07/10/19
Message Overview:
Fault Message:
HST MDU[CH2]/ACTUATOR FAULT
Fault Code:
27662242SX
Associated CAS:
| Reporting LRU: | Flight Control Unit (FCU) |
| System Description: | 27-40-00 |
| Schematic Diagram: | 27-41-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 27-41-02 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
Channel 2 of Flight Control Unit 1 or 2 reported small creeping from the Pitch Trim Actuator or small creeping from the Motor Drive Unit (MDU).
Possible Causes:
- Pitch Trim Actuator Motor Drive Unit (MDU) (A184)
- Pitch Trim Actuator (B44)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
The present MDU-5 is known to be susceptible to nuisance coasting if there is a fast trim cycle of NOSE-UP or NOSE-DOWN.
To prevent unnecessary troubleshooting and component removal after an occurrence of this phenomenon, it is recommended to do Flight Control System reset procedure before the next flight to determine if the STAB CH1 FAIL or STAB CH2 FAIL advisory or STAB TRIM caution message shows.
If one of these messages still show after the self-test, it is necessary to do troubleshooting. If during subsequent flights a STAB CH1 FAIL or STAB CH2 FAIL message shows more than once in 10 flight legs, we suggest that operators record the CAIMS flight fault history for FCU 1 and FCU 2 if the faults reported are:
- H STAB MOT DR UNIT [CH1]/WRG FAULT
- H STAB MOT DR UNIT [CH2]/WRG FAULT
It can be necessary to replace the motor drive unit. Contact your local field service representative for further troubleshooting.
Quick Links:
| Removal of the Pitch Trim Actuator | AMM 27-41-09-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Pitch Trim Actuator | AMM 27-41-09-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Pitch-Trim Actuator-Motor Drive-Unit | AMM 27-41-17-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Pitch-Trim Actuator-Motor Drive-Unit | AMM 27-41-17-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Perform Flight Control Systems reset procedure.
- If system checks are good, do close out.
- If fault remains (same CAIMS fault message), continue with next step.
- Replace Motor Drive Unit.
- If system checks are good, do close out.
- If fault remains (same CAS and CAIMS messages), continue with next step.
- Replace Pitch Trim Actuator.
- Do close out.