# SDR ASAA0954670

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 6, 2009
- Submitted: March 10, 2009
- Operation: Air carrier
- Aircraft: [N519AS](https://openairdocs.org/aircraft/N519AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 36482
- Aircraft time: 278 hours, 93 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Control Valve
- Part number: 3966081
- Part serial: 3579
- Condition: Faulty
- Location: Lt Ac Pack
- Part time: 278 hours, 93 cycles
- Stage of operation: TX
- How discovered: O
- Nature of condition: O
- Precautionary procedure: D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA0954670

## Discrepancy

ON TAXI OUT N1 RPM VALUES WERE SPLIT BY .7 (NR 1 ENG 86.1 NR 2 ENG 86.8).  N1 CARROTS WERE ALSO SPLIT.  LEFT PACK VALVE FAILED TO OPEN TWICE WHILE OPERATING.  PERFORMED FLOW CONTROL & SHUTOFF VALVE TEST REF MM 21 51 01 STEP G, ALL TESTS GOOD.  PERFORMED ENG RUN & ACCESSED THE DISCRETES PAGE FROM THE FMC'S & VERIFIED OVER 35 TIMES THAT THE LEFT & RIGHT PACKS TURN ON & OFF WITH SWITCH AND VERIFIED THE PACKS ARE ACTUALLY OPERATING & VERIFIED THE N1 CARROTS MATCH.  ALSO PERFORMED BITE CK OF BOTH ACAU'S NO FAULTS FOUND.  VERIFICATION FLIGHT SUCCESSFUL.  OPS NORMAL.

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