elevator for airspeed and...

[Hildy]

throttle for rate of descent.

 

why is rate of descent even a variable? I can't see how it matters what your rate of descent is, other than that it should be close to zero at 0ft AGL. otherwise, it is solely a proxy for glideslope - but that means that each particular approach speed needs to have its own rate of descent calculated (eg 500fpm at 60kt is the same (8%) as 1000fpm at 120kt).

 

 

[Camel]

Attitude airspeed, power height, so if you want to get down nose down power off and side slip because that is what you might have to do to get into a little short patch to park and as you come down like a brick you may want to reduce this rate of descent before impact / arrival / landing. I understand your point but if you need to get down you have to make adjustments or get to your arrival point.

 

Cam

 

 

[facthunter]

Might seem like a simple question , but it isn't. How far do you want to go? We have people who want all approaches to be power off, and in THAT situation, the only control you have is elevator and it will control your airspeed. If you hold the airspeed constant, the ROD is determined by your aircrafts lift/drag performance.( efficiency ). Any power added will enable you to adjust the elevators to maintain the airspeed constant and the ROD will reduce. If the power added is enough eventually you reach something like level flight. (again holding the airspeed constant). More power will result in a climb (again with airspeed constant).

 

What we have then is the essential concept of power enabling you to climb, or descend at varying rates. Nev

 

 

[Hildy]

Might seem like a simple question , but it isn't. How far do you want to go? We have people who want all approaches to be power off, and in THAT situation, the only control you have is elevator and it will control your airspeed. If you hold the airspeed constant, the ROD is determined by your aircrafts lift/drag performance.( efficiency ). Any power added will enable you to adjust the elevators to maintain the airspeed constant and the ROD will reduce. If the power added is enough eventually you reach something like level flight. (again holding the airspeed constant). More power will result in a climb (again with airspeed constant).What we have then is the essential concept of power enabling you to climb, or descend at varying rates. Nev

the other control you have is drag - which you can alter with flaps and slipping.

 

i was taught to have all approaches to be power off at my initial school, and at my new school (a GA school) they teach airspeed/ROD. the problem I have with it is that it doesn't control for aimpoint so I struggle to actually land at the right spot.

 

david: if you are travelling toward your aimpoint in a stabilised approach, your rate of descent isn't interesting. you might have a very steep approach or a very shallow one, but as long as it is stabilised and your aircraft's line of motion points toward the aimpoint, you will make it.

 

 

[facthunter]

Adding flaps really changes the aeroplane design. It has different L/D characteristics (worse). We have "dirtied up" the plane. So what do we then have? More drag, potentially steeper approach and larger sink rate. ( Lower stall speed and better vision over the nose too, as well as reduced float on flare).

 

If you keep the throttle closed on the approach the only adjustment you have is to increase drag. ( Flaps or sideslip) Sideslip is variable but flap is in stages. This technique presupposes that you commence the approach being high on profile. Very high sink rates can occurr and have to be managed. Some operating manuals set a max allowable sink rate for operations of the type. In U/L ops 1,000 fpm is MY maximum, but in critical stiuations, (turbulence and short field ) I never suggest a power-off approach...Nev

 

 

[motzartmerv]

When they say descent rate, they are referring to the aimpoint, if your overshooting or undershooting.Changes will effect a change on the vertical speed but this is secondary to the correct approach angle being maintained.

 

As Nev said, heavy sink is all too common and while the VSI can give you an indication of this, the most telling thing is the aimpoint moving up or down in the windscreen with a constant attitude being maintained.

 

The standard RAA approach is slightly steeper than that taught in GA due to our aircraft having less inertia. Its all about managing the energy, and flying with some energy in the bank down the entire approach.

 

cheers

 

 

[poteroo]

Merv has it right IMHO - you fly an approach angle.

 

It goes back to fundamentals. If you use the 3,4,5 or however many, 'fingers' below the horizon to initially adopt your S&L attitude.......... then this very same 'attitude' can be used to guide your approach. After final flap selection - adopt an attitude of the same 'fingers below the horizon' as you do for S&L, except the 'horizon' is now your aiming point. Adjust your power so as to maintain this angle - all the while focussing on your aim points' relativity to your top-of-panel. You are now flying the 'point & power' approach. It's too easy - we shouldn't be taking your money for this....it's money-for-jam!

 

happy days,

 

 

[facthunter]

Yeah, it all works fine as long as you can keep airspeed fairly constant, then your attitude relationship with your aimpoint work. There is an imaginary "slope" that you are on. Some students take a little while to work out if they are dropping below it or riding above it. The earlier the error is recognised the smaller the correction needed. Precise control of approach 'path".( angle and aim point) and airspeed is required on a minimum length strip. It's easy to get lazy at an aerodrome where there is plenty of runway, and land longer and faster than optimum. This becomes a habit and you don't do a good job at other aerodromes which are short. Nev