GEnxsux,
A few more possibilites for "orphan" AMM tasks:
- There used to be an MPD / MRBR item in previous issues (or even other aircraft models!); AMM taks hasnīt been deleted.
- There will be a MPD / MRBR item in the next revision of these documents, but the AMM revision comes in advance (not bearing the MPD ref. as it doesnīt exist at that time).
- The AMM task is a TSM task.
- The AMM task is associated to the MEL (De-/Reactivation procedure).
- The task gives instructions for "routine" / "non-routine" work that is not driven by the maintenance programme, e. g. inspection of certain A330/A340 LP-valve actuators for correct dimensions at installation.
I suppose there are many more routes...! Maintaining airplanes is a lot more complex than the MPD makes us believe...
Cheers,
J.V.