11/04/24
Message Overview:
Message Name:
INPUT Fault
Message Code:
B3-681726
Associated CAS:
| Reporting LRU: | Auto Throttle (AT) Computer |
| Effectivity: | Post SB350-22-002 Aircraft 20937 and Subs |
| System Description: | 22-30-00 |
| Schematic Diagram: | 22-30-00-801 - Auto Throttle System 31-45-00-101 - Integrated-Avionics Processor System (IAPS) |
| Wiring Diagram: | 22-30-00-801 - Auto Throttle System (ATS) |
Message Description:
Required input for AT function reported absent by the AT computer and IOC appears to be transmitting data.
Possible Causes:
- Input Missing - Refer to Troubleshooting Recommendations for a list of possible inputs.
- Autothrottle Computer (AT) (A252)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
NOTE: Review the Auto Throttle "AT Diagnostic Information", to find details about the MDC Data Reader Labels & bits.
NOTE: The Auto Throttle uses the same FGS, IRS, and ADS inputs as the transfer side Flight Director. Transferring the side of the Flight Guidance (XFR) will cause the Auto Throttle to switch input sides. In the event of a failure or erroneous data, although the Auto Throttle would initially disengage and report "AT FAIL" Advisory CAS, an alternative Flight Director source of data may be selected using the Reversion Control Panel. If the reselected inputs are sufficient, the Auto Throttle can be re-engaged.
Other inputs (FADEC, Flaps, SPC, Radio Altitude) have other reversion capabilities, but these functions are automatic and not controlled by the crew.
Quick Links:
| Removal of the Auto Throttle Computer | AMM 22-30-01-000-801 |
| Installation of the Auto Throttle Computer | AMM 22-30-01-400-801 |
| Removal of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-000-801 |
| Installation of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-400-801 |
| Operational Test of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-710-801 |
| Removal of the Integrated-Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-000-801 |
| Installation of the Integrated-Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-400-801 |
| Operational Test of the Integrated-Avionics Processor System (IAPS) | AMM 31-45-00-710-801 |
| Safety Precautions - Maintenance Practices - ALL | SPM 20-00-01-02-01 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
| Electrical Connectors - Maintenance Practice - ALL | SPM 20-20-00-02-01 |
Troubleshooting Recommendations:
- Review the NOTES found in the Troubleshooting Tips element prior to starting this troubleshooting.
- On the Cursor Control Panel press “A/ICE”, “ECS”, “FUEL” buttons simultaneously, access the MDC on MFD #2.
- Highlight “LRU INDEX/OPERATIONS” then press “ENTER” button.
- Highlight “AT COMPUTER” then press the “ENTER” button.
- Press the “SKIP” button.
- Highlight Label “352” then press the “ENTER” button.
- View and record label 352 data.
- Compare the data recorded with the table below to identify what AT computer input is missing.
LABEL BIT FIELD NAME FIELD DESCRIPTION 352 11 L PFD Input Fault 0 = False / 1 = True 352 12 L SPC Input Fault 0 = False / 1 = True 352 13 L DCU Input Fault 0 = False / 1 = True 352 14 L RA Input Fault 0 = False / 1 = True 352 15 L ADC Input Fault 0 = False / 1 = True 352 16 L IRS Input Fault 0 = False / 1 = True 352 17 LA FADEC Input Fault 0 = False / 1 = True 352 18 LB FADEC Input Fault 0 = False / 1 = True 352 19 L IOC Input Fault 0 = False / 1 = True 352 20 R PFD Input Fault 0 = False / 1 = True 352 21 R SPC Input Fault 0 = False / 1 = True 352 22 R DCU Input Fault 0 = False / 1 = True 352 23 R RA Input Fault 0 = False / 1 = True 352 24 R ADC Input Fault 0 = False / 1 = True 352 25 R IRS Input Fault 0 = False / 1 = True 352 26 RA FADEC Input Fault 0 = False / 1 = True 352 27 RB FADEC Input Fault 0 = False / 1 = True 352 28 R IOC Input Fault 0 = False / 1 = True 352 29 Spare - Use the MDC to view fault messages associated to system(s) identified in the previous step. Refer to SmartFix Plus troubleshooting procedures.
- Make sure the associated LRUs are powered and no communication faults are present.
- Do close out.