(767)What is the AFDS for?

[BMI701EGCC]

morning,

im just learning the 767 cockpit, converted for an all airbus junky..

and i came across the AFDS system, but what is it actually for,does it control the F/D according what the settings in the MCP, so waht does the Autopilot do then, just make the aircraft live!, follows the F/D?

Sorry if i seem abit dumb guys, its hard converting


thanks

[mbcxharm]

AFDS stands for Autopilot Flight Director System. I fly the 757, but I would imagine the 767 is basically the same. The AFDS consists of 3 FCCs (flight control computers, L C and R). Each one can EITHER provide a flight director or control the servos which operate the flight controls, as you say - controlled via the MCP.

Our company SOP is to use the centre autopilot so that the Captain and FO retain their FD information from the L and R FCCs respectively. Once all 3 autopilots are engaged for an autoland the flight directors will disappear.

If, for example, you chose to use the right autopilot, the first officer would have to select an alternate source for their flight director via the appropriate switch.

[BMI701EGCC]

thanks for the reply ,much appriciated

[Iz]

Hmm, after a few years on the 757, I completely do not remember that at all. My understanding is that any autopilot can provide both FD and FCC commands and I sure have not seen the FDs disappear on an autoland. Maybe it's a difference between older and newer 757s (we flew newer ones)?

[mbcxharm]

Well, ours aren't *that* old...

Picture passing through 1500ft radio altitude with the autopilot engaged on an ILS. A few clunks as the bus switching occurs - the remaining autopilots light up, and the flight directors disappear...

[ironbutt57]

Guess the command bars are considered not needed as the autopilots are flying...however they do reappear when the autopilot is disengaged..

[XL5]

It is possible - and some carriers do, have the avionics wired to allow any one FCC to simultaneously supply both a flight director and autopilot input. Under this arrangement flight directors remain available even with all three autopilots engaged during an approach. Muddies the waters a bit for BMI170 but serves to illustrate that it's a challenge to get a handle on the the auto flight system of the 76. I never cared for it . The big picture is represented by a mickey mouse virtual reality nav display cluttered to the point of being worthless. Worst of all, the 76 only has two engines Rant over!

[oceancrosser]

Ignoring xl5 rantings, most operators EXCEPT UK airlines keep the FD visible during approach. I have flown a few UK configured aircraft (on short-term leases) and on those the FD bars disappeared at 1500ft RA (initially we thought something was wrong, the first time we saw it!). Apparently has to do with required monitoring of raw ILS data during approach. On other a/c the FD bars remain visible throughout. Identical setup on 757/767s.

[Blacksheep]

There are several dozen pin-programable options for the B757/B767 AFDS and flight instrument Symbol Generators and you'll seldom get any two operators using exactly the same set-up for the whole aircraft. Far too many possible combinations to discuss on a bulletin board, that's for sure.

BMI701EGCC check your PMs.

[SeldomFixit]

grand, sweeping statement - at LOC APP (LAND mode selected ) F/D's more often than not are biased out of view ( notwhithstanding Blacky's comment that there are any number of pin programmable configs available )

[screw fix diret]

On my UK charter company's 757 and 767's the FD remaines in view with releveant information whether single or multi-channel approach.
Can I recommend '757/767 The Mysteries Revealed' by T.Gooch. I found it easier reading than the new Boeing manuals, and also more informative on occasions.

[Fuel Crossfeed]

Hi screw fix direct
I have been looking for the book you mention by t.gooch on the internet and did a search through waterstone book store - results nil - is that definitley the title and author?? where can I get a copy from??

[screw fix diret]

I've just put a search in through Google and loads of options came up. I'll try and put in the hyper link below.

http://ourworld.compuserve.com/homep...67/757_767.htm

[Fuel Crossfeed]

Thanks great help!