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**Bertie the Bunyip[_28_]** · October 3rd 08, 07:49 PM posted to aus.aviation,rec.aviation.piloting

wrote in
:

On 3 Okt, 18:13, Bertie the Bunyip wrote:
FriarTuck wrote

s2:

some questions if anyone knows the answers...

is 757 fly by wire or fly by cable?

Neither

The FMCS has full flight and landing capability, is it a separate
control system?

It can autland but it's seperate from the flight controls. You can
disengage it anytime you like.
It fails passive, which means you can manually oer-ride any time you
want.

The FANS network, is it capable of directing "goto
location/altitude" and "set airspeed to K" type commands to the
plane?

Doesn't have one

Is the yoke and throttle a completely separate control system from
the FMCS control system or are they common?

seperate

is the throttle control in cockpit only routed through FMCS ?

No

I read that the yoke was capable of exerting more power on the
surfaces than the FMCS could, essentially giving yoke priority, is
that correct? *If so can you describe how that works?

The stick will give more authority because the autopiot flies the
airplane in a more limited way than a pilot would. When it intercepts
an altitude, it does so smoothly with a limited G. A pilot can
manuever the airplane as abruptly as he likes, but of course, most do
so just as smoothly as the autopilot does.
Sometimes the autopilot isn't quite so smooth. If it gets "surprised"
by a track interception, for instance, it will be a bit jerky in
roll, or if it gets surprised by a pitch intercept it wasn't
expecting and the autothrottle gets a bit out of step it will pitch a
bit harshly. Ridig as a passenger this sort of thing is often felt in
the back and mistaken for hand flying.

Bertie

Thankyou. Very informative.

At the risk of filling your forum with kookery - Speaking as someone
who seems to have experienced these things, do you think that, once
getting in the general area using the autopilot, Hani Hanjour (or even
Friar Tuck or myself - a low hours, head-up-arse PPL) could have
performed a 360 degree turn, pointed it at the Pentagon, and smacked
into it?

Yep

Bertie