Landing Technique Help

[player123]

I currently use the point and power technique for landing (Power for Speed, Elevator for Flight Path). However I may need to learn the other commonly used technique of power controls RoD, Elevator controls Speed.

Because I have used point and power my entire flying career I am finding it very difficult to understand how this technique works?

It would seem to me that if you control your speed with attitude that you would end up undershooting or over shooting?

Thankyou

[lilflyboy262]

As you raise or lower the nose, the speed increases/decreases.
As you reduce power, you have to lower the nose to maintain airspeed, therefore increasing the RoD and vice versa.

Hope that helps... and hope I got it right lol.

[Cows getting bigger]

There was a big discussion about this recently. The techniques are in many respects the same. With point and power you use the throttle to change speed but every time you use the throttle you have to do something with the elevator to maintain your picture (don't tell me you don't). With the other technique you do exactly the same but the other way around (if you see what I mean). Throttle and elevator are inextricably linked as far as approaches go; IMHO the whole discussion is predominantly a mindset issue.

[sapperkenno]

The reason these techniques exist: You can't just say to a new student, "do this and this and this", as they won't know what it is they are trying to do. So, these methods are invented to try and make sense out of the initial mystery of flying an approach.

As a pilot gains experience, he/she may combine the two techniques, and fly a mish-mash of the two, without actually knowing what it is that they are doing. All they know is they can fly a safe approach, at a set speed without too much thought.

Do the two actions of elevator/throttle at the same time, and the two techniques mostly become one and the same anyway. For a pilot new to training, they won't know this, as there are too many variables for it to make sense to them, so it needs to be broken down into a technique they can use.

However I may need to learn the other commonly used technique of power controls RoD, Elevator controls Speed.
What you really need, is a good understanding of how angle of attack (alpha) works, and how it is alpha that you adjust with the elevator. (Read 'Stick and Rudder' ;))

Imagine starting a descent in a light single engine aeroplane (The usual, inherently stable training type like a PA28/C172). You set the power somewhere around 1800rpm and trim for 80kts say. So, hands-off, the aeroplane will happily descend at 80kts, because (whether you realised it or not) you have set an alpha at which the wing is maintaining 80kts. You are trimmed for 80kts, and the aeroplane will be in a steady state, where it will want to fly at 80kts no matter what you do with the throttle. Or, if you were to pitch up momentarily, and bleed the speed back 5 or so knots, then release the controls, the aeroplane would want to return to it's trimmed speed and the alpha required to fly at 80kts.

So now, in your hands-off 80kts descent, reduce power to 1500rpm from 1800... As the power reduces, the nose will drop as the wing tries to regain the 80kts it wants. Essentially, you are now controlling your RoD with power. The elevator is used to set the pitch to which the aeroplane would go if left to it's own devices. Hands-off, it would control it's own pitch to return to it's trimmed alpha at a certain speed, would it not? But, instead of allowing the aeroplane to wallow about and hunt the alpha it wants for a set airspeed, you pitch the elevator to set the speed after you have adjusted the throttle. If you chopped the power, obviously you're gonna need to pitch down to maintain the airspeed, and hopefully you already realise this. That's all there is to the Power=RoD/Pitch=Speed method.

The major problem with teaching this technique, is that a student will then firmly believe, that airspeed is controlled first and foremost, with elevator. So, in a time of crisis (where airspeed suddenly drops on short final) they will try and pitch forward, shoving the nose down to try and regain airspeed. Obviously, not a good idea at low altitude.

Because I have used point and power my entire flying career I am finding it very difficult to understand how this technique works?
Go for a play and experiment at altitude. Start a descent, trim for an airspeed then play about with the power. After adjusting power, pitch as necessary to maintain the airspeed you had before you altered power. That's all there is to it.

It would seem to me that if you control your speed with attitude that you would end up undershooting or over shooting?
The point-power version of events you use would always seem more accurate, simply because you're always pointing towards the TDZ. (You would probably be surprised that your airspeed holding isn't that accurate with this method.) You would literally be pointing at it, then faffing with the power to get the airspeed you want.

Imagine you turn final and it becomes apparent that you're WAAAAY high. What would you do? Point/power would dictate you'd stuff the nose down, then as the airspeed increases, bring back the power. If, instinctively, you'd chop the power first, then that's a good example that you've already started developing more of a feel for things instead of just "flying by numbers" in a monkey see monkey do kind of way. I'd argue that both techniques drift into insignificance once you have 50 odd approaches under your belt, as you find a way that works for you without thinking about it too much. If you're still flying about post-PPL, worrying about whether power or pitch comes first, then I would question the quality of your flight instruction up to this point.

I personally favour teaching "power then pitch" - with the caveats regarding low alt and diving for airspeed. The demonstrations mentioned above would also be given prior to flying a proper approach. I try to avoid breaking it down into 2 areas after the initial couple of approaches if a student is progressing well, preferring that power/pitch are adjusted simultaneously.

[DFC]

I currently use the point and power technique for landing (Power for Speed, Elevator for Flight Path). However I may need to learn the other commonly used technique


The technique you talk of is not used for landing, they are used for making a stable approach.

Are you having problems with landing or with making an approach?

As far as the approach is concerned, as "cows getting bigger" says, it is simply how you perceive what you are doing with the controls rather than what you physically do.

Therefore to change from the "I use point and power" to "I use attitude for speed and power for rate of descent" simply stop saying the first when you are talking to someone and start saying the latter.

Regards,

DFC

[Oktas8]

Therefore to change from the "I use point and power" to "I use attitude for speed and power for rate of descent" simply stop saying the first when you are talking to someone and start saying the latter.

I do the same - my patter changes, but not my approach technique. Students & trainee instructors don't know the "trick" unless my patter falters. And it means no more arguments about which is better; just nod & smile and deliver the patter with which the student is most familiar.

O8

[Intercepted]

If you have not already done so, get yourself a copy of the book Rudder and Stick. For a low hour pilot, like myself, this book has really helped me to understand what is going on during flight. It's all about Angle of Attack :ok:

[Duchess_Driver]

Did you perhaps mean...

Stick and Rudder: An Explanation of the Art of Flying.
by Wolfgang Langewiesche

Got mine from Amazon....but can't find it anymore. (Don't you hate it when you can't remember which friend you lent it to?)

[Intercepted]

Yes, thats the one. I got mine from Amazon UK.

Stick and Rudder: An Explanation of the Art of Flying:: Amazon.co.uk: Wolfgang Langewiesche: Books (http://www.amazon.co.uk/Stick-Rudder-Explanation-Art-Flying/dp/0070362408)

[boofhead]

Both techniques are applicable and most of the time you will be using them both without knowing it. In a classic airspeed case, whether climb, level or descent, you will hold and set speed with attitude (elevator). You will use power as a constant (climb power for climb, cruise power for cruise etc). Remember POWER + ATTITUDE = PERFORMANCE?
On approach, you will use the classic technique during the initial base and final until you have a more important parameter to control, that of the glide slope. The glide slope might be a VASIS, an ILS GS, or a visual glide slope based on what you are seeing out front.
Once on the glide slope, it makes more sense to use the elevator to stay there. A little speed excursion is not as important as remaining on the glide. If the airspeed is within a reasonable tolerance leave the power alone. Usually the speed has changed as a result of the airplane going above or below the glide, so if you simply return to the glide slope the airspeed will recover nicely all on its own. If the airspeed is consistently high or low, make a power adjustment while you continue to control the glide with elevator and all will come right.
A jet airplane will mostly use this technique, since an accurate glide slope is vital. An auto throttle is keyed to speed, not to approach angle, for this reason. However any airplane can be flown this way and it will result in more accurate landings.