GTN750 not picking up GS on RNAV/LPV approach (resolved)

[Daskal 9]

Hans,

I also have the Carenado F33A working with the 750. I'm very much a novice at this but after reading your posts I figured it was time for me to try an approach with GS. 

My FP consisted of departure from KLGA ( I'm from Queens NY 🙂 ) RW22 with the first waypoint as KEWR and the next waypoint as KLGA with the approach RNAV 04 Y gps LPV and a vector of PONAE. After takeoff I climbed to 3000ft with A/P on NAV. After my plane made its turn to PONAE at KEWR I switched the A/P to APR and set in 1700ft with a descent rate of -900 ft/min prepping for arrival at PONAE.

At PONAE I engaged the VS and armed the ALT. I kept the airspeed around 140kts. I reached 1700ft prior to the next waypoint which is DNNIS. Within a second of reaching DNNIS the plane captured the GS and brought me down perfectly onto RW 04. Pretty neat function. So neat in fact that I turned the plane around at the end of 04, took off on 22 and successfully repeated it again.

I have the latest version of the plane itself, the GTN is 2.5.3.0 and the latest released STEAM version 11.25 I believe. Other plugins are XPUIPC for ATC and FlyWithLua for some scenery effects. I haven't yet bought the REP but may do so in the future.

My current settings for the panel display are posted here:

[GTN_750_1]
; comma separated list of read only settings.
locked = CopilotSide, RadiosPair, AutoNavSource, UseAudioPanel, FuelType
; comma separated list of render targets.
drawto = WINDOW, PANEL3D
; is the master device if true.
MasterDevice = true
; connects GPS to copilot side if true.
CopilotSide = false
; selects COM/NAV Radios '1' or '2'.
RadiosPair = 1
; uses computer time if true, simulator time otherwise.
ComputerTime = false
; reduce screen update rate by half.
ReduceRate = false
; integral lighting rheostat index (0 to 3) or percent (-100 to 0)
Rheostat.Display = 0
; integral lighting rheostat index (0 to 3) or percent (-100 to 0)
Rheostat.Buttons = 2
; connects GPS to HSI if true.
LinkHsi = true
; connects GPS to HSI course motor if true.
LinkCrs = true
; connects GPS to OBS input if true (LinkHsi/OBS or AutoNavSource/OBS).
LinkObs = true
; connects GPS to VOR if true.
LinkVor = true
; connects GPS to Autopilot if true.
LinkOto = true
; connects CDI key to NAV/GPS switch if true.
AutoNavGps = true
; enables automatic GPS/VLOC selection.
AutoSelect = true
; selects VLOC NAV '1' or '2'. '0' selects same source as 'RadiosPair'.
AutoNavSource = 0
; sets device power source: ALWAYS_ON,AVIONICS_BUS,MAIN_BATTERY
PowerSource = AVIONICS_BUS
; connects GPS to Shadin Air Data computer if true.
UseAirData = true
; connects GPS to Shadin Fuel Data computer if true.
UseFuelData = true
; connects GPS to Audio Panel if true.
UseAudioPanel = true
; connects GPS to Transponder if true.
UseTransponder = true
; connects GPS to RYAN 9900BX if true.
UseRyanTcad = false
; sets TCAD sound alerts volume in percent: 0 to 100.
RyanTcadVolume = 50
; enable device failures if true.
UseFailures = false
; uses Simulator GPS commands if true.
UseSimGpsCmds = false
; sets transponder VFR code (octal default: #1200).
VFRcode = #1200
; sets fuel type: AVGAS,JETA,JETB,DIESEL
FuelType = AVGAS
; sets ownship icon type: 
; AUTO,LOW_WING,HIGH_WING,KIT_PLANE,TURBOPROP,TWIN_ENGINE,SINGLE_JET,BUSINESS_JET,2BLADES,3BLADES,4BLADES,ARROW
OwnshipIcon = AUTO
; sets TAWS type: TERR,TAWS_B,TAWS_A
TawsMode = TERR
; sets TAWS surface: HARD,HARD_SOFT,WATER,ANY
TawsSurface = HARD_SOFT
; TAWS minimum runway length (feet)
TawsMinLength = 40
; TAWS approach air speed (knots), or -1 (auto detect Vref: 83)
TawsApprSpeed = 88
; TAWS maximum flap extension speed (knots) or -1 (auto detect Vfe: 154)
TawsFlapSpeed = 154
; TAWS maximum gear extension speed (knots) or -1 (auto detect Vle: 154)
TawsGearSpeed = 154
; sets voice type: MALE,FEMALE
VoicePref = MALE
; sets master sound volume in percent: 0 to 100.
MasterVolume = 100
; selects the default database: 0: 'Garmin (North America)', 1: 'Jeppesen (Worldwide)'
NavDbType = 1
; selects the CPU running the trainer process: 1 to 32
; 0: last core, -1: automatic.
CpuAffinity = -1
; sets TCAD maximum number of targets to X-Plane AI Traffic Count.
UseTcadAiCount = true
; updates Simulator GPS flight plan if true.
LinkSimGps = false
; saves the active route as a Simulator flight plan if true.
AutoSavePln = false
; mute sound when simulator window looses focus if false.
NoAudioFocus = false

Hope this helps you.

 

Daskal

 

 

[Daskal 9]

Hans,

Forgot to add that my 750 shuts off using the master avionics switch. I did notice that the plane's battery switch can be off and the 750 can still be turned on with the master avionics switch. I'm not sure if that's the case IRL though?

Daskal

[SimPilotNL 3]

Hey Daskal,

Thanks for your reply. It is late here right now (the Netherlands here) but I will definitely check your settings versus mine.

The scenario you describe is exactly how it works for me if I use the default Cessna 172SP. I descend to the published glideslope intercept altitude using V/S, then the airplane stays at that altitude in ALT HOLD mode with APP mode selected and it will intercept the glideslope. Its also exactly how it works for my in any airplane if I use the default X-Plane GNS unit.

However for some reason it does not work in the Carenado F33 (with or without the REP). And I'm puzzled why that can be.

[SimPilotNL 3]

Tried with your settings (which are basically the same settings I had but without VC integration).

It all does not make any difference. The GTN750 does not pick up the glideslope but remains in ALT HOLD mode.
It also does not power off when I swtich off the Master Avionics Settings.

I am going to give this one more go:
@Jean-Luc: Can you please point me to all relevant folders and registry settings, so I can uninstall the GTN unit, delete every folder and every registry setting associated with the unit and then do a complete re-install of the Reality XP GTN750.

[RXP 2,336]

Hi Hans,

The issue you are experiencing couldn't be related to the installation itself, only to the 'communication' between the GTN plugin and X-Plane.

The first clue is the fact it does not power off. The code logic behind this is very simple: the plugin reads either 'battery' or 'avionics bus' datarefs, and power on/off the device accordingly. If this doesn't happen, it means the plugin is reading the wrong datarefs (improbable otherwise it would be widespread an issue), or something running in the context of your aircraft is preventing the dataref to update.

Let's focus on this one first then:

The two corresponding datarefs used (depending on your GTN power source setting) are:

"sim/cockpit/electrical/avionics_on"
"sim/cockpit/electrical/battery_on"

Can you cross check these change to 0 or 1 depending on your actions on the aircraft panel?

[SimPilotNL 3]

Jean-Luc,

I have tested this again.

I use a .ini file from the forums here that does integrate the GTN70 in the virtual cockpit (but when I tried the one posted above in this thread there was no difference).

I start the plane cold and dark, both datarefs you mention have the value 0. Flipping the battery switch turns the sim/cockpit/electrical/battery_on value to 1. I then startup the engine, after which i flip the Master Avionics switch. That makes that the sim/cockpit/electrical/avionocs_on value is set to 1. The GTN starts up, the blank (black) screen comes to live and the unit starts to work (thats also how i have set-up the unit, so this is all correct).

After the flight I switch the Master Avionics off, the value for sim/cockpit/electrical/avionics_on changes to 0. I see a quick flicker in the GTN screen, but it does not go to blank. However it does seem to be "off" in that clicking on any of the buttons seems not to do anything anymore. I would expect the unit to really switch off though, meaning the screen would be blank.

After that i switch the battery off and that means the value for sim/cockpit/electrical/battery_on  is set to 0.

[RXP 2,336]

Ok, so this seems normal (regarding datarefs). However, should the screen flickering and displaying the last visible screen image, instead of turning blank, there is something else not working correctly.

Can you please post the content of the RXP log files to cross check? (see User's Manual for file/path).

[SimPilotNL 3]

Holidays over, so less time to experiment unfortunately.

The log files do not seem very interesting:

rxpGTN.xpl.log

18/08/14 17:27:52.808 08244 -    ] # win.xpl version 2.5.3.0
18/08/14 17:27:52.808 08244 INFO ]

rxpGtnSim.dll.log

18/08/14 17:27:56.519 08244 -    ] # rxpGtnSim64.dll version 2.5.3.0
18/08/14 17:27:56.518 08244 INFO ]
18/08/14 17:28:44.219 02668 INFO ]

 

Edited August 14, 2018 by HansMatthijssen

[RXP 2,336]

Hi Hans and sorry for the delay.

Effectively the log files don't show anything meaningful. Nevertheless, lack of information isn't meaningless in itself!

What this most likely tells is that the GTN trainer seems closing fine (otherwise there would be log entries). Therefore, this shorten the probable cause list to a few candidates.

Can you please see if you are running near 100% RAM and video card resources when in the simulator? You can check the video card memory used directly in the X-Plane graphics settings (shown around the texture complexity slider). Otherwise, CTRL+SHIFT+ESC to open the task manager and check the 'memory' tab for any relevant information.

The 'stuck' screen roughly means there is something in the system preventing some 'final' communication between the trainer and the plugin (shut down notification) prior the trainer process closes. Our solution takes care to prevent the usual 'race conditions' when closing the process so I can only think of something 'delaying' the closing process somehow. This could be video card driver related, audio driver related, or usually anti-virus related.

[SimPilotNL 3]

XPlane tells me right before switching off the Master Avionics: 1536MB of textures loaded (on a 4GB Radeon 290).

System tells me 4.4GB RAM in use (8GB installed).

[RXP 2,336]

Hi Hans,

please allow us a few more days as we are working on the GTN Trainer v6.50 compatibility update.

Mind you, in this process we might have found a small potential bug in one of the code which runs right when the trainer shuts down, which may in effect get the trainer exit under some conditions. It seemed not triggered for the majority of our customers though, and this most likely is related to some other settings in Windows.

[SimPilotNL 3]

I haven't changed anything, but I did switch planes flying with the Carenado Baron now. And no idea why but the GTN750 does pick up the glideslope suddenly.

Im gonna test the Bonanza later this week or in the weekend.

[StLu1000 2]

Hi guys

I also have the same problem with capturing GS. Everthing else works fine.

I will check and try all the suggestions in this thread.

Im running X-plane 9.61, I dont think this is related to x-plane version at all. And XPR sell this as compatible with xp 9 as well!

After som test I will return with the results.

Note:  Why Im running XP 9.61? It is because of PFC hardware that does not have a plugin for newer X-plane version.  I spend a lot of money on PFC Cirrus II so I need to stay with XP9 (it is very stabile).

BR

Stefan

 

 

 

[RXP 2,336]

14 minutes ago, StLu1000 said:

It is because of PFC hardware that does not have a plugin for newer X-plane version.

At least, we do ship the 64bits PFC DLL which handles the PFC_430 hardware.

[StLu1000 2]

Hi Jean-Luc and others

I think I found something interesting today while testing many options due to RNP approach with GTN 750. Used different airplanes, different HSI, radar altitude, etc etc. No changes was the results that GS does not capturing by AP or flying by hand, however when I on the GTN push "visual" during approach procedure the AP and glide slope connects. This test was made on airport ESTA Angelholm, Sweden.

Im reading the GTN manual (many pages) to find out how it works and how it should be handled.

There is also when selecting approach a Approach ID to be filled in, I really dont know what that is and if it is needed if I got the approach and runway selected?

Im also use a real updated database. I have also manually edited the fix database with all fix that belongs to ESTA procedures, if that matters I dont know except that it is easier to follow the airplane on the map when flying the procedure route.  So if it doing something else I really dont know today?

Question:

How is RXP GTN calculating and get the glide slope information since there is no glide path transmitter at the airport?

Can we learn something from this?

BR

Stefan

Edited September 27, 2018 by StLu1000