Hello,
In the PMDG 737, disabling the autobrake on landing is quite hard I think, as there is no other indicator or so to see how much brake pressure you are applying and as you have the match the brake pressure with your pedals to disconnect the autobrake. And I think this is quite hard, especially when you are focussed on so much other things during the landing. The only indicator you have is the orange disabled light, which shows when you succeeded in disabling the autobrake.
I searched the internet to try to find a key for diabling the autobrake. And I tried some things myself. But nothing works.
Does anybody know how to setup a key on the keyboard or yoke to just disable the autobrake of the PMDG on landing?
Greetings,
Boudewijn
Well, two questions which may or
may not be helpful.
- Is there a key in MSFS/PMDG that rotates the Autobrake switch?
You might not be able to turn it OFF with a keypress, but you might find a way to rotate it to the OFF position if there is a keybind for that.
- Do you really need it on or off?
What I mean is that the Autobrake system in the 737 works great and will bring you to a stop with just a little jerk. Most pilots donât like the abrupt stop and override it, but that doesnât mean that it doesnât work.
Plus, doesnât whatever you use for the brake input deactivate the Autobrake?
Alternatively, manual braking is a perfectly viable way to stop the aircraft. One company I worked for didnât even USE the Autobrake except for Rejected Takeoffs.
IIRC=Autobrake goes to off once plane has stopped. If you apply brakes, believe (have not tested) it also goes to off, as system senses your brake actions. Or you can just leave it off.
The AB should kick off if enough pressure is applied to the brake pedals.
Thatâs why Iâm not sure why any significant amount of braking isnât deactivating his.
Yes this is true, the auto brakes disengage when you apply the toe brakes. I do this once I am under 60-knots and have disengaged the reverse thrusters.
OP - Do not think key bind or JS/button assignment is possible. PMDG had to work around lots of sim code which prevented their plane from working. If you read introduction it explains lots ot those things. Autobrake is not specifically mentioned. Itâs just a knob, and believe you can just leave it off. This is all assuming you are not Xbox owner/player, if so, I have no clue what happens in that situation.
In direct response, no, and in follow-up you donât need a button for this. As mentioned by others, sufficient manual brake pressure equal to or greater than the braking applied by AB will disarm it. This is different from the Bus where just a tap on the brakes release the AB, and the difference is intentional. Any forward thrust will also deactivate autobraking; however, the normal procedure is first ALWAYS use AB in normal conditions in spite of what some will say and then when below 60-80 kts use manual braking as required to safely maneuver to an exit from the runway. This is usually sufficient to disarm the AB.
Hello,
Thanks for all the input guys. I guess no button option for deactivation, which is too bad, as it is hard to guesstimate the right brake pressure to deactivate it.
Perhaps in the future this wil be updated.
Greetings,
Boudewijn
How is it difficult, if you manually brake and increase the deceleration then you have deactivated AB. Now I am curious as to exactly how to you complete your landing roll and exit the runway? The deactivation of AB shouldnât be a concern, it happens when you brake (with enough braking force).
Just for discussion sake, this isnât entirely correct. As I said, a part 121 carrier I worked for didnât even authorize pilots to use Autobrake on our 737s for quite some time.
Eventually, it was the cost savings that changed their minds. But, even then, its use was only mandated under certain specific circumstances, like poor braking action, short runways, etc.
Even my current company doesnât mandate AB as an absolute requirement, and thatâs on the 320 family.
Itâs a great system, on either aircraft. Likely its use was intended to be standard by the designers. But itâs not mandatory by any means and the aircraft stops just fine manually.
@Downscc brings up a good point, however.
Under normal circumstances, allowing the AB to work as advertised, then slowly applying increasing manual brake to override it, should make its deactivation pretty transparent.
Perhaps explaining what you think you need this switch for might be helpful in getting you the information you need.
Interesting. My first question would be how long ago was that change made in AB policy? Note I use the term ânormal procedureâ that has specific meaning in aviation, by no means did I intend to imply universal or mandated. However, in the simulation environment where the user has no sense of deceleration forces other than a 2D display and perhaps close inspection of the rate of change for GS I always recommend the use of AB above 60-80 kts to prevent cooking the brakes and blowing wheel fuses.
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Iâd say about 2009 or so. But even today there are guys I fly with on the Bus (generally older though I am no spring chicken 
) who have strong feelings about AB and prefer manual braking.
I think a lot of this stems from probably older attitudes and procedures, which were once recommended, then suddenly were not.
Many of the guys who have been around for decades perhaps justifiably look askance when the ânewâ procedures look a lot like the âoldâ procedures that were once bad mouthed as being outdated by the âold newâ procedures that sat between them. 
In the case of my old company, the procedure was, IIRC, to use TRs exclusively until 100kts. Then the brakes were applied manually.
This might have been a carryover from older brake pad design/materials which, again IIRC without looking it up, handled thermal load and braking efficiency differently.
In any case, when you are told one thing, to only brake below 100kts, and are then told to use AB, which does the opposite, itâs bound to make the average pilot question the efficacy of one or the other.
But, as I said, and as you suggest, the AB work great and there is no reason to not use them. The higher settings are particularly useful in circumstances where braking action/distance is a factor. And you can always override them.
Interesting discussion as always. I hope the OP got his question answered, though Iâd still like to know what issue he was having that needed addressing by turning AB off during landing rollout. 