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There are two sides I've heard when taking off in a Cessna 182 or other small airplane with a normally aspirated engine driving a constant speed propeller:

  1. As soon as your wheels are off the ground... Or,
  2. When you're 700-1,000 feet off the ground...

Reduce to about 23" of manifold pressure and then reduce the RPM to 2,450 (or 2,300) depending on the plane.

The POH or Owner's Manual (in my case a 1972 Cessna 182P) simply says Full Power under the Normal Take-Off procedure.

The reasoning I've heard is to try not to over-stress the engine (whatever that means exactly), but on the flip side, I've heard that if an engine is going to do something funky, it's probably going to happen when you do a power reduction, or otherwise do something.

I personally want all the power I can have until I'm far enough off the ground to have options if the engine quits or sputters (turn back if high enough, or glide to a suitable spot if not).

I'm asking is there an "official procedure" as to when you should perform this power reduction (inches off the ground or 700-1,000 feet), and if so, have there been actual studies that say why one way is better than the other, or is this one of those groundless, "endless debates" that are so prevalent in aviation?

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3 Answers 3

up vote 8 down vote accepted

The "official procedure" is the one dictated in your aircraft's POH/AFM.
Within the leeway that document gives you (and many of them give you a lot of leeway) this is definitely one of those "endless debate" subjects.


Personally in a single-engine piston aircraft unless the POH directs otherwise or operational considerations (like an altitude restriction from ATC) require something different I would maintain full power (and all other takeoff settings - fuel pumps, etc.) until reaching 1000-1500 feet AGL (depending on what the terrain and obstacles in the area are like), then configure the aircraft for a reduced-power cruise climb if appropriate.
Whether or not the first power reduction is a time of increased failure is irrelevant to me - I operate on the assumption that the engine can fail at any time, and should the engine fail (for whatever reason) I want adequate distance between myself and the ground to make some decisions, confirm my landing spot, and prepare myself, my passengers, and the aircraft for whatever is going to happen next.

1000 feet AGL is my minimum threshold for that sort of activity. It's possible (maybe even likely) that I'm imposing additional wear on the engine in requiring full power for this long, but if the engine decides to fail on climb-out it's not going to matter how "nice" I was being to it on all my previous flights - the only things that are going to matter are my altitude, airspeed, and landing options, and I'm going to want as much altitude and airspeed as I can get to help maximize my landing options!


There are some conditions where I would reduce power sooner than 1000 feet AGL if necessary - for example, if I can't maintain oil or cylinder head temperatures "in the green" in a full power climb a power reduction (or pitch reduction) to keep those engine parameters happy would be in order.

There are also some aircraft/engines which have a continuous power restriction (Full throttle operation limited to 3 minutes, maximum continuous power 2400 RPM, or similar admonitions you'd find in your POH). In those cases the restrictions should obviously be observed (the engineers who set the limitations had a good reason for doing so), and observing those requirements may necessitate a power reduction or other configuration changes prior to reaching 1000 feet AGL.


Finally, I'm not sure what kind of engine is in your hypothetical Cessna but as an additional point of reference Lycoming has this to say about takeoff operations:

Operating Your Lycoming Engines At Takeoff And Climb

Because there are a wide variety of Lycoming engines in operation, the paragraphs below may be helpful in understanding the different modes of operation required when operating each type at takeoff and climb power settings. The Pilots Operating Handbook for the aircraft in which the engines are installed should be the final authority as to how the engine should be operated.

DIRECT DRIVE ENGINES

Most normally aspirated engines are rated at full power for takeoff and climb indefinitely, provided engine temperatures and pressures are within the green arc area of the engine instruments. Extra fuel, sensible airspeed, and cowl flaps, if available, are all helpful in keeping cylinder head temperatures within desired limits during takeoff or climb.
Climb requirements may vary; as an example, on a warm day with the airplane close to gross weight, and a direct drive engine with a fixed pitch prop, the pilot will need full throttle all the way to cruise altitude. The same airplane on a cold day and lightly loaded may not require full power for climb. After full throttle at takeoff, the pilot may want to reduce power 100 or 200 RPM and still not see performance suffer. Those direct drive normally aspirated engines with a prop governor are also rated indefinitely at full power, and the manuals all recommend full power for takeoff, but specify a small reduction in power, generally to 85% power climb. Study the specific airplane Pilot's Operating Handbook for detailed power settings.

(They go on to talk about geared engines and turbocharged/supercharged engines, but your question was about normally-aspirated engines. This is from Lycoming Flyer "Key Reprints" - I grabbed it here but you can Google it up pretty easily, and I imagine Continental has analogous guidance somewhere.)

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Noise abatement procedures may also affect your takeoff and climb power. –  Lnafziger Mar 22 at 3:32
    
Also, for FAR Part 25 aircraft (and I think 23 but am not sure), takeoff power may be maintained for five minutes from the time that the throttle is advanced –  Lnafziger Mar 22 at 3:34
    
@Lnafziger Yup - that's another example of operational considerations. Santa Monica (KSMO) having some of the most publicized "strange" noise abatement procedures. –  voretaq7 Mar 22 at 3:37
    
Yeah, and Teterboro is the #2 crazy/psycho noise airport in the country. Speaking of SMO though, Falcon even developed a special procedure for their jets designed just to operate out of there without ringing the noise bells, along with a special (lower) maximum takeoff weight. –  Lnafziger Mar 22 at 3:42
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Great answer, thanks. I especially like your point that you "operate on the assumption that the engine can fail at any time." Further research lead me to this quote by Kas Thomas from his great book "Fly the Engine": "[reducing the power] doesn’t actually hurt anything, either. Unless your engine has a 5-minute power limitation, you can safely operate at full throttle all day long. Many jump planes, banner tugs, and towplanes do just that." Excerpt From: Kas Thomas. “Fly the Engine.” iBooks. itun.es/us/esgqC.l –  Canuk Mar 22 at 15:49

To add to voretaq7's answer: In addition to the desire to gain as much altitude as quickly possible, there is the following consideration: most engine failures happen when the power configuration is changed (a lot of oil is moving through the hub to adjust the rpm, for example), so changing the power should be delayed until you have gained enough altitude for a safe emergency landing (in real life this might not be possible, of course). Thus your second scenario is preferable under normal circumstances.

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'most engine failures happen when the power configuration is changed" I've heard this for years but nobody can point to statistics or a study of the problem to verify this. If you have the data to back this up please point us to it. Thanks! –  Skip Miller Jun 19 at 21:26
    
This is a very good point. I have not seen the statistics myself but the argument above seemed well reasoned when it was presented to me so I am repeating it here. I can also imagine such statistics would be hard to collect with most such incidents resulting in very unintentional landings and what not. –  alexsh Jul 21 at 6:04

Generally I would ease power back at circuit altitude, trim and then if a climb was required, then I would climb at cruise revs.

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