Airline's Operating Manual, more specifically the Operator's Approved MEL Preamble is where you find the binding definition.
With the exception of some strange ideas or achieved flexibility goals, the general idea is
A moment of dispatch is defined. Typically the first movement under own power for the purpose of taking-off.
Before dispatch, any failure
- should be written in the book
- must be approved for release by the responsible maintenance officer as per MEL which is binding
- MEL paperwork needs to be filled and signed by an authorized person (captain in some cases)
After dispatch
- the MEL (which is by its definition more restrictive compared to ABN section of AFM / FCOM) does not need to be taken into account
These would be the legal boundaries.
"Refer to MEL" at a time when MEL is still controlling = "Apply the authorized procedures, close with a new maintenance release"
There is no other explanation.
Last edited by FlightDetent; 2nd Dec 2019 at 22:09.