Airplane attitude when landing

[Rex Kramer]

For all I know you may be an ace, but really not a lot of help here. Sure, I maybe can Luke sky walker it, feel the force AFTER I do my homework, put the time in to learn how not to stall, how not to crash. But this is just gibberish to me at this stage. I'm still in ground school.

What I'm getting at is you are overthinking it when mentioning the effects of humidity on the pitch attitude of a light aircraft (or any aircraft) on landing.

As already mentioned before, the angle of your nose will depend on the aircraft you are flying. The airplane I fly happens to have about a 5.5deg angle of attack on final approach. Every plane is different.

For the elevator/power argument about what controls what, they are interdependent. It'll make a hell of a lot more sense when you're doing the flying portion.

 

[Stewartb]

Could you go into more detail on cruise? From my studies, and "stick and rudder" (and he makes a large point about it) the elevators always control speed, power controls altitude except in transition. By that I mean he points out the elvators will "balloon" the aircraft briefly, but not sustainably, just briefly until the plane adjusts. Maybe I'm missing something here?

Do a little internet research about being behind the power curve. How people describe it varies but the reversal of roles of the throttle and elevator is important to understand.

 

[MAKG1]

Do a little internet research about being behind the power curve. How people describe it varies but the reversal of roles of the throttle and elevator is important to understand.

It's quite real, and very misunderstood.

If you go flying around in slow flight at altitude, you can demonstrate it. If you pull the yoke back a little, you'll go down, because the loss of lift due to slowing down is greater than the gain in lift due to the larger angle of attack. If you pull it back a lot, you'll stall and REALLY go down, but that's not the point.

Usual instructions for student pilots to land keeps them ahead of the power curve (just barely) on approach, but it's really important to understand what happens when you get 5 knots slow. You will not speed up unless you get the nose down, and you can quite easily get yourself in the situation where you add more and more power, and still get slower (depends on the airplane, but if the prop is near centerline and blasting on the elevators, more power is likely to pitch you up and slow you down).

 

[Everskyward]

In reality everything is interconnected. If you want to make more of an absolute statement you could say, "When power is constant, the pitch controls airspeed, and when pitch is constant, power controls airspeed". However it's safer for new pilots to think of pitch controlling airspeed, especially when slow, because you run out of power on the back side of the power curve making power essentially constant. It's also a quicker process to gain airspeed using pitch in low powered airplanes.

 

[LongRoadBob]

For instance, from Instrument Flying Handbook:

"During a constant airspeed descent, any deviation from the desired airspeed calls for a pitch adjustment. For a constant rate descent, the entry is the same, but the VSI is primary for pitch control (after it stabilizes near the desired rate), and the ASI is primary for power control. Pitch and power must be closely coordinated when corrections are made, as they are in climbs."

Bolded/italics mine.

Like I said, I don't KNOW much at all, just learning. I was insteresting in the point about cruise altitude being different. That more angle of attack will give more lift but more drag and that it will slow the airplane, and lower AOA will raise the airspeed. I'm a little confused, in what I've read and also seen on video ground schools videos, that is the primary control (elevator) to change pitch, which changes AOA and speed. But I do get that this all is not straightforward, maybe saying then primarily?

If you are in a constant airspeed descent, is your quote saying that it is because it is not airspeed but descent that is being controlled? I'm not sure get it, but seems to as if the first sentence is saying because constant airspeed is the goal, adjust it by pitch, but if it is constant descent you want to use pitch still to control speed but now it is speed of descent? Not forward airspeed? It's confusing to me.

 

[Tarheelpilot]

As an aside...

WTF is up with this "new" trend of flight schools requiring that ground school be completed before flying? The local school does that too. There is so much of the book info that flying puts into context. Requiring that ground school be completed and the written passes before flying seems really stoopid and unproductive to me.

Plus, flying keeps people more excited about the process.

Couldn't agree more. I like integrating the ground with my flight training. my students seem to like that approach.

 

[MAKG1]

Like I said, I don't KNOW much at all, just learning. I was insteresting in the point about cruise altitude being different. That more angle of attack will give more lift but more drag and that it will slow the airplane, and lower AOA will raise the airspeed. I'm a little confused, in what I've read and also seen on video ground schools videos, that is the primary control (elevator) to change pitch, which changes AOA and speed. But I do get that this all is not straightforward, maybe saying then primarily?

If you are in a constant airspeed descent, is your quote saying that it is because it is not airspeed but descent that is being controlled? I'm not sure get it, but seems to as if the first sentence is saying because constant airspeed is the goal, adjust it by pitch, but if it is constant descent you want to use pitch still to control speed but now it is speed of descent? Not forward airspeed? It's confusing to me.

The quote is about instrument flight, and is correct. To add even more confusion to it, a stabilized approach is both constant airspeed and constant rate. Which do you use?

As a VFR pilot, I think it makes more sense to think about it this way. In cruise, you are at a set power setting. It may be full power, or 2500 RPM in a 172 at low altitude, or 23 inches MP in a 182 (etc). But you can't go higher without messing with mixture (at least). In a practical sense, this means cruise climbs are done with the yoke. The speed is slower, but the throttle is not adjusted. At really high altitudes, you simply can't climb faster (or slower) than Vy. It won't do it. So, that's what you pitch for.

If you're flying slow, you CAN add throttle, and there is nothing wrong with that.

On the other hand, while approaching to land, you are usually at very low power, perhaps even idle. There is lots of throttle to be added.

 

[LongRoadBob]

What I'm getting at is you are overthinking it when mentioning the effects of humidity on the pitch attitude of a light aircraft (or any aircraft) on landing.

As already mentioned before, the angle of your nose will depend on the aircraft you are flying. The airplane I fly happens to have about a 5.5deg angle of attack on final approach. Every plane is different.

For the elevator/power argument about what controls what, they are interdependent. It'll make a hell of a lot more sense when you're doing the flying portion.

Thanks! I'm sure you know the main problem with student is exactly that...interdependent controls, and lots of scenarios where one thing or another acts differently than "normal". I have studied the backside of the power curve and can't say I "have it" but am getting it slowly. It surprised me and seemed illogical but it is so.

I get a little bit of chicken and egg, back and forth in my understanding of controls. Not many cardinal rules to hold on to except AOA (specially understanding it in climbs and descents) being a huge focus point, and I kind of have it in my head that when in trouble with AOA in most forms, bring the nose down.

And just recently, if I understood it...in some tight turns the ailerons may have opposite effect.

Two points, I agree it would help a LOT to get to fly a little at the stage I'm at right now and experience these things to test or show theory in practice.

Second, I've mentioned before my dad was a pilot, and I've always known that there was a lot to know and learn, but there REALLY is. I get amazed that commercial pilots, of all kinds, don't get paid more and appreciated for the amount of knowledge and skill, as well as other qualities that aren't found so often in general.

My dad told me the altimeter tells how high the plane is...heh...little did I know how iffy THAT even was.

I'm overthinking for sure, because I want to "get it" as best I can. I know I won't be impressing anyone my first hundred flights, or maybe won't even grasp it, but it is fascinating, and it interesting, and I really hate waiting to get up there again, this time getting to control the plane.

 

[LongRoadBob]

The quote is about instrument flight, and is correct. To add even more confusion to it, a stabilized approach is both constant airspeed and constant rate. Which do you use?

As a VFR pilot, I think it makes more sense to think about it this way. In cruise, you are at a set power setting. It may be full power, or 2500 RPM in a 172 at low altitude, or 23 inches MP in a 182 (etc). But you can't go higher without messing with mixture (at least). In a practical sense, this means cruise climbs are done with the yoke. The speed is slower, but the throttle is not adjusted. At really high altitudes, you simply can't climb faster (or slower) than Vy. It won't do it. So, that's what you pitch for.

If you're flying slow, you CAN add throttle, and there is nothing wrong with that.

On the other hand, while approaching to land, you are usually at very low power, perhaps even idle. There is lots of throttle to be added.

Thanks. I'm going to have to "think on that" some more. I get what you are saying, it's just each new idea has to get integrated into my overall understanding, sometimes some other idea I thought I'd gotten may be wrong, or else something else has to be understood to see why it seemed to be a contradiction.

Let me ask though, in an actual stabilized approach, what I think I see happening is lots of small adjustments (in watching some actual landings) in both. Just YouTube (nobody is flying because of weather here when I can get out to the local airport) landings, I think I'm seeing small adjustment to pitch, hear the motor changing pitch either revving up or slowing down, back and forth to hold the right angle. Is that what is happening?

 

[MAKG1]

In a good approach, yes.

In a crappy approach, the changes are not small (hint: go around and try again).

 

[Cooter]

Thanks. I'm going to have to "think on that" some more. I get what you are saying, it's just each new idea has to get integrated into my overall understanding, sometimes some other idea I thought I'd gotten may be wrong, or else something else has to be understood to see why it seemed to be a contradiction.

Let me ask though, in an actual stabilized approach, what I think I see happening is lots of small adjustments (in watching some actual landings) in both. Just YouTube (nobody is flying because of weather here when I can get out to the local airport) landings, I think I'm seeing small adjustment to pitch, hear the motor changing pitch either revving up or slowing down, back and forth to hold the right angle. Is that what is happening?

It sounds like you are off to a good start but just recognize that a lot of it will make more sense once you've done it a few times. Your confusion about pitch/power and AOA is understandable because although everyone talks about it, few really get it. Very few GA pilots every fly on the back side of the power curve and even fewer do it on appch and landing. Almost everyone adjusts glidepath with nose attitude and then resets power accordingly. To really fly on the backside is uncomfortable unless you are used to it, and the concepts of power for altitude/pitch for airspeed don't really make sense unless you do. Power for altitude doesn't work very well on the frontside because you are carrying excess airspeed. For GA VFR, unless you are flying STOL, I would set the idea of backside flying aside. I know people will disagree with some of what I'm saying, but there is a tremendous amount of confusion about it and a lot of people get it wrong. AOA is misunderstood as well and most associate it with pitch attitude which can get you in trouble.

 

[Hank S]

You must maintain a cheerful attitude when landing. Being stressed will make landing much more difficult, as will being angry or frightened.

 

[Rook]

You must maintain a cheerful attitude when landing. Being stressed will make landing much more difficult, as will being angry or frightened.

That's kind of the opposite of how I think the real five hazardous attitudes are "inverted, nose straight up, nose straight down, 90 degree left bank, 90 degree right bank"

 

[MAKG1]

You must maintain a cheerful attitude when landing. Being stressed will make landing much more difficult, as will being angry or frightened.

A LITTLE stress is a good thing. Lack of it becomes complacency really fast.

 

[MikeELP]

I always encourage my airplane to go through life with a good attitude. If it gets out of shape, I tell it to straighten up and fly right!!

 

[ollopa]

Sassy, saucy, and indifferent.

As a student pilot, I tended to stare out the window at the runway the whole time on final, which led to unconscious pitch adjustments to stay on the glide path--usually pulling back and getting way too slow trying to "stretch" the glide. I had to break myself of this habit as it's obviously unsafe, especially when the stall horn is inop.

Airplane attitude isn't where I place the focus because it, along with the sight picture, are variable. If you have the configuration and the speeds right for the aircraft and conditions, the attitude is a natural consequence. I still spend most of my time looking out the window on final, but I continuously peek at airspeed and adjust pitch to maintain my desired speed, and adjust power to to stay on the glide path. For every few peeks of the airspeed, I glance over at the altimeter just for comfort.

It's important to look out the window so you can check for low-flying RV pilots and buzzards circling over final, stay lined up with the center-line, figure out your aiming point, and makes eyes with the buxom VASI. At the same time, airspeed is critical for safety and for minimizing float. Too fast and you'll run out of runway before you touch the ground, too slow and you're flirting with death. Gusting and shearing winds demand more attention to the airspeed and require a bit of buffer to account for sudden loss of airspeed and change in AOA.

Add a crosswind and the attitude of the airplane is further affected in roll and pitch, while you're giving rudder input to restore yaw.

It's nice to know the approximate attitude of your favorite plane for fair-weather landing at your home airport, but the expectation of a consistent attitude on every landing is going to be limiting and confusing when you switch airplanes, encounter wind, visit a high elevation airport on a hot day, etc.

Pretty much all aspects of flying an airplane boil down to operating in a closed-loop. When you're landing you're trying to follow a glide path (maybe not the glide path) to a point at a certain speed. You focus on that and adjust whatever you need to, including attitude, to correct for errors.

 

[GRG55]

If the elevator ALWAYS controls speed, why do we even have engines?

Because the Big Oil companies control the physics of flight - they bought all the competing patents years ago and have them in a safe somewhere.

And what about V-tails?

I thought those were just for looks, and to get the girls?

 

[LongRoadBob]

It sounds like you are off to a good start but just recognize that a lot of it will make more sense once you've done it a few times. Your confusion about pitch/power and AOA is understandable because although everyone talks about it, few really get it. Very few GA pilots every fly on the back side of the power curve and even fewer do it on appch and landing. Almost everyone adjusts glidepath with nose attitude and then resets power accordingly. To really fly on the backside is uncomfortable unless you are used to it, and the concepts of power for altitude/pitch for airspeed don't really make sense unless you do. Power for altitude doesn't work very well on the frontside because you are carrying excess airspeed. For GA VFR, unless you are flying STOL, I would set the idea of backside flying aside. I know people will disagree with some of what I'm saying, but there is a tremendous amount of confusion about it and a lot of people get it wrong. AOA is misunderstood as well and most associate it with pitch attitude which can get you in trouble.

Some great advice all through this thread, this one I took to hear too. I thought though that we are usually on the backside of the power curve during landings at least at some point before touching down, but am guessing that many still have enough speed that they haven't gotten to backside?
In any case, duly noted from you and others about attitude. I figured even when asking that it was of course dependent on other factors. That's why I phrased it in a way that meant if all factors were negated (no crosswind, no obstructions, etc.) and you were on approach, what typically would be the planes attitude. Just to get an idea if there was one. Thanks for pointing out that about excess airspeed, and power for altitude...that made sense.

Through further study, and from very much help here, I finally am getting the concept of AOA (on climbs, turns, descent...all the places where it is no longer assumed relative wind is coming in straight) and changes. I don't "have it" but I'm aware of it.

Thanks for the help! I do believe I'm overthinking. Just itching to get up in a plane and see for myself with the CFI's help how it all comes together.

 

[MAKG1]

You can get on the back side of the power curve if you're slow, but 1.3 Vs0 is not slow enough for that, at least for common light aircraft. You will pass through that regime in the flare.

 

[Cooter]

I thought though that we are usually on the backside of the power curve during landings at least at some point before touching down, but am guessing that many still have enough speed that they haven't gotten to backside?

MAKG1 is right, you will transition to backside in the flare. But, at that point you are already at idle so that you are not "flying" the backside and making power corrections for altitude. You are still using the nose to adjust glidepath while you hold it off until touchdown. Whereas in a true backside approach you are flying the power for glidepath all the way down and there isn't a need to flare. The "flare" will be a little shot of power to transition off of the approach glide path to a comfortable rate of decent for touchdown.

To help you visualize it, I used to fly an aircraft that required 9deg nose up for straight and level configured, on speed. At glide slope intercept (ILS), I would crack power, click two clicks of nose down trim and "bump" the nose to establish 6deg nose up. That would give me a 3deg start on the glideslope. After VSI stabilized, and aircraft re-trimmed for on-speed, the VSI was now the primary indicator for glideslope adjustments. So, power inputs would be referenced on the VSI and and nose attitude would be adjusted via trim to maintain airspeed (AOA). So instead of pulling the nose up for a low situation, I would add a little power, count two or three potatoes then see what kind of change in VSI that gave me. Opposite input for a for a high. The same technique can apply to a visual approach. That is roughly how a backside approach is flown. On more modern aircraft, the velocity vector or flight path marker can substitute for VSI, using the glideslope angle as the reference point.

 

[MAKG1]

You can use power in the flare to soften a landing. Sometimes arrest it entirely if the runway is over two miles long, it's hot as hell, and the FBO is on the other end....

 

[LongRoadBob]

MAKG1 is right, you will transition to backside in the flare. But, at that point you are already at idle so that you are not "flying" the backside and making power corrections for altitude. You are still using the nose to adjust glidepath while you hold it off until touchdown. Whereas in a true backside approach you are flying the power for glidepath all the way down and there isn't a need to flare. The "flare" will be a little shot of power to transition off of the approach glide path to a comfortable rate of decent for touchdown.

To help you visualize it, I used to fly an aircraft that required 9deg nose up for straight and level configured, on speed. At glide slope intercept (ILS), I would crack power, click two clicks of nose down trim and "bump" the nose to establish 6deg nose up. That would give me a 3deg start on the glideslope. After VSI stabilized, and aircraft re-trimmed for on-speed, the VSI was now the primary indicator for glideslope adjustments. So, power inputs would be referenced on the VSI and and nose attitude would be adjusted via trim to maintain airspeed (AOA). So instead of pulling the nose up for a low situation, I would add a little power, count two or three potatoes then see what kind of change in VSI that gave me. Opposite input for a for a high. The same technique can apply to a visual approach. That is roughly how a backside approach is flown. On more modern aircraft, the velocity vector or flight path marker can substitute for VSI, using the glideslope angle as the reference point.

As usual, I am going to have to reread and digest this slowly, but it's getting there and this is a huge help also.

Thanks!

 

[EdFred]

To help you visualize it, I used to fly an aircraft that required 9deg nose up for straight and level configured, on speed.

Which aircraft was this?

 

[Stewartb]

Talk to taildragger pilots about attitude. 3-point or wheelers? Level wheelers or tail low? Lots of variables, lots of opinions.

 

[midlifeflyer]

As usual, I am going to have to reread and digest this slowly, but it's getting there and this is a huge help also.

Thanks!

It is a good thing to understand what is happening. Just be careful of letting theory interfere with landing the airplane.