Autobrake Selection Md11

[trisager 2]

Hi,How does one select an appropriate level of autobraking (min, med, max) in the MD-11? Is there a table somewhere that can be used with airplane weight and runway length/condition to make this choice? I looked through the documentation, but if it is there I can't find it.Tom

[downscc 1,327]

You are correct, performance tables should would be nice but PMDG couldn't get rights to them; so I understand.I've been lucky using max when I'm heavy, otherwise I use mid... always been a little timid to use min. This assumes the landing is on a runway that has at least 8000 ft.

[trisager 2]

You are correct, performance tables should would be nice but PMDG couldn't get rights to them; so I understand.

OK, thanks. Do you happen to know what kind of braking assumptions are used in the landing distance tables in the performance section of the FCOM? That could serve as a guideline for selecting more/less autobrake.Cheers,Tom

[badderjet 181]

Ok well I have no idea either how things are done in the plane that you mention, but from different r/w operators I hear that lower autobrake settings will decrease brake life more than the higher settings. More than that, I have not heard of anyone using the maximum setting in any case, but who knows maybe they use it on ultra short runways. Not sure about where to find such tables either... huhm hard to say anything smart without them haha :(For example, a 737 has settings 1-2-3-MAX, and even on a 4000m (13000ft) runway they would use e. g. 3. Again, same runway, but the other time an A320 and similar conditions, they would only use LO, so I suppose there are more factors than just rwy length etc. But to conclude from all I have seen so far, you'd be well off with medium to med-high settings most of the time.One more comment on the 'heavy' thing. Basically selecting a higher brake setting wont do anything if you are just heavy. The autobrake system just preselects and maintains a certain deceleration rate, so if anything changes if youre heavy than it will be brake PX. But no matter what, same speed - you'd stop within the same distance. Same with reverse thrust. If you are autobraking, reverse thrust will not at all change your deceleration rate or braking distance at all but simply easen the brakes' work by taking part of the brake energy.Of course when heavy the distance will usually be slightly longer since you will very likely be touching down at a slightly higher speed. :(Best regards,Etienne