PPRuNe Forums - B744 Autobrake

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main_dog

11th December 2009 09:34

B744 Autobrake

Hello all,

Does anyone know how the B744 autobrake works in terms of programmed deceleration? A previous type I was on (from "Brand A" :}) specified the target deceleration rates for the various settings (believe it was 1.7m per second squared for Low, and 3.0m per second squared for Medium).

Does the Boeing autobrake aim for a target deceleration rate or a target brake pressure? If it's the former, any idea what these are?

MD

Jumbo Driver

11th December 2009 10:01

With regard to Autobrake operation on the B744, my TM says ...

Quote:

The RTO (rejected take-off) position provides maximum braking.

Also that ...

Quote:

Landing autobrakes are armed by positioning the Autobrake Selector to one of the landing deceleration rates.

I'm afraid I have no information on the numbers involved. My guess is that on MAX setting, it is not a deceleration rate that applies but the maximum braking that surface conditions and antiskid will allow. However, I can tell you that, on landing, the MAX setting is impressive!

JD
:)

Mac74

11th December 2009 10:34

Autobrake deceleration rates:

1 - 4.0 ft/sec^2
2 - 5.0 ft/sec^2
3 - 6.0 ft/sec^2
4 - 7.5 ft/sec^2
max - 11 ft/sec^2

Spanner Turner

11th December 2009 19:20

If you really want the "nitty gritty", then have a read of a previous post here:

http://www.pprune.org/tech-log/28768...ml#post3476982

Enjoy.

:ok:
.

main_dog

12th December 2009 00:14

Thanks guys! :ok:

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