02/26/21
Message Overview:
Message Description:
Integrated Standby Instrument output (BUS ISI-1) is reported missing by the Stall Protection Computer.
Possible Causes:
- Junction Box 3 (JB3)
- Integrated Standby Instrument (ISI) (A90)
- Stall Protection Computer (SPC) (A178)
- Data Concentrator Unit (DCU) (A14)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin:
- AW300-27-0081 - Spoiler Electronic Control Unit (SECU) and Horizontal Stabilizer Electronic Control Unit (HSTECU) - Cold Temperature Circuit Breaker Reset Procedure (20501 - 20999)
- SB 100-27-14 - MODIFICATION - STALL PROTECTION SYSTEM - Introduction of the Stall Protection Computer (SPC) Part No. 822-1792-003 to Correct Loopback ARINC 429 Failure Messages
Forum Articles/Infoservice/Newsletter: None
- If the 'STALL PROTECT FAIL' message appears after SPC power up, reset the SPC circuit breakers 'SPC CH A' (CBP1-B10) and 'SPC CH B' (CBP2-B10).
- If the message appears following a PAT, then reset the SPC circuit breakers 'SPC CH A' (CBP1-B10) and "SPC CH B" (CBP2-B10). Perform another PAT and make sure the message does not come back.
If the 'STALL PROTECT FAIL' CAS message and associated cascading messages do not clear after performing the steps above, troubleshooting should be performed.
Quick Links:
| Removal of the Junction Box JB3 | AMM 24-63-09-000-802 |
| Installation of the Junction Box JB3 | AMM 24-63-09-400-802 |
| Functional Test of Junction Box JB3 | AMM 24-63-09-720-801 |
| Functional Test of the Stall Protection System | AMM 27-32-00-720-801 |
| Removal of the Stall Protection Computer | AMM 27-32-01-000-801 |
| Installation of the Stall Protection Computer | AMM 27-32-01-400-801 |
| Removal of the Data Concentrator Unit (DCU) | AMM 31-41-01-000-802 |
| Installation of the Data Concentrator Unit (DCU) | AMM 31-41-01-400-802 |
| Removal of the Integrated Standby Instrument | AMM 34-12-01-000-801 |
| Installation of the Integrated Standby Instrument | AMM 34-12-01-400-801 |
| Functional Test of the Integrated Standby Instrument | AMM 34-12-01-720-801 |
| 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 the following circuit breakers and perform the Pilot Activated Test (PAT) of the Stall Protection System on the Systems Test control-panel located on the center pedestal.
STALL L PWR CB1-B10 STALL R PWR CB2-B10 - If system checks are good, do close out.
- If fault remains, continue with next step.
- Do wiring check of the ISI-1 ARINC bus from Junction Box #3 Test Points (TP58-ARINC Hi / TP71-ARINC Lo) to SPC connectors A178AP1 / A178BP1. Repair/replace as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace SPC.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Do close out.