Does the 747-400 behave similarly with V/S selected (aircraft previously in ALT hold or VNAV cruise) and the selected Altitude equal to the current altitude?
I did some FD tests on the ground (IRU's aligned) last week. I adjusted the baro to a few hundred feet and selected the same feet on the MCP. Then I selected ALT Hold, then V/S.
V/S was then annuciated on the FMA.
Thanks
Rgds
NSEU