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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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04/26/21

Message Overview:

Message Name:

PITCH OSCILLATION WITH AUTOPILOT ENGAGED

Identifier: 221OBS003
Effectivity: AIRCRAFT: 20501 - 20999
System: Auto Flight
Associated CAS: None
System Description: 22-11-00
Schematic Diagram: 22-11-00
Wiring Diagram: 22-11-17
22-11-21

Message Description:

Pitch oscillation with Autopilot engaged.

NOTE: There will be no faults in the MDC or Advanced diagnosis from the A/P FCC diagnostics.

Possible Causes:

  • Elevator Servo (A125)
  • Elevator Servo Mount
  • Flight Guidance Panel (FGP) (PL9)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Functional Test of the Elevator Servo Mount AMM 22-11-13-720-802
Operational Test of the Elevator Servo AMM 22-11-21-710-801
Removal of the Flight Guidance Panel (FGP) AMM 22-11-05-000-801
Installation of the Flight Guidance Panel (FGP) AMM 22-11-05-400-801
Removal of the Elevator Servo Mount AMM 22-11-13-000-801
Installation of the Elevator Servo Mount AMM 22-11-13-400-801
Removal of the Elevator Servo AMM 22-11-21-000-801
Installation of the Elevator Servo AMM 22-11-21-400-801
Standard Practices - Wire Repair SPM 20-12-10-02

Troubleshooting Recommendations:

  1. There will be no faults in the MDC or Advanced diagnosis from the A/P FCC diagnostics.
  2. Did the flight crew select a different ADC source?

    1. The fault is most likely unable to be reproduced on the ground and a complete air data system check should be carried out.

  3. If there are no faults with the Air Data System check the following:

    1. Did the fault occur on the left and/or right flight director?
    2. Did the flight crew select the XFER button on the FCP and the condition was the same left or right?

  4. Perform Functional Test of the Elevator Servo Mount per AMM 22-11-13-720-802.
  5. Does Elevator Servo and rigging meet specifications?
    NOTE: Make sure the Elevator Servo rigging values are not too close to the low or high end of the tolerance spectrum. Try to adjust as close to the middle of the spectrum as possible.

    1. If NO, properly rig Elevator Servo.
    2. If YES, replace Elevator Servo and Mount and perform rigging.

  6. Do close out.

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