Not sure that the rate of attitude change for the flare has been mentioned but I feel this can be a significant factor. Generally I think it is better to start the flare relatively higher at a slower rate rather than flaring lower and then having to change the attitude at a higher rate (which can risk driving the main wheels in also - I wonder if this is what is causing the "firm" landings?).

I am not suggesting of course that the flare is initiated at anything other than what the FCTM suggests but generally it is better to have a few "bites of the cherry" and a slower rate of change of pitch means you have more room for manoeuvre and adjustment.

Ok maybe the landing was "firm" but assuming it was not a "heavy" landing what's wrong with that? Was the landing on or close to the TDZ, on the centreline etc - not sure what you mean by an "untidy" landing - can you be more specific?

landing
 

books help to understand how it works
with experience you land the way you want
just make it safe
i have around 18 000 h that is about 6000 landings
when i m tired i land hard
something else :my landings are better when crosswind than no wind
can someone explain

happy landings

50' call-wake up and prepare to do something.
20' call-close eyes and do something.
Quality of resulting landing is entirely dependant on side off hair parting but is just as consistent as all the above

AirRabbit, no one is trying to insult anyone here. Bit direct at times but just healthy banter.

You have still not addressed my observation about your definition of the straight and level attitude. In your first post you said.

If you select that attitude it is too high. Why ?

Remember Boeing ask you to flare 2-3 degrees from your approach attitude.

Take a calm day. 3 degree glide at a constant Vref +5, constant power and landing config. Now we raise the nose 3 degrees (max Boeing recommend) in order to flare and we will have selected the straight and level attitude for that config at Vref +5. However in reality we know the speed will have decreased in the flare so our nose attitude will in reality be too low for straight and level if we only raise it 3 degrees. Boeing assume Vref at the end of the flare so we have lost 5kts of speed which Boeing equates to 1 degree of nose attitude. So if we want the straight and level attitude at the speed at the completion of the flare, as you recommend, we will have to raise the nose by another degree. That will mean we will have raised the nose 4 degrees overall, from the approach attitude, which is too much.
Why is this significant.

a. its nice to get it correct

b. tailstrike. In a 800 the tail bangs at just over 9 degrees oleos extended. Boeing assume a landing attitude of anywhere between 4 and 7 degrees depending on weight, flare etc. So if you flare 4 degrees you may have just over a degree of grace or put another way just over 5kts of grace. Not so much then.

I would appreciate it if you could address this concern over your definition of the attitude.

Cheers

Well, if it is a crosswind, it's probably gusty. You carry more speed in that situation, which gives you more energy to flatten out your touchdown. That's my guess anyway.

ashling,

enjoying reading this thread but with the greatest respect, it wasn't healthy banter and it was disrespectful.

given your absolute convictions in your ability and knowledge would it be fair to ask you what your experience level is and what, if any, instructional roles you've held? rabbit has shared his.

having flown the 737-3/4/5 i always was of the opinion that landing the 737 was a flexible feast! haven't flown the -800 but that as you say i have no doubt that that the boeing method works every time. just lacks a little finesse occasionally! like you i totally agree that on the dark wet windy nights impact in the right place is the single most important thing. the are other times when i' might have used up 500ft to grease it on, bad me.

as for the original post. i for one have found on the 2 boeings i've flown that copying the a/p a/land was a good place to start when trying to get my eye in whilst in the sim.

cheers,

thh

FFS
 

Some of you lot need to get out and fly a few airplanes a bit more . Never heard so much theoretical claptrap in my life.

To think the uk openly discriminates against good honest bush pilots over cadets belies reason. Its plain to see the outcome of such a policy. Its called this thread. A good pilot doesnt need these theories , just a cou[le of goes in the new type and they are sorted.

Hi Ashling:

Sorry, I didn’t realize you thought that I hadn’t answered your question. I was attempting to do just that in an earlier post … but let me repeat it here. Level flight attitude with landing flaps and a speed between 1.1 and 1.2 times the stall speed in that configuration (the landing configuration) should be between 3 and 6 degrees of nose up pitch. One of the commenters on this thread, chksix, had posted a link to a page copied from a B737NG manual. Here’s the link (thanks again, chksix)
http://img390.imageshack.us/my.php?image=landqq1.jpg
That link clearly shows the B737NG on the ground with the nose at “4 to 6 degrees” of nose up pitch.

What I am advocating is that when you fly the approach, you get to the point where you have determined you should initiate the flare (and chksix’s link shows that the speed up to flare initiation should be Vref+5), initiate the flare to the level flight attitude (which I’m saying – depending on gross weight – will be between 3 and 6 degrees nose up attitude) and that should scrub off some of the airspeed – particularly if you’re the type to start gradually reducing thrust as you initiate the flare (but that’s more of a technique and I really don’t care about that – well, of course, I’d care, but it’s not a huge thing), and that should leave you about 1.1 to 1.2 times the stall speed in that configuration (1.3 times Vstall is Vref). So there should be no time that you should flare the airplane to anything above about 6 degrees nose up pitch. Even with, as you say, the B737-800 risking a tail strike at something just over 9 degrees of nose up pitch – you should be quite comfortably safe from such an occurrence at 6 degrees or less. When you are next in the simulator you should really try to see what it would take to get a tail strike. Try a full stall landing and see if you can put the tail on the runway before the MLG. This is the advantage of a properly built, programmed, and tested flight simulator. You might be surprised.

Perhaps I should make this more clear as well. Lets assume that 5 degrees nose up pitch and 1.2Vs is what would be necessary to maintain level flight. This means that if you added power and held both that attitude and airspeed, you would fly down the runway without climbing, descending, accelerating, or decelerating. However, you are not going to be adding power … your airspeed will continue to decrease even though you are in the level flight attitude for the speed reached at the end of the flare. If you initiated the flare at 15 – 20 feet and took between 1.5 and 3.0 seconds to flare (and 3.0 seconds is a very long time to flare … but …) you would likely be something like 5 feet above the runway. Because you are descending (while you have a level flight attitude, you don’t have the airspeed to maintain level flight) and because you are decelerating (you’ve put the airplane in an attitude where it cannot maintain the airspeed without additional power – in fact you may have already started to reduce the power – although that isn’t absolutely necessary yet), you are going to continue to “go down” (although at a slower rate, because you are now at that “level flight attitude”) and you will continue to “slow down.” The idea is to have the throttles at flight idle at (or just prior to or just after) MLG touchdown. The most you will have the nose in the air would be 6 degrees at touchdown, giving you adequate airflow over the rudder to maintain directional control until you fly the nose to the ground and can control that with rudder pedal steering. What’s more, since you are going to be getting slower in this attitude (which is what is wanted) and getting lower (which is also what is wanted) the airplane will want to “nose-over.” Additional back-stick pressure will be needed to keep the nose at the desired attitude – not raise it, just maintain it.

The height above the runway you are at the end of the flare and the time it takes you to close that distance will give you the rate of descent at touchdown. Like I said earlier, probably somewhere between 100 and 600 fpm. Obviously 600 is something a little more firm than “firm,” and 100 is a little light – for most, that is, although that is still some distance away from a round of applause from First Class. What is nice is that you have considerable control over that rate of descent because of the attitude in which you have the airplane. How? Merely “goosing” the throttles (sorry, American term, meaning stabbing the throttles forward and then back almost immediately) will temporarily reduce your rate of descent without you having to do anything with the pitch, which, of course, you are just maintaining. Not screwing around with the pitch attitude is a desirable practice at such close distances to the runway surface. And, this is why it is not necessarily advisable to have the throttles in flight idle too quickly – it might take the engines a small bit longer to spool up from flight idle if a “goose” is needed.

In another life I flew the B737-100 and soon after went on to the 737-200. My check captain (instructor pilot was the parlance in those halycon days) was the original Boeing Seattle pilot who signed off the first Flight Crew Training Manual. His name was Joe Zizovsky who was a US Navy ordance rating during the Battle for Guadacanal. He advised me that the very moment the flare for landing was commenced, the thrust levers must be sharply closed against the stops. He wanted to hear the sound of metal hitting metal with those thrust levers. There was to be no smoothly reducing power - it was whack bang against the stops. The reason (he explained) was that it takes time for the thrust to bleed down after thrust lever closure, and the last thing you want on a landing is superfluous thrust associated with a nicy easy ever so gently pulling back of the thrust levers in an attempt to grease it on. Maybe so in a turbo-prop - but no way in the 737.
Keep in mind that Boeing assume the landing technique is based on a performance limiting runway length - not a 8000 ft highway.
The slow thrust lever closure favoured by many pilots often ensures touch down is further in than ideal and often with the thrust levers still not closed on wheel impact. Not good technique in my book - nor Boeing's if I hazard a guess.

AirRabbit

Look at your quote on the definition of the attitude from your original post.

That is what I want you to address.

It is wrong as I have demonstrated.

If there is an error in my demonstration please point it out.

It is because you gave the wrong attitude and then hung so much on it that I have chased it. If that attitude is wrong so is the rest.

By the way the diagram he gave you is incorrect, not in current manual, its 2-4 degrees on approach 4-7 degrees after flare. Current Boeing FCTM. You said you had access to that.

That's interesting Centaurus.

I have the greatest of respect for someone such as Mr Zizovski, I really do.

I'm just trying to imagine what difference whacking the thrust levers closed makes compared to taking one or two seconds to close the thrust levers to idle and allowing them to gently rest against the stops.

As far as time verses engine thrust is concerned, I see no difference.
As far as freaking out the pilot next to you, I see a difference.

Some points worth considering.

1. If I start reducing thrust at the same time as Mr Zizovski, but take 2 seconds longer to reach the idle stops, at the very worst, all you could say is that I am adding 2 seconds worth of energy to the aircraft. Compare this to the total amount of kinetic energy 60 tons of metal has at 130 kt and you will find that it is insignificant.

But even this is not true. You are not adding two seconds of thrust because the majority of the thrust is reduced at the same time. Remembering that Thrust vs % N1 is not linear but more parabolic. i.e. reducing N1 from 60% to 42% reduces the thrust by half. Reducing from 60% to 30% reduces it to a quarter of what it was.

2. What is the absolute minimum time it takes the engines to reduce from approach thrust to flight idle? (60% to 25% N1) Three seconds? (that would be an absolute minimum I reckon).

If so how does taking three seconds to bring the thrust levers to idle make any difference to the rate of engine thrust reduction? In other words I am moving the thrust levers as fast as the engines can react, moving them any faster would make no difference to what the engines do.

Same thing if I am increasing thrust. If the thrust levers are at idle and I want go-around thrust, if the engines take 5 seconds to spool up, it doesn't matter if I take 1 second or 3 seconds to move the thrust levers to the fwd stops, it will still take 5 seconds for the engines to spool up.

3. How long does the auto-throttle take to close the thrust levers during an autoland? My guess is somewhere around five seconds.

May I throw a cat amongst the pigeons??

Jacobson Flare. ;)

There have been numerous discussions about that one.
(Yes I do think it works well.)

Hi Ashling:
I guess you and I are just failing to communicate. I have gone back and re-read my original post, with particular scrutiny directed to how I used the term “attitude.” I’ll quote below the way I defined “level flight attitude,” the areas with which I think you had an “issue.” Here is what I said in my original post:
…and here is what I said later on in that same posting…
I don’t see any change from my original reference to “attitude” in any of my subsequent references to that term. As I read your concerns, in your rebuttal post you said, and, again, I’ll quote…
Because of what you said in your 6th sentence (“Irrespective of the runway available if you keep raising the nose to prevent the aircraft descending you will bang the tail before you stall on.”), I was of the opinion that you misunderstood what I had said. Please note, nowhere have I said that once achieving the “level flight attitude” (the “landing attitude”) the pilot was to continue to raise the pitch attitude; and, in fact, I have determinedly said that the pilot was to maintain that level flight attitude (the “landing attitude”) through the touchdown.

In my attempt to clarify this position further, I have said that the “level flight attitude” (the “landing attitude”) I was describing would only maintain level flight if power were added to maintain that airspeed … which, of course, you would not do. The only other way to maintain level flight at that time would be to increase the pitch attitude … and that is what I have said should not be done.

I am sorry, Ashling. I just don’t see where you have, as you say, “demonstrated” that my description is “wrong.” You say that that diagram that chksix provided is wrong. You also said that I had indicated that I had access to that manual. Well, I checked, and I no longer have the manual I thought I still had – my excuse is that if I kept all the manuals I once had I’d need a larger place to live. Sorry. But my comment stands as stated. I DO read and comply with the FCTM and FCOM for any airplane I fly – and I was responding to what I thought was your allegation that I had not done so. As for that diagram being in error – it seems to be correct from my memory – and, with respect, you’d have to take up that accusation with chksix. However, I’m quite sure that he copied that page from an “NG” manual since I’m reasonably sure that he didn’t make it up himself.

You say that I “gave the wrong attitude” in my postings and then “hung so much on it” that you’ve chased the error. I’m not sure what attitude you’re referencing. The only “attitude” I’ve described is the attitude that would produce level flight for the airplane in the existing configuration, gross weight, and airspeed reached at the end of the flare. That attitude is the attitude from which the landing should be made – the landing attitude. I have also provided 2 separate approximations – one for a speed range and one for a pitch range – depending on gross weight. The speed range, again, is 1.1 to 1.2 times Vstall, where Vref is 1.3 times Vstall. The pitch range, again, is 3 to 6 degrees of pitch. The attitude I’m describing (the “level flight attitude,” the “landing attitude”) is the attitude that would provide level flight, presuming one had sufficient power to maintain the 1.1 to 1.2 times Vstall airspeed (the airspeed reached at the end of the flare) while at a constant pitch attitude of between 3 and 6 degrees, depending on the existing gross weight. Perhaps we would do well to recall that we’re discussing an airplane with full landing flaps operating within ground effect.

One last thing, regarding my tendency to provide very long replies to what some think are easy, direct, simple questions. In my view, there are 3 types of instructors: The perfect one, who provides the perfect amount of information in a perfect way; the one who provides not quite enough information for the pilot to understand what is going on; and the one who provides more information than is necessary for the pilot to understand what is going on. I recognized, quite a long time ago that I am far from perfect. In that I am not perfect, and know it, I’ll let you guess as to which of the other 2 possibilities I would rather plead guilty.

Hi. I edited my post with the schematic above but I'll clarify here that I took screenshots from a 737 manual with the following info:
http://img209.imageshack.us/img209/4554/afmqa2.jpg
It's outdated so not to be used in real flight etc......:}
I need it for performance tuning of one of the xplane versions of the 737 NG.

I quite agree with Centaurus that the landing process should be adequate for all runways – with the particular emphasis placed on those that are more performance limiting… and I certainly wouldn’t want to stand toe-to-toe in a flying technique argument with the likes of Joe Zizovsky! For performance limited runways, I think I understand completely his preference for maintaining Vref+5 knots to the initiation of the flare – particularly were he describing initiating the flare at 10 to 15 feet above the runway with the “aiming” point on the runway something short of the 1000-foot fixed distance markers (FDM). In that particular instance, I would presume Mr. Zizovsky would not appreciate taking 3 seconds to reach the flare attitude (what I’m calling the level flight attitude). In fact, I would suspect his preference would be more in the neighborhood of 0.5 to 1.0 second flare and something similar from flare to touchdown. Sawing the power levers to idle – “whack bang” – with the initiation of that 0.5 to 1.0 second flare, would be perfectly appropriate when landing on a performance limited runway. Such an abrupt change of attitude and change in power, would allow the airspeed to bleed down more quickly; initiating the flare closer to the runway would cause you to reach the landing attitude closer to the runway; and with the aim point short of the FDM, the process would likely result in placing the MLG tires ON the 1000-foot FDM, at the appropriate attitude and airspeed. After all, THAT is what the B737 was originally designed to do – be able to get into and out of airport runways that simply would be inadequate for the B727 and B720 aircraft. However, relaxing this particular method of approach and landing just slightly would be perfectly acceptable, and appropriate, when the runway isn’t so performance limited.

Air Rabbit

Read my post, numbered 95, that is were I deomstrate why the attitude as you define it is incorrect.

Boeing clearly ask you to flare 2-3 degrees based on the APPROACH attitude and speed. As speed bleeds in a flare you will not achieve a straight and level attitude, even momentarily, even if you flare the full 3 degrees. So Boeing clearly do not intend you to select any kind of straight and level attitude. To suppose they do is an simply incorrect and a misrepresentation of what is in the FCTM.

Like you I do not claim to be perfect, I have done a great deal of instructing and taught instructors their trade. I very much like simple repeatable techniques that the individual can use as a framework to develop from.

My view is that in this case you are both technicaly and conceptualy in error.

Technicaly because if you flare to a straight and level attitude based on the speed after the flare you must change the nose attitude by more than the recommended 3 degrees.

Conceptualy because you are overcomplicating things by a margin in my view.

Sorry but unless you, or someone else, can correct my demo in post 95 then that is my view.

My stars. You guys are all out of you minds. Way way to complicated. Just get the bird close to the ground, cut the power, check the descent rate a little and let it settle onto the ground. The more you do the better you will get at it. It is that simple. Some things cannot be explained, they have to be practiced.

7

Airbus 757: AMEN!!
As long as he impacts in the touchdown zone on the center line and the o2 mask dont drop. good job.:D
WD

C´mon guys! It´s only a bloody aircraft, not rocket science:rolleyes: Practise makes perfect, it´s tricky in the begining, but hey, it does´nt take a doctors diploma to land... GL

Cheers:ok:

OK Ashling. Please feel welcome to disregard everything I've said. As I've said repeatedly, everyone is free to fly and train in anyway they, their company, and their regulator say is OK. I wish you well and hope that you stay safe.

Uh ... for what its worth, I wasn't able to identify your post #95, as you suggested. I think this post will be #60 in this thread.

Cheers.

airbus757

I know of good people who's airline career was ruined (promotion training terminated or self funded jet endorsement failed) because for whatever reason they just couldn't make it happen in the last 50 ft.

They were otherwise smart and co-ordinated people. All they needed was some guidance or framework to work off while they got the experience you talk about.

It might be difficult for someone like you or I to understand what the real problem is, but then in my case I have had my own landing framework since I was flying C-152's. It's called the Jacobson Flare. There have been numerous discussions about it here in PPRuNe.

Here's the last one: http://www.pprune.org/forums/showthread.php?t=280481

Obviously there is a need for guidance in this area:

It's this sort of advice that simply isn't helpful. I mean don't you think they've landed an aeroplane before? They were probably flying Barons or C 310's in their previous jobs.

I think one of the problems people have is that below about 100 ft they don't have the confidence to continue driving the aircraft down the 3 degree path to the aiming point because they can't identify with any certainty when to give up that aiming point and concentrate on the next one, which is the centre of the far end of the runway.

The Jacobson Flare determines that point and gives you the confidence. This change in aiming point does not rely on the "look" of the picture outside, and therefore not influenced by such things as runway width, or slope, or flap setting. I won't go through it all again here. Anyone interested should simply do their own search both here on PPRuNe and else where. Or PM me for information I can send via email.


Jacobson would beg to differ.

PS It's comments like those made by Whaledog and paperdragon that can destroy a pilot's confidence. They are simply left thinking to themselves "I'm #$%^ hopeless." "There must be something wrong with me". If I can't do this now I will never be able to".

It doesn't have to be that way.

Hi AirRabbit

My mistake, try post #45

Ooooh! I hate that word IMPACT.....could we use something a little more politically correct - like GREASE It:ok:

You boys should try landing a Dash 8 Q400 consistently! Its a dog too land!! Good luck in your efforts people!!

Speaking as an FO I can tell you that if you have done nothing by 20 - 30ft the captain will start getting worried! Especially if he/she hasn’t flown with you before!

OK Ashling … I was about to let this go as it appears that for you (and at least several others here) I am wasting my time and yours trying to describe what I’ve been saying; but, ...:ugh: Here’s what you said in your post, #45:
I’ll take your comments from your quoting of my statement: “It is whatever attitude that is the “level flight” attitude for that airplane, in that configuration, and at that airspeed. What airspeed? The airspeed you have upon completing the flare.”

You say “that attitude it is too high,” and then provide the example. A calm day on a 3-degree glide slope, at a constant Vref+5 knots. What information you do not provide is the pitch attitude originally necessary to maintain that situation. As I am sure you are aware, maintaining a 3-degree glide slope does not mean an airplane pitch attitude of 3 degrees. Also, as I’m sure you’re aware, flight inside ground effect is not quite the same as flight outside of ground effect. For example, if you were able to trim the airplane to maintain the glide slope exactly centered and didn’t touch the controls or the power you would see the airplane “flare” itself to some degree upon entering and descending through ground effect. It will not be enough to make a nice landing but it will change the flight path angle at which the airplane will hit the ground. Level flight attitude inside and outside of ground effect are not necessarily the same – and more often than not, “inside” requires less than “outside.”

You say “now we raise the nose 3 degrees in order to flare and we will have selected the straight and level attitude for that configuration at Vref +5.” What is it that makes you believe that if you added 3 degrees to the pitch you were holding on final you would arrive at the level flight attitude for that gross weight, airplane configuration, and a speed of Vref+5 knots? Does Boeing say that? Is that supposed to be a level flight attitude inside of or outside of ground effect? What pitch were you holding on final?

Without trying to sound terribly offensive or critical, might I suggest that the next time you are on final you check the attitude as you describe it? With landing flaps; moderate gross weight; centered on, trimmed for, and maintaining a 3-degree glide slope; calm day; and at Vref+5 knots … I’ll say that you’ll be between 1.5 and 2.5 degrees of pitch during final. Recall that in one of my earlier posts, I said that with landing flaps, moderate gross weight, initiating the flare at 15 feet above the runway with the airspeed still at Vref+5 knots, depending on when you start throttle reduction and the speed with which you make that reduction, if you bring the nose of the airplane up to what would hold level flight, you would be between 1.1 and 1.2 times Vstall and depending on how aggressive you were with the flare you would likely be between 3 and 10 feet above the runway. At moderate gross weights you would likely be between 4 and 5 degrees of pitch to hold level flight at those airspeeds. Of course, without adding power or increasing pitch you will not be able to maintain level flight – you will descend. If you were somewhat lighter, you probably would be closer to 4 degrees … heavier, and you would be closer to 6 degrees of pitch - maybe up to 7 degrees if very heavy, but I would think that would be very unusual – and anything above that, personally, I’d just accept the harder touchdown. If you HOLD that level flight attitude – do not raise the attitude, do not let the nose fall – all the way to touchdown – there is very little chance of you striking the tail and you will have adequate airflow across the vertical stabilizer/rudder to maintain directional control.

You have a lot of control of the descent rate … with both elevator and power controls … and, if you’re only 3 to 5 feet above the runway the use of power will not terribly affect (negatively) the amount of runway you use. My preference is to use power, leaving the pitch at the attitude I’ve selected, primarily because screwing around with pitch attitude that close to the runway is the best way to make something worse out of whatever you have.

One main difference between what you advocate and what I’m advocating is that the amount of pitch added to whatever attitude you had during final is going to be different for each pitch attitude flown on final (affected by whether or not there is a crosswind, tailwind, or headwind). I am advocating level flight attitude at the end of the flare – regardless of what you were doing on final approach. What I’m advocating is not a mechanical response to a set of circumstances. What I’m advocating will require some practice while understanding what is being practiced. This is because the pilot has to learn to recognize when the airplane is in an attitude from which level flight can be achieved with very little added thrust - the definition of "level flight attitude."

What I’m advocating, at least I believe, will provide you better control of the airplane between the end of the flare and having all three wheels on the runway – and will do so whether you’re dealing with wet, snow covered, or dry runways and whether you’re dealing with headwind, tailwind, or crosswind. I also believe it will give you better control of the airplane if you have to recover from a bounced landing, and it will give you better control if you elect to go around. Why? You will not have to worry about what pitch attitude to hold. You will already have achieved it and will have practiced maintaining it.

As I suggested earlier … don’t take my word for it. Give it a try the next time you’re in the simulator. Deliberately see if you can land the airplane on the tail and see what attitude it takes and how far beyond level flight it really is. Try flying down the length of the runway at a constant airspeed of 1.1 to 1.2 Vstall at a constant altitude of 3 to 5 feet. Try doing it with tailwinds and crosswinds – and make sure they’re pretty stiff crosswinds. Land out of each. Go around from each. Try to bounce the landing. Try it. Don’t take my word for it.

Blip

Have you read the last post? It is ridiculous to think that all that information is going to help some Pilot who is in training and trying to get used to a new airplane. I am not disputing what it is saying, I am disputing the idea that it will help someone who is learning to land a new type. You mention people have failed because of the last 50ft before touchdown. I say if things were kept simple they would have a better chance of passing, after all they are allready pilots. People just need some simple tips, practice, and confidence.

All this complicated and theroetical talk is fine, but it my opinion it should be meant to help fine tune someone who aready has experience's technique. It will not help someone who is still trying to pick out where the N1 indicator is.

7

AirRabbit

Thanks at last for answering my query, it took a while so maybe I didn't ask clearly enough.

I just said maintaining a 3 degree glide I did not define the attitude needed to maintain that glide. The point was to show you would need to raise the nose more than 3 degrees to maintain level if the speed decreased as it does in a flare. If you lower the nose three degrees from a level attitude you will follow a 3 degree slope provided you maintain your speed. If we make it specific to a 737 then the attitude will be anywhere from 2.5 to 3.5 at Vref +5, thats my guess as the QRH figures apply to Vref +10.

Look at the velocity vector when you are level, it will sit at 0 degrees irrespective of the actual nose attitude. Now, maintaining your speed, lower your attitude 3 degrees from that level attitude and you will see the velocity vector sit on 3 degrees nose down, you are now on a 3 degree glide, very usefull for non precision approach's. Raise the nose 3 degrees maintaining the speed and you'll be back at level. If the speed reduces, as it would in a flare, you will have to raise your nose more.

How much will ground effect alter that, to be honest I don't know and it will vary depending on a number of the factors you mention but then I guess you don't really know the answer to that either and lots of other factors will play their part, thermals, wind etc which is why you have to keep flying all the way down. Its also why your level attitude will be different each time and therefore not repeatable. My thought was to take the unquantifiable out of the equation with my example. My view would be that unless you flare early, too much, don't close your thrust levers or are hot the effect will be minimal at best and certainly not compensate for the speed lost in the flare. But as I say I don't really know how big an effect it has in terms of altering your attitude.

Certainly mentioning ground effect has helped me understand your point of view on this and perhaps why you feel you don't actually have to raise the nose as much as you otherwise would to achieve a straight and level attitude. So thanks for that. Did you mention it earlier or were you just assuming it as I can't recall reading it in your posts ?

Still don't like it though I'm afraid.

Take care, safe flying and happy landings.

Well Ashling – I think we’ve broken the ice here. When you mentioned “velocity vectors,” I understood that you’re describing flying with an operational HUD system – at least some of the time. I don’t know the specific system you use, but I’ll bet it has a “flare cue,” and when you follow it, by placing the flight path vector in proper relation to that cue, it will put you on the runway pretty nicely all the time. I believe it will also give you a different flare attitude for differing weight conditions; but I also believe that if you follow it, it will initially take you a level flight attitude for a specific airspeed. However, because your airspeed will be decaying, you won’t fly at a level height above the runway, even though you keep the FPV in the proper reference to the flare cue. I also suspect that the flare cue will have you keep your pitch attitude constant through to the touchdown.

Again, I’m not sure how your HUD system works – you describe a velocity vector – I’m going out on a limb here, but I think I would call that the flight path vector … where the airplane is actually heading. It is not the “boresight” (the nose of the aircraft), but actually where the airplane is headed – the vector of the airplane’s flight path at that moment. If you put the FPV on the horizon, you’ll be flying level with the horizon (or level). If you place that FPV at 3 degrees down, you’ll be flying a path that is 3 degrees below level – but you’ll be doing that at whatever airspeed you have – and you can increase or decrease the airspeed, keeping the FPV on that 3 degree reference and you’ll still be flying a flight path that is 3 degrees below level – and you’ll be changing your rate of descent as you change your airspeed.

Your statement …
…is accurate, but you are descending on an angle that is 3 degrees below “level” – and while you say you should “maintain your airspeed,” I think it is true that you will be on a 3 degree angle regardless of your airspeed; resulting in varying rates of descent depending on that airspeed. A 3-degree ILS glide slope is a hard 3 degree angle – irrespective of speed flown on that angle. You can come down that angular glide path at any airspeed you choose, but your rate of descent will be different as you adjust your airspeed; shallower at slower speeds, and steeper at higher airspeeds all while maintaining that 3-degree glide slope.

Additionally, I would suspect that if you pay attention to where that flare cue is directing the FPV, and associate that with what the airplane “feels” like each time you do that, regardless of the aircraft gross weight, you will become quite adept at being able to “feel” that same thing at differing weights on your own. Being able to “feel” that level flight attitude is what I’m describing. THAT attitude that the flare cue initially takes you to is the level flight attitude I am describing. You won’t fly level because your airspeed is decreasing. But you hold that attitude anyway. Using a HUD system is probably the very best aid in helping pilots learn this. Of course, if you use the HUD all the time, and it never fails, you won’t ever have to depend on anything other than following the flare cue. But … show me something that never changes and never breaks and always works correctly.

Try something … the next time you’re in the simulator (as I don’t recommend doing this in the airplane, ha) …as you approach to land, using the HUD, follow the flare cue to the attitude it directs – but just a scant whisper before you get to that flare attitude, engage the autothrottles (or advance the power slightly) to maintain THAT airspeed. See what happens at that airspeed and at that “flare attitude.” I don’t know what the flare cue will do – increase, decrease, go away – I don’t know … but maintain the FPV at the attitude the flare cue directed you to achieve initially – and maintain that attitude and airspeed. I’d be curious to know what happens to the airplane … Climb? Descend? Fly level?

Ashling, my friend, I also hope your days are uneventful, full of sunshine, and nothing more than calm winds.


I recognize that some here are way too over-taxed to learn to do this. Fine. Don’t attempt it. Different instructors attempt to do different things with their students. I know what I do with mine … please feel free to do what you, your company, and your regulatory authority deem to be appropriate with yours. Aside from the fact that I’m confused about trying to teach someone about landing when they can’t find the N1 indicator, my question would be, is there any appropriate time to provide a “new” student with an understanding of what is going on in the airplane – or do we let him or her pick that up individually, by themselves? Forgive me, I was taught that flying isn’t necessarily supposed to be “easy.” I’m not interested in simply getting the pilot to “pass” the check. I want to make sure that when that student heads to the airplane, we’ve given him, or her, the very best opportunity to understand how the airplane performs and handles. It’s complicated and demanding. Of course anyone may argue with me (many do, in fact) but I believe that the more a student understands about the “why” and “how,” the better he or she will be able to handle the “what” and “when.”

AirRabbit
Your right, I think Boeing call it a Flight Path Vector (FPV), Velocity Vector came from my whizz jet days. As you say if you hold the FPV on 3 degree down you will follow a 3 degree glide irrespective of speed its just that to do that you will have to alter the nose attitude as the speed alters. Thats one reason its so usefull on non precision approach's. I was just using constant speed to simplify things.

Sadly no HUD, though the FPV is displayed head down on the PFD if you select it on the EFIS control. Otherwise its just the datum locked to the aircrafts nose position relative to the horizon. Shame as I'd love to have a HUD.

As I said last post at least I understand better were your coming from. Although I think its too complicated for normal training (I see no reason to express the basic technique differently from the FCTM) remedial flying is a different thing and then it may indeed become worthwhile trying a few different things in order to unlock the key and help the student progress. Always assuming you've tried the obvious fix's first. Provided your still teaching the same technique, albeit expressed differently, there is no reason not to if it might help someone. In fact its your job as an instructor to do just that.

I might even try it in the sim one day for a giggle but I wouldn't hold your breath ;)

Anyway I'll bow out for now, I'm glad we seem to have reached some kind of mutual understanding if not agreement and the discussion has made me think which can only be good. Sadly in the UK days full of sun and calm winds are rather rare but I appreciate the sentiment.

Good luck to you, if you put in the same effort with your students as you have done with your posts I am sure they will appreciate and benefit from your instruction.

P.S. No ground effect at Malaga today, thankfully a burst of power sorted things nicely. Guess I lack finesse.

Flying B737-800. Maintain 3 degree slope. Where you look you land! Wait until 10' then check back so nose raises 2-3 degrees and close the thrust levers. Don't get slow.
Another guy I used to know (very experienced on -800s) used to close the thrust levers and flare about 15' then used to check forward slightly so the mains touched more gently.
More than one way to skin a cat!

That would give the captain a heart attack!!!!

Quite an interesting thread to us NG operators and a lot of the comments and tips have been of value to us all I'm sure.

Just a personal observation, but I find that the "mechanics" of the flare technique remain similar whether it's a flaps30/40 landing. When winglets are thrown into the equation it mixes things up further still!!

But the ball park figure of flare once the 20 call has left your ears is what I apply whatever the flap setting or whether I'm flying with winglets or not.

What I vary, sometimes to a large degree, particularly in differing weather, is the point at which I start reducing power. Flaps 30 in a winglet aircraft with an element of tailwind means I'm reducing the power substantially earlier than I would when landing flap 40, non winglets with a 10 kt headwind!!

That's OK TolTol I don't usually fly with Captains.

Ashling - thanks for the comments.

No worries ... I won't hold my breath ... but I would be interested in what you find to giggle over!

Stay safe my friend!

Interesting comment Bonernow ... not having had the pleasure of attempting to slip the surly bonds with a machine having winglets, do I understand that those additions make the airplane a bit more slippery and want to keep airspeed longer?

A B73-800 is a longer aeroplane than a B73-700. They have slightly different flare techniques. The B737 can be flared slightly stonger but if you do the same with the B738 it'll be a firmer landing. Either way, the important thing is not to let the nose drop when you close the thrust levers; maintain the attitude you adopted at the entrance to the flare. The other important item, especially on the B738, is not to make a double flare. That will just increase the ROD of the gear and be even firmer.
At the beginning, the advice I read in earlier posts of starting to do things gently after 30' is sound. I'm assuming that in the early days you'll be landing on the longer runways in your network. As experince builds confidence and judgement you'll find that you will delay things by 10' or so. Try to be too chique in the beginning can be a real confidence and runway denter.

Air Rabbit,

From my own personal experience, it took some "adjustment" to the landing technique when our fleet was retro fitted with winglets. Get the flare just right and everything was great. But a little too much aggression in the flare, flaps 30 with a slight tail wind element and weight in the region of 55 tons meant you were eating up a hell of a lot of runway (Two guys got caught out on short fields and had to go around as a result).

There was a lot of discussion in the crew room on how best to adjust the technique as the FCTM doesn't stipulate a technique that differentiates between winglet and non winglet aircraft.

But it is fair to say that the winglets do add a significant amount of efficiency to the wing and (early) adjustments in power settings dependant upon your weight, flap setting and landing distance available can prove prudent.

Safe Landings!