LancairLegacy V2 and GSX HSI , Heading refresh problem

[Charles246]

I recently bought this amazing aircraft, LancairLegacyv2 from Realair and have been having a rather unique problem with the HSI not indicating the correct aircraft heading. See topic here:

http://www.simforums.com/forums/topic55043_post346042.html#346042

Today, I did these tests:
These are my conclusions. Please be aware that between each test, I reloaded FSX completely and under the same conditions.

 #1

Situation: KPAE parking (I think #9) facing Heading 160. Default ac, Cessna 172

 1.       After load, changed to Legacyv2 with the default 500 GPS. Battery on, engine off.

2.       Called GSX Ground Services.

3.       During pushback (nose right, tail left) started engine. Heading remained 160 during and after pushback even though I turned 90 degrees.

4.       Taxied to and lined up with  Rwy 34. Direction remained 160. GPS setting on switch not NAV

 I didn’t this time but if I had reloaded the Legacy at this point heading would have been correct. Also I discovered a simple press of “D” key would also have fixed the HSI.

 

#2

Exactly the same as #1 BUT with default Cessna 172. STILL using GSX

However, in this case, the heading changed accordingly during pushback and right turn. Correct heading on Runway.

 #3


Situation: KPAE parking (I think #9) facing Heading 160. Default ac, Cessna 172

 1.       After load, changed to Legacyv2 with the default 500 GPS. Battery on, engine off.

2.       DID NOT Call GSX Ground Services.

3.       SHift “P” for default straight push back. Started engine. After pushback manually turned right and headed to Rwy 34. HSI changed accordingly.

4.       Taxied to and lined up with  Rwy 34. Direction correctly indicated 340. GPS setting on switch not NAV

 Conclusion.

 In my opinion there is a small conflict with GSX and the Legacy.  Now, I did report earlier that the HSI was not correct during flight. I suspect that I had taken off, using GSX without noticing the Heading error.  GTN 750 is certainly not to blame for this because I was not using it in these tests.

BTW, I have not encountered this problem using GSX with any other aircraft, including PMDG and A2A. Now that I am aware of this, it will be a simple matter of re-syncing the gyro using the “D” key, which works in flight and on the ground. This is not “gyro drift” because the discrepancy between the real heading and the HSI indicator is as much as 90 degrees if it is not caught on the ground.

I would like to point out that these are simply my own personal observations and they may not be correct with other systems. I would also like to point out that I have received excellent, prompt support from the Realair team.

I would be interested to know if anyone with this aircraft has experienced the same anomaly.

[virtuali]

BTW, I have not encountered this problem using GSX with any other aircraft, including PMDG and A2A

And every other airplane out there, I'm sure, since this is the first report ever of such issue.

Now that I am aware of this, it will be a simple matter of re-syncing the gyro using the “D” key, which works in flight and on the ground. This is not “gyro drift” because the discrepancy between the real heading and the HSI indicator is as much as 90 degrees if it is not caught on the ground.

This explains both why it happens and how RealAir *might* be able to fix it.

It seems that instrument is not updating its value *directly* from the standard FSX variable that holds the current heading, but it's taken from some kind of internal custom variable, that is normally supposed to be in sync with the official one, but it's seems to be not updated when the airplane is "frozen", since GSX in order to be sure the plane stay attached to the truck while pushing (the plane could drift after you start the engines), sends the plane to disable the flight model while the sim is attached.

Depending on the method they use to remain in sync with the standard variables (which are always updated, that's why standard planes works), their routine might have not be called as long the sim is disabled.

The D key probably triggered a re-sync, because they might have programmed the instrument to specifically reacts to the gyro-drift event, which seems to be logical. So, the whole issue seems to be caused by that HSI not displaying the "real" heading (the FSX one, but some internal value that must be kept in sync with it.

[Charles246]

 Thank you for your comments. I am sure that  Realair programmers would be interested in this.

I know it is a little silly to use pushback on a GA aircraft  but at present my loading position leaves me no other choice and besides,  I enjoy using GSX.