When the student has shown an appreciation of what is trying to be achieved; and only then; we can then allow the introduction of alternative methods of flightpath control.
There is no "alternative method of flightpath control".
One controls the flight path by moving the elevator, ailerons, rudder and (for powered aircraft) using the throttle to vary the force along the thrust vector.
For the constant correct approach you need;
1. The flight path to be towards the aiming point or put another way, you need to be on a collision course with the aiming point and to hit it (like anything else) it must remain static in the window.
2. The angle between the flight path and the horizontal must be correct
3. The track over the ground must equal the runway centerline; and
4. The airspeed must be correct.
No matter how you think of it, how experienced or not, you can not complete a stable approach without the above.
So when you want to teach a person how to do number 1 above is it not very simple to say - use the controls to keep the aim point steady in the window?
Then one can remind them of the secondary effects that they covered some time earlier and remind them that then the flight path angle steepens gravity accelerates the aircraft along the flight path and vice versa so if they need to correct by using a different flight path then there will be a need for a thrust change so that speed remains constant.
I can explain - pitch up and increase thrust to conteract the secondary effect of reducing airspeed in 10 seconds and it has already been covered on exercise 4 as the primary and secondary effects of moving the elevator.
In exercise 4 the student will also have been shown the primary and secondary effects on increasing and decreasing the thrust settings.
I can also explain why one can think of it as increase thrust to change the flight path and adjust attitude to counteract the change in airspeed but it takes longer, doe snot relate to the previous lessons and is harder to relate to what one is trying to acheive.
In the end however, if a "point and power" pilot and an "power for height" pilot both fly the same aircraft along the same approach they will both manipulate the controls in the exact same way. The only difference is in the mind!
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The main reason why this issue rarely comes up until pilots start flying ILS approaches or something for which a constant approach angle is essential is that for PPL and CPLs in training, instructors simply require that the flight continues towards the aiming point at a constant speed.
Too often if the aircraft becomes a bit high, the answer is to fly a steeper flight path towards the aiming point with reduced thrust to offset the resultant increase in airspeed. If the aircraft is a bit low, the flight path is aning flown towards the aiming point but with higher thrust.................and people are thus dragged into the mindset of power for height.
In effect, PPL and CPL training do not concentrate on re-intercepting the correct approach angle and everything is based on travelling towards the aiming point.
When it comes to flying the ILS, then if the aircraft is not on the correct path, a new path must be flown that does not take the aircraft towards the aiming point (they may already be heading there) but to regain the correct glidepath.
Far too many PPLs and CPLs do not understand that travelling towards the aiming point is not all there is to flying the correct approach.
While every instructor will draw lovely intercept lines for getting back onto the centerline, very few do the same in a vertical sense whan talking about the appropriate approach angle.
Regards,
DFC