Originally Posted by
BraceBrace
From the FCOM: "A path descent uses the target speed for planning purposes only. There is no attempt to maintain the target speed during the idle portion of the descent"
There is actually a very nice option available for the operators in which the FMC "speed range" is shown on the speed tape like a magenta bar when in VNAV descent. Making this option a standard would make a lot of pilots more comfortable with the speed situation and let VNAV do its job the way it was designed to. This is still different from the "energy compensation" when a temporary level off is made through a MCP altitude (however, reading the FCOM I'm not sure if this is an option or a standard).
PF uses basic modes, time available PM makes the changes in the FMC. Either you continue to fly with basic modes or you revert to VNAV is up to you. But you get a second opinion that is - if programmed correctly - a good guideline for the PF. Not sure how many times the chit-chat on the flightdeck takes over (because we love to finish the story we started...), and the VNAV path becomes an "oh !!!!" realization.
The speed band!!! I didn’t know was a thing and googling it seems to show up not a whole lot which I guess means it’s not popular with companies but I’m betting would make a lot of people trust the speed deviation a lot more.