The Importance of a good Landing

[Meikleour]

Cosmo Kramer: In quoting the Airbus FTM I think you are making my point for me! Quote: mainly heads up ........ until visual reference is lost. When taking off at night from ( especially ) coastal airfields I think everyone would have trouble detecting the actual aircraft attitude accurately. You seem to assume that all types "leap off the ground" in the same manner as the A320.
All pilots should be aware of their current type's tail scrape attitude oleos compressed. Sadly tailscapes do occur from time to time and only come as a surprise to those crews who do not have this knowledge. To cite the B747 and A340 - both types exhibit a marked slowing of the rotation rate around 10 NU due to the tailplane being affected by its proximity to the runway during the rotation. This tends to lead to a slowing down of the rotation then a subsequent climb out at too fast a speed.
For the avoidance of doubt - I am not saying that the entire rotation be done with reference to the PFD but rather more useful information is given to the pilot regarding rate and achieved attitude by looking at the PFD once nothing visible is to be seen over the coming. In other words, as others have pointed out - no special techniques are required for night/fog departures.

[RAT 5]

For the avoidance of doubt - I am not saying that the entire rotation be done with reference to the PFD but rather more useful information is given to the pilot regarding rate and achieved attitude by looking at the PFD once nothing visible is to be seen over the coming.

I can't remember back to B757/767 days, but on current B738 F5 non LVO takeoffs: absolutely, the keeping of the centreline until airborne is visual; has to be. The initial rotation is visual. This is the best way to keep wings level under all circumstances and assess the correct rate. The a/c will pause at 10 degrees NU, and the nose cuts the horizon at the same time. The a/c becomes airborne as the elevator deflection is increased slightly. This is when the PFD becomes primary as you need to stop the rotation at 15 degrees. Thus, the a/c becomes airborne as the outside visual clues disappear. This is even more important with an engine failure before VR. Now the a/c will become airborne at the same point but you must stop the rotation at only 12-12.5 degrees. Thus, as you increase the elevator deflection to maintain the same rate you have only another 2 degrees to go. The PFD becomes very important. I've seen guys in the sim who tried to look over the nose after 10 degrees and they bounced again as they subconsciously pushed. If understood correctly, taught and practiced correctly, it is a doddle in any visibility, cross wind, engine failure scenario. Even more important if the engine fails in low vis/night just as gear is selected up. KISS.

[cosmo kramer]

When taking off at night from ( especially ) coastal airfields I think everyone would have trouble detecting the actual aircraft attitude accurately.

Meikleour,
I take of regularly from dark costal airports (Red sea airports). A completely (until established in 15 deg climb) visual rotation is not a problem at all. Remember that we are still close to the ground and ambient light from the airport is always sufficient to make the rotation. And to that dots of light here and there, reflections etc etc. You will even still see the lit runway ahead of you until well into the rotation (12 degs at least). Even when the nose starts to block your view ahead, add to that you still have peripheral vision that see "around" the nose.
Obviously, it can be more difficult to know when 15 degs has been achieved, in which case, you phase in the PFD slightly earlier, to stop the rotation.

For the avoidance of doubt - I am not saying that the entire rotation be done with reference to the PFD but rather more useful information is given to the pilot regarding rate and achieved attitude by looking at the PFD once nothing visible is to be seen over the coming.

...So I guess we are saying the same then?

To reiterate, some are of the impression that you have to switch to the PFD from the moment you start the rotation. This is wrong!

You seem to assume that all types "leap off the ground" in the same manner as the A320.

What you need to detect during the rotation is the RATE. No matter if the plane if the plane leaps off or not. 3D vision is superior to a 2D instrument for detecting accelerations, rates etc. And I have never flown an A320, I just provided the information from Airbus.

RAT 5:
The a/c will pause at 10 degrees NU, and the nose cuts the horizon at the same time.

RAT5,
The aircraft will only pause if you let it! By looking outside, it's easy to detect a change in the rate (again 3D vision catches a change immediately). So it's just a matter of adjusting your pull. Rotation should NOT be paused at 10 degs. This is a wrong technique. Boeing says to make a smooth continuous rotation.

The a/c becomes airborne as the elevator deflection is increased slightly. This is when the PFD becomes primary as you need to stop the rotation at 15 degrees. Thus, the a/c becomes airborne as the outside visual clues disappear.

Liftoff attitude for a 737-800 is 8.5 degs at flaps 1, 8 degs at flaps 5. So liftoff doesn't happen at 10 degs.

Also, the nose doesn't obscure the horizon at 10 degs pitch. On a day with full derate, long runway and improved climb (11-12 degs pitch), you can comfortably fly the aircraft with visual reference to the horizon - provided you are seated correctly.

Crude demonstration. It works in real life too.



I am not advocating to fly with reference to the horizon, merely saying that it can be done, and that the nose doesn't obscure the horizon to prevent a visual rotation. Also, as mentioned in the reply to Meikleour, your peripheral vision allows you to look "around" the nose.

What should be done at the end of the rotation, is to check speed and speed trend as the first, there after switch to the PFD and make fine adjustments to stop the speed from trending in either direction.

[cosmo kramer]

Wanted to comment on this one too:

RAT5
...but on current B738 F5 non LVO takeoffs: absolutely, the keeping of the centreline until airborne is visual; has to be. The initial rotation is visual. This is the best way to keep wings level under all circumstances and assess the correct rate.

So it seems we are starting to agree too. Visual until airborne. I like to complete the rotation fully visually and that works for me. If someone want to transition a couple of degrees earlier I won't argue about that.

Of course that goes for any flap setting. My company uses flaps 1 on most takeoffs (I know a lot of airlines banned flaps 1).

Maintaining center line AFTER airborne is something that seems to be largely ignored (as can be seen from lining up behind departing traffic in crosswind). Protected area for obstacle clearance seems to be disregarded.

Doing the rotation visually (and completing it visually), helps in that respect too. And the crossed controls that at being applied during the rotation (rudder to keep the center line and aileron to keep wings level), can more easily be coordinated phased out so that the aircraft comes out in crab angle according to crosswind exactly maintaining the center line.

[Meikleour]

Cosmo: I think we may be arguing type specifics. A heavy A340-300 will not unstick at 10 NU , with the correct eye position forward view is lost and finally a tail scrape will occur at 14 NU with the oleos compressed! I am suggesting to you that not all rotations are done at the ideal constant correct rate. Tailscapes do happen from time to time so. ....... how do you protect yourself from this with possible gusty conditions or the over enthusiastic F/O who gives it a " hefty heave ho" around the 10 NU mark? Next time you get a chance watch a B747-400 take-off. The rear fuselage often gets to within 1metre of the runway even on correctly flown, ideal takeoffs.

[TyroPicard]

No resistance to looking out.. to start the rotation. Airbus say once airborne you must look at the PFD... A320 gets airborne at 8-10 degrees of pitch .. that is when you need to be head down, for accurate pitch and speed control.

[cosmo kramer]

how do you protect yourself from this with possible gusty conditions or the over enthusiastic F/O who gives it a " hefty heave ho" around the 10 NU mark?

If I am PF I look outside. Looking outside and feeling how the aircraft responds to the environment, makes adjustments quite easy - including adjustments for gusts.

If I am pilot monitoring, I look at the PFD, because I can't feel the control wheel of my F/O, and don't know how hard he/she pulls. I have my hands on my knees, with my thumbs ready to push against the control wheel, should they be over eager. With 33 cm tail clearance, it's occasionally necessary - especially with those that are doing the rotation heads down.

Next time you get a chance watch a B747-400 take-off. The rear fuselage often gets to within 1metre of the runway even on correctly flown, ideal takeoffs.

The minimum tail clearance for a 737-800 at flaps 1 and normal rotation is only 33 cm by the way - that's why many airlines have a ban on flaps 1 takeoffs.

that is when you need to be head down, for accurate pitch and speed control.

TyroPicard, you don't need to control pitch or speed during rotation, you need to control your rotation rate. It's done much easier by looking outside at at 3D environment, than on a flat 2D instrument. Once established in climb (rotation completed), you need to adjust the pitch to control speed.

[FullWings]

I agree about rotation rate being the most important. “Speed control” is driven largely by that rate: too slow and you’ll be fast, too rapid and you’ll be slower than you want by the end of the manoeuvre. During rotation, the speed will increase from Vr to V2 and on to whatever is normal for your type. Playing around with the rate while chasing airspeed is not generally a manufacturer recommended technique; a constant rate rotation to an initial pitch attitude is.

[piratepete]

PAUSE IN ROTATION: ALL JET TRANSPORTS

The reason why so many rotations in large transport jets pause around the 8-10 degrees nose up attitude has absolutely NOTHING to do with the elevator being in close contact with the ground.That (according to Mr Boeing- I asked him), is just rubbish.When the WHEELS ARE ON THE GROUND the weight vector (remember from your PPL days?) goes through the wheels.Once the wheels leave the ground (757/767 8 degrees roughly) the weight vector of the whole airplane MOVES FORWARD TO THE CENTER OF PRESSURE ON THE WING.This causes a slight NOSE DOWN effect, stopping or slowing the rotation unless THE PILOT AVOIDS THIS BY INCREASING THE back pressure slightly to KEEP THE ROTATION RATE CONSTANT............ Pete

[TyroPicard]

cosmo
If you read my last post again you will see I recommend looking at the PFD passing 8-10 degrees pitch, not to start the rotation. I did it that way for 30 years and it is the most accurate way of ensuring obstacle clearance, which is arguably the most important aspect of a take-off.
If the RVR is on minimums, it looks the same (almost).
And if an engine fails you are totally in the loop re speed trend. What's not to like?

[TyroPicard]

piratepete
I thought the weight vector acted through the a/c CG.... if it acts through the CofP does that not make the a/c neutrally stable and difficult to fly?
On the runway the a/c rotates about the wheels, which reduces the horizontal stabiliser downforce during rotation.. once airborne it rotates about the CG, restoring normality.

[Meikleour]

TyroPicard: I agree with both your posts. What you say is, in my experience, industry standard. In typical PPRUNE fashion we will always have posters who " know the true way"!!
Cosmo has yet to explain just how he knows how close he can get to a tail scrape on takeoff using his peripheral vision. Despite quoting Airbus FTM then saying he has never flown one, he goes on to assume that cockpit cutoff angles are the same on all types as on his current type ( 738? )

[cosmo kramer]

TyroPicard: I agree with both your posts. What you say is, in my experience, industry standard. In typical PPRuNe fashion we will always have posters who " know the true way"!!

Running out of arguments and becoming personal in indeed the "typical PPRuNe fashion". God forbid you would learn anything.

Cosmo has yet to explain just how he knows how close he can get to a tail scrape on takeoff using his peripheral vision.

33 cm. I provided the figure a few posts ago. We do flaps 1 takeoffs at MTOM regularly due to long tankering sectors. It easy to judge a rate by looking outside.
Just like flare, you judge the closure rate with the ground visually. Try doing that PFD only next time you are in the sim.

Despite quoting Airbus FTM then saying he has never flown one

I quoted airbus because they write explicitly that rotation is a visual and conventional manoeuvre.
Boeing doesn't write it explicitly, probably because it's a conventional aircraft and they didn't see the need to do so.
I mentioned the reason for the airbus quote in a previous post too.

he goes on to assume that cockpit cutoff angles are the same on all types as on his current type ( 738? )

That was a reply to RAT5, who is also on 738 (as far as I can tell).
I doubt though, that the variance will be that great with other aircraft types (need to be able to see way over the nose during CAT3 approaches and flares). As mentioned as well, you can see "around the nose" with you peripheral vision.

[Meikleour]

Cosmo: I think we are in agreement that correct rotation rate is required. Where we disagree is the method by which this is monitored versus tail scrape protection. Your posting history suggests that you have advocated your method for some time. Equally other posters have continued to disagree with you - few seem to endorse you.
Airbus say, depending on where you look, "rotate at ABOUT 3 degrees/sec. " or
"rotate at between 2.5 to 3.5 degrees/sec". Now, on the twins I have flown (B737 , A320 & A330) the unstick occurs quite dynamically. Not so the quads. (B707, B747-2/300 & A340-300/600) The typical twin thrust/weight ratio of 1/3 is more like 1/4 on the quad. This makes the possibility of a tailscrape on the quad much more of a risk. In my own airline we had a tailscrape with a new captain on the A340 where 14 NU was achieved prior to unstick - however he escaped censure because the FDR showed that his rotation rate was " within the normal accepted parameters" !! Quote from Airbus. So yes, rotation rate is not an absolutely precise science. So, why not use all the available information to safeguard the rotation phase?
You seem to have a reluctance to acknowledge that others' experiences may not match your own. If your preferred method suited all types and all operations I am sure it would have been "industry standard" by now.

[stilton]

Cosmo is completely correct.


Rotation, just like the flare is a VISUAL maneuver and that's been recommended for every Boeing and Douglas aircraft I have flown.


If you're doing it by looking at the PFD you are doing it WRONG and are more likely to have a tailscrape

[Meikleour]

Stilton: If you are new to this thread, I have never advocated rotating on the ADI. The discussion is about the phase when useful visual reference is lost.

[cosmo kramer]

Useful visual reference is not lost at 8-10 degs pitch.

We can continue this discussion forever. But I think at the end of the day we are all pretty much in agreement.

I did a ferry flight last night as PF. With the usual back pressure the rotation felt quite slow, so I glanced at the RA to check when I could increase the rate to 4-5 degs per second, to catch up. Thereafter I switched back to visual and completed the rotation. I am saying this, because I agree that in some cases, useful information can be picked up from the PFD. Like height, which eyes are bad at judging (that's why we should look at the far end of the runway during the flare, as the eyes can't accurately judge the height, but excellently judge the closure rate).

BUT, during a normal rotation it shouldn't be necessary. This is just like the discussion about thrust reduction during flare. During a normal flare, the thrust should be reduced as per respective FCTM (30 feet for a 737 e.g.). However, in special circumstances it might be prudent to reduce later or even add thrust.

That's why we are in the cockpit and it's not just runned by computer. Improvise, adapt, overcome.

To get back on topic:

The problem, and in my opinion the core problem, and where the relevance of the discussion about rotation fits in with landing is this:

Too many are SOP/magenta line driven to the extreme and are incapable of improvising and adapting when necessary. They stare at their instruments to keep everything within the limits of the FODA ghost. In turn, they forget to do what they are supposed to do: Aviate!

[RAT 5]

Too many are SOP/magenta line driven to the extreme and are incapable of improvising and adapting when necessary. They stare at their instruments to keep everything within the limits of the FODA ghost. In turn, they forget to do what they are supposed to do: Aviate!

Aaah. Violent agreement at last. Wonderful.

[TyroPicard]

This is what the current airbus FCTM says on the subject of rotation..

Rotation is conventional. During the takeoff roll and the rotation, the pilot flying scans rapidly the outside references and the PFD. Until airborne, or at least until visual cues are lost, this scanning depends on visibility conditions (the better the visibility, the higher the priority given to outside references). Once airborne, the PF must then controls the pitch attitude on the PFD using FD bars in SRS mode which is then valid.

And an old Boeing 737NG FCT .. these a/c lift off at between 8-10 degrees as well...

After liftoff use the flight director as the primary pitch reference cross checking indicated airspeed and other flight instruments.

I am quite clear in my own mind that the PFD is the pitch reference to be used after lift-off... i.e. after 8-10 pitch, or earlier if necessary due to weather conditions.
Any questions?

[cosmo kramer]

So Airbus changed the wording slightly.

You are missing 3 things though:

1) "Scan rapidly", doesn't mean to fly ONLY with reference to the PFD after the aircraft unsticks. As you advocate doing from 8-10 deg pitch.

2) Airbus tells you to give the highest priority to outside, when visual conditions permit (most takeoffs, depending if your homebase is in a swamp or not). Not switching to watch your PFD?

3) I think your definition of airborne is wrong. The aircraft is airborne at the end of the maneuver (rotation) and not in the middle, when the wheels unstick.

Your Boeing quote proves point 3. As Boeing says not to follow the FD during rotation, but only to use it AFTER, when airborne.

For optimum takeoff and initial climb performance, initiate a smooth continuous rotation at VR toward 15° of pitch attitude. ... After liftoff, use the attitude indicator as the primary pitch reference. The flight director, in conjunction with indicated airspeed and other flight instruments is used to maintain the proper vertical flight path.

Note: The flight director pitch command is not used for rotation.

Takeoff Risk Factors
Any one of the following takeoff risk factors may precede a tail strike:
...
Improper Use of the Flight Director
The flight director provides accurate pitch guidance only after the airplane is airborne. With the proper rotation rate, the airplane reaches 35 feet with the desired pitch attitude of about 15°. However, an aggressive rotation into the pitch bar at takeoff is not appropriate and can cause a tail strike.

So no, I don't have any questions. I think your quotes just reinforced my points.