Re: Auto rejected take-off on 767?

From:         geohull@ditell.com (George Hull)
Organization: DirecTell L.C. - Park City, UT. - 1.801.647.0214
Date:         06 Sep 95 01:04:06 
References:   1
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In article <airliners.1995.1351@ohare.Chicago.COM>, Martin Fiddler
<entmlf@staffs.ac.uk> wrote:

> A couple of years ago, I was on the flight deck of a 767 and the captain
> told me that to assist a rejected take-off, if the throttles were retarded
> during the take-off roll, after being at 'full' (toga) power, then there
> was an automatic process which would (a) deploy the spoilers (b) deploy
> the thrust reversers (I guess with auto-throttle setting rev thrust power)
> and (c) apply max auto-brakes.
>
> Since then I have been on other 767's and the crew all state that their
> aircraft doesn't have this system, and also that they have never heard of
> it!
>
> So, did I imagine this conversation with the crew, were they making it
> up, or is it a rare option on the 767?

I fly B767s and I think that I can shed a little light on this subject.

Three systems are involved in this scenario.  The autobrake system is
normally used in the "RTO" mode during takeoff.  In this mode, if the
aircraft has accelerated above a certain value and the throttles are
retarded the system will apply "Max Antiskid Braking" through the
autobrake system . . and that amount of braking will truly make your tie
stick straight out in front of you.  The spoilers will automatically
deploy when the pilot selects reverse thrust.  So when the pilot retards
the throttles to idle it will result in lots of braking.  When he then
selects reverse thrust by moving the reverser levers it will cause the
reversers to operate and the spoilers will deploy.

To my knowledge these systems are fundamental parts of the aircraft and I
would be surprised to hear that other operators have different systems.

Occasionally it is necessary to reject a takeoff at low speed and that is
the reason for arming the system at higher speeds . . you wouldn't want
maximum braking if you were aborting a takeoff due to a door light or
other small problem at slow speeds.

George