# SDR ASAA2017070921328

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 9, 2017
- Submitted: July 11, 2017
- Operation: Air carrier
- Aircraft: [N538AS](https://openairdocs.org/aircraft/N538AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 41188
- Aircraft time: 20,391 hours, 5,948 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Control Valve
- Part number: 3966081
- Part serial: 3439
- Condition: Faulted
- Location: A/C Bay
- Part time: 32,797 hours, 9,687 cycles
- Stage of operation: TX
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2017070921328

## Discrepancy

AFTER ENGINE START WITH BLEEDS AND PACKS ON AND ALL OTHER SYSTEMS SWITCHES POSITIONED NORMAL (AI OFF). THE NR 1 ENGINE INDICATED 88.8 AND NR 2 ENGINE INDICATED 88.0 N1. WHEN THE NR 1 BLEED AIR SWITCH WAS MOVED TO OFF, THE NR 1 ENGINE N1 VALVE DID NOT CHANGE. WHEN THE NR 2 ENGINE BLEED AIR SWITCH WAS MOVED TO OFF, THE NR 2 ENGINE N1 INDICATIONS READING 88.0. NORMAL OPS ESTABLISHED.  ACFT GROUNDED. ACCOMPLISHED FIM 34-61, TASK 839.  NO DEFECTS NOTED.  REPLACED THE LEFT FLOW CONTROL AND SHUTOFF VALVE IAW AMM 21-51-01. OPS CHECKED GOOD. LEAK CHECKED GOOD. . NO DEFECTS NOTED.

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