Cactus Charlie
Well-known member
- Joined
- Mar 1, 2025
- Posts
- 254
- Type aircraft owned
- CCX-2000 (FX-3)
- Base airport
- KDVT
- Ratings
- Commercial ASEL, ASES, AMEL, glider. CFI glider, ASE, Instrument.
Most who have a G3X Touch system using GSU 25 ADAHRS and a G5 will never see a source reversion. This is what an attitude reversion looks like after G3X Touch detects a problem with GSU 25 attitude data:
Indicated pitch attitude is about 17 degrees nose up but velocity vector and VS show aircraft is not climbing. An impossible condition at IAS 90 mph. G3X Touch alerts to ATT MISCOMP (attitude miscompare) indicating that GSU 25 and G5 pitch attitude do not agree. It has not yet decided which pitch source is correct -
7:56:02 local time
The GSU 25 recovered for a while and ATT MISCOMP was removed:
7:57:07 local:
Later GSU 25 pitch attitude goes bad again and for long enough that G3X Touch reverts to G5 as source for PFD attitude. GSU 25 remains as source for PFD air data. GSU 25 goes into align mode in an attempt to recover to normal operation -
7:59:32 local:
Then all back to normal (no image captured)
These images were captured in an FX-3 with a wing mounted GSU 25C. The rubber isolator option was not installed and the GSU 25C was a -50 part number not the newer -55 version.
If you have this configuration be aware that, if GSU 25C outputs misleading pitch attitude, it may take several seconds for there to be any alerting. If AP is engaged it will follow the spurious pitch attitude. If AP is disconnected the FD will still follow the spurious pitch attitude.
Indicated pitch attitude is about 17 degrees nose up but velocity vector and VS show aircraft is not climbing. An impossible condition at IAS 90 mph. G3X Touch alerts to ATT MISCOMP (attitude miscompare) indicating that GSU 25 and G5 pitch attitude do not agree. It has not yet decided which pitch source is correct -
7:56:02 local time
The GSU 25 recovered for a while and ATT MISCOMP was removed:
7:57:07 local:
Later GSU 25 pitch attitude goes bad again and for long enough that G3X Touch reverts to G5 as source for PFD attitude. GSU 25 remains as source for PFD air data. GSU 25 goes into align mode in an attempt to recover to normal operation -
7:59:32 local:
Then all back to normal (no image captured)
These images were captured in an FX-3 with a wing mounted GSU 25C. The rubber isolator option was not installed and the GSU 25C was a -50 part number not the newer -55 version.
If you have this configuration be aware that, if GSU 25C outputs misleading pitch attitude, it may take several seconds for there to be any alerting. If AP is engaged it will follow the spurious pitch attitude. If AP is disconnected the FD will still follow the spurious pitch attitude.
Last edited:
