Trial by newspaper

Charles Oppermann wrote:

I'll be curious to know how the Autobrakes usage (if in fact that is true)
affects the outcome. On one hand, the Autobrakes can prevent wheel lockup
and keep the aircraft under control. On the otherhand, manual braking
should be able to result in shorter ground rolls, generally.

I disagree that this is true generally. Everything I've read about
anti-lock braking systems suggests that they will outperform humans
under all but a few special conditions. The special conditions are the
cases where locking the wheels is beneficial to a short stop. These
conditions are basically deep snow or other soft material such as sand.
In these cases, the material builds up in front of the lock tires and
increases the resistance of the tire moving through the material (forms
a bow wave essential). However on dry or wet pavement, ice, light snow,
light layer of sand or loose dirt, etc., the ABS wins.

I have seen a few tests (auto and motorcycle, not airplane) where very
highly skilled racers have been able to outbrake and ABS vehicle on dry
pavement. However, the margin of winning was very small, and only a few
REALLY skilled drivers/riders could beat the ABS with any regularity.
And through in a patch of loose dirt or oil, etc., and, at least with
the motorcycles, the ABS would allow control to be maintained.


Matt