# SDR AALA202302018831

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 28, 2023
- Submitted: February 1, 2023
- Operation: Air carrier
- Aircraft: [N927NN](https://openairdocs.org/aircraft/N927NN), registered now
- Make and model: Boeing 737823
- Aircraft serial: 31171
- Aircraft time: 28,772 hours, 12,224 cycles
- System (JASC): [3620 · Pneumatic Indicating System](https://openairdocs.org/jasc/3620)
- Part: Valve
- Condition: Abnormal
- Location: Zone 400 - Nac/P
- Stage of operation: CL
- How discovered: V
- Nature of condition: J
- Precautionary procedure: A, D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202302018831

## Discrepancy

AIRCRAFT WAS GROUNDED: LEFT ENGINE DUCT PRESSURE INDICATES 0 ON CLIMB AND CRUISE. FLIGHT ATTENDANT REPORT NO AIRFLOW IN CABIN. FLIGHT AIR INTERRUPTED BACK TO MIA. NO EMERGENCY DECLARED. REMOVED AND REPLACED PRESSURE REGULATING SHUT OFF VALVE (AALA202302015650) IAW AMM 36-11-03,REMOVED AND REPLACED PRE-COOLER VALVE (AALA202302018831) IAW AMM 36-12-02. REMOVED AND REPLACED HIGH PRESSURE REGULATOR (AALA202302012675).

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