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Old 1st Oct 2007, 01:40
  #2576 (permalink)  
xulabias_bent
 
Join Date: Sep 2007
Location: Istanbul
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Austrian Simon,

The AutoThrust kept engaged after the left engine reverse was fully deployed for c. 2 secs as per design (as a consequence of a comparision between target FMGC EPR and target FADEC EPR at reverse). It disengaged by letting eng. 2 at c. 1.18 EPR, far above idle.

As it was an involuntary disconnection the general consequence would be a thrust lock at the last EPR commanded (or achieved) by the Autothrust regardeless of the right engine TLA (aside from the max. thrust limit set by this TLA).

The crew should be warned of this thrust lock by a flashing (ECAM ?) with the message "ENG THRUST LOCKED" (and the messages AUTO FLT A/THR OFF in amber and THR LEVERS...MOVE in blue) with a single chime and the Master Caution Light flashing every five seconds (or something similar to that).

The problem with this warning as I could learn from a discussion some X posts ago was that it is (supposedly) inhibited after touchdown and when (at the same time) the a/c speed is above 80 knots.

There must be a logic diagram of this warning as there probably is one for the autothrust in speed mode behaviour. In the case of the warning someone probably saw in the logic diagram that "phase 8" and above 80 knots were inputs to a NAND gate in the diagram (or something equivalent).

Maybe this participant could help us in this quest for the logic diagram of the A320 autothrust system.

Last edited by xulabias_bent; 1st Oct 2007 at 02:47.
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