PJ2,
yeah, your document is good until t/o roll begins. So it's tailored to only address no-go items, or alternatively items that the POI (Principle Operations Inspector) or his equivalent in France has determined that you deserve to get relief on.....your ETOPs inventory audits, etc, etc, qualify you to have that item put in your document. (defered mtc items.) For example, ETOPs was denied us because our spare parts inventory sucked, so our MEL was way different than other airbus operators.
After t/o roll ATA mtc books take over which are much amplified. However, mtc still references Master MELs en route in the interest of having parts and people prepared at the next through stop to continue, if necessary with deferred equipment for x days. Since at that point they know the MEL will take over at block in.
That's how I understand it. I know that MEL interpretation is one of the most disputed aspects of airline life. :-)
But that's why they pay us the big bucks, huh?
C