final approach technique: pitch vs power
 

Gentlemen,

I have a very basic question regarding teaching the final approach technique.

When I learned to fly I was taught to keep the airspeed constant and the aircraft in trim and correct the sink-rate with power. If you are getting high - reduce power, if you are getting low - add power.

This was called "power for altitude, pitch for speed".

I am now in the process of refreshing/converting my FAA CFI to JAA FI(A) and I was just a bit surprised to learn about the "point and power" technique, from a very respectful flying school, stating basically the opposite: you control your altitude with pitch and then control your speed with power.

Well, since all of us landed so far using either of these two techniques, it is obviously they both work.

However, can somebody explain to me the advantage of constantly varying your airspeed during the final approach?

Is it only because some students might otherwise have problems judging their touchdown point?

Kind regards,

SC

Good morning!

Try "power for altitude, pitch for speed" on a slippery jet with slowly responding engines and you will know what the advantage is. And if you do it with some anticipation, then there is not much (unwanted) variation in your airspeed.

As long as your school trains mainly private pilots, there really isn't much difference. But if your school is aimed at ATPL students (like the one I instruct for) it makes a lot of sense to teach it the way they will need it later for their job.

Regards,
max

NB: The search function will find hundreds (maybe thousands) of threads regarding this issue!

There is no advantage, the object is to retain a constant speed whether by attitude adjustment or by small power changes.

The principle of Point and Power is to retain a line of constant angle with the touch down point my means of small pitch changes. Any pitch change will also change the speed, so a comensurate power change is made to retain it at a constant value.

Can you elaborate please?

In a post in an earlier thread on this same topic, Whopity said:
Which has improved my approaches beyond recognition. So thanks for that!

1) Do a search for Point and Power. 2) Read for the next three weeks....

Clearly both work, but point'n'power (power adjusts speed) tends to give a more stable approach and a more accurate touchdown position. The bottom line is that you have to teach what everyone else in the school teaches or students are going to become confused.
Most SEP instructors seem to teach attitude for speed so I only tend to introduce p'n'p when converting people onto complex types, to twins, or if they ask to do it on a BFR.

(Small error in the OP - the aiming point is held constant in the windscreen until the flare; the power is adjusted to maintain the correct speed - the airspeed is not "constantly varying")

HFD

I do not quite understand why point-and-power method is more suitable for complex types (what does complexity has to do with the flight path?) or larger airplanes.

If you hold the aiming point constant on the windshield wouldn't it result in a different glide path angle every time? (depending on where you initiate you final descend)

It seems to me that to get back on the 3 degree glide (in case of being above it) one has to point the airplane short of the aiming point to get back to the glide path first and then re-aim for the 3 degree.

Am I wrong?

The basic problem is that a pilot needs to know when the approach needs to be corrected.

The pilot needs to have some sort of 'error-ometer' to assess this. With 'point and power', it's easy - the 'error-ometer' is the ASI if the touchdown aiming point is kept stationary in the windscreen.

But with the 'other' technique, pilots have to assess whether they are above or below their desired glidepath. That is a skill which is MUCH more difficult to learn to the same degree of precision as 'point and power' achieves; most pilots using this 'other' technique take a long time to develop their personal glidpath 'error-ometer' and often leave things until very late, then add a huge amount of power and attempt to get back onto their original glidepath. This is particularly true when landing on a long runway as, unless he/she is grossly undershooting, the approach probably 'looks OK' to the student pilot, although he/she might eventually land anywhere within hundreds of feet of the correct touchdown point.

With 'point and power', pilots rapidly gain the skill of keeping the touchdown aiming point steady in the windscreen. As experience is gained, corrective power changes to correct speed errors become smaller, because they are applied sooner. I used to teach turning final at approach speed +10, then roll out, select full flap, adjust and trim to approach speed before concentrating on 'point and power' all the way to the flare. Dead easy - and that's why 'point and power' students usually solo at least 2 hours sooner than 'other' technique students

But others persist in making things TFD for the student pilot to cope with particularly, regrettably..... They probably teach them a mnemonic as well...:\

When you learn to teach 'point and power', you should also be taught the 'glidpath error' sequence - it is not essential to fly a 3 deg glidepath as 'point and power' can be used over a range of acceptable glidepath angles, which you demonstrate to the student from a long, straight-in approach flown at a constant height of about 4-500 ft.

Probably only those playing airliners and flying long final approaches insist on 3 deg visual glidepaths in light aeroplanes.

During my many years as a PPL when I taught on single engine aircraft we always used the pitch for speed, power for rate of loss of height technique. Why should we use any other? As time progressed, ILS systems appeared on light aircraft and at more airfields. By this time I had managed to get my IR and can remember the countless times I sorted out PPLs who were trying to fly the ILS glideslope by using pitch for speed and power for rate of loss of height. Converting them to the other technique worked like magic and left them with smiles on their faces as, at last, they had conquered what they had previously considered to be the trickiest of approach manoeuvres.

P.P.

Unfortunately there are CFIs out there (mostly the type who have never done anything but instruct) who think PnP is the work of the devil. I would love to be allowed to teach it but our SOPs say not. :ugh:

It's all in the mind.

It is not about technique is is about understanding actions and reactions.

Whopity has it perfect with their piece of string idea.

The best way to look at this is to put 2 people from opposing camps in the sim ( a good sim!!).

get them to stabilise on an approach and then pout them at the correct speed and below the glide path (safe approach path if one prefers).

One will add power (thinking they are low) and will also at the same time pitch up to cancel the increasing speed trend. In other words they will will flatten the trajectory while maintaining a constant speed and by this regain their ideal trajectory.

The other will pitch up (thinking they are low) and also at the same time add power to cancle the decreasing speed trend. In other words they will flatten the trajectory while maintaining a constant speed and by this regain their ideal trajectory.

The difference in the highlighted parts in the above to examples is the difference between the mind-set of "point and power" and "power for altitude".

Having said that, in my experience candidates who think in terms of "point and power" perform better than those that think in terms of "power for altitude, attitude for speed".

Why is there a difference when it is only a mindset?

The answer is that in the power for altitude case there is no real emphasis on learning to recognise where the trajectory of the aircraft is pointing. People who are good at recognising where the trajectory of the aircraft is going to hit the ground will not only do accurate approaches with power but they will also use that information to make critical decisions in PFL / glide approach situations.

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skipping classes,

Absolutely correct, and if you find while trying to correct that you have the throttle closed and the trajectory is still beyond the aiming point with the correct speed, you are going to miss the aiming point unless you can add more drag.

As I said above it is this critical ability to recognise the current trajectory of the aircraft and to change it if required that is essential no matter how your mind works. Every pilot should be able to fly a constant angle approach at a constant speed and every time be in a position that if they did nothing else they would smash the nose into the aiming point at the correct speed.

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Probably before your time but I think that you will find that 3 degrees is used because it is a natural approach angle that pilots prefer and enables the majority of powered aircraft flying to make stable approaches while clearing obstacles by a safe margin.

Many palces specify it as a minimum for noise.

It is what the figures in most performance tables/charts are based upon.

As soon as one makes steeper approaches then other factors some into play - for your average light trainer - more groundrush and more positive roundout all of which make the basic approach a bit harder for the student doing it for the first time.

I am all for making a glide approach and being able to say "I don't care if the engine stops because I will get in anyway" but I think that when training one has to start with the easiest method and expand from there.

We agree about "long approaches" though establishing final at about 1.5 miles and 500ft is far enough out and if every one did it there would be some noce and tidy circuits......and that is about 3 degrees!! :)

A while ago, I had to do some mathematical analysis after some CFS Trapper told us our approaches were too steep. He was a dyed-in-the-wool Jet Provost person...

The analysis proved that the RAF circuit as taught for the Bulldog resulted in an approach angle of roughly 4.4 deg. When presented with that information and an invitation to disprove it, he admitted we were right and he was wrong.

High on the approach (for obstacle clearance) throttle closed. What now?

Sideslip if the POH allows it or more likely, go around.

By the way, I was recently taught to use throttle for speed on approach and it worked like magic!

The trees won't move. No matter how many times you go around, and power is removed from the equation, leaving only pitch to control speed. Welcome to the real world.

But then you are not flying a constant sight line to the runway which is fundamental to Point and Power.

Try Point and Power on your next PFL.

IMHO, using power to control rate of descent and nose position to control speed is the appropriate way of teaching basic approaches in a light single engined aircraft in visual conditions. This is because any angle of approach may be necessary due to the circumstances of the approach be they flap failure, engine failure e.t.c, e.t.c. The approach technique using power to control speed and nose attitude to control rate of descent is another technique in the armoury of an instructor to enable a student to gain the basic principles. "The vital thing is to appreciate the visual picture," as Firefly Bob's Dad used to say. The other technique is however the appropriate way of flying approaches on instruments as I have said previously. From my own experience, it was a number of years after I gained my PPL and instructor rating that I had the opportunity to try and fly a full ILS approach. I was heavily grounded in the nose for speed, power for rate of descent technique then which I taught exclusively. When I had a go" at using such things as ADF's and a full ILS system I found following the glideslope accurately very difficult: "And commercial pilots are able to follow it to 200' AGL - coo they must be clever!" It was only when I was taught the technique mentioned above on my own IR course that I found out how to do it properly.

I used to say that "flying a glideslope is just like flying straight and level - on a bit of a slope" and when you are used to flying the usual 3 degree glideslope, the visual picture of flying a 5.5 degree one at London City is totally wrong - it works though - all you have to do is to follow your instruments!

P.P.

Spot on P.P. Horses for courses as they say.