Thank you for your contribution !
It makes perfect sense for answers A & B !
I've been thinking about question C. Maybe there is a bit more involved.
It is interesting to see that in the supplementary procedures, whenever one loop is failed, we have to select either loop A or loop B (whichever is operational) at the end of the procedure, and keep it this way.
So I came with the following explanation:
- If a low gas pressure is sensed in a loop, it is automatically detected and the loop is deselected without any pilot input (that would be the answers to questions A & B).
- If any other type of failure is present, it would be detected by the system test performed by the pilot before starting the engines. Such a failure would not be tested automatically, and that's why the pilot is asked to select either loop A or loop B following the identification of a failure.
Otherwise I don't see why the pilot would have to manually select loop A or loop B following the application of the supplementary procedure when one loop is known to be failed (it probably implies that the NORMAL mode of operation cannot monitor all the failures).
What do you think ? If someone has some useful info...