03/25/21
Message Overview:
Message Description:
Left PFD data buses are reported absent by Left IOC and reported failed by 2 of the following: Left MFD, Right MFD, Right PFD.
Possible Causes:
- Adaptive Flight-Display Unit (PFD) (A27)
- L PFD Circuit Breaker (CB1-C3)
- Left Cockpit Breaker Panel (CBP1)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Replacement of DC Circuit Breakers | AMM 24-65-00-960-801 |
| Removal of the Cockpit Circuit-Breaker Panel (CCBP) | AMM 24-65-01-000-801 |
| Installation of the Cockpit Circuit-Breaker Panel (CCBP) | AMM 24-65-01-400-801 |
| Removal of the Adaptive Flight-Display Unit | AMM 31-61-01-000-801 |
| Installation of the Adaptive Flight-Display Unit | AMM 31-61-01-400-801 |
| Operational Test of the Adaptive Flight-Display Unit | AMM 31-61-01-710-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
| Electrical Connectors - Maintenance Practice - ALL | SPM 20-20-00-02 |
Troubleshooting Recommendations:
- Reset L PFD Circuit Breaker CB1-C3. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Swap L PFD (A27) with R PFD (A26). Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Confirm presence of the Ground, and the configuration discrete, at the right MFD (A28).
Measurement at Expected Result Result Notes Conn. A27P3 - E GND Power Ground Conn. A27P3 - C GND Chassis Ground Conn. A27P3 - F GND Chassis Ground Conn. A27P2 - 43 GND Config. Disc. Conn. A27P2 - 45 GND Config. Disc. Conn. A27P2 - 16 GND Chassis Ground Conn. A27P2 - 25 GND Chassis Ground - If the check is not satisfactory, repair defective wiring.
- If the check is satisfactory, continue with next step.
- Confirm presence of the 28 VDC at the left PFD (A27).
Measurement at Expected Result Result Conn. A27P3 - G 28 VDC - If the check is not satisfactory, continue with next step.
- If the check is satisfactory, do close out.
- Do wiring check from L PFD (A27) to left Cockpit Breaker Panel (CBP1) for the following wire:
From: To: Result Conn. A27P3 - G Conn. CBP1P/J3 - 48 - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair wiring.
- Replace L PFD Circuit Breaker CB1-C3. Is the fault still present?
- If NO, do close out.
- If YES, replace defective right Cockpit Breaker Panel (CBP1).
- Do close out.