# SDR ASAA1159454

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 15, 2011
- Submitted: April 19, 2011
- Operation: Air carrier
- Aircraft: [N533AS](https://openairdocs.org/aircraft/N533AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35201
- Aircraft time: 806 hours, 276 cycles
- System (JASC): [2131 · Cabin Pressure Controller](https://openairdocs.org/jasc/2131)
- Part: Controller
- Part number: 2193301AC
- Part serial: 1096469
- Condition: Defective
- Location: Cabin Pressure
- Part time: 820 hours, 283 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA1159454

## Discrepancy

DURING CRUISE IT WAS OBSERVED CABIN ALTITUDE TO BE FREQUENTLY OSCILLATING BETWEEN 500 FPM RATE OF CLIMB AND 300 FPM RATE OF DESCENT.  REMOVED AND REPLACED NR 1 CABIN PRESSURE CONTROLLER IAW AMM 21 31 01 AND OPS CHECK GOOD IAW AMM 21 31 00 700 802.

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