during all my PPL training, the Mantra of 'Stick for speed' and 'Throttle for height' was taught. I'm aware that there is in fact a couple between the stick and throttle and in reality co-ordination of both are required, but I think its more about the way you think about it, than the actaul effect of the controls.

However I'm just reading Thom 5 for my IMC and all the way through this the philosophy appears to have changed to "Stick for height / glideslope / flightpath", and "Throttle for speed"
Is there any particular reason for this change in thinking? or is it authors and instructors preference? What gets taught on IR's and to commercial airline pilots? Or given that its really a co-ordination of the controls thats required is it really down to personal preference?

Think this is one that's been argued since the Wright Brothers. Depends on who you talk to really... tend to go with the co-ordination model myself.

Its becasue you normally fly the ILS (or any IAP) at a much higher speed than when you are on a visual approach. I normally aim for 100kts on an IAP in a SEP. Its all to do with where you are on the drag curve.

EA

I don't really think it matters. Like riding a bike, you don't analyze it - you just do what you need to do to make the aeroplane do what you want. If you are lucky enough to fly a Chipmunk, you don't worry about moving the stick - it's all done by thought processes anyway.

SSD

ahh, Englishal , I think I can see that. So at low speed close to the back of the drag curve, putting the nose down is a much more responsive way to gain speed? and at higher speeds with higher energy and less drag, raising the nose, say, will just alter flightpath and not have much effect on speed? Is that it? Kinda makes sense to me if thats the case.

Yep, thats about it

John Farley's articles in Flyer magazine addressed this at some length. With a Jet Provost very low and slow on short final, he asked the QFI to demonstrate how lowering the nose would get the speed back. Needless to say, the only thing to do in that situation is to put the power on, controlling speed with throttle. I recall John wrote that only the US Navy and GA used 'attitude for speed' on landing, with all others using 'throttle for speed'.

Initially at our school we teach attitude for speed; when climbing at full power, or descending in the glide, there is obviously no option. However, we 'flick the switch' once the student has reached a designated 500 foot point and revert to 'point and shoot', using attitude to point at a consistent spot on the runway and throttle to manage speed, and find that most people find ths an easier approach to make consistent early landings.

After a while people stop thinking about which control affects what (as they are of course inter-related) and 'use the force, Luke', but you can't start out like that!

I started out as a glider pilot so I know that it's stick for speed/throttle for height.

I think it's poorly explained so that one gets the impression that things are not done the same way for IMC.

The trick, espacially for instrument flying, is to have the aircraft trimmed to the correct speed. Thus, if one starts going a little low on the glidepath, I'll maintain the glide with a pitch correction and add power until there is no longer a stick force, then reduce the power again to a little more than I had initially. I'll never retrim.

TRIM for the desired speed is the best kept secret in flying

Once you know that the trim determines the speed, the workload of flying a plane falls drastically. None of the PPL instructors I flew with ever told me that though. It was only an IR one I had for the IMCR that seemed to know it.

Trim trim, trim, trim...

And keep triming.

See:

John Denker's 'See How It Flies'

Stick & Rudder

Miserlou

Unless I misread your post, your technique is to adjust the rate of descent with the stick and then use the power to safeguard the airspeed

For a constant glideslope, visual or instrument, if you are above it you reduce power then lower the nose to retain airspeed, if you are below it, you add power and raise the nose to maintain airspeed and regain the slope. that seems to add up to power for rate of descent, attitude for airspeed. Power plus attitude equals performance.

I was always taught stick for speed, power for rate of descent during VFR training. That motto works well with the constant aiming point method.

In IFR it's all change - now I'm told stick for ROD, power for speed. I'm finding that a high speed ILS in a twin requires very subtle applications of the new formula!

Of course the real trick in VFR is to set the power on base prior to descent and then not touch the throttle until at/very near the threshold - in my experience only works with a light wind and an empty circuit, or maybe thats just me!

AlexL,

Instrument flying is just like VFR flying, except for having the outside horizon, you have an artifical one.

Instrument flying is about setting attitudes..and achieving a desired performance.

So for example in a descent on an ILS you will have a target pitch attitude, target rate of descent...maybe 600 fpm on an ILS, and a target airspeed. You will need to adjust you pitch attitude to the desired one, and adjust your power for the desired airspeed.

So for any phase of flight you should know the target pitch attitude, and power setting, if you set these initially, you can then adjust to refine fine tune your performance. Just like you do when flying VFR.

F3G.
Perhaps, not sufficiently clear. Not trying to get into deep discussion I tried to keep it short.
Very minor corrections to glidepath made with the stick. Any trend, that is a correction which continues to be required, corrected by power; these are very small, needle-width corrections I'm refering to here.
For the ILS it is more critical to maintain the flightpath so the pitch correction is only temporary to avoid the slight time delay and any further deviation. The causes and effects do overlap a little.

The trim setting remains the same.

Miserlou

I was being a little naughty

In a steep turn you maintain level with elevator and maintain speed with throttle

S & L you maintain a level attitude with elevator and control speed with throttle

why should a powered approach be any different?

Marvelous.
After100 years of airplanes we still don't have a a universal method of handling one of the more dangerous phases of flight.

One can certainly understand the differences that may be required to handle heavies, or even just jets, given their mass and the spool up time etc however it seems there is no clear picture even for SEP GA.

When I was taught (40 yrs ago) there was absolutely no doubt. Attitude for speed and throttle for descent was universal and the only way to go. Like a lot of simple things it seems to have been forgotten in a plethora of theories and complications. When I started again 5 years ago I was astonished and dismayed that my instructor told me to "hold the nose up with the yoke" all the way through the climb out instead of trimming for speed and no control pressure. I have even seendiscussions of pilots "Holding the nose down with stick on approach so you can just relax the pressure to flare" which seems to me to be the epitome of poor practice. Perfectly barmy.

(As an aside. If you get slow on approach the AOA increases. Lowering the nose not only speeds the plane up quickly but also temporarily relieves the wing load and lowers the AOA. (Adding throttle doesn't do that until the air speed rises. In fact on some planes the chage intrim actually increase the AOA with throttle. If you are near critical AOA that might make a difference.)

Couldn't agree more Chris.

Once again I highly recommend either Wolfgang Langeweische's 'Stick & Rudder' and John Denker's 'See How It Flies'.

'See How it Flies' is free online, and covers much the same material as 'Stick & Rudder'. A few hours on that site and you'll have gained a few hundred (or thousand) hours worth of flying experience.

Conf

Thanks for the replies. I've always been happy with "stick for speed", but it was reading the IMC book that added the confusion. I've got 'Stick and Rudder' for christmas, so I just need to get round to reading it now!