landing technique B737NG [Archive]

AirRabbit

26th Aug 2007, 17:52

I'll go ahead and apologize for the length of this before I write it ... this is simply an attempt to do justice to this particular question.

I know, and I recognize, that “landing an airplane” is everyone’s point of pride – and everyone has their own technique for getting to that point. So, without trying to step on anyone’s technique (or their pride) I thought I’d offer my version of 2 cents (or pence) on the things that pretty much have to go right as a result of whatever technique is applied.

Almost everyone knows about and understands the term, “flare,” when talking about landing an airplane. However, not everyone understands this term in the same way. Basically, the flare is pulling back on the elevator controls to raise the nose (increase the pitch attitude) to “break” or “reduce” the rate of descent prior to touchdown. But, where is that you want the nose to go? Can you put it anywhere? No, certainly not. Well, if that’s true, then you want it to go to some specific spot. What is that spot? 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. What height above the runway should you be at the completion of the flare? Well, the closer to the runway the better, as long as you don’t drive it into the runway before completing the flare. Most people believe that something between 2 and 5 feet above the surface is a good target to shoot for at the end of the flare, just to help ensure that you don’t land before you are ready to land.

By deflecting the elevator and rotating the airplane to the flare attitude, kinetic energy is dissipated – the airplane slows down – in fact, it slows so much that the “level flight attitude” will not keep the airplane in level flight; it WILL descend – unless you increase the attitude to something higher OR you add power. The fact is that if you flared to the level flight attitude and left the power alone (i.e., kept what you had to maintain airspeed on final), the airplane would descend – just not as fast and you’d be much farther down the runway by the time you actually touched down – but you WOULD touch down. If you pushed the power up a bit, you could maintain that level flight attitude AND airspeed and fly at that altitude and airspeed. If you pulled the power OFF, you would descend a bit more quickly than you would without the power reduction, but at a significantly less rate than what you had on final – and this is precisely what you’re trying to do – descend the airplane at a rate that will allow a firm but satisfactory touchdown.

An aside: why you might need or want to I wouldn’t know, and I would never recommend doing this in a transport category airplane, but if you had the runway necessary, you could keep the nose attitude coming up to keep the airplane from descending (because you would need a higher and higher angle of attack to compensate for the slower and slower forward speed) until you get to that point where the wing would stall. If you did this correctly you would have landed the airplane with the least amount of forward velocity. Of course your nose position would be really high and you very well may not have enough forward velocity to keep the elevator effective, and, as a result, the nose would likely fall.

So, as I said, you have to pull back on the elevator control to arrest your rate of descent – the flare. OK. You pull back on the controls to raise the nose to the level flight attitude. THIS is the attitude in which you want to touch down. However, from this point the airplane is going to slow – and more so as you pull the throttle(s) to idle. This will cause the airplane to want to pitch down. Why? Because you would have had the airplane trimmed for the final approach – configuration, airspeed, power, and rate of descent. You’ve now changed this. You now are at the level flight attitude and probably beginning to reduce power (if you haven’t started already). The airplane will want to pitch down, but you must not let it. To keep the airplane from pitching down, you would need to pull back on the elevator control. Notice, this “pull” is to keep the nose of the airplane in the level flight attitude; it is NOT to bring the nose any higher than what is necessary to maintain level flight. If you do bring the nose any higher, while you may continue to descend, you will increase the likelihood of touching down and “skipping” back into the air – sometimes before the signal to deploy the spoilers is generated; and sometimes just after – meaning that you might get airborne a bit, have the spoilers deploy – and drop whatever distance you’ve managed to skip to! Not very pleasant!

This may seem to be a rather small point, but it is significant in landing the airplane. Normally, it should take a pilot between 1½ and 3 seconds to flare the airplane – and the airplane should not be held in the flare (off the ground) for more than 3 seconds … this means reaching the level flight attitude and saying “thousand one, thousand two, thousand three, touchdown” (uh … I’d do this to myself or in a whisper if there is someone else one the flightdeck with you). This is true in no wind, headwind, tailwind, and crosswind conditions. And, also importantly, at the end of that 3 seconds, I’d recommend PUTTING the airplane on the ground, now! You chew up a good deal of runway while in the air, giving you less and less concrete on which you can count for good surface contact and good brakes to get you stopped.

There are several techniques regarding the retardation of the throttles – and each airplane requires that you become familiar with the technique that best fits the way you fly and how the airplane responds. Some pilots will start retarding the throttles over the runway threshold; others will wait until level flight attitude is achieved. The speed at which the throttles are retarded will be directly dependent on where you start to reduce power and how quickly the airplane will decelerate in this configuration and in ground effect. The throttle(s) should be in idle at, or just prior to, touchdown.

Airplanes are designed, for the greater part, to be landed from the level flight attitude; and by that I mean the attitude that would produce level flight at the airspeed achieved at the end of the flare, the existing GW, and the existing configuration. When I teach, to help my students to understand, for themselves, what this attitude really is, I have often asked them to make an approach to land the airplane, except that when they complete the flare, I ask them to continue to fly down the entire length of the runway AT THAT ALTITUDE and AT THAT AIRSPEED, without climbing or descending; and without accelerating or decelerating. The height I ask them to shoot for is something less than 5 feet. As you would understand, no doubt, in order to do this, the pilot MUST achieve, and keep, the airplane at “the level flight attitude;” or the height would not be maintained. This practice helps to “fix” the level flight attitude picture for them. If we are fortunate enough over a several-day period to have varying weather conditions, I’ll ask them to do the same thing in each of those different conditions. This allows them to see that level flight attitude is the same (as long as the weight and configuration of the airplane is the same) regardless of the weather conditions; and, most importantly, it allows them to find what cues they want to use to determine that the airplane IS in that level flight attitude; i.e., they are not dependent on what someone else has used and likes … they can “do it for themselves.” Admittedly, we don't often get a chance to do this in larger airplanes anymore, alas. But, this can also be done very satisfactorily in a properly qualified flight simulator with sufficient motion, sound, and visual cues. Why do I recommend this approach? It’s my opinion that landing an airplane is anything BUT a mechanical exercise. In my years of doing this, I have found that by asking my students to do something “the way I do it” works only for a small fraction of my students. But when I describe what I want as an “outcome,” and let them determine, on their own, “how” to do what I’ve asked them to do, they normally learn it better and learn it faster, because it’s something with which they feel comfortable, and it seems more “natural” for them. Therefore when I say, “flare the airplane to achieve a level flight attitude a small distance above the runway surface,” it makes little difference to me what technique they use to achieve that specific goal (within reason, of course) – as long as that goal is achieved. The biggest reason landing “mechanically” won’t work, is that none of us humans are as precise and as capable of repeatable performance as we would like to think we are. Remember, when we depend on the autopilot to land, we usually rely on 3 of them, at least two of which must be in agreement – and as you all know, “George” is a lot better at doing things precisely and repeatably. The only thing that shouldn’t change from landing to landing (and the thing that “George” gets right all the time) is that the airplane lands from the level flight attitude – for that configuration and that airspeed.

Ashling

26th Aug 2007, 19:09

AirRabbit

27th Aug 2007, 16:38

Couple of points on the above
You are NOT trying to find a level attitude. When you flare you are merely slowing the rate of descent.
You do NOT allow the airplane to float and certainly not for 3 seconds.
Boeing are very clear on both these points and it is a boeing we are talking about. That said its true for any aircraft.
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.
To flare the NG you start at about 15' then increase pitch attitude by 2-3 degrees. After you initiate the flare smoothly retard the thrust levers to idle aiming for idle as the wheels touchdown. Make small pitch adjustments after the flare to maintain the desired descent rate to the runway.

I certainly don't mean to get into a "technique discussion" with you, but a pilot most definitely IS, or SHOULD BE, trying to find the level flight attitude - please note, I did not say that you are going to "level off." That would only be possible if you added power. If you read through my comments completely I think I mentioned that. If you flare to the level flight attitude (the attitude from which the airplane SHOULD be landed all the time, in any and all weather conditions) and do nothing else, you will land - it will just be farther down the runway than desired. If you flare to the level flight attitude either while you are reducing power, or reduce power reasonably quickly after reaching that attitude, you will continue your descent (even though you maintain that level flight ATTITIDE - not altitude - and WILL likely require a small but definite increase in back pressure if not a small amount of back-stick movement to maintain that level flight attitude) and you should land comfortably (not a "greased" landing, but very acceptable) within the touchdown zone. However, if you do as I have suggeted, you will be in a position for YOU to land the airplane if you need to get it on the ground sooner - for example, on a 6000-foot runway. Here, you'd want to be on the ground within the first 2000 feet - NOT take the traditional 3000 as a touchdown zone.

Also the 3 seconds I referenced, was, as you should note, a maximum time to stay in the "flared," level flight, attitude. You should also know that I am describing the time to descend from the height above the runway that was achieved during the flare. A pilot is NOT doing himself (herself) any favors by flaring at a height above the runway that will take anything beyond 3 seconds to reach the runway. Of course, unless you touchdown at the end of the flare (which is not recommended because of the possibility of misjudging and contacting the runway prior to reducing the rate of descent sufficiently), you are going to end the flare at some distance above the runway. It is going to take some amount of time to close that distance to the runway. I'm suggesting that anything beyond that 3-second time should be avoided in almost all cases - the only exception is those very rare cases where you are completely knowledgeable about the runway remaining, it is more than sufficient for you to complete the landing and roll-out, and you are planning to land "long" down the runway. The 1 1/2-second timing is merely an estimated time for the aircraft to continue the shorter descent from the height above the runway that was achieved at the end of the flare maneuver.

This procedure applies to every airplane. There are several "techniques" that can be used to accomplish what I have suggested, and I don't care (within reason) what technique is used. In fact, if the student selects and uses his or her own cues to accomplish what I've described - then they will learn better, and it will provide them a sound basis for landing the airplane in any weather conditions - AND - perhaps most importantly - they will NOT be trying to fly their airplane the way I fly mine.

Ashling

28th Aug 2007, 08:32

Boeing tell you to raise the nose attitude by 2-3 degrees from the approach attitude in order to reduce the rate of descent then smoothly close the thrust levers. So you are shooting for an attitude a little lower than the staight and level one. If you raise the nose by the maximum they recommend you will approach the level attitude (for the approach config and speed) briefly but that is clearly not their aim especially as the 2-3 degrees are based on approach speed and attitudes. They will also tell you that 3 secs airborne after the flare will use between 515' and 775' of extra runway. As a comparison 10 kts extra speed uses 170' - 310' extra. Boeing figures. You aim to put the wheels on firmly at the normal touchdown point.

You defined your level attitude "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."

So level attitude at the airspeed AFTER the flare. As speed reduces in the flare that will raise your nose higher than Boeings 2-3 degrees on the approach attitude. Now your potentialy in tailstrike territory as the level attitude will adjust by approx 1 degree for every 5 kts of speed in a NG and given that you will bleed 5-10kts in the flare you could be raiseing your attitude by 5 degrees in total over the approach attitude.

You went on to say "If you flare to the level flight attitude (the attitude from which the airplane SHOULD be landed all the time, in any and all weather conditions) "

Snag is on wet or contaminated runways you risk too gentle a touchdown when you need a firm one to break through the surface layer and avoid aquaplaning.

Boeings Flight Crew Training Manual for the type gives you a perfectly good repeatable technique for landing the aircraft. Its written down for a purpose I suggest you read it.

airbond

28th Aug 2007, 09:22

start the flare at 15'. Bit late !! Especially for the inexperienced.

Have a look how the B737 autoland systems works, it begins to start the flare at 50 ft.
Thrust retards to idle at 27 ft.

For new students, if you follow these parameters you cant go to far wrong.

paperdragon

28th Aug 2007, 09:59

Would also add, that landing a -700 or a -800 and even -800W requires quite different technique, landing speeds (in a -700) is generally 7kts slower for any given weight, and the -700 mlw is about 58tonnes / -800 about 65tonnes, hence the -700 requires thrust closer to the ground to avoid planting it into the runway. I found the 737NG is quite hard:} (at least initially) to land smooth with good consistency, but never mind you will get the hang of it! :D
Cheers:ok:

Pilot Pete

28th Aug 2007, 11:59

Ignore AirRabbit's advice, it is NOT 737 technique as has been pointed out by others. The FCTM is the definitive guide and input from your Training Captains. AirRabbit's overly complicated waffle will lead you into flight regimes close to the ground that could result in tailstrike, and you don't want to be there.

If you follow Airbond's advice you WILL end up falling out of the sky onto the runway and probably beyond the touchdown point. It could well be a HARD landing.

The FCTM says to flare at 15' AGL and to reduce the thrust to be at idle when the main gear touches down. That is what you are aiming for having flown a stabilised approach. How do you best achieve that? Consistent stable approaches, fully configured early until you have mastered it and only then do low drag approaches. Think about nailing the centreline with whatever aileron control inputs you need, don't let it diverge. Same with the glideslope, remember how sensitive it gets as you get closer; nail it and keep it there with elevator. Start the transition from instruments to visual (on a cavok day) at about 1000'. Start bringing the touchdown zone into your instrument scan. Ensure you are fully trimmed and then don't trim below 500'. Make sure you have a target thrust setting in your head for your fully configured approach (get it before you descend from the PI). Make small adjustments as required to this target and THINK about the cause and effect (I mean if your set target is not enough and you as decelerating down the approach then you will need more thrust to regain speed and then slightly less to maintain speed, but this figure will be more than your original target and thus becomes your new target).

At 500' you should be bringing the touchdown point outside even more into your scan. As you approach 200' you want that touchdown point nailed in your screen, just like in a C152. Keep scanning speed, G/S and PAPIs to ensure all is well though. As you cross the fence at 50' you should be looking completely outside, with small inputs of aileron to nail that centreline and elevator to maintain your rate of descent. When you hear that call of "FIFTY" you should raise your stare from the touchdown point that is going to disappear under the nose, to 2/3 the way down the runway (I just look to the end personally), which gives you the horizon in your peripheral vision to judge your sink rate.

Keep it descending and listen to the "FORTY", "THIRTY", "TWENTY" calls. The speed at which these occur tells you how quickly you are sinking! When you hear the "TWENTY" you should be starting the flare, as there will be a delay between you hearing it and applying the required control input to actually initiate the flare. If you leave it below the call of "TWENTY" you will probably hit the ground with too high a rate of descent. Remember, with experience this can all be fine tuned, but to start with you will not have quite the same 'feel' as an experienced pilot on type.

There are many variables, but assuming you are ON SPEED exactly as you initiate the flare, in smooth light wind conditions, then you can start to close the thrust levers as per the FCTM so that the main gear touches as they reach the back stops. One such variable is if you have carried an extra few knots; you may need to close the levers earlier, if you are a few knots slower than your Vref you may need to slightly delay closing of the thrust levers to prevent a harsh touchdown. This comes with experience. Add in crosswinds, gusty winds, lots of rain etc and it all gets a little harder still, but the same principles apply.

When the main gear touches down, swiftly apply reverse thrust to the interlocks and apply slight back pressure on the reverse levers until the interlocks release. Avoid pulling back or pushing forward on the column. FLY the nose down onto the runway (which requires a check back on the column to prevent it 'falling' onto the runway). Put the upwind aileron into wind (if required) and nail that centreline with rudder inputs. Take more than idle reverse thrust as required and/ or briefed. As an F/O or S/O in the right seat, keep control of the aircraft until it is relinquished. Do not start 'thinking' that the captain is going to take it from you. Disarm the autobrakes (usually by pushing the toe-brakes) before you come to a stop and pull up straight ahead on the centreline unless you have briefed that you are going to steer the aircraft off on a high speed exit. Even if you have briefed this intention, ensure you are at a suitably slow groundspeed before turning off the centreline; it can be deceptive looking outside, when you think you are going quite slowly, but in fact you are still doing 70kts! Ensure that when you briefed you used the landing performance figures and measured the distance from the thrshold to the intended turnoff to ensure your autobrake setting is going to give you a reasonable chance of making that turnoff. If you hear nothing from the left seat (like our standard "SIXTY" knots call), pull up straight ahead, the captain may be incapacitated......

Keep reverse thrust as taken until below 60kts. When you hear the sixty knot call, REDUCE REVERSE THRUST TO BE AT REVERSE IDLE AS YOU SLOW TO TAXI SPEED and then stow the reversers, don't (as many do), stow the reversers abruptly when they hear the 60kt call.

The one thing to remember is the option to GO AROUND if you get it all wrong (until reverse thrust is initiated). When this is necessary will not ALWAYS be obvious to you in the heat of the moment, even when you get more experienced as we have all landed an aircraft when with hindsight we should have gone around.:ok: That is where a positive call from the PM can be worth its weight in gold.

Happy landings.

PP

despegue

28th Aug 2007, 12:16

One addition here on PilotPete's generally excellent post.

Do not overcontrol when trying flying the ILS! I see way to many pilots battling the controls in order not to be 1/4th of a dot high/low or left/right:ugh:
Don't constantly yank the controls, this is a jet and all control inputs need to be done smoothly, including the throttle controls. Start the flare at around 20'. If you are used to the EFIS B737's, you will notice that you have to flare around 8' later then with the classic, due to a greater ground-effect ( much larger wings remember:ok:)
Finally, try to feel the aircraft. Don't just mechanise your landings according to what a book says, again, feel what the plane is doing and wants you to do.
And one more thing: RELAX!

Also , if your company allows it, and on long, dry runways, keep the Autobrake off. It will give you much better ideas how to handle the aircraft after touchdown.

Ashling

28th Aug 2007, 12:24

airbond
The thrust levers start to retard to idle at 27' to be at idle as the wheels touch. They are not at idle at 27'. The Flare mode does become active at 50' and that is when the mvr begins but the aircraft does not pitch until much lower it starts by feeding in additional trim and the gap between the mode becoming active and the pitch occuring gives the PM a chance to call if the mode fails to become active.

Anyone beginning a visual flare at 50' will land long, or level too high stall on and have a heavy landing, it is the wrong visual technique. 15' is not too late and is easily judged using the auto callouts as astro described earlier and if these are not available your mate can call 20' for you.

Boeing FCTM

If automatic callots are not available, the radio altimeter should be used to assist the pilot in judging terrain clearance, threshold height and flare initiation height.

Maintaining a constant airspeed and descent rate assists in determining the flare point. Initiate the flare when the main gear is approximately 15 feet above the runway by increasing pitch attitude approximately 2-3 degrees. This slows the rate of descent.

AFTER the flare is initiated, smoothly retard the thrust levers to idle, and make small pitch attitude adjustments to maintain the desired descent rate to the runway. Ideally, main gear touchdown should occur simultaneously with thrust levers reaching idle.

Me again

One of the main reasons people find the NG and in particular the 700 tricky to land is because they persist in using their own technique rather than the one written down by the manufacturer. As far as I know no airline has written a different technique into their ops manual for the landing. If others feel they know better than Boeing fine but I'll be sticking to their way of doing things. I would suggest we all do.

Pilot Pete, I was busy typing so didn't see your post until I put my latest one up but yours puts the meat on the bones of the FCTM nicely although personaly I do trim below 500'

Depesques tip about the autobrake is a good one. Far too many people touch down then do little in the way of braking and then realise the high speed they briefed is rushing up which is followed by a large, clumsy and uncomfortable application of the brakes which could have been avoided by a consistent brake application on touchdown.

Bullethead

28th Aug 2007, 12:26

I usually flare when the guy in the other seat says "OMG" or something similar, did it as an F/O and I'm still doing it. It only fails if he's asleep also! :E

Regards,
BH.

Tee Emm

28th Aug 2007, 14:21

reverse thrust is only available when engines have spooled down to idle.

No quite true. Just because the throttles are closed at touch down does not mean the engines are at idle thrust - in fact they could be passing through 45%-50% and that means spooling up to high power reverse will be quicker and thus more effective retardation.

coonass one

28th Aug 2007, 15:06

I've flown many variants of the 73, and each feel a slight bit different. But the one thing that seems to work well for me is to start my transition from the glideslope to the runway at or slightly below 200' with no power change. At 30', begin to slowly reduce power and start a very light flare to attain a shallower descent rate (I don't look at vsi, but I'm guessing about 2-400 fpm). At 10' start to slowly reduce the pitch (the roll-on technique). If you have plenty of runway, and the other pilot doesn't mind, try this with the power set until touchdown, as it will help you learn to fly it onto the runway instead of planting it. Hope this helps, and good luck!

looseobject

29th Aug 2007, 22:12

flare technique for all the aircraft i ve already flown (B737-200, B737-800, A330),(the A330 was the easiest):
1. Being stabilised with appropriate thrust settig, spped, vs etc.
2.The last 100 feet AGL are crucial to achieve a normal landing, be stabilised, ie if for any reason you became above the G/S do not chase it by increasing the rate of descent but shift your new aim point beyond the touch down zone to remain on a constant 3 degrees angle, obviously this is valid if you have a long RWY, otherwise a GO AROUND should be considered.
3.When passing above the RWY threshold, shift your angle of view to the end of the RWY or 3/4 of it, this gives a very good assessement of your height above the paved and helps you to commence your flare when apropriate.
4.When comencing the flare manoeuver thrust reduction must be smooth and continous to reach idle or nerar idle thrust at touchdown.
5.RDO ALT call out are useful on those acft,( especialy during night ldg,poor visi etc), but in my opinion, pilots should rely on their skills and judgement during landing flare.

AirRabbit

30th Aug 2007, 02:11

Thanks for the response, Ashling.

I appreciate the fact that you fly your airplane the way you choose to fly it, and I have no intent to even try to convince you to do otherwise. However, I would respectfully suggest that you re-read what I posted. I did not say that you were to maintain “level flight,” nor did I say that you should “continue raising your attitude as the speed decreases” as you suggest I said. I specifically said that you maintain level flight attitude.

I also said that while you were obtaining that attitude, and after you achieved it, you would still be descending. While this would be true even if you did not reduce power (although you would land an unacceptable distance down the runway), if you were to flare to the level flight attitude either while reducing power, or reduce power reasonably quickly after reaching that attitude, the airplane will continue to descend. The only thing I said that you would have to “increase” at this time would be “back stick” pressure, and perhaps a bit of back stick movement. But that would be to MAINTAIN the attitude, not increase it.

Next, you seem to be correcting me in that somehow you presume that what I am advocating will result in “too gentle a touchdown.” Please note, that is not what I said either. I said what I am advocating should provide touchdown at a comfortable rate - not a "greased" landing, but very acceptable. Usually, a descent rate at touchdown of something less than 25 fpm will get you the accolades of a “greased” landing – depending on your particular definition of “grease.” An acceptable, comfortable rate of descent at touchdown will be “firm;” and a firm touchdown is all you need to “break through the surface layer” and give you a better chance to avoid hydroplaning if the runway is wet. By way of comparison let me point out that if the flare height you reach is between 5 and 15 feet above the runway, if you take between 1.5 and 3.0 seconds to get to the runway, you will arrive at the runway at a rate of descent between 100 and 600 feet per minute. The 100 fpm rate would be taking the full 3.0 seconds to descend 5 feet. The 600 fpm rate would be taking the 1.5 seconds to descend 15 feet. The preferred situation is to take the (plus or minus) 1.5 seconds to descend the (plus or minus) 5-foot distance – giving you a (plus or minus) 200 fpm rate of descent at touchdown; as I said, “firm but acceptable.”

Next, if you flare to achieve a level flight attitude, I would argue that you are not, as you suggest, “in tail strike territory.” I think you’ll find that you get into that territory when you get to 10 degrees of pitch. You can correct me if I’m mistaken, but I was under the impression that the B737-800 tail strike attitude is about 11 degrees with the gear struts fully extended. Level flight attitude with landing flaps, and a speed between 1.1 and 1.2 of stall speed should be in the neighborhood of 3 - 6 degrees of pitch; a considerable angular distance below that “tail strike territory.”

Obviously, I have no way of knowing your experience level; nor you mine. A part of that experience includes reading, understanding, working in compliance with, and collaborating (with pilot groups, regulatory authorities, airplane manufacturers, and others) regarding suggestions for changes to Flight Crew Training Manuals. That being a fact, statements like…
Boeings Flight Crew Training Manual for the type gives you a perfectly good repeatable technique for landing the aircraft. Its written down for a purpose I suggest you read it.
…I believe come off carrying just a bit too much of an arrogantly condescending tone – at least for my taste.

AirRabbit

30th Aug 2007, 02:40

Hello, Pilot Pete,

With comments like...
Ignore AirRabbit's advice, it is NOT 737 technique as has been pointed out by others. The FCTM is the definitive guide and input from your Training Captains. AirRabbit's overly complicated waffle will lead you into flight regimes close to the ground that could result in tailstrike, and you don't want to be there.
...it is apparent, to me at least, that you believe you have the definitive knowledge in this area. Perhaps you do. Perhaps if everyone were to fly airplanes the way you fly airplanes we’d never have another pilot error problem. However, I suspect that even you would say that was going overboard.

A couple of comments, s'il vous plait: First; while you apparently are of the opinion that what I’ve proposed is most assuredly NOT B737 technique, I believe that if you performed an exhaustive search of such proposals you might be surprised at the results. Second; I have not ever advocated, and still do not advocate, ignoring the FCTM or any instructor’s teaching. Third; if what I have proposed sounds to be a “complicated waffle,” I’m puzzled at how you would fly a non-precision instrument approach. Fourth; I’d like to know why it is you believe that flaring to a level flight attitude, doing so to reach that flared attitude between 5 and 15 above the runway, retarding the throttle to idle during or after the flare (to have the throttles at flight idle at or just after touchdown), maintaining the achieved attitude (please note – I did not say maintain altitude – I said maintain attitude), taking less than 3 seconds to flare, and suggesting that the wheels be on the runway absolutely not more than 3 seconds after flaring … taken together would put a pilot in a position of a possible tailstrike. As I mentioned to Mr. Ashling, above, the B737-800 tail strike attitude is about 11 degrees with the gear struts fully extended. Level flight attitude, with landing flaps and a speed between 1.1 and 1.2 of stall speed, should be in the neighborhood of 3 - 6 degrees of pitch; a considerable angular distance below “tail strike territory.

I would also point out that there is a difference between teaching pilots to fly the way you fly and teaching pilots to fly the way they fly best.

Pilot Pete

30th Aug 2007, 03:27

Level flight attitude is waffle. The guy wants to know how to land. Level flight attitude (whatever that is defined as) is nothing to do with flying a stable approach and then raising the nose by 2-3 degrees, as per the FCTM, at the correct point. What 'level flight attitude', which varies so much with config, has to do with a descending aeroplane about to land is at best confusing. You are overly complicating the explanation of a manoeuvre. How does the student know what 2-3 degrees looks like? It's approximately the thickness of the coming. Relate that to the outside and that's how much the horizon should move by when you raise the nose. K.I.S.S.

PP

I would also point out that there is a difference between teaching pilots to fly the way you fly and teaching pilots to fly the way they fly best Your way is best then?:rolleyes: Pot, kettle, black? I'd get on to Boeing and let them know they are not providing BEST info to their customers.;)

Ashling

30th Aug 2007, 08:44

AirRabbit, the snag I have with your "level flight attitude" is that you define it as the level flight attitude at the airspeed at the end of the flare. This will be a different, and higher, attitude to the one directed by Boeing and written in their FCTM. Sure if you raise the nose the full 3 degrees from the approach attitude and speed you will briefly approach a level flight attitude but with what you suggest the level flight attitude will have to be higher as the speed will have reduced in the flare and as the aircraft will be slower the attitude will have to be higher than it would be at approach speed and therefore incorrect. You ahve not answered that inconsistancy as yet.

Your right about the tailstrike attitude but its more like 12 degrees min on a 700 but only 9 degrees or so on an 800. If you let the speed drop to ref -5 at 55 tonnes you will have just over 3 degrees of clearance and at vref -10 just 1.5 degrees so not as much as you might think. If you talk about straight and level attitudes some muppet might decide to develop the flare on an already high attitude, especially if he starts to sink suddenly, and there you go. I'm going nowhere remotely near it ta very much.

I do realise you are not suggesting maintaining level and of course as speed reduces the aircraft will descend if you do not select a higher attitude and this will be compounded if you reduce power. However your initial attitude as you have previously defined it is too high and that is the rub technicaly for me.

The above said I have to agree with PP, all this chat about level flight attitudes in relation to the flare is over complicated. Boeings explanation is very simple. It also has the benefit of being repeatable for any combination of weight, speed and flap setting including one engine inop. Selecting a level flight attitude does not have that advantage as by definition it will change with all of the above so you'll just find yourself asking which attiude now rather than doing what Boeing say and raising the nose a set amount each time.

Reading this thread is a real insight into why so many of the people who sit beside me cannot land the aircraft in the right place at the right speed. Far too many suggest raising the nose early. This can have but one result, a long landing. It may also lead to the need to increase power compounding the problem. If the aircraft is light you may even unintentionaly level off too high and then you really do have a problem unless you go-around.

You need to practise the right technique so that on a dark wet windy night on a short runway with a problem you can get the job done. If you don't practise it then when you need them the skills won't be there.

On an instructional and standardisation point it is v important for instructors to train their students in the correct published techniques. I have had to fail or mark students lower than I otherwise would due to incorrect technique which in some cases lead to major errors. When asked why they did it that way the reply was along the lines of "well thats what I was taught" or "I didn't realise it said that" I would suggest that the arrogant and condescending attitude comes from those who make up their own techniques.

fireflybob

30th Aug 2007, 19:07

And I thought landing was simple!:rolleyes:

I think we have definitive proof here that most pilots are predominantly "left-brain" thinkers! It makes us more comfortable to think that landing an aeroplane safely is "logical".

Years ago there was an interesting article in the Log highlighting the experience that when the landing conditions are ideal we sometimes tend to plant the a/c on the runway but when it's right on crosswind limits, blowing a gale and/or raining we end up greasing it on without intending to do so!

The explanation is that when we have lots of spare capacity we are using the logical left brain (flying more "mechanically") but when we are working hard we are using more of the creative right brain. Whether you think the pyschologists are correct is another matter of course.

However returning to the question posed at the beginning of the thread as to how to land I would remind everyone that the brain cannot differentiate between a real experience and one thats vividly imagined. Put quite simply if you practice imagining yourself doing a "good" landing then you are more likely to do so in practice because you are "hard-wiring" the neurons! Another avenue is to use affirmations - something like "I am in the process of improving my landing technique everyday" might suit the bill. Just recite this phrase ten times after you wake up, during the day at least once and then last thing before sleep. By doing so you are programming the sub conscious which will work on bringing the affirmation into your reality. Dont even think about how it will do this - thats the whole point you dont need to. The affirmation needs to be done for at least 21 days for full effect.

Much of our self programming is very "negative" because thats the way we have often been previously programmed (usually as a child by people like parents and teachers). Statements like "I am still having problems landing" are really going to set you up for "failure" so avoid making them and replace them with something better, eg. "I am in the process of learning how to land accurately and safely".

Hope this helps!

fireflybob

30th Aug 2007, 19:46

1. Watch carefully how other pilots fly the approach and landing - best to do so from the jump seat so you have more spare capacity to just observe. When doing so critically evaluate the landing - where was the touchdown point, was the speed correct, what was the feel of the touchdown like, was the a/c on the centreline, what was the speed control etc like on the approach. Copy what you see as correct.

2. Whenever given a choice opt for the more "difficult" landing (ie crosswind, limiting runway etc) - this will stretch your skills. (I digress here but its a bit like teaching 45 degree bank turns in basic flying - if they can do a 60 degree bank turn the 45 er is a piece of cake!)

3. Just do more landings! It takes time to programme the brain. Do NOT expect to get better from every "try" but LEARN from every "try" - plateaus and regressions in learning are often signs of progress - dont treat them as "failure". But remember practice makes permanent so make sure what you practice is correct!

Happy Landings:D

DC-8

30th Aug 2007, 20:23

Another avenue is to use affirmations - something like "I am in the process of improving my landing technique everyday" might suit the bill. Just recite this phrase ten times after you wake up, during the day at least once and then last thing before sleep. By doing so you are programming the sub conscious which will work on bringing the affirmation into your reality. Dont even think about how it will do this - thats the whole point you dont need to. The affirmation needs to be done for at least 21 days for full effect.

Is that in the FCTM? :E

AirRabbit

30th Aug 2007, 22:26

Hi Pilot Pete:
I am well aware of the question asked. And, of course, you are correct about the stabilized approach being critical to the accomplishment of a reasonable flare, descent, and touchdown. Additionally, of course, I recognize that “level flight attitude” varies with a lot of things, including, but not limited to configuration; however, I’m surprised that you believe that “understanding level flight attitude” is confusing when discussing descent and landing. I have had the opportunity to fly quite a range of aircraft in my career – and the one constant through all of it is that airplanes land best from a level flight attitude – from Cessna trainers to military fast jets (fighters) to miltary and civilian transport category including several of the Douglas and most of the Boeing family, including the B747. I’m not saying this to “impress” you with my credentials – somehow I think you would be more or less immune to such an attempt – I merely point that out to confirm my earlier comment about this being applicable to “every airplane.”

I’m afraid you’ve misunderstood my comment about teaching students to fly and the “Pot, kettle, black” comment is, I believe, unnecessary. I haven’t said that flying “my way” is best. What I AM saying is that teaching the pilot to determine his or her own technique for getting the airplane into the proper attitude for landing is likely to be better than having them learn a specific technique – particularly if that technique seems awkward to them. Will the technique you advocate work? Of course it will. But is it the technique that suits every pilot? I doubt it.

I recognize that you think I’ve tried, probably in your view, unsuccessfully, to put you down or criticize your way of describing your technique. That is truly NOT my intent. The individual asked a question. I believe that if I’m going to offer an answer, it should help – not hinder. If you believe that the explanation I offer is too much of a hinder – please feel welcome to disregard it completely. I would only point out that many of the things we do that appear to be “simple,” are far more complex when you try to explain it in detail; for example, try describing to someone, who has no idea of the mechanics involved, how to button a shirt, or tie a “bow tie,” or tie a pair of shoe laces. It seems to me that the business of flying has gotten down to the point of asking for and being provided a whole series of “short cut gouges:” e.g., “What power setting should I use for final approach of an XYZ make, 123 model airplane with landing flaps?” “How much nose up trim should I use to maintain a 30-degree bank turn at 200 knots?” If you need or want to provide those kinds of gouges, be my guest. Personally, if I’m a bit slow on final approach, I say “add some power.” Still a bit slow, I say “add some more.” How much more? I say “enough to go a bit faster.” When someone says what’s the best way to land XYZ make, 123 model airplane, I could give them the “gouges” that a lot of people believe work for them. However, I’d rather have that questioner be able to understand what is happening so that he (or she) has the best opportunity to learn how his (or her) airplane performs and handles.

Perhaps an example? I’m sure you know of Tiger Woods. When he drives a golf ball off a tee, he places the ball, selects a club for distance, addresses the ball, executes a back swing, a down swing, and a follow-through. Simple, right? If Mr. Woods was asked, “how should I drive a golf ball,” I would imagine if he thought it was a serious question, we would likely provide a dissertation on how much research he’s done on shaft length, shaft bending, constant arc swings and their variations, and club head face effect when contacting the ball, including the effect of contacting the ball while the club head is still descending, or has reached bottom-dead-center of the swing, or has started on the up-swing; to mention only a very, very few areas he would touch on. Would that be considered too complicated an answer? Not if the questioner was serious about his question.

Lastly, while I appreciate your frustrations, I would appreciate it if you’d dial back the insults, just a small bit. Thanks.

AirRabbit

30th Aug 2007, 23:41

Hi Ashling:

First, let me say that I’m trying diligently to keep this on a professional, hopefully respectful, level. I took your comment, “I-suggest-you-read-the-Boeing-FTCM,” as an indication of your opinion that I’ve certainly not done so. I hope it would make a difference if I told you that I have. The bottom line here is I’d like to stay out of the mud and am going to side-step your suggestion that I’m making up my own techniques. My intent is NOT to insult you, sir … at all. I appreciate your comment about my description being more complicated than you typically hear. As for its being “overly complicated,” I would take exception to that characterization. Please see my detailed response to Pilot Pete above. If my “attitude” comes across to you as being arrogant and condescending, I apologize. Again, that is not my intent.

You say that your “snag” with a “level flight attitude” is that it will not only be different, the difference will be that it will be a greater attitude than described in the Boeing FCTM. I don’t agree with your assessment. And to demonstrate that, I would ask, if it is at all possible, the next time you have an opportunity to be in a simulator, that, after you’ve finished all of the requirements, and if you have time available, you fly a normal final approach, flare the airplane (simulator), as you would normally, to land, but do not land. Instead, add the power necessary to fly down the runway at the height above the runway and at the airspeed you achieved at the end of the flare. As you fly down the runway, do not climb, do not descend, do not accelerate, and do not decelerate (the definition of straight and level, unaccelerated flight). Note the airspeed you have. Note the attitude you have. The reason I’m suggesting not to accelerate or decelerate is to avoid necessarily changing the pitch attitude accordingly.
Do the same thing a second time. Flare as you would to land. Achieve the same level flight attitude as you had the previous run down the runway, but this time instead of adding power to fly down the runway, pull the throttles to idle in the manner that best suits your particular situation (i.e., some begin retarding the throttles over the threshold; some begin retarding at flare initiation, some begin retarding when the flare attitude is reached; some snatch to idle as the mains touch), such that the throttles are at flight idle at (or just slightly prior to or just slightly after) main gear touch down. Do not adjust the pitch and do not accept a change in pitch – maintain it to touchdown. I’d be interested in your comments.

It is my expectation that, if you were to do as I have suggested, you would see that I am not advocating doing anything differently than what is described in the Boeing FCTM; despite your opinion to the contrary.

Please understand, I do not attempt to negate whatever a qualified instructor teaches – and if anyone got that impression, let me correct that right now. Each instructor has a right and a responsibility when it comes to his or her own students.

I am more than a little concerned that pilots are repeatedly being provided a quick, easy-to-understand series of mechanical inputs that will yield a result that will be acceptable in most cases. Without throwing darts at ANY airplane manufacturer, we all know that all of any manufacturer’s customers are not necessarily candidates for the “ace of the base” award. For some, such mechanical instructions are an acceptable way of achieving acceptable performance. Some of these pilots will, over time, become curious or seek better ways of performing the task – not dramatically different ways, but different – perhaps only in a manner of understanding what is happening. It is my opinion that when a pilot learns mechanically, he or she will fly mechanically – including those situations that the mechanical method isn’t exactly what is necessary. Does that happen frequently? Certainly not. In today’s environment, there will be quite a few pilots who will go an entire career without seeing anything out of the ordinary. And in those few times when an “ordinary abnormality” DOES stick its head into the mix, (e.g., dark, stormy night; ILS approach at minimums; variable head, cross, and tail winds; wet and short runway) a combination of airplane and systems reliability, other-pilot-in-the-cockpit experience, and a kind wink from the good fortune fairy, maybe nothing untoward will occur. Maybe. Sometimes, it sneaks up and bites some long-time veterans.

My goal is to provide an understanding of not only “how” but “why” regarding the way the airplane performs and handles. Again, my opinion only, if we teach pilots to understand the various “whys” involved in flying, we will have provided each pilot with the best opportunity to be able to deal competently with those rare, but potentially disastrous circumstances where the specific “mechanical” approach will not work.

gimmesumvalium

31st Aug 2007, 04:37

Good post PP.
Never having flown 737 (never had enough seniority!) but other Boeing types e.g.76, 74 I concur.
Reduce your rate of descent so that impact is acceptable (until you get a feel for the airplane) BUT ensure you touchdown in the Touchdown Zone defined by your company's SOPs (and on the 1000ft marker if the runway is limiting), Refer Normal Touchdown distances in the QRH Perf TAB. Float for a smooth touchdown at your peril.
GSV

Pilot Pete

31st Aug 2007, 10:23

Air Rabbit
The length of your posts says it all. It seems to take you an awful lot of effort to explain it to us, therefore I draw my own conclusion from that. I've not flown in an airline which would advocate your method. They have all based their training around the FCTM description. Why? Because it is straightforward, simple, easy to visualise and it works. That is what the newbie needs until they get a feel for the aircraft. Not some idea that varies so much and that each new pilot needs to find their own 'way' of doing it. They WANT to be told/ shown a simple method to aim at.
Be careful about claiming people are insulting you. There has been no such insult thrown from me. If you believe you haven't been waffling then that is up to you, I sir think you have, so it is a statement, not an insult.
You ask I’m puzzled at how you would fly a non-precision instrument approach. In the same way. I would start a descent at the descent point and use V/S to control my rate of descent over distance. I would aim (as per my company SOPs) to fly a constant descent to 50ft above MDA at which point I would either see the visual reference and continue FULLY STABILISED, or go around. As I came over the threshold I would use exactly the same technique as described by the FCTM to flare and land the aircraft. Again, simple as the same method works again. Why would you think there must be a different technique for a non-precision approach? You imply the Boeing method would not work if it wasn't off an ILS.
...it is apparent, to me at least, that you believe you have the definitive knowledge in this area. No, I believe Boeing do. That's what I follow every time as it works and what I am reciting here. That is what my training department would have me teach and what every other airline that I have worked in (four Boeing airlines) have advocated. I'm not the one going against the grain here Air Rabbit.
I wish you well, but will continue to disagree that your method has merits in a 737.
PP

chksix

31st Aug 2007, 11:31

http://img390.imageshack.us/my.php?image=landqq1.jpg
From a 737NG manual from 2002. Just trying to help here... :}

EMIT

31st Aug 2007, 12:27

That is a lot of text explaining those few seconds of flight,but only once, in post #21 (by looseobject), point 3, I have seen the extremely important tip to shift your focus from the intended touch down point towards a point far down the runway. Only that way you will be able to judge your vertical rate from your peripheral vision, and without that, all you will be doing is monkey tricks.

AirRabbit

31st Aug 2007, 12:42

Hello Pilot Pete:
Perhaps, then, I misunderstood your comment, "I'd get on to Boeing and let them know they are not providing BEST info to their customers" as an insult. It certainly sounded like an insult. But, if you say it was not, then I'll take you at your word, since it was your statement. I also regret that you think that the verbosity of my efforts to explain things is evidence that I don't know what I'm talking about.

Also, perhaps I misunderstood your use of the term "waffle." In the US that term is used to describe the inability of someone to make up their mind about a specific issue; an insult, if you will. As far as I am aware, what I've described here hasn't changed in the 30 plus years I've been involved in teaching and evaluating pilots. At least in the US, a 30-year consistent positon would be exactly the opposite of "waffling." Again, I am willing to take your word that your description of my advocacy as "waffling" as being merely your observation and not an insult - I'll chalk that up to my not understanding the colloquialism you chose as a descriptor.

As I said initially, anyone here (and elsewhere, for that matter) is free to think, believe, or fly any way they choose. That includes teaching any way they choose. Those who choose to fly via specific, mechanical responses to given circumstances are free to do just that, and I wish all of them well in their endeavors. That includes you as well.

AirRabbit

31st Aug 2007, 13:07

Hey chksix:
Thanks for the link. While I recognize that you are not “taking sides” in this on-going debate … (perhaps discussion is a better word) … I think that the diagram of the airplane in the landing attitude provided in your link sheds some additional light on the subject. This diagram clearly indicates that the proper pitch attitude for landing is between 4 and 6 degrees. I made a statement earlier that “Level flight attitude, with landing flaps and a speed between 1.1 and 1.2 of stall speed should be in the neighborhood of 3 - 6 degrees of pitch…” The 1.1 to 1.2 of stall speed range I described is the airspeed you should have at the end of the flare if you maintain Vref+5 until start of the flare.

I’ll not go any further with that explanation and rationale for this attitude being appropriate for recovery from a bounced landing or the initiation of a go-around, as it seems that my use of extended descriptions are interpreted by some as an indication of ignorance on the subject.
Thanks again.

Kerosine

31st Aug 2007, 13:14

you tell 'im rabbit! ;)

Pilot Pete

31st Aug 2007, 15:15

Emit That is a lot of text explaining those few seconds of flight,but only once, in post #21 (by looseobject), point 3, I have seen the extremely important tip to shift your focus from the intended touch down point towards a point far down the runway. Only that way you will be able to judge your vertical rate from your peripheral vision, and without that, all you will be doing is monkey tricks.

You missed the reference in my first post about it then.

From post number 15 When you hear that call of "FIFTY" you should raise your stare from the touchdown point that is going to disappear under the nose, to 2/3 the way down the runway (I just look to the end personally), which gives you the horizon in your peripheral vision to judge your sink rate.

PP

Sky Wave

31st Aug 2007, 16:03

Firefly Bob.

Your technique does not work!! I told myself how perfect my landing was going to be today, I visualised a nice stable approach, flaring, kicking off the drift and gently easing the into wind wheel onto the runway, quickly followed by the other main gear, and gentle flying the nose wheel onto the runway, all on the centre line and in the touchdown zone of course. Nowhere in my visualisation was the FIRM untidy landing that I managed to achieved!!

Air Rabbit, as a new 737 pilot I have to say your explanation is far too complex for me to try and think about at 50ft. I need it in very simple terms, and Pilot Pete’s explanation is easier for me to understand and remember when I'm landing.

PP and other 737NG pilots. My landings are sometimes (today for instance) a tad on the firm side and it seems it's because my speed decays in the flare, the aircraft runs out of energy and drops onto the runway. Should I be keeping my approach speed right up to the point that my wheels touch the runway and if so, should I be scanning the speed IN the flare? If that's the case should I also add thrust momentarily to maintain speed if it starts decaying before I touchdown? The FCTM does say that thrust should not be adjusted near to the ground. My guess is I shouldn’t get into that low speed situation in the first place, however all the time I’m scanning the speed up to the point when I’m looking completely outside, my speed is on target.

Obviously I’ll ask the pilots and trainers that I work with, but I'm off work for a few days and since I'm still sulking about my landing today it would be nice to hear 737NG pilots views.

Cheers.

SW

AirRabbit

31st Aug 2007, 17:34

Hey Ski Wave:

I certainly understand your position. I am not saying that what I’ve described is what you have to do each time you descend through 50 feet. After you’ve worked through what is happening – you won’t even have to think it through. Example – how many times do you check your rear-view mirror driving to work? But, I’d bet you do it and take what ever action you need to take (if any) without thinking about it.

Like I was trying to describe to PP, anything you do sounds a lot more complex than actually doing it when it is described in any detail. And within a reasonably short time, you will not realize that you’re doing all that you thought was so complex when you started. I am advocating achieving level flight attitude (which should be somewhere between 3 and 6 degrees of pitch – depending on the weight of the airplane), and doing so somewhere between 3 and 5 feet above the runway at the end of the flare, with an airspeed something on the order of 1.1 to 1.2 times the stalling speed in that configuration and weight. The more you land, the more you’re going to understand the sight picture you want to see; and the more you’re going to be able to “feel” what level flight feels like. I think it important that YOU pick whatever YOU use to determine level flight – some look at the departure end of the runway; others place certain windshield bolts on a tree line or horizon line; others use a side-glance at the distance to the runway edge (paint stripe); others use the windshield bolt and runway edge (paint stripe) match-up; and there are probably dozens of other “techniques” that work for different pilots. I don’t want to teach you to recognize level flight the way I recognize it. I want you to pick what seems easiest and most natural for you.

The very best way isn’t available to many of us any longer – that is to fly level down the runway at a 5-foot height and proper speed (1.1 – 1.2 Vsl). But, you CAN do that in a simulator, and do it quite nicely – assuming your instructor or the simulator guys are agreeable. Using the simulator you can try it from landing weights that run the range from max to minimum. You can do it for various flap settings. Use whatever cues you need to maintain level flight. You ARE allowed to “cheat” if you desire. Raise the nose the recommended number of degrees to see if that is enough if you want. Crosscheck the vertical speed indicator if you want. Check the attitude indicator and/or the airspeed indicator, if you want. Look at the end of the runway. Look directly over the nose. Look out the side windows. Determine what spot on the runway surface that does not move up or down in the windscreen (where you are actually headed). Take into consideration your peripheral view of the world. Use the tiny burble you get in the column as the tail plane settles into ground effect. Use whatever you feel most comfortably and most accurately gets you to achieve level flight attitude. What attitude is that? Well, you’ll have to experiment a couple of times. You’ll also have to add some power – not a lot – in order to maintain the airspeed. Fly down the length of the runway way. Crosschecking whatever you desire to see and checking all of the possible confirmations available to you to be sure that you are, indeed, in level flight. This is to be able to recognize the attitude. If you change airspeed the attitude will change as well. In a rather short time you will determine what you are most comfortable with taking into your scan to determine that attitude.

After you’ve done this a few times (some people need 2 or 3 passes – some either like it or want to experiment and take 10 or more times – not a real cost in the simulator). The next time do exactly the same thing, but instead of adding power, pull it off. Change nothing else. Do not let the attitude of the airplane change – don’t increase it, don’t allow it to decrease with the reduction of power – this will likely require a bit of an increase in back pressure, but don’t raise the nose – use just enough back pressure to keep it from falling. Don’t stay in that attitude beyond 3 seconds. Usually you’ll be close enough to the ground that you’ll touchdown in less than 2 seconds. The landing will likely be “firm,” but not uncomfortably so. Once on the ground and the spoilers have deployed, fly the nose to the ground quickly but smoothly. Reverse thrust is used according to the situation and, obviously, in accordance with your company procedures.

The value here is actually multiple: If you add power in this condition – you’ll gain forward speed rather quickly and level off without having to do anything to the nose position. If you need to climb slightly, add just a bit more power, you don’t need to adjust the nose position. Both of these are valuable pieces of information should you ever have to recover from a bounced landing. We’ve all done them – so will you. Should you need to go around, as you add go around thrust and increase forward speed, you will begin to climb slightly, which is an advantage in tail clearance when you rotate to the takeoff / go-around attitude. Also, once you start perfecting your crosswind landing techniques, you’ll already have this part of the puzzle worked out. Now all you’ll have to get is the timing of pressuring the nose around to line up with the runway during the flare and, at the same time, be able to finesse the amount of “aileron into the wind” that you might need to keep that wing from rising.

So that I don't incur the ire of those who may read this - I am not advocating that you do ANYTHING contrary to what your instructors have taught you to do. If you have the opportunity to check this out ... do so ... I'd be interested in hearing what you have to say.

Cheers!

fireflybob

31st Aug 2007, 18:17

Your technique does not work!! I told myself how perfect my landing was going to be today, I visualised a nice stable approach, flaring, kicking off the drift and gently easing the into wind wheel onto the runway, quickly followed by the other main gear, and gentle flying the nose wheel onto the runway, all on the centre line and in the touchdown zone of course. Nowhere in my visualisation was the FIRM untidy landing that I managed to achieved!!

Sky Wave - you have all my sympathies!

Firstly, it's not "my" technique! There are plenty of good books on the market about how to programme yourself for success (at anything) - try Tony Buzan's book called Head Strong for starters. If, as you say, you "...told yourself how perfect the landing was going to be today..." then this will always be in the future and never "now". How long and how often have you been practising the visualisation? Try the visualisation as though you are observing yourself from, say, the jump seat or even outside the a/c.

Many will think this is new age mumbo jumbo but I can tell you it works if you work it!. Jack Nicklaus the champion golfer said he always pictured how he wanted a shot to proceed in his mind before he actually took the shot.

Happy Landings

fireflybob

31st Aug 2007, 19:01

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.

Nowhere in my visualisation was the FIRM untidy landing that I managed to achieved!!

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?

naceur

31st Aug 2007, 19:05

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

HOMER SIMPSONS LOVECHILD

31st Aug 2007, 20:18

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

Ashling

31st Aug 2007, 21:30

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.

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.

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

coonass one

31st Aug 2007, 21:31

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.

the heavy heavy

31st Aug 2007, 22:02

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

bushbolox

31st Aug 2007, 22:15

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.

AirRabbit

31st Aug 2007, 23:08

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.

Centaurus

1st Sep 2007, 00:20

in fact you may have already started to reduce the power – although that isn’t absolutely necessary yet), you are going to continue
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.

Ashling

1st Sep 2007, 04:29

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.

Blip

1st Sep 2007, 05:33

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.)

AirRabbit

1st Sep 2007, 17:00

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:
…the flare is pulling back on the elevator controls to raise the nose (increase the pitch attitude) to “break” or “reduce” the rate of descent prior to touchdown. But, where is it you want the nose to go? Can you put it anywhere? No, certainly not. Well, if that’s true, then you want it to go to some specific spot. What is that spot? 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.
…and here is what I said later on in that same posting…
Airplanes are designed, for the greater part, to be landed from the level flight attitude; and by that I mean the attitude that would produce level flight at the airspeed achieved at the end of the flare, the existing GW, and the existing configuration.
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…
You are NOT trying to find a level attitude. When you flare you are merely slowing the rate of descent.
You do NOT allow the airplane to float and certainly not for 3 seconds.
Boeing are very clear on both these points and it is a boeing we are talking about. That said its true for any aircraft.
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.
To flare the NG you start at about 15' then increase pitch attitude by 2-3 degrees. After you initiate the flare smoothly retard the thrust levers to idle aiming for idle as the wheels touchdown. Make small pitch adjustments after the flare to maintain the desired descent rate to the runway.
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.

chksix

1st Sep 2007, 17:25

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.

AirRabbit

1st Sep 2007, 17:30

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.

Ashling

1st Sep 2007, 17:52

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.

airbus757

1st Sep 2007, 19:44

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

Whaledog

1st Sep 2007, 22:40

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

paperdragon

1st Sep 2007, 23:34

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:

AirRabbit

2nd Sep 2007, 00:50

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.

Blip

2nd Sep 2007, 00:57

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:

Just get the bird close to the ground, cut the power, check the descent rate a little and let it settle onto the ground.

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.

Some things cannot be explained.

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.

Ashling

2nd Sep 2007, 04:57

Hi AirRabbit

My mistake, try post #45

Centaurus

2nd Sep 2007, 07:27

As long as he impacts in the touchdown zone on the center line

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

Taiguin

2nd Sep 2007, 10:00

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

TolTol

3rd Sep 2007, 12:11

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!

AirRabbit

3rd Sep 2007, 17:27

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:

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

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.

airbus757

3rd Sep 2007, 18:02

Blip

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.

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

Ashling

3rd Sep 2007, 19:36

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.

AirRabbit

4th Sep 2007, 17:24

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 …

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…
…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. 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 disputing the idea that it will help someone who is learning to land a new type … I say if things were kept simple they would have a better chance of passing, after all they are already pilots … People just need some simple tips, practice, and confidence ... All this complicated and theoretical talk is fine, but it my opinion it should be meant to help fine tune someone who already has experience's technique … It will not help someone who is still trying to pick out where the N1 indicator is.
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.”

Ashling

4th Sep 2007, 19:09

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.