Pwr off lndg practice pre-solo students

Ron Levy said:
I've got to see you fly a Baron some time.
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You have a point - I will never fly a Baron...nor a 747. I am talking typical GA singles and sport/experimental/antique-classic/acro planes.

Ron Levy said:
Actually, it does. The basic equations of lift, thrust, weight, and drag make it impossible to maintain the same descent gradient power-off, so the pattern must be tighter than using a partial-power stabilized approach.

And there's a big difference between flying a proper partial-power stabilized approach and "dragging it in."
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If you missed my original post, or the point I was making, I'll put it another way. It is possible to fly a power-off approach starting from pattern altitude 10 miles out straight-in? Of course not. But this does not mean you must fly a powered approach all the way to the numbers. You can fly "final" at pattern altitude, making the typical power changes you would make on downwind and base, until you reach the point where you have the runway made, and then pull power to idle and make a normal power-off approach the same as if you were flying a tight pattern. My point is you can make a normal power-off approach regardless of the pattern size you're flying.

OK, so technically the whole approach would not be power-off, but the part that matters would be (the point from which you have the field made)...which is fundamentally no different whether you intercept this point from a straight-in or long final, or you intercept it from the more typical base leg. The point is that you're practicing putting the plane down where you want it, from any position, without relying on power. Maybe my opinion that this is a good skill to constantly practice is a minority one. It costs you nothing to make a power-off approach.

The challenge and satisfaction is worth something to me as well. The constant challenge and pursuit of perfection is what keeps flying interesting. I guess powered VFR approaches just don't fit into that aesthetic for me. Or maybe I'm just and "old school" 32 year old. I did learn to fly in an Aeronca Champ with a carb-ice-maker Continental...
 
whifferdill said:
You have a point - I will never fly a Baron...nor a 747. I am talking typical GA singles and sport/experimental/antique-classic/acro planes.
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Thank you.

If you missed my original post, or the point I was making, I'll put it another way. It is possible to fly a power-off approach starting from pattern altitude 10 miles out straight-in? Of course not. But this does not mean you must fly a powered approach all the way to the numbers. You can fly "final" at pattern altitude, making the typical power changes you would make on downwind and base, until you reach the point where you have the runway made, and then pull power to idle and make a normal power-off approach the same as if you were flying a tight pattern. My point is you can make a normal power-off approach regardless of the pattern size you're flying.
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I guess by your definition of a "power-off approach," virtually every light plane approach is "power-off," since even the FAA's stabilized approach in light planes calls for smooth reduction to idle when the runway is made.

The challenge and satisfaction is worth something to me as well. The constant challenge and pursuit of perfection is what keeps flying interesting. I guess powered VFR approaches just don't fit into that aesthetic for me. Or maybe I'm just and "old school" 32 year old. I did learn to fly in an Aeronca Champ with a carb-ice-maker Continental...
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I understand your point, but when teaching primary students in typical "modern" trainers, the FAA recommends, the partial-power stabilized VFR approrach as the "normal" approach technique ab initio. Lacking a good reason to do otherwise, I accept the FAA's recommendation and teach it accordingly.

BTW, as I, too, learned to fly behind a "carb-ice-maker Continental" (both A-65 and O-200), I learned that a little power goes a long way to providing enough heat to be sure no ice will form. That's also why I get upset with folks who turn carb heat off before adding power on a T&G, missed approach, or go-around. ;)
 
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airguy said:
As a matter of personal preference, I actually like to make all my landings power off, as Whifferdill says. It obviously can't happen ALL the time, and does not apply to flying an instrument glideslope, but VMC operations? You bet.
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I started in gliders. Power off landings happened all the time. :wink2:

The closest thing to a throttle in the SGS 2-33 I started training in was the dive brake. That and slips were pretty much it for descent control. Naturally you can't recover from an undershoot in a glider since a dive brake isn't really analogous to a throttle, so it isn't hard to see which way glider pilots err if they have to err at all. (Also known as err speed control. :D)
 
Ron Levy said:
I guess by your definition of a "power-off approach," virtually every light plane approach is "power-off," since even the FAA's stabilized approach in light planes calls for smooth reduction to idle when the runway is made.
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I like the FAA's idea as stated, but the typical trainer approach that I see involves making this "smooth reduction to idle" after the crossing the threshold within feet of the runway, not as soon as the plane has reached the angle above the selected touchdown point where the entire (or remainder of the) approach can be made power off. That's power off for touchdown, not power off on approach. Except for the occasional "emergency engine out", I almost never see (flight school) training activity (pre or post-solo) that involves power off as soon as the runway is made. I know independent CFI's who teach otherwise.
 
Jeanie said:
From a regulatory standpoint, it is required before solo. The only question is whether the instructor should teach that as the "standard" landing up through solo, or only as an emergency maneuver in event of engine failure.
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Thanks for clearing that up.

Jeanie said:
~~~~~~~~~ I realize that it's required pre solo to practice engine out approach/landing procedures... just wondered if folks did that at their airports all the way to a landing or only out over fields to no lower than 500 AGL

Now I know!
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You know that there are all kinds of opinions on this subject. :D
 
Ron Levy said:
You suggested that the Law of Primacy means whatever we did in infancy is what we'll continue to do all our lives, and that is both untrue and not what that law says. What it really says is that the first way we're taught how to do something has a very strong influence on how we do it later on, especially under stress, and that if we're taught incorrectly or inappropriately the first time we learn a task, it's much harder to learn how to do that task properly or better later on.

The problem here is that is we teach folks initially to use only pitch to manage both speed and descent rate, they don't get the fundamental understanding of the relationship between pitch/power and speed/descent rate that is essential for precise aircraft control. That manifests itself later, when trying to teach them skills such as maintaining glide path without large variations in airspeed, or staying at an appropriate altitude in the pattern when following other aircraft.
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I agree that things learned first are typically hard to unlearn, but a universally recognized principal (with several names in learning theory) assumes the learner will have incomplete knowledge that is only gradually expanded over time.

For example, "Pitch for speed, power for altitude" is a woefully incomplete description of what is happening in the pattern, but can be an incomplete aid until more information is obtained.
 
You guys had me worried that I'd learned it wrong, WHEW! At my field, you will NOT land unless you pull the power appropriately, so its a necessity.
 
Jeanie said:
~~~~ Airguy, do you fly out of Midland Airpark KMDD?
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Sometimes, yes. I'm actually based at a private strip 30 miles from Midland, directly under V68, just south of Garden City. I do get into MDD and 7T7 quite a bit.
 
Ron Levy said:
It may be good practice for engine failures, but Lycoming thinks making idle descents routinely isn't good for their engines. For anyone interested, see the engine managment articles in their Key Reprints text.

http://www.lycoming.textron.com/support/tips-advice/key-reprints/index.html
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Lycoming is also in the business of selling you your next engine, which is why they advocate leaning to 50 ROP, which is precisely the WORST place to run your engine.

The rapid cooling idea has advocates on BOTH sides, and no real evidence on either. In my case, when I make a prolonged idle power descent (injected engine, no carb ice) I make it a practice to reduce power slowly over the course of a couple minutes. I watch my CHT's (full engine monitoring) to make sure I'm not dropping them too fast if I'm going to take them down below 250.
 
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airguy said:
Lycoming is also in the business of selling you your next engine, which is why they advocate leaning to 50 ROP, which is precisely the WORST place to run your engine.
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Actually, they don't, and it isn't. If you lean as they suggest ("lean to rough, enrich to smooth"), you'll end up right about peak EGT. Also, 50 ROP isn't at all bad unless you're looking for best economy or the CHT is going too high. and they do make additional recommendations in that regard. And 50 ROP is a very good place to be if you want max power (although just a tad on the lean side of that).

The rapid cooling idea has advocates on BOTH sides, and no real evidence on either. In my case, when I make a prolonged idle power descent (injected engine, no carb ice) I make it a practice to reduce power slowly over the course of a couple minutes. I watch my CHT's (full engine monitoring) to make sure I'm not dropping them too fast if I'm going to take them down below 250.
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That's fine as far as CHT's are concerned, but you'd best lean it further at such low power settings so you don't lead up the plugs, etc (although that's more of an issue with carburetors than injectors).
 
Ron Levy said:
Also, 50 ROP isn't at all bad unless you're looking for best economy or the CHT is going too high. and they do make additional recommendations in that regard.
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Most of the data that I have seen on the subject shows you will typically see the highest CHT at 50 ROP. While that may not be all that detrimental to most GA engines under 200 HP, when you start getting into the bigger bore engines, 50 ROP puts your CHTs up in the range where the metal can start to weaken....not good.
 
airguy said:
Lycoming is also in the business of selling you your next engine, which is why they advocate leaning to 50 ROP, which is precisely the WORST place to run your engine.
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Most of the 50 deg ROP recommendations I have seen are in the Airplane Flight Manauls (put out by Cessna, Piper....etc) not the actual engine manuals.
 
Mike Busch covered this subject pretty well here:

http://www.avweb.com/news/savvyaviator/savvy_aviator_59_egt_cht_and_leaning_198162-1.html

"Unfortunately, this POH guidance leaves a lot to be desired. 50°F ROP is almost precisely the worst possible mixture setting from the standpoint of engine longevity. The maximum cylinder head temperature (CHT) and peak internal cylinder pressure (ICP) occurs almost precisely at 50°F ROP. So using the "recommended lean mixture" assures that your engine operates at the hottest, most stressful corner of its operating envelope."

John Deakin also wrote some incredibly informative articles on many things, including the leaning controversy. He debunks a lot of OWT, and describes potentially harmful mixture settings. At power settings over 60%, 50 deg. ROP falls into the "red box" associated with very high combustion pressures.

See article #84 :

http://www.avweb.com/news/pelican/pelicans_perch_84_mixture_cht_194816-1.html

And #18, 65, and 66 (which includes "jump plane" engine operation) here:

http://www.avweb.com/news/pelican/182146-1.html

Pretty much all the rest of his articles are well-worth reading too.
 
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Fearless Tower said:
Most of the data that I have seen on the subject shows you will typically see the highest CHT at 50 ROP. While that may not be all that detrimental to most GA engines under 200 HP, when you start getting into the bigger bore engines, 50 ROP puts your CHTs up in the range where the metal can start to weaken....not good.
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If the CHT at 50 ROP is down in the acceptable range, it doesn't matter. If 50 ROP is above 450F, then you've got problems far beyond your mixture setting. And those are true no matter how big your bore is or what your HP rating is. That's the problem with generalizations like those stated above -- they don't take into account the totality of the various parameters. There are just too many variables involved to make such definitive statements.
 
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Ron Levy said:
If the CHT at 50 ROP is down in the acceptable range, it doesn't matter. If 50 ROP is above 450F, then you've got problems far beyond your mixture setting. And those are true no matter how big your bore is or what your HP rating is. That's the problem with generalizations like those stated above -- they don't take into account the totality of the various parameters. There are just too many variables involved to make such definitive statements.
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Granted. So can we at least agree that 50 ROP is a poor place to run your engine when operating at a manifold pressure that delivers 75% or more total power? To do otherwise will place your engine in the "Red Box" of highest CHT's and ICP's - not conducive to making TBO.
 
airguy said:
Granted. So can we at least agree that 50 ROP is a poor place to run your engine when operating at a manifold pressure that delivers 75% or more total power? To do otherwise will place your engine in the "Red Box" of highest CHT's and ICP's - not conducive to making TBO.
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No, we can't agree on that. I'll agree to that only if the CHT is running above recommended values, and if that's happening, it's bad no matter where you've set the mixture. It's all about the actual CHT numbers, not where the EGT is relative to peak. You can have cylinders pushing the redline even when full rich, or you can have nice cool sub-400 CHT's even at peak power. I'll take the latter any day of the week, but reject the former just as often.
 
Ron Levy said:
There are just too many variables involved to make such definitive statements.
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But Ron, you make definitive statements all the time based on scant information.

The point is, your general statement that 50 ROP is 'a good place to be' is really not much different than what I just stated. The bottom line is that a pilot should really dig into the information that is available (Deakin is a good starting point) and draw their own conclusions based on their flying patterns and the equipment they use.
 
Moving the thread back on track, I was taught power-off landings pre solo. For a while it seemed like I was learning more emergency procedures than how to fly.
 
Cap'n Jack said:
Moving the thread back on track, I was taught power-off landings pre solo. For a while it seemed like I was learning more emergency procedures than how to fly.
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I guess I don't understand why a power-off approach is considered an emergency procedure in airplanes that can easily do them (all trainers, and most GA singles). IMHO, one hasn't learned to fly their airplane unless they can consistently, safely, and comfortably do this.
 
whifferdill said:
I guess I don't understand why a power-off approach is considered an emergency procedure in airplanes that can easily do them (all trainers, and most GA singles).
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Not necessarily an "emergency procedure," but not the "normal" procedure either. I learned to fly back in the late 60's, when the FAA recommended the 180 power-off approach as the "standard" landing approach procedure for light planes. The rationale was rooted in the experience of those flying behind things like OX-5's in the 20's and 30's, when engine failures were so common, it was important to keep the plane always within gliding distance of a suitable landing area.

However, in the early-mid 70's, a study of accident data showed there were significantly more landing accidents due to overshoots, undershoots, stall/spin in the pattern, etc, than there were due to engine failures. In fact, thanks to more modern metallurgical, manufacturing, and quality control technologies, the number of reported engine failures in the traffic pattern had declined to near insignificance compared to the data from the "bad old days."

The FAA decided that using the more-reliable engines of the modern era to help stabilize approaches could reduce the landing accident rate. That's when they revised their guidance to switch from the 180 power-off approach to the partial-power stabilized VFR approach as the recommended "normal" VFR approach-to-landing technique, and the reduction in landing accident rates since then has, in their eyes, justified that decision.

IMHO, one hasn't learned to fly their airplane unless they can consistently, safely, and comfortably do this.
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While that may be true, it is also true of other non-standard techniques and procedures we save for the proverbial "rainy day," such as partial-panel "needle/ball/airspeed" instrument flying. While those techniques and procedures are necessary to assure safety when things go wrong (e.g., vacuum pump or engine failure), they aren't necessarily the best techniques or procedures to maximize safety in "normal" operations. That's why the FAA recommends the partial-power stabilized VFR approach and attitude-based instrument flying techniques as the "normal" way of doing things.
 
whifferdill said:
I guess I don't understand why a power-off approach is considered an emergency procedure in airplanes that can easily do them (all trainers, and most GA singles). IMHO, one hasn't learned to fly their airplane unless they can consistently, safely, and comfortably do this.
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Glider students learn power off approaches from day 1.
 
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