Originally Posted by OutOfRunWay
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)
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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.
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Ingo