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Aviation Alerts and Advisories

Service Advisory 1842: Nuisance unsuccessful AFCS Preflight Test (PFT) on Power-Up


All G5000-equipped Textron Aviation Inc. Model 400A (Beechjet) aircraft with System Software Version 2091.03 are affected.


Nuisance AP/YD FAIL CAS message on the MFD CAS window and an amber RUD BST FAIL Master Annunciator Panel following an unsuccessful completion of the AFCS PFT may occur.

Unsuccessful completion of the PFT disables the GFC 700 Autopilot, Yaw Damper, and Rudder Boost.


Do one of the following to resolve the nuisance unsuccessful PFT.

Only perform this action once to resolve the nuisance unsuccessful PFT. If the unsuccessful PFT persists determine the cause of the unsuccessful PFT.

  1. Stop power to the aircraft.
  2. Wait at least 30 seconds.
  3. Apply power to the aircraft.


  1. Open the following circuit breakers on the Forward Circuit Breaker Panel:
    • A/P Servos
    • GIA 1 (PRI)
    • GIA 1 (SEC)
    • GIA 2
  2. Wait at least 30 seconds.
  3. Close the circuit breakers listed in Step 1.


This issue will be fixed in a later software version.

Service Advisory 1842 Rev A