CRJ ignores the V/S input...overshooting the runway

[Bontana Mack 0]

I've been flying from Bremen to Søderberg for the past few days. Søderberg is a small airport in Denmark with no ILS only with RNAV.

If I fly there manually it works reasonably well. But when I want to set the V/S to get the 3 degree glideslop, the CRJ keeps changing the sink rate.

 

In order to be able to activate the V/S, I always turn the altitude down to 0.

That's why I always overshoot the runway or come down way too early.

 

Is this normal in the CRJ? What is the error here? How do I get the 3 degree glideslope like it says on the chart (Groundspeed and vertical sink rate) ?

[Richard Dastardly 108]

I don't think the aircraft is capable of generating a synthetic glideslope, is it? I haven't investigated the coupled VNAV option, I have to admit. Presumably you've looked up your approach speed on the plate ( the airspeed allowing for wind is above Vapp, right? usually around Vapp+10 ) and picked the suitable V/S and rigidly stuck to the groundspeed. If the airspeed you ended up with is too slow the a/c will probably sink, because the current AP prefers to do that than hit the stick shaker, it seems.

 

What's the airport code btw?

[Bontana Mack 0]

vor 1 Stunde schrieb Richard Dastardly:

I don't think the aircraft is capable of generating a synthetic glideslope, is it? I haven't investigated the coupled VNAV option, I have to admit. Presumably you've looked up your approach speed on the plate ( the airspeed allowing for wind is above Vapp, right? usually around Vapp+10 ) and picked the suitable V/S and rigidly stuck to the groundspeed. If the airspeed you ended up with is too slow the a/c will probably sink, because the current AP prefers to do that than hit the stick shaker, it seems.

 

What's the airport code btw?

Thanks for your answer. 
But.. how do you fly a planned glideslope in the CRJ? It must be possible to fly an RNAV approach...because you can't always fly all approaches manually if there is no ILS.
If the pilot sets a virtual sink rate then the aircraft must follow this. The aircraft cannot simply overwrite the input..

Maybe one of the developers should explain that or a real CRJ pilot.

The airport code is EKSB. Beautiful AddOn for sale in the marketplace.

[Richard Dastardly 108]

Unless there's a function of coupled VNAV ( which again, I don't know anything about - VNAV is a rare option on CRJs ) if you want a precision approach, then you need ILS. VS is vertical speed, just how many feet per min the a/c is going up or down - if you want to fly a fixed angle descent then you'll need to hold groundspeed too or obviously you're not going to follow the right path.

 

EKSB has ILS on runway 32. If you need RW14 and the cloudbase is too low for a fully visual approach you could always fly the ILS until cloudbreak or circuit altitude & then circle to land, or I guess land with a tailwind if it's not too strong.

[CRJay 429]

14 hours ago, Bontana Mack said:

But.. how do you fly a planned glideslope in the CRJ?

 

Distance vs. altitude (eg. 1nm out altitude should be 317ft assuming field elevation at sea level etc) and vertical speed mode, which is the grounds for any non-precision approach basically. If the addon is not holding the vertical speed that you select, that is likely just another issue with the addon. The real plane does keep the selected vertical speed.

[Bontana Mack 0]

vor 23 Minuten schrieb CRJay:

 

Distance vs. altitude (eg. 1nm out altitude should be 317ft assuming field elevation at sea level etc) and vertical speed mode, which is the grounds for any non-precision approach basically. If the addon is not holding the vertical speed that you select, that is likely just another issue with the addon. The real plane does keep the selected vertical speed.

Its so sad...I love this little regional jets.

[Richard Dastardly 108]

3 hours ago, CRJay said:

 

Distance vs. altitude (eg. 1nm out altitude should be 317ft assuming field elevation at sea level etc) and vertical speed mode, which is the grounds for any non-precision approach basically. If the addon is not holding the vertical speed that you select, that is likely just another issue with the addon. The real plane does keep the selected vertical speed.

 

I think I've only had it not hold VS when airspeed's got in that region we know the AP doesn't like, and then it doesn't really matter what vertical mode it's in, it'll still sink anyway.

[Moar Right Rudder 10]

On 6/7/2022 at 3:15 PM, Richard Dastardly said:

I don't think the aircraft is capable of generating a synthetic glideslope, is it? I haven't investigated the coupled VNAV option, I have to admit. Presumably you've looked up your approach speed on the plate ( the airspeed allowing for wind is above Vapp, right? usually around Vapp+10 ) and picked the suitable V/S and rigidly stuck to the groundspeed. If the airspeed you ended up with is too slow the a/c will probably sink, because the current AP prefers to do that than hit the stick shaker, it seems.

 

What's the airport code btw?

 

The aircraft is capable of providing advisory VNAV on the PFD in the form of a deviation indicator on the same scale as the glideslope indicator (pseudo - synthetic glideslope). It appears as a white asterisk which is colloquially called "the snowflake." It appears on the PFD if advisory VNAV is enabled on the FMS, and when the aircraft is within 1000 feet of the calculated descent path. I don't believe I've seen that in the simulator yet though.

 

On 6/7/2022 at 4:58 PM, Bontana Mack said:

Thanks for your answer. 
But.. how do you fly a planned glideslope in the CRJ? It must be possible to fly an RNAV approach...because you can't always fly all approaches manually if there is no ILS.
If the pilot sets a virtual sink rate then the aircraft must follow this. The aircraft cannot simply overwrite the input..

Maybe one of the developers should explain that or a real CRJ pilot.

The airport code is EKSB. Beautiful AddOn for sale in the marketplace.

 

Normal procedure for LNAV approaches is to calculate the required descent rate in feet per minute after being fully configured. The aircraft's current groundspeed is referenced on the descent rate chart located on the approach plate. When at 0.2NM from the final approach fix, select VS mode and roll in the required descent rate. The CRJ takes time to begin a descent which is why VS is selected at 0.2NM.  Once past the final approach fix, the FMS should begin calculating the required rate of descent to the runway and display it on the MFD (provided VNAV is selected on the MFD Menu page for at least one MFD) and in the DIR INTC page on the FMS. At that point, the required VS can be monitored and adjusted as needed by the pilot flying. The advisory VNAV snowflake would also appear during the approach if advisory VNAV is enabled in the PERF MENU page of the FMS.

 

As to the aircraft not holding its VS correctly, Richard Dastardly has already summarized my own experiences. For now, the solution seems to be to fly just a tad faster until crossing the threshold if that issue is encountered.

[CRJay 429]

11 hours ago, Robert Klein said:

and display it on the MFD (provided VNAV is selected on the MFD Menu page for at least one MFD)

 

This part has never been implemented in the AS CRJ unfortunately. It's been missing since the original CRJ X.