# SDR ASAA2023100745480

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 7, 2023
- Submitted: October 9, 2023
- Operation: Air carrier
- Aircraft: [N538AS](https://openairdocs.org/aircraft/N538AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 41188
- Aircraft time: 40,753 hours, 11,959 cycles
- System (JASC): [2130 · Cabin Pressure Control System](https://openairdocs.org/jasc/2130)
- Part: Control Module
- Part number: 8243922002
- Part serial: 99064308
- Condition: Faulty
- Location: Flight Deck
- Part time: 77,875 hours, 29,015 cycles
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2023100745480

## Discrepancy

UNABLE TO SELECT LANDING ALTITUDE. LANDING ALTITUDE FROZEN WITH KNOB SELECTOR MOVING. GROUNDED - YES. REMOVED AND REPLACED PRESSURE SELECTOR UNIT REF B737-800 AMM 21-31-02/401. PERFORMED PRESSURIZATION SYS GROUND TEST OF AMM TASK 21-31-00-700-802. BOTH TEST SUCCESSFUL FUNCTIONAL TEST OF PRESSURE SELECTOR GOOD.

---
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.