level off. Simple eh?

[@Flight-Instructor]

Janet, you're not taking into account the effects of the engine's fuel economizer (fuel enrichment valve) on takeoff at a low density altitude airport. I wouldn't recommend that method for setting the mixture. Rod

[@ATC-Zero]

Some people don't have the luxury of taking off at sea level. Not so simple.

[@mannypuerta5086]

Chris James The EGT value for a normally aspirated engine during sea level takeoff should be 1200-1250F. For a turbo engine it’s a little higher...1300F. This assumes the engine’s fuel system is set correctly and operating normally. If your mixture is set correctly for the actual density altitude, the EGT will be at the above values for takeoff. Lean during the climb to maintain those values and you will have good power and adequate cooling throughout the climb. Of course, all this assumes you have an engine monitor for accurate EGT/CHT readings. FWIW...I live and fly above 5400’.

[@AllanFolm]

A clear example of a pilot who hasn't understood what the controls actually do.

[@Flight-Instructor]

For example?

[@AllanFolm]

@@Flight-Instructor He had his mixture set for takeoff. He didn't have his mixture set for his actual altitude. If he had known the mechanics behind the mixture control, he might have understood better why the mixture should have been adjusted.

[@Flight-Instructor]

@@AllanFolm So true. Best, Rod

[@realnewsthatmatters9319]

This seems like more than just a fuel mixture issue, these look like 4 huge guys that hadn't missed a meal in a while, I'm thinking this was also a weight and balance issue, and quite possibly too much luggage and camera gear as well.

[@Flight-Instructor]

It might be. I don't recall the NTSB saying anything about this. But clearly, if takeoff performance is reduced, you can increase performance by reducing the weight.

[@realnewsthatmatters9319]

Rod Machado Thanks for the reply, are you still Physically training?, if so where? I'm not interested in flying commercially, but I would like to get my ppl for personal use. Love your videos, sense of humor, ( terrible way to install a pine scented air freshener🤣) and calm demeanor. If I'm going to give someone 10k of my hard earned money, I'd like for it to be someone with the good reputation, based on the research I have done you seem to be always at the top of the list.

[@Flight-Instructor]

B4Real 1: I still train but do a lot of solo work with the Jo (short staff) and regular bag work, running, weights, etc. Consider coming to the US for your PPL, too. And thanks for the tree-top reference. I sure felt for that pilot irrespective of the poor judgment used here. Best, Rod

[@mannypuerta5086]

Yes, that accident was more than just a leaning issue, but setting the mixture improperly was a major contributor. With the density altitude the day of that accident, that 165hp Stinson should have only had two onboard, instead of four, and a reduced fuel load. Even a 182 under those conditions would have an issue. High DA’s are not to be trifled with, especially in heavy, underpowered airplanes.

[@oneskydog4401]

They also did not take off early morning and the wind was downslope they were departing into sinking air.

[@JoelLinus]

Why does my right ear has to suffer

[@orlandospencer]

7 persons mistakenly hit the dislike button.

[@Flight-Instructor]

Orlando, that's funny. Very clever. I like it.

[@orlandospencer]

Rod Machado I learned form the best ;). I watch practically all your videos though this is my first comment. You are responsible for over 30% of my success in getting my PPL a month ago. PS. I watched your debate with J. King Loved it. Oh.. I got me some pine freshener, (the correct way)

[@jefar53]

I blame it on turbulence lol

[@larryehrlich8702]

If you don't want to have to lean your engine in Leadville Colorado, elevation 10,152 feet then get a jet engine or turbo prop engine as the fuel governor will lean it for you. You have no means available to lean a Jet or turbo prop engine.

[@Ryzler13]

Yeah I thought I was reading that wrong. The term "High density altitude" should be changed. Firt time i read it i assumed that there was HIGHER density at altitude not lower. This used to be refered to as an airpocket where there would be pockets of lower density air during flights and the plane would suddenly lose altitude a few hundred feet.... this should be reworded..high density altitude just doesnt explain ...lower pressure than expected at altitude.

[@Flight-Instructor]

Greetings Ryan: Yes, I do understand your confusion. But that's the way the term is correctly used in aviation. Best, Rod

[@esimm595]

Hi, Rod, This video was very helpful, but then just in the middle of it, you made a comment that distracted me from your video so that I didn't want to watch any more of it until I wrote to you. You said, "It makes me feel as uncomfortable as a Border Patrol Agent at a 5 de Mayo festival." I happen to have Mexican family members that do not have any problem with the US controlling its borders. According to the following article from a writer in the border town of Nogales, Arizona, half of all border patrol agents are Latinos. Yup, half: www.theguardian.com/us-news/2016/dec/12/mexican-american-border-patrol-agent-vincente-paco. And they don't all hide out during 5 de Mayo celebrations. ( Read the page of the Nogales Arizona 5 de Mayo committee acknowledging assistance by the US Border Patrol, among others.) bordereco.com/events/2013/05/08/scc-cinco-de-mayo-celebration-hugh-success/. These topics are very complex, and very distracting. Were you trying to help Mexican Americans practice recovering from distractions from an Examiner during Practical Test?

[@DiegoTheGreat89]

E Simm c'mon man, don't be so sensible. Nowadays you can't joke about anything without someone getting offended.

[@Flight-Instructor]

I think Diego said it best in the comment below. But I do thank you for that comment referencing the video itself. Rod

[@Flight-Instructor]

Thank you, Diego. That was a harmless comment that I've use in audiences all over the US and never had one person feel offended. This sensitivity is why Seinfeld, Leno and many other comics no longer play at colleges and universities. Our colleges and universities have taught people to be easily offended at the silliest of things nowadays. I sure do appreciate your taking the time to post your comment, too. That means a lot to me. And, for the record, I"m half Portuguese and half German, which explains my insatiable desire to take over a country and then go fishing. Best, Rod

[@cesarquintana9034]

Cheer up man. It's a joke.

[@lebojay]

Cars have had electronic fuel injection for 40 years now... 😞

[@steveparker576]

Good video, helpful. Drop the INS vs. Hispanics joke. Don't drag politics into every f'ing thing.