# SDR USAA20101025SB175

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 22, 2010
- Submitted: October 25, 2010
- Operation: Air carrier
- Aircraft: [N438US](https://openairdocs.org/aircraft/N438US), registered now
- Make and model: Boeing 737-4B7
- Registry model: [Boeing 737-4B7](https://openairdocs.org/model/boeing-737-4b7) (OpenAirDocs)
- Aircraft serial: 24560
- System (JASC): [2120 · Air Distribution System](https://openairdocs.org/jasc/2120)
- Part: Filter
- Part number: 21FA507
- Condition: Dirty
- Location: Ac Bay
- Stage of operation: NR
- How discovered: O
- Nature of condition: B
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USAA20101025SB175

## Discrepancy

CLT - CREW REPORTED THE AIR CONDITIONING HAS A PUTRID SOCK SMELL.  MAINTENANCE RAN BOTH PACKS WITH ENGINES AND APU.  DID NOT SMELL ANY FOUL ODORS.  REPLACED BOTH LT AND RT RECIRCULATION FAN'S HEPA FILTERS.  REFERENCE MM 21-21-23 AND 21-00-01-1.  AIRCRAFT OK FOR SERVICE.

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