Thrust on during flare...Q for AIRBUS test pilots...

[RAM777]

Well i keep slight power only when its very windy or in summers due to the updrafts.If my speed is approaching the VLs i reduce the power a little late.This has helped me in making smooth landings..Other then that i dont think so its a good idea to land with power because that eats up lot of runway..

[InSoMnIaC]

Vilas - I wasn't advocating using thrust to control RoD. Quite the opposite actually. Please re-read my post. My point was although controlling RoD by thrust is possible (just like controlling bank with yaw is possible) it is not preferred.

[nitpicker330]

Yes Ram777 that's how it should be done. You decide, depending on situation, the exact time to close the thrust, sometimes you may have to leave a bit on until touchdown.


Q---2 dots high? Ans:- Ease forward on the elevator to reduce the pitch attitude by say 1 to 2 deg? That increased your ROD ( obviously ) then perhaps you "may" have to reduce thrust a little, say 5% N1 to keep the IAS nailed. Then when back on slope ease up 1 to 2 deg and apply 5% more N1 to maintain the slope. All Jet Pilots are trained in what pitch attitude and thrust setting to aim for in approach, initially on conversion you fly these NUMBERS. Later on you "just do it"

Haven't you guys see the unreliable Airspeed checklist which contains a table showing you PITCH ATTITUDE and THRUST settings ??

Any of you flown the A330 using the BUSS? ( yes Noodle do you know what the BUSS is? )

Airbus strongly recommend and teach that during an approach flown by the BACKUP SPEED SCALE ( BUSS ) that to maintain in the green you fly a fixed pitch and then adjust THRUST to keep it IN THE GREEN. Why? Because that's the easiest way to remain "stable" AND keep the process as normal as is possible.

This is "their training" using Thrust to control speed just as you do ON A NORMAL LANDING.


P.s. I would have loved to read what 411A would have said about his beloved L1011. That beast used DLC and in theory your Pitch attitude remained constant, still they used Thrust for Speed though!!

[737Jock]

If you did this is a C150, yes, you would see a increase in speed and yes, you probably would have to throttle back a bit and yes, you could descend back to the GS by pulling off the power. But we're not in a C150. The 737 by virtue of it's pitch/power coupling may also let you get away with using the throttles to fly the GS, but that's trick-flying and I contend that it's not the speed-stability effect, it's only because of the underslung engines.

Well then you just disqualified yourself for lack of aerodynamic understanding. It's the basic principle of trimming the aircraft for speed. It's how aircraft have managed to land without any elevator control.
Why do you think the stabilizer can be trimmed?

Never heard such a bunch of crap in my life from someone who is supposed to be a line trainer. Then again I recognize the type.

In a 737 or any other speedstable aircraft you can reduce thrust and the nose lowers simultaneously if it's too slow for you can push on the yoke and help it. This will increase your rate of descent while maintaining airspeed. As you approach the glideslope you simply add thrust which also raises the nose to reduce the rate of descent. You should not need to retrim the aircraft as it is still trimmed the same way as when you started the excercise.

In a airbus (manual thrust) (an airbus in normal law is not speedstable although the airframe design is) you will reduce thrust and simultaneously push on the sidestick as you know you would lose speed otherwise. (Hey maybe that's the same as saying: I push on the stick and the airspeed increase so I need to reduce thrust)

Pitch and thrust /thrust and pitch go hand in hand. The starting point doesn't even matter in fact a reasonably experienced pilot who doesn't consistently use the a/p and a/t does it simultaneously.
But apparently someone decided that stupid pilots need a more simple method as they don't understand the link between pitch and power?
So someone came up with thrust is speed. Which basicly means you are always reacting after the fact with thrust due to a speed change that happened because of a pitch change. Instead of being proactive and anticipating the effects of your inputs.

One of the reasons to reduce thrust in the flare is because you enter the groundeffect. Another is that runway lenght is limited and you want to slow down as soon as you can.

I find it very interesting though that someone keeps power on to compensate for updrafts that by definition increase the energy of the aircraft. And that someone else then says that this is the way to do it??? I reduce thrust when I encounter updrafts (and I add or maintain when I sink).
But maybe as the aircraft starts to balloon due to the updraft you then just point the nose at the runway for a nice nosewheel landing in order to manage your path? Or you just float and call it a smooth landing?

No wonder statistics show more long landings in summer if this is how you manage energy.

[NoodleAir]

I told you earlier, it is obvious he does not fly a jet.

Thats the reason I suspected both of them being the same person, they support each other's views and have a history of doing so.

Post pairs 92-97 and 99-100 are the finest example of it.

Misd-agin gives some clues in a tricky manner that they (the same person or both?) don't understand, exactly like he did in his first post, and then they come back with some laughable examples that have nothing to do with reality (post 97, the example being about LEVEL FLIGHT!!!!!). AND he stated "like your stupid comments on page 1, you just don't get it". !!!!!

We are talking about someone who does not understand the balancing force of steady level flight………

Regarding Bloggs, don't bother at all, he needs to complete his PPL first.

Nitpicker may have been too long on an Airbus (he insists on quoting Airbus FCTM parts etc), but he still hash' answered on what his old book (the one he bought in '82) says about PRINCIPLES of Flight.

Responding to his post #97, on approach (in a Boeing) you control speed with pitch NOT with thrust. Thrust controls your path.
I do not expect you to agree or accept anything.

Over and out

[737Jock]

http://www.faa.gov/regulations_polic.../00-80T-80.pdf

I have taken the liberty to find your manual Noodle. And I would like to quote from page 360. Noodle's statement is in bold.

The proper coordination of the controls is an absolute necessity during the approach. In this sense, due respect must be given to the primary control of airspeed and rate of descent for the conditions of the steady approach. This the proper angle of attack will produce the desired approach airspeed; too low an angle of attack will incur an excess speed while an excessive angle of attack will produce a deficiency of speed and may cause stall or control problems. Once the proper airspeed and angle of attack are attained the primary control of rate of descent during the steady approach will be the power setting.

and this is the answer from the manual regarding the question posted earlier about being high on glideslope

For example, if it is realized that the airplane is above the desired glide path, a more nose-down attitude without a decrease in power will result in a gain of airspeed. On the other hand, if it is realized that the airplane is below the desired glide path, a more nose-up attitude without an increase in power will simply allow the airplane to fly more slowly and - in the region of reversed command- eventually produce a greater rate of descent.

[Trackdiamond]

pitch and power debate

Guys..this is one of those long historic banters of course..lemme join in!
(Pitch +/- power)trim 〓performance..is widely understood.

The argument of what controls vertical speed and what controls forward speed depends on which flight phas we plan to be in..or happen to find ourselves in.

Straight and level..Power controls speed. Pitch controls Altitude(Vert speed)

Climb....Power controls Vert Speed. Pitch controls forward Speed.

Descent...Power(or lack there of) controls Vert speed...Pitch controls forward speed.

Approach Power controls forward speed pitch controls Vert speed(glide path)..however...if excess deviation occurs on glide..use power reduction(if above sope) or power increase(if below slope) appraching half FSD.When at or beyond half scale dev..consider Go Around.

Missed Approach; Pitch first and Power to TOGA setting.Arrest sink and inject further climbing energy.

Flare: Pitch...to arrest sink from that required to maintain Glideslope..and gently retard from the recommended power reduction Radio height..eg 20-10ft depending on weightyn wind etc...and that should give you if gentle with pitch demand rate and your distant vision should assist in gauging your bum sink rate...shoud settle you on terra forma with a subtle 200-300 fpm close to or just past the touch down zone.

If you have passed the touch down zone markers and haven't gotten ypur greaser..you will probably raise hell if you continue.Abort landing and Go Around..eat your Ego out!

[737Jock]

http://www.faa.gov/regulations_polic...apter%2004.pdf

If, during the landing phase of flight, the aircraft is brought into ground effect with a constant AOA, the aircraft experiences an increase in CL and a reduction in the thrust required, and a “floating” effect may occur. Because of the reduced drag and power-off deceleration in ground effect, any excess speed at the point of flare may incur a considerable “float” distance. As the aircraft nears the point of touchdown, ground effect is most realized at altitudes less than the wingspan. During the final phases of the approach as the aircraft nears the ground, a reduced power setting is necessary or the reduced thrust required would allow the aircraft to climb above the desired glidepath (GP).

[Trackdiamond]

keeping the power during the flare on Airbus FBW

Guys..this is one of those long historic banters of course..lemme join in!
(Pitch +/- power)trim 〓performance..is widely understood.

The argument of what controls vertical speed and what controls forward speed depends on which flight phas we plan to be in..or happen to find ourselves in.

Straight and level..Power controls speed. Pitch controls Altitude(Vert speed)

Climb....Power controls Vert Speed. Pitch controls forward Speed.

Descent...Power(or lack there of) controls Vert speed...Pitch controls forward speed.

Approach Power controls forward speed pitch controls Vert speed(glide path)..however...if excess deviation occurs on glide..use power reduction(if above sope) or power increase(if below slope) appraching half FSD.When at or beyond half scale dev..consider Go Around.

Missed Approach; Pitch first and Power to TOGA setting.Arrest sink and inject further climbing energy.

Flare: Pitch...to arrest sink from that required to maintain Glideslope..and gently retard from the recommended power reduction Radio height..eg 20-10ft depending on weightyn wind etc...and that should give you if gentle with pitch demand rate and your distant vision should assist in gauging your bum sink rate...shoud settle you on terra forma with a subtle 200-300 fpm close to or just past the touch down zone.

If you have passed the touch down zone markers and haven't gotten ypur greaser..you will probably raise hell if you continue.Abort landing and Go Around..eat your Ego out!

[nitpicker330]

Noodle, what type do you fly exactly? Are you an FO? SO? Or heaven help us CN?

What's you experience?? Sounds to me like you must be a US Navy Top Gun test Pilot guru that knows the books inside and out by the holier than thou attitude you display.

Trackdiamond knows what he's talking about. I suppose I'm him too?

I'm only telling you the way I was taught to fly Jets 15,000 Jet hours ago in 1988. Since then I've managed more than a few approach and landings including ones in Typhoons at Kai Tak on the famous IGS ( you've heard of Kai Tak haven't you? )

Go on, I've waved my willy out.......how bigs yours? Put you experience levels on the table so we can all judge..

You too 737Jock....

[Capn Bloggs]

Thank you, Track Diamond.

Aerodynamics For Naval Aviators is just that. Modern airliners do not operate near the region of reversed command!

Jock, let me get this straight...

Originally Posted by 737jock

In a 737 or any other speedstable aircraft you can reduce thrust and the nose lowers simultaneously if it's too slow for you can push on the yoke and help it. This will increase your rate of descent while maintaining airspeed. As you approach the glideslope you simply add thrust which also raises the nose to reduce the rate of descent. You should not need to retrim the aircraft as it is still trimmed the same way as when you started the excercise.

Could you confirm that if you get fast whilst on the glideslope (for whatever reason-maybe a windshift), you will first pull the nose up to get back on speed and that this is what you would teach a newbe?

[737Jock]

Bloggs, aerodynamically speaking If I get fast on an approach a speedstable aircraft will reduce its vertical speed aerodynamically. Remember speedstable, I explained that a few times but maybe you check this link:http://www.faa.gov/regulations_polic...apter%2004.pdf . To increase the rate of descent I reduce thrust.
oh BTW even if you would not notice the decreasing vertical speed, you still approach the runway at a faster rate. so your path over the ground gets more shallow.

Sure thing nitpicker, flight instructing for about 500 hours, 737 about 2500 hrs, A320 about 3500 hours. A320 Command about 1500 hrs. I clocked up my hours quite a bit faster nitpicker.

[FullWings]

In a 737 or any other speedstable aircraft you can reduce thrust and the nose lowers simultaneously if it's too slow for you can push on the yoke and help it. This will increase your rate of descent while maintaining airspeed. As you approach the glideslope you simply add thrust which also raises the nose to reduce the rate of descent. You should not need to retrim the aircraft as it is still trimmed the same way as when you started the excercise.

This is true up to a point but you are relying on secondary effects rather than directly controlling pitch. That technique doesn't work so well on the 1-11/DC-9/CRJ, etc. or FBW aircraft that modify/remove the pitch/power couple.

In free flight, such as a climb or descent, allowing the aircraft to reach equilibrium by using pitch/power against trim works well. If you are constrained to a path, e.g. close to landing or needing to maintain a given altitude, controlling pitch directly through the elevator leads to a more stable profile and less of an excursion from the desired path.

[Capn Bloggs]

737Jock, I say again:

Could you confirm that if you get fast whilst on the glideslope (for whatever reason-maybe a windshift), you will first pull the nose up to get back on speed and that this is what you would teach a newbe?

A Yes/Yes, No/Yes, Yes/No or No/No will be fine thanks.

[737Jock]

I'm not going to answer a question that is more complex then you clearly understand with a yes or no answer.

I'm not talking to a newbie, I'm talking to an experienced pilot who should know his aerodynamics. I'm not joining you in your black and white world of ignorance.

As I said before, a speedstable aircraft will raise its nose aerodynamically after an increase in speed thus reducing its vertical speed. This happens in a phugoid movement that will find a new equilibrium at its original trimmed speed and reduced vertical speed. Reducing the thrust will increase the vertical speed.

You may remember the feeling of the aircraft ballooning when you hit an updraft. the speed itself might not even increase, did you ever consider that the speed increases because you stick to the path by pushing the nose down.

An experienced pilot controls thrust and pitch simultaneously! Simply because they interact with each other all the time.

[Trackdiamond]

thrust hold during flare on Airbus FBW

I posted earlier specifically for the Airbus FBW case but mods dropped it..wonder why? Here I am re posting the same.

With AT engaged 20ft Retard call is advisory(not command) to start retarding PL to idle.
The retard audio advisory repeats all the way to 5 ..and after repeated calls at 5 ft...it silences. That can be taken as an alarming silence(especialy when you have crossed the 3000ft..even on an average long runway.

Question is..is it SOP to disengage the Auto Thrust?

If on mnual Thrust and "keeping power ON"..what % Thrust are we looking at?Same as Approach thrust or reduced Aproach thrust?
(To cushion your perhaps alarming sink rate??)
In any case if you are FORCED to keep power ON something is not right and unless you have the luxury of a very long runway..beer do a Balked Landing and Go Around.

[737Jock]

Straight and level..Power controls speed. Pitch controls Altitude(Vert speed)

Yet as the speed increases the pitch is lowered, so they interact!

Climb....Power controls Vert Speed. Pitch controls forward Speed.

You could also argue that Power controls forward speed. if you reduce thrust while maintaining pitch the speed reduces. Then if you lower the pitch it controls the vertical speed as well as forward speed. Pitch and power interact!

Descent...Power(or lack there of) controls Vert speed...Pitch controls forward speed.

See above

Approach Power controls forward speed pitch controls Vert speed(glide path)..however...if excess deviation occurs on glide..use power reduction(if above sope) or power increase(if below slope) appraching half FSD.When at or beyond half scale dev..consider Go Around.

Increasing power adds energy to the airplane, the pitch determines if this is converted into speed/vertical speed/both. If power response is fast enough nothing might happen as the energy added counterbalances the upset that required the extra energy.
Likewise with decreasing power.

[Capn Bloggs]

Originally Posted by 737Jock

I'm not going to answer a question that is more complex then you clearly understand with a yes or no answer.

Rubbish. You won't answer because it'll prove your method doesn't work well. The answer is simple, so simple even a newbie can understand without all that scientific energy stuff.

You get fast, you pull the power back until you get on speed, then put the power up. You get high on slope, you put the nose down to get back on slope. If the speed changes (if only a smallish pitch correction, the speed probably won't change enough to worry about) you fix it with the throttles, just like the autopilot/autothrottles do it. Handfly an ILS and watch the throttles work.

Answer? Yes/Yes.

Simple!

You may have a few or many seconds to sit on the approach (off slope and/or off speed) waiting for the secondary effects of controls to fly your aeroplane but I don't. Pitch for glideslope and throttles for speed. Simple!

[nitpicker330]

Exactly, seems to me that any other way is too damn complicated.

KISS method.

Noodle or 737Jock haven't answered my question regarding:--
1/ Unreliable Airspeed checklist in the QRH containing Pitch and Thrust tables for Approach.

2/ Flying the BUSS on the Airbus is taught BY Airbus to hold a constant Pitch and Adjust Thrust to stay "in the green" ( correct AOA and therefore IAS for the Config )

[nitpicker330]

Still rummaging through the newly issued revised A330 FCTM and found these:--

( my bolding )

USE OF A/THR The pilot should use the A/THR for approaches as it provides accurate speed control The pilot will keep the hand on the thrust levers so as to be prepared to react if needed.

TRAJECTORY STABILIZATION The first prerequisite for safe final approach and landing is to stabilize the aircraft on the final approach flight path laterally and longitudinally, in landing configuration, at VAPP speed, i.e: • Only small corrections are necessary to rectify minor deviations from stabilized conditions • The thrust is stabilized, usually above idle, to maintain the target approach speed along the desired final approach path


FINAL APPROACH Roll out of the turn on the extended runway centreline and maintain VAPP. Thrust should be stable by 1 000 ft. Use the speed trend arrow to anticipate thrust changes and the FPV to monitor approach path deviations. Use available G/S and/or PAPIs as well as the visual picture to assist in maintaining a stable approach. A continuous visual/instrument scan is required to fly a successful approach. An effective scan will assist in highlighting small errors, allowing small, early corrections to be made. A 3 ° slope will normally be flown with a ROD of approximately 700 ft/min; a higher ROD is an indication that the aircraft is about to descend below the ideal approach path. A small correction of approx 1 ° of pitch will change the ROD by approximately 100 ft/min. Azimuth errors will require bank angle changes both to stop the drift and then to recover to the centreline. Avoid using bank angles greater than 10 ° for small corrections.