Originally Posted by
Bleve
In nil wind that would true, but the real world is not like that. As you descend (or climb) the head/tail wind component will change. That will change your IAS and if you have select a 'pitch for speed' mode, the pitch attitude (and thus the V/S) will change to maintain the selected speed.
I've never noticed the oscillations like that in my V/S in VNAV PATH after the descent stabilizes. While I have seen V/S variations in LVL CHG and VNAV SPD, they are generally trending either up OR down and not up AND down. Is this behavior peculiar to the Airbus managed descent? Oh, and I think you mean GS not IAS regarding winds aloft change through the layers. Thanks for the response.
Originally Posted by
busTRE
Yes there is. Not sure which but you're not sure of.
In an IAS/Mach Idle descent the VS and thus vertical path will vary with wind, temperature/density changes, vertical currents, IAS/Mach switchover and other factors. An Open Descent is always quite variable in terms of achieved profile.
Thanks BusTRE! So, as I understand this, Open Descent is another way of describing the Airbus Managed Descent - and if so, on a Boeing, the corollary would be VNAV SPD, not PATH.
Have you ever heard of wind?
Yes, NoD, and either my wife or my nephew's dog broke some just now.