Carenado F33A: No glidepath LPV approaches? (resolved)

[Kakugo 5]

I noticed something weird with the RXP GNS 430 in the Carenado F33A. If I do an LPV approach, the autopilot will capture the glideslope but the glidepath pointer in the HSI is not visible.

For an ILS approach on the contrary the glidepath pointer is visible and works normally.

I am not totally sure that the cause of the problem is the RXP GNS 430 (the settings are pretty standard, by the way) but it would be good to have some suggestion...

What could technically make the vertical CDI invisible for LPV approaches only, considering that the vertical guidance is actually there and it's working?

[RXP 2,338]

Hi,

A possible cause is that vertical guidance and vertical indication are unrelated in this case. Here is:

- The guidance is under control of the autopilot depending on its armed/engaged modes and the source signals it is using. In this case, it is using the XP11 vertical deviation signals which we can override but only to some extent with the SDK.

- The indication is under control of the gauge displaying it only, and to some extent, the underlying dataref the gauge is using for source data. It is possible the gauge is using another dataref source data than the one we're feeding through (RXP GNS setting like "Link HSI" and "Link VOR" controls which set of dataref the GNS overrides). It is also possible the gauge logic doesn't display any deviation from the GPS because it wasn't coded to support any indication when the NAV/GPS switch is set to GPS...

My suggestion would be to try finding whether this aircraft instrument is 3D only and whether you can find the datarefs it is using internally to drive the instrument needles (as defined inside the .acf and/or .obj files - these are just text files). This can give some indications about the nature of the issue. Otherwise, you might want to inquire with Carenado what is their gauge logic for CDI deviation when the HSI/GPS switch is in GPS mode, and cross check whether the datarefs they are supposed to be using are reflecting the deviations from the RXP GNS (using dataref editor for example).

[Bert Pieke 7,594]

1 hour ago, RXP said:

It is also possible the gauge logic doesn't display any deviation from the GPS because it wasn't coded to support any indication when the NAV/GPS switch is set to GPS...

That is certainly the case with Carenado, both in P3D and MSFS...  The HSI will display the ILS glideslope, but not the LPV glidepath.

[Kakugo 5]

12 hours ago, RXP said:

My suggestion would be to try finding whether this aircraft instrument is 3D only and whether you can find the datarefs it is using internally to drive the instrument needles (as defined inside the .acf and/or .obj files - these are just text files). This can give some indications about the nature of the issue. Otherwise, you might want to inquire with Carenado what is their gauge logic for CDI deviation when the HSI/GPS switch is in GPS mode, and cross check whether the datarefs they are supposed to be using are reflecting the deviations from the RXP GNS (using dataref editor for example).

I'm trying to familiarize myself with the aircraft definition, but it will take time... For the moment I found this piece of code in an *.obj file:

ANIM_begin
ANIM_trans_begin    sim/cockpit2/radios/indicators/hsi_vdef_dots_pilot
ANIM_trans_key    0    -0.24516    0.16553    -0.30094001
ANIM_trans_key    2    -0.24516    0.15153    -0.30094001
ANIM_trans_key    3    -0.24516    0.15153    -0.30094001
ANIM_trans_key    -2    -0.24516    0.17952999    -0.30094001
ANIM_trans_key    -3    -0.24516    0.17952999    -0.30094001
ANIM_trans_end
ANIM_hide    0    0    sim/cockpit2/radios/indicators/hsi_display_vertical_pilot
ANIM_hide    1    1    sim/cockpit2/radios/indicators/nav1_flag_glideslope
TRIS    2556 96
ANIM_end

I don't know what to make of it, though (for example, I don't know the meaning of the arguments to the various statements).

I also sent an email to Carenado, hoping that they will shed some light.

Something I haven't tried to do yet is to check if the problem is there also for the Laminar GNS.

[RXP 2,338]

6 hours ago, Kakugo said:

ANIM_hide    1    1    sim/cockpit2/radios/indicators/nav1_flag_glideslope

This is most likely the culprit:

This aircraft is using the NAV1 glideslope flag to hide the HSI driven needle... the problem is that NAV1 flag is based on radio signal, and HSI needle is based on NAV/GPS source selector. Mixing dataref is unfortunately very common in many aircraft gauges and lead to these kind of problems.

1) You might want to try this:

- replace sim/cockpit2/radios/indicators/nav1_flag_glideslope
  with: sim/cockpit2/radios/indicators/hsi_flag_glideslope_pilot

- enable "Link HSI" in the RXP options.

 

2) Otherwise you could replace them all directly with the RXP published equivalent:

(documented p16 of the RXP GNS User's Manual)

sim/cockpit2/radios/indicators/hsi_vdef_dots_pilot --> RXP/radios/indicators/hsi_vdef_dots_pilot
sim/cockpit2/radios/indicators/hsi_display_vertical_pilot --> RXP/radios/indicators/hsi_display_vertical_pilot
sim/cockpit2/radios/indicators/nav1_flag_glideslope --> RXP/radios/indicators/hsi_flag_glideslope_pilot

NB: if you do, the HSI won't display any radio deviation though, only GPS deviation.

NB: _pilot suffix to use the "Master Device" data, regardless it is a RXP GNS or GTN, and regardless it is unit1 or unit2.

[Kakugo 5]

6 hours ago, RXP said:

1) You might want to try this:

- replace sim/cockpit2/radios/indicators/nav1_flag_glideslope
  with: sim/cockpit2/radios/indicators/hsi_flag_glideslope_pilot

- enable "Link HSI" in the RXP options.

It worked beautifully, now the vertical deviation indicator works perfectly for both ILS and LPV approaches!

[RXP 2,338]

I'm glad this helped! I'm also glad X-Plane is a true platform and a true simulator... so that users can make it their way!

[Bert Pieke 7,594]

3 hours ago, RXP said:

I'm glad this helped! I'm also glad X-Plane is a true platform and a true simulator... so that users can make it their way!

Indeed... in MSFS, we are stuck with what Carenado chooses to dish up..