# SDR UIEA2021021100280

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 11, 2021
- Submitted: February 12, 2021
- Operation: Air carrier
- Aircraft: [N1997A](https://openairdocs.org/aircraft/N1997A), registered now
- Make and model: Boeing 767-33A
- Registry model: [Boeing 767-33A](https://openairdocs.org/model/boeing-767-33a) (OpenAirDocs)
- Aircraft serial: 27310
- Aircraft time: 99,592 hours, 20,666 cycles
- System (JASC): [2131 · Cabin Pressure Controller](https://openairdocs.org/jasc/2131)
- Part: Controller
- Part number: 21173888
- Part serial: 73A0559
- Condition: Fluctuates
- Location: Cabin Pressure
- Stage of operation: CR
- 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/UIEA2021021100280

## Discrepancy

AT CRUISE AND ON DESCENT OBSERVED OUTFLOW VALVE FLUCTUATING. AUDIBLE FLUCTUATIONS IN PRESSURE AIR FLOW CHANGES. EAR POPPING. VALVE MOVED FROM 3/4 CLOSED TICK TO 1/2 TICK EACH TIME.(<P>REMOVED AND REPLACED #1 AUTO PRESSURE CONTROLLER IAW AMM 21-31-02. OPS CHECK SAT AT THIS TIME. NO FAULTS PRESENT.</P>)

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