Flapless B737 LDG

[J.B. de Jong]

Hello,

In the unlikely need for a flapless landing I read in a procedures manual to choose the runway with No crosswind.

What would be the considerations to go for the runway with the least crosswind, other than having the best landing distance performance?

As I was taught flying GA aircraft, in the event of heavy crosswind we were to land with less/no flaps. This is reversed thinking I know, but the influence of xwind would be less on a B737 without flaps compared to with flaps just as on a C172.

Thanks for the input.

[Lord Spandex Masher]

Doesn't it imply that you'll have more headwind, which is preferable with no flaps.

[Cough]

From a Boeing article on tailstrike avoidance (http://www.boeing.com/commercial/aeromagazine/aero_04/textonly/tr01txt.html).

MISHANDLING OF CROSSWINDS
A crosswind approach and landing contains many elements that may increase the risk of tail strike, particularly in the presence of gusty conditions (figure 3). Wind directions near 90 deg to the runway heading are often strong at pattern altitude, and with little headwind component, the airplane flies the final approach with a rapid rate of closure on the runway. To stay on the glidepath at that high groundspeed (figure 4), descent rates of 700 to 900 ft (214 to 274 m) per minute may be required. Engine power is likely to be well back, approaching idle in some cases, to avoid accelerating the airplane. If the airplane is placed in a forward slip attitude to compensate for the wind effects, this cross-control maneuver reduces lift, increases drag, and may increase the rate of descent. If the airplane then descends into a turbulent surface layer, particularly if the wind is shifting toward the tail, the stage is set for tail strike.

The combined effects of high closure rate, shifting winds with the potential for a quartering tail wind, the sudden drop in wind velocity commonly found below 100 ft (31 m), and turbulence can make the timing of the flare very difficult. The PF can best handle the situation by exercising active control of the sink rate and making sure that additional thrust is available if needed. Flight crews should clearly understand the criteria for initiating a go-around and plan to use this time-honored avoidance maneuver when needed.

When landing (any?) aircraft flapless, a tailstrike is a real risk as the pitch attitude on final is already high. When you add the factors above, Boeing are trying to keep you in the 'hero' category when you read their advice on flapless landings.

[john_tullamarine]

Not much difference to normal, but significant, crosswind landings .. when one pushes off the drift to fly whatever is left to go cross controlled, simultaneously the pitch attitude has to be increased somewhat to prevent a sink rate increase .. just becomes a bit more clearance critical with lesser flap selections, including clean .. so, perhaps, better to find the least crosswind option sensibly available ?

[BluSdUp]

This may be the time for a firm landing , no crosscontroll , then rudder as needed and do not try a smooth nosewheel touchdown. Max reverse and max autobrake.
After all the crosswind vector is marginal at V ref 40 plus 70 kts, Eh John?
I would think floating and rwy distance is main problem.

[framer]

Max reverse and max autobrake.
From my FCTM
Use of autobrakes is recommended. Autobrake setting should be consistent with runway length. (See Autobrakes Landing distance in the PI section of the QRH, Performance Limitations and Planning Manual or EFB). Use manual braking if deceleration is not suitable for the desired stopping distance. Immediate initiation of reverse thrust at main gear touchdown (reverse thrust is more effective at high speeds) and full reverse thrust allows the autobrake system to reduce brake pressure to the minimum level. Less than maximum reverse thrust increases brake energy requirements and may result in excessive brake temperatures.
I think using max reverse is a great idea but using max auto-brake would be something that needs serious thought. For example, at my home base we have over 3400m of runway. At max landing weight, nil wind, you'll chew up 1400m using max manual braking if you do everything correctly. Using Auto Brake 3 you'll use about 2600m. That leaves 800m up your sleeve.
Let's say you stuffed up the flare and floated all the way to the 2000ft mark before touching down, and when you did you were ten knots fast, you'd still stop 400m before the end of the runway.
On a runway of that length I'd use AutoBrake 3 and I would go around if a float looked like taking me past the 1500ft touch down marker.
Obviously that is just my own opinion of the risks involved but I thought it worth mentioning that max auto brake isn't a given and (in my mind at least) should be avoided if possible at those high speeds.

[de facto]

Indeed if not runway limited,max autobrake use is plain stupid.

[BluSdUp]

You are funny
Max autobrake is mandatory in this case ,flapless,
Anything else is gross incompetence,,,,
Practicaly ,I allways land standar F 30 auto brake 3 and squice it of when happy.
I am a firm beliver in speed , energy squear root etc, but mostley I hate paperwork and the press so I stop befor runway end, always,. End.

[porch monkey]

Hey blusdup, I think you're funny. What part of "here's what the FCTM says" didn't you understand? Don't see the word "mandatory" in there anywhere, do you?

[de facto]

Blusdup,
[QUOTE]Max autobrake is mandatory in this case ,flapless,
Anything else is gross incompetence,,/QUOTE]
Are you just having a laugh or?:eek:

[Cough]

This may be the time for a firm landing , no crosscontroll , then rudder as needed and do not try a smooth nosewheel touchdown. Max reverse and max autobrake.

So rudder as needed and no crosscontrol.

But, how are you going to counter the rolling action of yaw without using opposite aileron?

I think however we need to keep this in perspective. It will land in a crosswind but choosing a runway with a headwind with the large energy involved will be preferable. Command stuff...

[BOAC]

Obviously has his own manual printed.

[framer]

Blusdup
You are funny
I know, that's why I have such a hot wife. In this case however, I wasn't joking. Where did you get the idea that Max was mandatory? From a manual?

[JeroenC]

Since all non normal landing distance calcs assume max manual braking. No data provided for less.

[framer]

Yip. What's the relevance though?
Boeing suggest AutoBrake commensurate with runway length in order to prevent exceeding brake energy limits. They certainly don't want you to use max for all non normals just because they haven't provided the data. If that was the case we'd have Boeings blowing fuse plugs every day.

[de facto]

Since all non normal landing distance calcs assume max manual braking. No data provided for less.

Open your QRH,go to your normal landing distance,check your weight and the rest then add the SPEED INCREMENT above VREF,you are using all flaps up the it should be about vref40+50kts.
You use the AB 2 column first ,if not enough margin use AB3 .....

Not brain science really...

[Jwscud]

Are the corrections for landing distance linear?

Energy to be dissipated increases with the square of the speed don't forget. I would suggest that using the QRH Normal landing distance figures to extrapolate to Vref40+70 would not give you an accurate answer, and you have know knowledge in which direction the error is.

I would class that as "brave" behaviour personally.

"So, Bloggs, with the QRH non-normal distance there why did you invent your own landing distance calculations?"

[flying apple]

De Facto: why would you use the normal configuration landing distance if you have clearly a non normal.
why would you use the figures for XXXm/5kts above Vref when Boeing gives you the figures they calculated in the exact non normal configuration you are in.
And the NON-NORMAL landing distance table says those distances assume max manual braking, we use max autobrake because then the brakes will be applied sooner after touchdown and take over manually straight after.
When you have a non normal you don't have to think about brake energy, these figures are approved by the FAA and JAA so why would you use anything else?

[Skyjob]

de facto:
add the SPEED INCREMENT above VREF, you are using all flaps up the it should be about vref40+50kts
Last time I looked, Flaps Up speed was F40+70...

Jwscud:
Are the corrections for landing distance linear?
No they are not, as it is roughly: Energy = Mass * Vg*Vg (squared Vground) thus the speed has a squared effect on the energy contained within the object, thus the energy required to be absorbed to facilitate a stop.

using the QRH Normal landing distance figures to extrapolate to Vref40+70 would not give you an accurate answer
I would agree with this, reference above.

Although the distance from the Normal Landing Distance tables should never be used, it does give you a good starting point. But only for instance by comparing the additive (difference) for Normal and Non-Normal Max Manual Braking as published in BOTH Normal and Non-Normal tables. This must then not be used as factual but can be used as a guidance on an indicative increment requirement.

It could indeed be professionally sound to adjust Max Manual Braking with a lesser Autobrake requirement if runway length allows, most airfields we fly into do not have 3400m available to them, if you do operate into those lengths, then use a lower setting but with caution as no guidance exists on them.

Finally, it may be a good idea to have in your mind the deceleration rates for auto brake settings, allowing thus for a rough distance calculation to be made based on any touchdown speed. This rate is what is achieved by auto brakes and is modulated to be achieved, by adding/removing brake pressure due to other stopping factors such as reverse (primary), drag and friction.

[flyingchanges]

737-800, max landing weight at 2000' PA, 5650' with a 15% margin and 1,000 feet of air distance from threshold. Actual stopping distance is around 3,800 feet. This is flaps zero at VREF 40 + 55.

Why you would arbitrarily throw max brakes into that situation is beyond reason. Just a good way to ruin a set of brakes, tires, and possibly axles.

Our QRH makes no mention of crosswind, and states "brakes consistent with runway conditions".

[framer]

And the NON-NORMAL landing distance table says those distances assume max manual braking, we use max autobrake because then the brakes will be applied sooner after touchdown and take over manually straight after.
Is that really what your company suggests?
If it is SOP do you mind telling us what airline?

[flyingchanges]

So, lets put a lot of energy into the brakes when they are least effective...

We had some 777 crews trash tires, brakes, and axles using max brakes on single engine landings. Totally unnecessary, especially on 12,000' of pavement.

[de facto]

Skyjob,
de facto:
Quote:
add the SPEED INCREMENT above VREF, you are using all flaps up the it should be about vref40+50kts
Last time I looked, Flaps Up speed was F40+70...

What aircraft do you fly??
The b737 all flaps up landing is vref +55 kts.(this time i checked,i was off 5 kts i give you that ..
Flying apple,
De Facto: why would you use the normal configuration landing distance if you have clearly a non normal.
why would you use the figures for XXXm/5kts above Vref when Boeing gives you the figures they calculated in the exact non normal configuration you are in.
And the NON-NORMAL landing distance table says those distances assume max manual braking, we use max autobrake because then the brakes will be applied sooner after touchdown and take over manually straight after.
When you have a non normal you don't have to think about brake energy, these figures are approved by the FAA and JAA so why would you use anything else?

Damn and you get hot brakes for no reason:ugh:
The speed additive above vref in the normal gives you a quite accurate landing distance...this gives a good idea of your landing distance and allow to chose an AB setting CONSISTENT with the runway lengh.
The non normal gives you a distance if runway is limited and how much you can achieve not the only way to brake.
Sometimes i really wonder what you are doing in an aircraft.
Flyingchanges,
So, lets put a lot of energy into the brakes when they are least effective...
We had some 777 crews trash tires, brakes, and axles using max brakes on single engine landings. Totally unnecessary, especially on 12,000' of pavement.

Exactly...same type of people writing here.

[de facto]

Energy to be dissipated increases with the square of the speed don't forget. I would suggest that using the QRH Normal landing distance figures to extrapolate to Vref40+70 would not give you an accurate answer, and you have know knowledge in which direction the error is.

I would class that as "brave" behaviour personally.

I hope more people were braver then,if thinking and professional is your definition of being brave.
Again all flaps up is vref 40+55kts.
Any idea how Auto brakes work?:ugh:

[captjns]

As per our QRH, reference to Autobrakes is at the discretion of the flight crew.

[flying apple]

Quote:
And the NON-NORMAL landing distance table says those distances assume max manual braking, we use max autobrake because then the brakes will be applied sooner after touchdown and take over manually straight after.
Is that really what your company suggests?
If it is SOP do you mind telling us what airline?

This comes out of our FCTM in the general NNC handling part

In the part specific for all flaps up landing they talk about AB being consistent with the runway, which in my opinion is dealt with by using manual braking.
It seems more logical to brake faster in the beginning and decreasing brake pressure when you are sure you can make it then it is to slam on the brakes in the end because something went wrong

I fly for a big european company

[de facto]

It seems more logical to brake faster in the beginning and decreasing brake pressure when you are sure you can make it then it is to slam on the brakes in the end because something went wrong

If you habe no idea of your landing distance or runway limited yes.
If you want to use the extra runway to reduce the potential issue of your tires delflating as you stop,initially use an AB lower when at high speed (distance checked ok with ab2 and speed increment)as speed is the biggest factor in hot brakes and when the sppeed goes below a certain value( about 150 kts) select higher AB(ie 3).

If you are runway limited and nowhere else to go,and manual braking distance is what you have the yes PLEASE set AB MAX (it will quick in faster than you can lift your feet)then as soon as possible (physically) apply max manual braking.

[latetonite]

Your autobrake will modulate the braking action better than yourself.

Now, with a 12000' rwy, I do not see the reason to get your wheels on fire, either with max manual, or max autobrake.

You can always override, and brake in function of the remaining runway. That is what one does with normal landings anyway, no?

Judgement does not come straight out of a reference book.

[sheppey]

If you are runway limited and nowhere else to go,and manual braking distance is what you have the yes PLEASE set AB MAX (it will quick in faster than you can lift your feet)then as soon as possible (physically) apply max manual braking.

Agree. If runway performance limited for all flaps up then immediate full reverse on touch down and autobrake MAX but be ready to apply full manual braking if you need more braking than MAX autobrake. Be prepared for red hot brakes once you have stopped on the runway and ask ATC for a tow rather than attempt to taxi with possible brake fire.

On the other hand, if the runway is not limited in any way, then do not use autobrakes and providing full reverse is used immediately on main wheel touch down there may be no need to use any brakes at all, since the spoilers are much more effective at high speed to decelerate, as is reverse. In other words, use careful judgement and energy management and even with a 8000 ft length runway dry sea level, you should not need to apply brakes until around 80 knots. If no float and accurate touchdown point at 185 knots touch down speed, let the spoilers and reverse do their job losing about 100 knots of energy before falling back on manual braking. That means relatively cool brakes to taxi with.

[Denti]

Simply calculate the landing distances with the different auto brake settings and then choose the most fitting one with a little wiggle room (well, there's the 20% factor anyway). After all, it's just a click of a button for each calculation.