Point & Power Approach Technique
'Flanker' - sounds rather like Wa... no, too cheap a shot. But thank you for your well-researched, articulate and constructive comment.
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fireflybob and flanker, thanks for the vote of confidence. BEagle, you seem to be outvoted.
The technique we (and the major airlines I train for) teach works - so that is really all the justfication we need. For example, on go-arounds, where you dismiss it as inappropriate, the rate of climb is controlled by reducing the pitch attitude, then speed is controlled by reducing power. This gives a nice, manageable climb rate without the speed getting away from you. It is also what I used to do on VC10's, getting the "organic autothrottle" (FE) to reduce the power on my call.
As I said, if you are hand flying with the autothrottle engaged (acting as a silicon based FE) then the same technique is the ONLY one that will work without a) a bunting level off (negative g + passengers = them flying with someone else next time) or b) a risk of level bust (biggest safety risk to passenger carrying aircraft in UK airspace).
Also, the majority of flight schools teach trainees to enter a climb by applying power as "this will make the nose go up" and the converse for descents. Well, yes it does, but only if you have props - a jet will raise it's nose only as the speed builds (probably to something in excess of the desired climb speed). If you try it for descent, you will find the speed reduces eventually, then the nose drops and then you need a big nose down attitude to recover the speed.
From reading your posts, you seem to advocate power for ROD only on the stabilised approach, and a different technique for other eventualities. However, the technique advocate by myself, fireflybob and flanker works all the time - surely that makes it more valid?
Harrier GR3 - pitch AND flight path vector mode. Tornado F3 - flight path vector or velocity vector (which was regarded by the pilots as unuseable). So - set the flight path and adjust power, with the Specific Excess Power bars on the F3 facilitating this method.
flanker is right - you do sound pompous, escpecially trying to use technical phraseology to justify unsound technique.
(sits back to await barrage of personal abuse).
The technique we (and the major airlines I train for) teach works - so that is really all the justfication we need. For example, on go-arounds, where you dismiss it as inappropriate, the rate of climb is controlled by reducing the pitch attitude, then speed is controlled by reducing power. This gives a nice, manageable climb rate without the speed getting away from you. It is also what I used to do on VC10's, getting the "organic autothrottle" (FE) to reduce the power on my call.
As I said, if you are hand flying with the autothrottle engaged (acting as a silicon based FE) then the same technique is the ONLY one that will work without a) a bunting level off (negative g + passengers = them flying with someone else next time) or b) a risk of level bust (biggest safety risk to passenger carrying aircraft in UK airspace).
Also, the majority of flight schools teach trainees to enter a climb by applying power as "this will make the nose go up" and the converse for descents. Well, yes it does, but only if you have props - a jet will raise it's nose only as the speed builds (probably to something in excess of the desired climb speed). If you try it for descent, you will find the speed reduces eventually, then the nose drops and then you need a big nose down attitude to recover the speed.
From reading your posts, you seem to advocate power for ROD only on the stabilised approach, and a different technique for other eventualities. However, the technique advocate by myself, fireflybob and flanker works all the time - surely that makes it more valid?
Harrier GR3 - pitch AND flight path vector mode. Tornado F3 - flight path vector or velocity vector (which was regarded by the pilots as unuseable). So - set the flight path and adjust power, with the Specific Excess Power bars on the F3 facilitating this method.
flanker is right - you do sound pompous, escpecially trying to use technical phraseology to justify unsound technique.
(sits back to await barrage of personal abuse).
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BEagle - having re-read your last post, a couple of extra points.
The "un-necessary pitching" you refer to amounts to +/- 1 degree on average - the pax will not notice.
"Wriggling off the power with the attitude held" will not produce an immediate increase in ROD, just a decreas in IAS, especially on a stabilised approach in the full flap landing configuration. Pitch reduction is immediate in it's effect on ROD and the power may then be reduced to catch the speed before it even moves. Just the way the AP does it.
If you reduce power on a go-around, without FIRST reducing the pitch attitude you will find the IAS reducing while the ROC initally remains constant. Then the reduced IAS will cause the nose to drop, reducing ROC as a secondary effect. This adds a lag and do you really want to climb with the IAS reducing? Ideally of course, the pitch and power are adjusted simultaneously - but better safe than sorry.
The "un-necessary pitching" you refer to amounts to +/- 1 degree on average - the pax will not notice.
"Wriggling off the power with the attitude held" will not produce an immediate increase in ROD, just a decreas in IAS, especially on a stabilised approach in the full flap landing configuration. Pitch reduction is immediate in it's effect on ROD and the power may then be reduced to catch the speed before it even moves. Just the way the AP does it.
If you reduce power on a go-around, without FIRST reducing the pitch attitude you will find the IAS reducing while the ROC initally remains constant. Then the reduced IAS will cause the nose to drop, reducing ROC as a secondary effect. This adds a lag and do you really want to climb with the IAS reducing? Ideally of course, the pitch and power are adjusted simultaneously - but better safe than sorry.
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FFB,
The ‘Point & Power’ approach technique is more applicable to turbine aircraft than piston types, particularly jet aircraft with low drag. By adjusting the attitude on such aircraft, an immediate speed change is not evident, but a change of flight path will result. If flying an ILS for instance, a change in attitude will not have much affect on IAS but will repostion the aircraft relevant to the glide-path. Conversely a reduction in power will result in an immediate increase in drag causing a noticeable speed variation. Momentum will maintain the glide-path to a certain degree. Obviously this leads to a simpler method of stabilizing the approach. Turbine engines also have a spool-up delay. Applying power to regain the glide-path is less fruitful than changing pitch.
On the other hand piston engine aircraft will respond well using the conventional technique (attitude controls airspeed - power controls rate of descent). But this does not mean that the ‘point & power’ technique will not work, provided the student is taught to fly a consistent approach angle. An added advantage will be an automatic recovery to windshear. However in teaching the technique the student should be aware that it is a variation as the technique is not without some inherent dangers.
A student flying a short-field approach who rounds-out too high will experience an immediate increase in rate of descent and reduction in airspeed. If the high sink rate is recognized (and remember at such a low altitude airspeed is not part of the scan) his/her recovery technique to regain the aiming point will be an application of back pressure leading to premature stall and heavy landing. The correct technique is of course the application of power to arrest the rate of descent!
If the technique is used to promote early solo, reverse training must be used to re-train the student in the short-field landing. This can be accomplished by flying such approaches at 1.3 Vs, stressing the need to wind off throttle friction and insisting the student use power to control ROD (and aiming point) – attitude to pin the airspeed.
I guess I prefer the conventional method in light piston trainers and the ‘power & point’ method in jet aircraft.
The ‘Point & Power’ approach technique is more applicable to turbine aircraft than piston types, particularly jet aircraft with low drag. By adjusting the attitude on such aircraft, an immediate speed change is not evident, but a change of flight path will result. If flying an ILS for instance, a change in attitude will not have much affect on IAS but will repostion the aircraft relevant to the glide-path. Conversely a reduction in power will result in an immediate increase in drag causing a noticeable speed variation. Momentum will maintain the glide-path to a certain degree. Obviously this leads to a simpler method of stabilizing the approach. Turbine engines also have a spool-up delay. Applying power to regain the glide-path is less fruitful than changing pitch.
On the other hand piston engine aircraft will respond well using the conventional technique (attitude controls airspeed - power controls rate of descent). But this does not mean that the ‘point & power’ technique will not work, provided the student is taught to fly a consistent approach angle. An added advantage will be an automatic recovery to windshear. However in teaching the technique the student should be aware that it is a variation as the technique is not without some inherent dangers.
A student flying a short-field approach who rounds-out too high will experience an immediate increase in rate of descent and reduction in airspeed. If the high sink rate is recognized (and remember at such a low altitude airspeed is not part of the scan) his/her recovery technique to regain the aiming point will be an application of back pressure leading to premature stall and heavy landing. The correct technique is of course the application of power to arrest the rate of descent!
If the technique is used to promote early solo, reverse training must be used to re-train the student in the short-field landing. This can be accomplished by flying such approaches at 1.3 Vs, stressing the need to wind off throttle friction and insisting the student use power to control ROD (and aiming point) – attitude to pin the airspeed.
I guess I prefer the conventional method in light piston trainers and the ‘power & point’ method in jet aircraft.
I suspect that we're probably all arguing about different descriptions of the same thing, to a large extent. 'Point and Power' is an approach technique, 'Select Hold Trim' to another attitude and manager the power appropriately to govern the IAS is waht is really being advocated - particularly where the ac has a lot of inertia. Power/RoD and Attitude/IAS only works in a steady state - and small pitch corrections to restore towards a glideslope with a relevant AT or mandraulic thrust control setting are the techniques used in the main; you're 'technically' selecting a brief new attitude to aim at your glideslope 'target point', holding it until you've NB'd it's working and trimmed (slightly) whilst managing the thrust to stop acceleration.
My mistake was to perceive that you were advocating a 'needle chase' rather than a corrective flightpath selection - we are, in fact, agreeing on the same thing. Blatant pushing and pulling to achieve the glideslope in an agricultural manner is what would upset the SLF!!
Amazing how ac manage to fly without knowing why!
[ 22 October 2001: Message edited by: BEagle ]
My mistake was to perceive that you were advocating a 'needle chase' rather than a corrective flightpath selection - we are, in fact, agreeing on the same thing. Blatant pushing and pulling to achieve the glideslope in an agricultural manner is what would upset the SLF!!
Amazing how ac manage to fly without knowing why!
[ 22 October 2001: Message edited by: BEagle ]
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I hear the sound of rapid backtracking. BEagle - you were promoting a different technique from the rest of us . Full stop. Re-read your posts if you do not agree - each one came closer to the rest of us until we magically all agreed!
Blah!
Blah!
As you wish, moggie. Don't feel much like arguing about anything at the moment as I've just read that Air Cdre Bruce Latton, ex-CFS Commandant, boss at OATS and all round good guy has just passed away from cancer.
Hope that anyone at J-de-la-F who knew him will raise una copita or two to his memory.
Hope that anyone at J-de-la-F who knew him will raise una copita or two to his memory.
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Only met Bruce a couple of times - when I was at CFS and also at OATS when applying for a job. Seemed like a good guy and anyway, no-one should have to deal with cancer.
TTFN Bruce - beer will be consumed.
TTFN Bruce - beer will be consumed.
