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FD shows too high at ILS GS and afterwards


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Just made a flight from EDDE to EDDG (flying ILS manually), the FD showed the GS much higher than the diamond, even LOC and GS were active at APPR Mode. The diamond corresponded 3° and the PAPI.

I tried to reset FD and APPR Mode setting off/on several times, but it didn´t change.

V 1.0.5

Interestingly the FD stayed there even during taxiing.

EDDE/28 ERSIL4W ERSIL Y220 ELNAT Z190 WRB P12 ESADU Z858 MABAB T845 ADEMI DCT DOMEG DOMEG2J EDDG/25

EDDG is third party, but I doubt, that a scenery can produce that issue (?)

 

Regards, Herbert

FD EDDG RW25.jpg

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  • CRJ Forum Moderator

The flight director does not show the relative position of the glideslope in relation to the airplane - it shows the pitch angle you need to use in order to descend on the glideslope at your current airspeed and flap setting. 


Also, the pitch angle of the airplane does not necessarily correspond to the descent angle when flying a glideslope. Depending on the specific make and model of aircraft, and flap and engine power configuration, it is possible to be descending on a 3 degree glideslope, with the nose pitched 3 degrees above horizontal. (Or anywhere in between).
 

In your screen shot (taken on the ground) the flight director is in basic roll and pitch mode, so it has nothing to do (in this case) with whatever ILS is tuned on your nav radio.

 

On some airliners, such as the 737, the flight director command bars can be turned off on the pilot’s flight display, without the autopilot disconnecting, and some airlines do this as an SOP when flying an ILS to avoid distracting the pilot. (This cannot be done on the CRJ). You cannot fly the FD command bars as if they were indicating the deviation of the localizer and glideslope, that is not their purpose.

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Thanks for the important info, at all aircraft on ILS I was always chasing the FD which worked well till just before the flare, when diamond and FD tend to deviate.

Yesterday they differed a lot for the first time at the whole final approach, if I would have followed the vertical bar, I would have been leveled, no descend at all, that's why I thought about a bug.

Regards, Herbert

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  • CRJ Forum Moderator
8 hours ago, Puukka said:

Thanks for the important info, at all aircraft on ILS I was always chasing the FD which worked well till just before the flare, when diamond and FD tend to deviate.

Yesterday they differed a lot for the first time at the whole final approach, if I would have followed the vertical bar, I would have been leveled, no descend at all, that's why I thought about a bug.

Regards, Herbert

There does indeed seem to be an intermittent bug where the FD horizontal bar sometimes freezes, which apparently can be resolved by re-selecting APP a second time. (I posted that to our bug tracker). But, in general, the FD bar does not directly indicate glideslope deviation, but rather, the pitch angle you need for your current airspeed and flap configuration. It’s also important to always check the FMA (flight mode annunciation) in the upper left corner of the PFD to see what is driving the horizontal and vertical bars of the FD. The default on the ground (when no specific mode is selected) is ROLL/PTCH.

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  • 2 weeks later...

Sorry to chime in again, but I have the feeling that the vertical bar of the FD was more in the middle when on the glidepath before the last update.

I understood, that the FD shows the pitch, not the path, but I still wonder, if that big deviation is "normal".

My sinkrate at this picture was bit too much, but if I would have hold the pitch the FD is suggesting, I wouldn´t sink at all.

Regards,

Herbert

 

FD ILS too high.jpg

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I did several test landings.

Here it looks like when I steer after the FD. (Seems the FD would show me a level flight)

1039169064_FlyingFD.thumb.jpg.fc811d060bf31fa897dfdbb3ed1703c9.jpg

 

And here when I steer after the GS, about same glide path angle as the real CRJ, the FD bar stays well above, same position after resetting the AP or APP mode.

Can live with it but maybe there is room for improvement.

Kind regards,

Herbert

628597694_FlyingGS.thumb.jpg.ddfc989b84174ee8eee69cc2930fb100.jpg

 

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  • Aerosoft

Hi Herbert,

Like JRBarrett already mentioned, this is a know issue and has been added onto our issue backlog. However it's currently impossible to give any further time estimate on this. 

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