Dash-8 Q300 ILS Approach Glideslope Capture Suggestion

[sab12 6]

Based on a considerable amount of fooling around with this (what at least for me has been an) issue, if you are experiencing failure to capture the glideslope in the Dash-8 Q300 try this.I have found that if I DON'T USE THE Q300 MAP DISPLAY MODE AT ALL DURING A FLIGHT I DON'T HAVE A CAPTURE PROBLEM.I tumbled to this after noticing that I didn't have capture problems with the plain 300 and then exercising things that were different about the Q300.I also standardized on these PSS suggested practices:(1) Begin your Dash-8 flight from the Default Cessna flight.(2) Make sure that you switch from AUX to V/L before engaging APP. This is easier in the 300 because annunciators confirm the status.(3) Once you are within ILS range, you can engage the APP before the glideslope marker appears.

[Guest buffedub]

Hi SteveCouldn't get this to work either. At some airports the GS capture works fine. At others its no joy. My test case is CYVR. Have never been able to hold the glideslope here. RegardsRoger

[sab12 6]

Roger,Thanks for your response.When I tried this I had a list of airports that did and didn't work for me - like CYVR for you. I eventually hit on what I posted which worked for all on my list with my test setup.Today, I tried runways 8L, 8R, 26L, and 26R at CYVR with the plain 300 and they worked. Did 8R with the Q300 and it was OK too. Ran out of time at that point.Beside what was in my original post, my testing method includes the following:(1) I am using the BarryWard12345 modifications (see stickies)(2) Fuel 25%(3) Payload 4,375 passengers and 1,250 cargo(4) Capture attempted when level at an altitude of 4,000 feet(5) Capture attempted when at a airspeed of 150 (6) Capture attempted when near the runway centerline and with heading close to approach course. As noted in the PSS instructions, not having LOC capture delays or thwarts GS capture. Just as with the GS capture indication, having the LOC capture indication on doesn't seem to guarantee that you have it. The DASH-8's tolerance on this seems small - being off the centerline or approach course by a small distance or a few degrees (as in a crosswind landing situation) is all it takes.Hope that this may help.

[Guest buffedub]

Hi SteveI do have the BarryWard changes included in my config. All except the textures. I didn't see where that would have any effect on ILS. My normal approach to CYVR is at 2400 ft. The LOC is captured at quite a distance before the GS kicks in. The GS will hold for a short time, then the aircraft just flys through it. Initial capture is 150 knots reducing to 120-130 after GS capture. I have tried just about everything but CYVR remains a mystery. Its not really a big problem because being aware of this shortcoming, the plane is very easy to hand fly to touchdown. Grateful for any additional thoughts you may have.RegardsRoger

[sab12 6]

Roger,I don't use the BarryWard textures either.I have nothing else to suggest at this point beyond trying to reproduce what I've been successful with.......Sorry,Community - If someone who is knows how to look at FS scenery ILS parameters is reading this, is there anything unusual about the ILS parameters at CYVR (Vancouver Intl)? At MYGF (Grand Bahamas Intl) which used to be my most predictable GS nemesis?Thanks,

[Guest RoSPA_David]

Just a thought, but are you using approach plates for the runways? You may be too high! David

[Guest buffedub]

Hi DavidCan't speak for Steve but I do use approach plates. Doesn't seem to matter. At some airports the plane will just not hold the GS.Roger

[sab12 6]

Hi David,I haven't been using approach plates - just making sure that at 4000' I am coming at the glideslope from below.I'll check them from now on - I've wondered if the glideslope angle of different approaches varies enough to be an issue.Roger mentioned that he comes in at 2400'. Could he be too low?Thanks,

[Guest NormanB]

Most aircraft in real life are vectored to an ILS from as last as 6 miles but as far out (for heavies) as 15 miles. Generally 10 miles at 3000' is a good rule of thumb. The Dash could easily take a 6nm final though.At 2400' you wouldnt want to be any closer than 8 miles otherwise on a 3deg glide you would be above it - a recipe for messing it up.

[Guest sickparrot]

Hi,Ive just been doing some circuits of Manchester airport EGCC, one of the many airports I've come across where the Dash won't follow the glideslope. Nothing I seem to do will make it work (low fuel, approaching at a shallow angle etc). I originally thought it might be something to do with the ILS being the same at both ends of the runway, but it doesn't work at Geneva (LSGG) either. Both these airports have 3 deg glideslopes.Works fine at Brussels (for example), also default 737 approaches OK at Manchester.Someone please put me out of my misery and tell be it's a bug and there's nothing I can do about it, so I might have a little hair left for my old age.Ady

[Guest buffedub]

I'm not sure altitude has anything to do with it as long as you capture from below. The problem is that when the glide slope is captured, at some airports it will not hold it. It captures for a period of time and then loses it. I have not seen this behavior on any other aircraft. It would appear to be a bug.Roger

[steveark 0]

Don't think it has to do with your problem since it's happening at other airports. However, you may want to go to http://www.czvr.ca/_Pilot_Resources/_Navaids/index.php and download the navaid fix to correct the FS9 error for Vancouver 26L. This fixes the frequency for the ILS26R at CYVR to 111.95 as published in the charts.Also, I have landed the Dash 8 300Q at CYYZ Toronto on 24R many times (with the map display) and never had an ILS problem. However, during the last three attempts at 24R, I have blown right over the airport at 3000' even though the glideslope was active. Hmmmm?Steve A.