# SDR AALA202004289001

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 18, 2020
- Submitted: April 28, 2020
- Operation: Air carrier
- Aircraft: [N971AN](https://openairdocs.org/aircraft/N971AN), registered now
- Make and model: Boeing 737823
- Aircraft serial: 29547
- Aircraft time: 54,759 hours, 22,742 cycles
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Outflow Valve
- Part number: 40631997201AB
- Part serial: 9961222
- Condition: Faulty
- Location: Cabin Pressure
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202004289001

## Discrepancy

AIRCRAFT NOT GROUNDED: AT LEVEL OFF AT FL370. 15 MIN INTO FLIGHT, THE AUTO FAIL LT ILLUMINATED AND THE ALTN LT DIDNT ILLUMINATE. CABIN WAS DESENDING AT 2000 / MIN AND PSID WAS 8.5 WHEN ALTN SELECTED THE ALTN LT NEVER ILLUMINATED AND PRESS WAS NOT UNDER CONTROL. STILL DESENDING 2000 / MIN. WORKED IN MANUAL MODE. REMOVED AND REPLACED CABIN PRESSURE OUTFLOW VALVE IAW AMM 21-31-03.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.