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Azman2010

PMDG 747-400 Autobrake Question/Problem

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Hi All,

 

Has anyone else had problems with the Autobrake on the 747-400?

 

I configure the a/c to land, all good when landing on the tarmac, usually on the keys! however when on the tarmac reverse thrusters engage, spoilers up but the autobrake just does nothing, even though it shows on the screen being set to my required braking action.

 

So I am using manual brakes as soon as i hit the tarmac as the Autobrake is doing very little if nothing at all.

 

I also tested it in RTO mode, after V1, reverse thrustrers engaged, spoilers up the nose does dip as if the brakes are working, yet when looking at the speed tape, its a very small amount of brakes. So yet again i brake manually.

 

Thanks in advance

 

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What assignment do you have set for brakes in the sim ?  If you are using toe pedals and don't set a sufficient null zone, it could be that your toe brakes are registering as "on" and thus cancelling the autobrake. Do you see a brake message?..... either the red band produced by your sim (FS9 or FSX), or a messsage on the PMDG panel that autobrakes are disengaged ?

 

I dont know to what extent the 747 autobrakes are accurately modelled. If you land on a dry runway at a light landing weight, and engage full reverse thrust it is highly likely the autobrake will not engage, as you are already decelerating at a rate in excess of the rate set on the autobrakes.


Peter Schluter

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What autobrake setting are you using?

 

Autobrake 1 is virtually useless (and indeed most real world operators discourage its use except on long, hot & high runways where brake temperatures could be an issue as it tends to wear the carbon brakes rapidly (carbon brake wear is related to the number of applications -- AB1 tends to cycle on and off a lot as the selected deceleration rate is so low).

 

Otherwise I've always found the brakes if anything too effective. As Peter says, are you seeing the red BRAKES message at the bottom left of the screen? Is the autobrake selector remaining on the selection or is it moving to DISARM?

 

 


usually on the keys!

 

Not being the landing police, but if you're landing on the piano keys in the 747-400 you're a bit short -- ideally should be around 50R over the threshold for the mains to touch around the 1000/1500ft markers ;-)


Simon Kelsey

sig_FSLBetaTester.jpg

 

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Not being the landing police, but if you're landing on the piano keys in the 747-400 you're a bit short -- ideally should be around 50R over the threshold for the mains to touch around the 1000/1500ft markers ;-)

 

 

Haaa no its fine Skelsey that what I mean, I call them all the keys. Not over shooting them...well sometimes!


What assignment do you have set for brakes in the sim ?  If you are using toe pedals and don't set a sufficient null zone, it could be that your toe brakes are registering as "on" and thus cancelling the autobrake. Do you see a brake message?..... either the red band produced by your sim (FS9 or FSX), or a messsage on the PMDG panel that autobrakes are disengaged ?

 

I dont know to what extent the 747 autobrakes are accurately modelled. If you land on a dry runway at a light landing weight, and engage full reverse thrust it is highly likely the autobrake will not engage, as you are already decelerating at a rate in excess of the rate set on the autobrakes.

 

Thanks for your reply. The null zone is all set to 0 the autobrakes remain on the panel. It could be that I am landing light but not sure too. I flew this morning and ended up manually breaking but might do some test flights with some extra fuel to make me heavy.

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On ‎5‎/‎26‎/‎2015 at 1:32 PM, Azman2010 said:

Has anyone else had problems with the Autobrake on the 747-400?

I have such problem with Autobrake. after landing on St.Maarten TNCM rwy 10. I press Brakes from my Joystick and the AC keeps moving and going straight to over the end of runway. I used Autobrake 2 and 4. I might not be using brakes properly?


Patricio Valdes

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On ‎9‎/‎10‎/‎2017 at 8:39 PM, trisho0 said:

I have such problem with Autobrake. after landing on St.Maarten TNCM rwy 10. I press Brakes from my Joystick and the AC keeps moving and going straight to over the end of runway. I used Autobrake 2 and 4. I might not be using brakes properly?

Autobrakes problem again but with flight plan KCDW-KLDJ. Captain Kevin already explained me about and his professional experience cleared my question. I wonder if other pilots got similar problem with autobrakes and how it was resolved. I am sure I did something wrong with brakes.

NonILSlanding.jpg


Patricio Valdes

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