VNAV question
I'm having some difficulty with VNAV. I was on a flight and initially set up vnav for a waypoint before the initial fix for landing. That worked fine. When the magenta V appeared I set altitude and hit alt sel. The next waypoint was the initial fix and all of the waypoints including the initial fix had restricted altitudes which I could see in the flight plan. As I approached the next waypoint I got a vert. alert and hit the vnav button but the altitude never changed. I did get a pitch hold message and then nothing. I got this to work perfectly once but now I can't duplicate. After vnav was active all I did was select the vnav button when I got the vertical alert as I understood that I did not have to change alt and hit alt select after activating vnav. I am currently running the pilot edition. This was a saved flight.
What am I doing wrong ?
Comments
Try setting the altitude selector to the lowest altitude on your VNAV path. If you're flying an approach, set it to approximately the minimum descent altitude.
Well I figured I did something stupid and I did. I was hitting the nav button instead of the app button when I switched nav source to vor 1. I was so used to the app button being used for autoland that I just ignored it.
Yours has autoland?
The Q400 doe not have autoland
Don't hit alt sel! When in VNAV the plane will hold all constraints automatically so you do not need and shouldn't use ALT SEL while in VNAV.
Sometimes I start a descend in VNAV and let VNAV fly the plane all the way towards the runway: I simply set a lower altitude (any altitude will do) so I can enable VNAV and then of it goes on VNAV PATH all the way: the ALT you set on the AP is disregarded while in VNAV: you only need it in order to set a lower alt and start it.
BTW Nowadays I only use VNAV for RNAV approaches and descend in VS, as is done in real life.
Well I don't think it is autoland which can just about put you on the runway. However, if you have nav source set to localizer (vor 1) and come in above the glide slope when the plane intercepts and app has been selected the plane will follow the slope. It does not seem to be as accurate as autoland, but it's still useful for low vis landings.
I saw some other posts which said the same thing about using VNAV. If I was to use VNAV for RNAV when would I set the altidude? I was thinking maybe to do it at the IAF and set the altitude for something like MDA.
I also tried setting up VNAV but never engaging it for descent. I used VS and basically used VNAV for orientation. I've been manually calculating descents for years and frankly it has worked surprisingly well.
I had one other question about VNAV. There is an option to disconnect VNAV on the FMS. I clicked it but the magenta v was still there. It looked as though it was still engaged.