Last night I was trying to shoot ILS approach in Dash 8 Pro. I intercepted localizer  and hit APR button on autopilot. Autopilot held localizer only but didn't follow glideslope.

Is there something else has to be turned on in approach mode so that autopilot follow LOC+GS?

 

Thanks

Did you hit the localiser before you hit the GS?  The only time I've failed to capture is because I hit the GS first.

 

Just tested and yes, it does enforce LOC capture before GS.

another thing i would check is the nav source knob has to be set to NAV and not FMS (blue needles instead of purple on the PFD.)

 

cheers

-andy crosby

Both the guys above give good advice.  Also, when you establish on the LOC, look at the GS diamond to the left of your altitude tape and that will show where your aircraft in in relation to the GS. You'll want to be BELOW the GS (diamond high) to intercept the GS. If the diamond is lower than the center, you'll never intercept it as you would have already missed it.

 

Hope this helps!

You might have inadvertently hit 'NAV' instead of 'APPR', which is the selection you'd make for either a VOR approach where there's obviously no glideslope, or a LOC DME approach where there might be one showing but you only want to use the LOC part of it, perhaps if it was under maintenance or calibration. 

Thanks I will try again . I think I left nav selection on FMC. Although in FMC was set up correct approach.

 

P.S. And yes I intercepted localizer first , then glide slope came alive until GS interception point.

Only other thing I will add to this topic, in the FMA (Flight Mode Annunciator just above the artificial horizon) check after you hit the APPR button that you have LOC in white in the left column  (where you would see the lateral navigation (LNAV HDG ect...) and GS in white on the right column where you see the Vertical navigation ( ATL, VNAV, V/S ect...) the white colours on the FMA means a guidance mode has been armed (can mostly be seen with a Nav mode such as VOR tracking, Alt SEL or VNAV) once each has been captured (LOC first) they should turn green (meaning it it now active) and take over from the previous active guidance mode.

One thing thing I forgot to say:

 

Any time you make a change to the autopilot modes or selections, confirm they are present and even if you are flying solo, announce them outloud, this is good airmanship so you dont miss anything