Changing auto brake setting during roll out

[stilton]

I’ve not seen any specific guidance against this or done it personally


If I’m not getting the required deceleration
i’ll disconnect the AB and manually brake


But I’ve seen it done and curious as to
thoughts on this technique

[BluSdUp]

Madness...

[Tee Emm]

Technically possible but what's the point? It's a gimmick and lacks class

[InSoMnIaC]

It seems like a good/acceptable idea until you accidentally hit MAX

[N1EPR]

I often changed the auto brake settings on the B757. It was a smooth operation. I never used the technique to increase braking.

[pineteam]

Originally Posted by InSoMnIaC

It seems like a good/acceptable idea until you accidentally hit MAX

Exactly my thought too. I often use Autobrake low and disconnect it if I need more or less braking. I always try to brake as smooth as possible and take the last high speed exit for the sake of confort and brakes life. If a pilot relies so much on automation on the ground, I would be concerned.

[FlyingStone]

Seen it being done, never really understood the point, especially when people would change it mutiple times during rollout (i.e. 3 to 2, then 2 to 1).

Isn’t it much easier just to press the pedals to disconnect the autobrake and brake manually?

[AmarokGTI]

If you are not getting the required deceleration changing the setting might not work if the reason is a fault with the system. Once you work that out you have even less time for the manual option.

[172_driver]

I often changed the auto brake settings on the B757. It was a smooth operation. I never used the technique to increase braking.

Same here.

It's in the 737 FCOM that autobrakes can be selected and changed during landing roll out. No warning or caution.

[73qanda]

It seems like a good/acceptable idea until you accidentally hit MAX

Exactly my thought too.

I can’t imagine anyone ever ‘accidentally ‘ selecting MAX. Would you accidentally lift the knob up and over ? It’s not that easy to do.
I don’t use the above technique and prefer to select a slightly lower setting than required and override to disengage.

[CaptainProp]

Originally Posted by InSoMnIaC

It seems like a good/acceptable idea until you accidentally hit MAX

Exactly THAT! What a load of BS! Taking your eyes of the runway on rollout to “locate” switches and stuff is simply unprofessional. As far as I’m concerned you touch nothing until clear of runway and spoilers are being disarmed.

CP

[InSoMnIaC]

Not all aircraft use knobs to set autobrake.

[ACMS]

Ummmmmm..........

[Skyjob]

Originally Posted by AmarokGTI

If you are not getting the required deceleration changing the setting might not work if the reason is a fault with the system. Once you work that out you have even less time for the manual option.

I'd only use it the other way around:

Say you've prepared performance rollout data for a WET runway but during landing its damp at best if anything.
Having checked DRY and WET performance prior to landing, you know that a lower AB setting would make the desired exit in DRY conditions.
Lowering the AB eating to the desired lower one is good airmanship in this case, alternatively, manual braking to disconnect the higher auto brake selected the other option.

[FlightDetent]

Skyjob: AB usually provides a controlled deceleration rate.

The Boeing RTO OFF-1-2-3-MAX is far superior to AB's LO-MED MAX in the interface, given the task suggested above.

AB: no, unless you really want to do the inevitable.
B: to reduce decel rate? Worked nicely, I seem to remember (steel brakes at the time).

[vilas]

Routinely in normal conditions doesn't make any sense. But in rain and crosswind etc. if one wants to increase braking effect not a bad idea to change to medium from low. You are assured of even braking.

[FullWings]

It’s the poor man’s Brake To Vacate...!

[Tee Emm]

Lowering the AB eating to the desired lower one is good airmanship in this case, alternatively, manual braking to disconnect the higher auto brake selected the other option.

All very complicated and unnecessary fiddling about. If you land with autobrake MEL'd u/s, should you declare Mayday or simply PAN? Or just land and use normal manual braking like ordinary pilots have done so in the past 50 years. Much ado about nothing, IMHO

[stilton]

Not necessarily against it, particularly in
adverse conditions with gusty winds and
a wet / short runway


But If you do, I think it should be the PNF
that adjusts the setting, it’s an awkward reach to where the selector is usually
located and an unnecessary distraction to the PF



I was in the jump seat of a 747 Classic a
few years ago however that had the AB selector mounted on the left side of the overhead panel in easy reach of the CA

[Old Fella]

Changing Auto Brake Selection after touchdown.

Originally Posted by InSoMnIaC

Not all aircraft use knobs to set autobrake.

No, but some other knobs might change the setting during roll out.