Originally Posted by
212man
It doesn't differentiate between modes deselcted by button pushing or those that have been forced out for other reasons - low IAS, system faults etc.
Although it would be better if it did. A pilot should know when he presses a button to decouple a mode, as should his colleague if there are even baseline SOPs for automation use. A warning that is routinely heard is one that is no longer heard.
Yes there is the possibility of a double-press by accident but again baseline SOPs should require mode engagement to be checked at the time of engagement.
What is difficult to cover by SOPs is the unexpected decouple without pilot action, and IMO that is the only time a "decouple" warning should be heard.