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redout
17th Jan 2008, 23:42
I am looking for some confirmation of the following. If you press the instinctive disconnect pb for more than 15 sec I have read that the ATHR will be disconnected for the remainder of the flight. I queried this to an A340 captain (former A320) and was told that this is not true and that it can be reconnected by just arming it with the pb and selecting the climb detent. Also the ailerons of the A320 droop 5 degrees when flaps are lowered to provide more lift, is this true ?

idg
18th Jan 2008, 00:41
FCOM says that if A/T disconnect p/bs are pushed for more that 15 secs the AT is disabled until the next FMGEC power up which is usually on the ground.

Dream Land
18th Jan 2008, 05:10
Your friend is obviously wrong, no big deal if you can't use the A/TH, the big item would be that A/Floor is now OFF. :eek:

Jonty
18th Jan 2008, 07:12
currently on an airbus 320 conversion course and according to our FCOMs the ATHR disconnection is correct, after 15 secs it will not reconnect, even if alpha floor is reached.

Also the ailerons do droop on flap extension, by 5deg.

Wonder Boy
18th Jan 2008, 22:35
I did it in the sim just to see and after 15 seconds of the buttons held, it refuses to reconnect.

redout
21st Jan 2008, 14:03
Thanks for that lads. I wonder shall I try the disconnection in the sim tomorrow with the instructor who told me it was not possible ? Better not though, cant envisage it going down to well ! Nice to know that it is possible but worrying that the instructor did not considering he was a former A320 captain and now a A340 captain. Maybe he was thinking of the A340, does anybody know if this is common to all airbus aircraft as I would dare not accuse him of being wrong considering the wealth of knowledge and experience which he has compared to myself.

CONF iture
21st Jan 2008, 15:32
Don't bother with that and let your instructor in a good mood, the sim cession will be more relax and productive for the three of you.
But in that case, airplane does what the FCOM says.

420
21st Jan 2008, 18:22
i cant seem to find where this 15 seconds thing is stated in the Fcoms. can anyone provide me with the page. the french really know how to jumble things up:confused:

Office Pest
21st Jan 2008, 18:46
FCOM 1.22.30 AUTOTHRUST.
It's right at the bottom of the page.

Best regards,

Office Pest.

Chrome
21st Jan 2008, 19:08
420, from the company provided FCOM1 CD:

AUTO FLIGHT FLIGHT GUIDANCE
A/THR ARMING CONDITIONS
1.22.30 P60

or

AUTO FLIGHT FLIGHT GUIDANCE
1.22.30 P63
Caution - If the pilot pushes and holds one instinctive disconnect pushbutton for more than 15 seconds, the A/THR system is disconnected for the remainder of the flight. All A/THR functions including ALPHA FLOOR are lost, and they can be recovered only at the next FMGC power-up (on ground).

ppppilot
21st Jan 2008, 21:07
The A340 does the same

OutOfRunWay
22nd Jan 2008, 17:33
can anyone explain to me why airbus thought that pressing the instinctive disconnect pb should kill the a/t for the rest of the flight? I cant for the life of me think of a reason.
If there were any reason to disconnect the a/t and the alpha floor protection semipermanently wouldnt the button for doing it be more appropropriately located on the overhead somewhere?

Thanks

IFixPlanes
22nd Jan 2008, 18:23
can anyone explain to me why airbus thought that pressing the instinctive disconnect pb should kill the a/t for the rest of the flight? I cant for the life of me think of a reason. ...

AMM says: (highlighted by me)
...
Isolation of the Engines from the A/THR System
(Ref. Fig.)
The engine control is no longer dependent on the throttle control levers when the conditions below (elaborated by the FMGC and transmitted to the ECU) are met:
- A/THR ENGD
- A/THR ACT
- TARGET N1/EPR VALID
- throttle control lever in the area which authorizes the autothrust control or Alpha floor protection active.
Action on one of the two A/THR instinctive disconnect pushbutton switches or the disengagement of the A/THR function detected by the FMGCs on the command or monitoring channels forces the thrust control function of the throttle control lever position.
This is done through the wired discretes that the ECU receives directly.
This device permits to get rid of any failure downstream of the FMGC which might cause an untimely engagement of the A/THR function.
At level of the A/THR engage logic performed by the FMGC, an action on one of the two A/THR instinctive disconnect pushbutton switches for more than 15 s. inhibits any engagement of the A/THR function, whatever the reason (A/THR pushbutton switch on the FCU, Alpha floor protection etc.)
A similar protection is available at level of each ECU/EEC. Action on one of the two A/THR instinctive disconnect pushbutton switches for more than 15 s. inhibits operation of each ECU/EEC in autothrust control mode.
...
http://img250.imageshack.us/img250/6581/athrisolationoh9.th.jpg (http://img250.imageshack.us/my.php?image=athrisolationoh9.jpg)

Ingo

OutOfRunWay
22nd Jan 2008, 19:24
Thanks very much for that very prompt answer!

Still, from the viewpoint of my very very shallow understanding of the airbus' systems, I find this a rather bizarre place to hide this effect. Judging by the previous posts, it looks like some of the operators out there weren't fully aware of the connection between the instinctive disconnect and the a/t either.

But then again, who am I to badmouth these design decisions..

Greets, OORW

Dream Land
23rd Jan 2008, 02:11
It turns off the A/TH for the remainder of the flight, what more to understand? :hmm:

420
23rd Jan 2008, 14:07
its not that we dont understand Dream Land,

its just that its absolutely bizarre why the french would make in such a way. the reason by iFix is kinda understandable but still.... why???