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Flapless B737 LDG

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Flapless B737 LDG

Old 10th Apr 2014, 13:11
  #21 (permalink)  
 
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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?
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Old 10th Apr 2014, 13:20
  #22 (permalink)  
 
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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.
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Old 10th Apr 2014, 14:00
  #23 (permalink)  
 
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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
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.
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Old 10th Apr 2014, 14:03
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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?
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Old 10th Apr 2014, 20:47
  #25 (permalink)  
 
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As per our QRH, reference to Autobrakes is at the discretion of the flight crew.
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Old 11th Apr 2014, 01:08
  #26 (permalink)  
 
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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
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Old 11th Apr 2014, 06:15
  #27 (permalink)  
 
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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.
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Old 11th Apr 2014, 11:04
  #28 (permalink)  
 
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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.
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Old 11th Apr 2014, 11:20
  #29 (permalink)  
 
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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.
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Old 11th Apr 2014, 12:55
  #30 (permalink)  
 
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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.
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