Hello,

 

I have a problem with approaches in the q400 with the autopilot disconnecting multiple times during the final approach. I set up for the approach with the ILS frequency tuned in nav 1 & 2 and the course set on both sides. I use nav1 on the left & 2 on the right side as the navigation sources. The LOC and GS seem to capture well and the plane follows the glide path. But once or twice every approach the AP disconnects and the plane goes in to Wings Level and Pitch Hold mode.

 

I removed all No Route lines from the FMS flight plan. Does any of you have the same problem or could hand me a possible solution for this? Or is this the normal behavior for the Q400?

 

I use Fsx with Saitek yoke, throttles and pedals. I use Rex and Opus for weather, but the problems also occurred when I used Fsx default weather.

 

Thanks in advance.

Hi Bastiaan,

 

Could you please give me the airport and ILS approach which you are attempting to execute.  Hopefully we can replicate the issue.

 

Thanks

I also had this issue when landing yesterday on EPKK ILS25. I use custom scenery by Drzewiecki Design. 

I think It happened around the time when I lowered the flaps once, but the second time when the aircraft was pretty stable on approach.

It happened to me on multiple airports. For instance on:

 

- Airports of Norway ENEV rwy ILS RWY 17;

- Aerosoft EDDH rwy RWY 23;

 

And a couple of other airports I cannot remember. I believe it also happened to me on FSX default KEWR during the second tutorial flight.

 

The times it happened to me I was stable on approach, Flaps 10 or 15 (landing flaps).  

During the last time, the disconnection of the AP seemed to coincide with me adding a little power on the throttle. But I do not know wether this was a coincidende or not. Cause I do that multiple times during an approach.

 

I have my yoke and throttle setup via default FSX settings, not via FSUIPC.

 

I hope you can help me or otherwise tell me if I am doing something wrong. It BTW still is an awesome plane! The AP disconnection is just an inconvenience. Now I know it happens, I'm alert for it and just press the APPR button as soon as I see it happen. That reconnects the AP.

Ok thank you......I will have a quick look and see if I am am able to replicate

Ok thank you......I will have a quick look and see if I am am able to replicate

Thank you. Today it's Queensday over here, but if later this week I have the time and opportunity, I will try to make a recording of the issue.

This happened to me last night - KEWR ILS 22L. Resulted in more manual approach and landing practice!

Just a thought, and maybe not a factor, but you folks aren't in heavy turbulence when it disconnects, nor are you making any sudden, significant control moves manually (i.e. bumping the ailerons or elevators by accident) when this happens? I believe most A/P's will disconnect under those circumstances by design. It's not likely this is the case here, but I thought I'd mention it just in case.

 

Glenn

Just a thought, and maybe not a factor, but you folks aren't in heavy turbulence when it disconnects, nor are you making any sudden, significant control moves manually (i.e. bumping the ailerons or elevators by accident) when this happens? I believe most A/P's will disconnect under those circumstances by design. It's not likely this is the case here, but I thought I'd mention it just in case.

 

Glenn

This has occurred to me, Glenn, and you're right to suggest it. I suspect that my issue was related to poor management of airspeed on final approach, rather than turbulence or sudden moves of the flight controls. This morning, I flew the ILS 4R approach into KEWR without issue while paying close attention to my final approach speed...and indeed, close attention is necessary at all times!

 

Great aircraft.

I hadn't thought of speed as a possible issue, but likely if you get too close to the stall, that maybe would do it. I know rapid movements of the control surfaces or manually overriding the autopilot can cause a disconnect IRL, but I don't know about the Dash 8 specifically. Would be good to keep an eye on it to see if we can find a common deonominator. I've not had it myself, but I've done mostly all manually flown approaches.

Well I tested it again this evening and everything worked as it should. I did watch my approach speed very carefully and kept it a lot higher than I used to. So I think that speed is the issue.

Well I tested it again this evening and everything worked as it should. I did watch my approach speed very carefully and kept it a lot higher than I used to. So I think that speed is the issue.

Nice, and I'm going to add an extra 5-10 or so to my app speed as well.

Approaching stall speeds does disconnect the autopilot in my experience...  (in the sim)

Don't be adding "lots" of speed to the approach speed, or you'll start overshooting shorter runways. You'll be fine as long as you use Vref + 5 from the FAF on in. That gives you lots of cushion. You should cross the threshold at Vref, but by that time the A/P should be disconnected anyway. The Vref speed is what you calculate somewhere just before or just after starting your descent typically.

I can confirm getting too close to stall speed will do that. I had a few "head scratching" moments (meaning me muttering words that will only show up as asteriks on the forum) while on approach too before coming to that conclusion.