ILS w/ localizer only, what system is set causing trim wheel to override/move from a pilot set position?

Question

I press/click the localizer box on the autopilot & it captures the localizer.  I press the glideslope in order to waken that needle capture & get nothing.

As a work around, I fly the localizer & try to manage glide slope management by power manipulation.

I am a CFI/MEII/ATP.  We teach that pitch controls speed and power controls altitude.  In the real world, if I trim the plane up in the approach phase to fly 90 knots, when the glide slope is ready to be "followed" down, a power reduction allows the plane to descend in concert.  No real change in trim is necessary, but somethine here is out of bed because the trim wheel indicator shows the wheel moved like a "big dog" in a pitch up direction.

The altitude box of the autopilot isn't checked and yet, something/some switch is still moving the trim wheel in a hard pitch up direction.  

Thank you.

Comments

I forgot to mention this is on the 172 X-Plane platform.

Answer 1

Hi PeytonPlace,

Which version of X-Plane are you using? Do you know if this issue is apparent in 10.45 as well as 10.50? If it is in 10.50 please go ahead and file a bug report for us here.

Comments

I am new to this universe, thank you for gracious interactivity.  My X-Plane version shows as being 10.45.  I know nothing about the version 10.50.  Where do I find the log.txt file so I can include it for relevant consideration?

HERE'S THE SEQUENCE OF EVENT'S

Preceded by level flight using the heading & altitude modules of the 172 autopilot, when the ILS localizer wakes up, I button switch to the LOC and the module captures, turns to & holds the center-line like a champion.  When the ILS glide slope wakes up, I click the G/S button on the autopilot radio face.  That action does nothing but turn the autopilot radio face G/S button perimeter line to a pale yellow color.  Repeatedly clicking that button toggles the button's color endlessly between pale yellow & no color.  It never once imposes any effect upon the planes vertical descent performance profile.  

By reducing the power to idle to get the plane to descend, I can fly the approach without ever suffering any full glide slope needle deflections, but my airspeed will drop to below 60 knts on the airspeed gauge in the course of my doing so.

In a properly trimmed airplane, on the glide-slope and without any windage, no more than a 100-125 RPM level of power change is required to hold needle deflection to within ATP levels of check ride performance.

It isn't clear whether or not my understanding of that radio's design capabilities yet remains incomplete or wrong.

Thank you for any insight casually allowed.

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The log.txt file is in the main X-Plane folder. It is overwritten any time X-Plane starts and is not complete until X-Plane is shut down. X-Plane 10.50 is still in beta, but is getting close to final.

I'd recommend you either download a copy of the demo or make another copy of your 10.45 install just in case you have worse issues with 10.50 (since it's not final yet).

To get the beta, run the installer, pick "update" and check the box to get betas. Continue through the installer to update to 10.50.

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Download file

 

J.Roberts..........Here's the log file from a clean software wake up.

I took phone pics of the panel and all the instruments showing the systemic flight dynamic dysfunction outlined below I currently am afflicted with.  Reach out to me & I will send those images if this log doesn't wholly & completely inform you.

Notably, the dysfunction has progressively worsened as of today.  At brake set on the runway, I set the trim wheel to it's Neutral position and took off.

1. ON CLIMB OUT with only the Autopilot heading module engaged:  The Trim wheel, on and of it's own volition, moved from Neutral to 2 notches of nose down trim.  
   1. That yielded these instrument indications:  
      1. The VSI read +500 FPM 
      2. The Artificial Horizon showed level  
      3. The altimeter steadily gained appropriate for climb, 
      4. While the speedo read 93 knots steady in a climb up to 10k' which isn't close to an appropriate climb speed for a 172.
2. GOING TO CRUISE:   Still using only the Autopilot Heading module, and, leveling off @ 10k by touching the Autopilot altitude hold button,....that action brought these instrument indications:   
   1. The Trim wheel moving of it's own volition to greater than 2 notches of Nose down trim, and:  
      1. The Artificial Horizon still showed level, 
      2. the Altimeter and VSI being appropriately stable and 
      3. the speedo steady increased to reading 105 knots.
3. Still using the Autopilot Heading module and the Altitude hold Autopilot button:  By then touching off the Autopilot altitude hold button, and, pulling power to idle......that action brought these instrument indications: 
   1. The Artificial Horizon yet showed level, 
   2. The Trim wheel of it's own volition moved down to +3 notches of pitch up trim,   
   3. The speedo dropped to 55 knots.

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How do I save a copy of the 10.45 that I currently have downloaded?  Given the above, do I even want to?  You're saying what I have is worth saving?  

If I ask X-Plane to give me another copy of 10.45. will that create confusion in my desktop having the bad copy?  How do I separate them?  Or does the act of asking again just overwrite?

 

 

 

 

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The attached file appeared to be a copy of "Sending Data to X-Plane."

You can simply make a new folder with a different name and copy your existing install into it. Or if you don't think you want to keep it, you can overwrite it with 10.50.

One thing you can try first is delete the preferences folder to make sure no keys or settings got messed up by accident that are causing strange issues.

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Deeper X-Plane Handbook research solved the glide slope issues.  

I still have a gremlin within the Trim and Artificial Horizon modules that I think a reinstall might be best applied to.

If I download the 10.5 & don't like it, is it casual for me to just delete .50 & redownload 10.45?

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Right now, while 10.50 is still in beta, you can update to it and then change your mind later and go back to 10.45. You just have to uncheck the box to "get betas."

Once 10.50 goes final you'll never be able to get an older version though, so if you particularly like 10.45 better you might want to keep a copy around.

(One other slightly annoying thing is that if you update to 10.50 then decide to go back to 10.45 the installer will ask for confirmation before overwriting any of the 10.50 files since they are newer. That can be a lot of "overwrite" screens to click through.)