B777 V/S Mode
hi
looking for some write up on the following mode of B777:
Condition 1: Maintaining an altitude e.g. 1000 feet with "ALT" indicated on FMA.
The aircraft does not descent in V/S below 1000 if altitude set in MCP altitude window is 1000 or above.
Condition 2: Maintaining an altitude e.g. 1000 feet (which is also the MDA and is set as minimums on the PFD).
The aircraft descends in V/S below 1000 even though the altitude set in the MCP altitude window is 1000 or above.
Is this logic (if I am correct) mentioned any where in the Boeing manuals?
thanks