scoreboardII
Well-known member
- Joined
- Apr 15, 2008
- Posts
- 2,694
I'm not going to disagree with your other points as we have more than enough Tyrannosaurus Rex pilots trying to make the stuff work. Very amusing mostly...The other common mistake I've seen SWA pilots do when trying to change speed to stay in VNAV Path is to do so by using speed intervention and then wonder why it goes to VNAV Speed mode. Unless you are in the approach phase within the FMS logic, you need to change the speed within the FMS and not set a manually selected speed. Any other time speed intervention automatically takes it out of VNAV Path.
.
However, your point above is counter intuitive and against common strategies to make the system work.
We know it goes into VNAV SPD when you select intervention, it's supposed to. That does not mean it's off VNAV profile. If a higher speed is selected, it descends to lowest altitude available, and speeds up, and continues until returned to VNAV un-interventioned.
However, entering a change into the FMC descent speed will cause the system, at least our version (which may be one step above Fred Flinstones version) to hiccup, puke, and probably leave you with a VNAV disconnect.
Additionally, intervention allows you to return to expected speeds as that is the VNAV profile the FMC is referencing. Changing the descent speeds manually buys you zero flexibility end game if they descend you at a higher speed. If they descend you at a slower speed, your comment has some merit, but that is usually not the case and if inside the geometric/idle descent point, you're screwed either way.
Or, I'm wrong, and you need to show me the reference
Last edited: