AP Sel Problem

  • Hi, I'm working on getting the Q400 under control, and struggling a bit with autopilot. I can get Alt to hold, but I'm not able to set a new altitude and get Alt Sel to capture it.


    I am able to preset the altitude with the knob, but pressing Alt Sel does nothing. Is there anything I could be missing?

  • If you need a new level you need to set up a climb or descent first and then set ALT SEL. Try a VS entry and then ALT SEL.


    I haven’t tried VNAV in the Dash 8, it might work too. (I’m a tiny bit intolerant😬 of a FMC/CDU that isn’t 100% fully functional and 100% perfect yet, perhaps PC FS4 will have something special there?).

  • If you need a new level you need to set up a climb or descent first and then set ALT SEL. Try a VS entry and then ALT SEL.


    I haven’t tried VNAV in the Dash 8, it might work too. (I’m a tiny bit intolerant😬 of a FMC/CDU that isn’t 100% fully functional and 100% perfect yet, perhaps PC FS4 will have something special there?).

    ok thanks that makes sesnse! So it can't be engaged when holding level. I'll try to set a climbing VS hold first and then click Alt Sel to capture a higher altitude.


    Am I right to assume then that an AP vertucal mode has to be active first before clickingAlt Sel....that Alt Sel can't work if the aircraft is under manual control?

  • The wiki has am in depth tutorial which covers the autopilot, too.

    Thanks, I'm glad to say that I completed a short flight successfully, Innsbruck to Salzburg, and got the altitude captures sorted.


    The big challenge for a new user here is the interactive cockpit, as zooming in to click the Autopilot buttons means losing wider visual references to the outside and the flight instruments. So its a constant back and forward as you learn and check the effect of your AP inputs.


    I am still a bit confused about AP on the Q400 as activating one mode seems to disengage another. But its early days, I'll try another flight tonight.....

    • Official Post

    Yes, you can only have one vertical mode active and one lateral mode active at one time. Armed modes require certain conditions before they become the active mode. For example the altitude capture at selected altitude (ALT SEL) only engages when the aircraft is close to the target altitude selected by the pilot.

  • Yes, you can only have one vertical mode active and one lateral mode active at one time. Armed modes require certain conditions before they become the active mode. For example the altitude capture at selected altitude (ALT SEL) only engages when the aircraft is close to the target altitude selected by the pilot.

    Ok I see, its one at a time from each side, thanks. I suppose while using VNAV plus Alt Hold then speed has to be managed with small power adjustments.