# SDR UIEA2023090400826

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 4, 2023
- Submitted: September 7, 2023
- Operation: Air carrier
- Aircraft: [N407KZ](https://openairdocs.org/aircraft/N407KZ), registered now
- Make and model: Boeing 747-4KZF
- Registry model: [Boeing 747-4KZF](https://openairdocs.org/model/boeing-747-4kzf) (OpenAirDocs)
- Aircraft serial: 36134
- Aircraft time: 56,751 hours, 10,412 cycles
- System (JASC): [2131 · Cabin Pressure Controller](https://openairdocs.org/jasc/2131)
- Part: Controller
- Part number: 7968842008
- Part serial: 04038497
- Condition: Faulted
- Location: Cabin Pressure
- Stage of operation: TO
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2023090400826

## Discrepancy

CABIN ALT AUTO FAILED JUST AFTER TAKEOFF. EICAS MSGS: "CABIN ALT AUTO" & "OUTFLOW VLV L" DISPLAYED. RT OUTFLOW VALVE PREVIOUSLY DEFERRED.(<P>REMOVED AND REPLACED CABIN PRESSURE CONTROLLER A PER AMM 21-31-02. CPCS-A & -B GROUND TESTS PASSED, NO FAULTS NOTED. OUTFLOW VALVE R REMAINS ON DEFERRAL. </P>)

---
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.