Elevator PCU Issue

The elevator PCU bearings have shown susceptibility to seizure caused by in-service contamination, corrosion or a breakdown of the nitrided bearing race . In the case of one aircraft in service, this condition has led to escalation of failure within the attachment hardware that resulted in the bolt failure.

• Transport Canada Airworthiness Directive (CF-2008-31)
• FAA Airworthiness Directive (2009-15-03)
• Elevator PCU Bolts Sheared Advisory Wire (AW700-27-0256)
• Aileron, Elevator and Rudder PCU Lubrication Advisory Wire (AW700-27-0268)
• Elevator PCU Customer Presentation
• Parker Elevator PCU Service Bulletin (376100-27-306)

Global Express and Global Express XRS

• PCU Special Check/Rework Service Bulletin (A700-27-066)
• Rework PCU Corrosion Prevention Service Bulletin (700-27-067)
• Rework PCU Corrosion Prevention Service Bulletin Information Sheet (700-27-067-is1)

Global 5000

• PCU Special Check/Rework Service Bulletin (A700-1A11-27-024)
• Rework PCU Corrosion Prevention Service Bulletin (700-1A11-27-025)
• Rework PCU Corrosion Prevention Service Bulletin Information Sheet (700-1A11-27-025-is1)

The SPCs (GH582-3001-13 for Global XRS and GH582-3001-15 for Global 5000) were introduced at aircraft serial number 9281 to address part obsolescence issues related to internal circuit card assemblies. A "STALL PROTECT FAIL" and "SHAKER 1 FAIL" or "SHAKER 2 FAIL" CAS messages can be sporadically posted at the initial SPC power-up or at the end of the Stall Warning System Pilot Activated Test (PAT) performed on the EMS CDU. The condition can be cleared by resetting the power on the SPC or reactivating the PAT.

For more information on this issue, refer to the following Advisory Wire:

• "STALL PROTECT FAIL" Nuisance CAS Message Advisory Wire (AW700-27-0275)

The following diagram shows and explains the relation between all of the SFCS related CAS messages and the different inputs in the system.

• SFCS EICAS Messages Logic Diagram

An SFCU is considered locked up when it does not respond to "Clear latched faults" and the reset procedure. If an SFCU is in a locked up state, you may need to use this procedure to "wake" the unit out of its state by voluntarily inducing a fault.

NOTE: Optionally in the procedure, any component of the SLAT FLAP system can be disconnected.

1. Set the FLAPS down.
2. Set both SFCU Circuit Breakers (CB) to OUT.
3. Access and disconnect any of the FLAP resolver's connector.
4. Set both SFCU CB back to IN.
5. Wait for the SLAT FLAP system to stabilize.
6. Set both SFCU CB to OUT.
7. Reconnect the component that was disconnected for this procedure.
8. Set both SFCU CB back to IN.
9. Wait for the SLAT FLAP system to stabilize.
10. Raise the FLAPS.
11. Perform two consecutive electrical rigging (Dual Rig) per AMM 27-51-05-820-801 - Electronic Rigging of the Slat/Flap Control Unit (SFCU).
12. Check that the SFCU is now operative and out of its locked up state.

The Flight Control System Reset procedure may be performed in an attempt to clear flight control fault messages.