# SDR 0002396634

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 5, 2000
- Submitted: July 14, 2000
- Operation: Air carrier
- Aircraft: [N634US](https://openairdocs.org/aircraft/N634US), registered now
- Make and model: Boeing 747227B
- Aircraft serial: 22234
- Aircraft time: 65,376 hours, 9,865 cycles
- System (JASC): [2120 · Air Distribution System](https://openairdocs.org/jasc/2120)
- Part: Duct
- Condition: Ruptured
- Location: Cabin
- Stage of operation: CL
- How discovered: V
- Nature of condition: B
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/0002396634

## Discrepancy

DURING CLIMB, THE FLIGHT CREW HAD DIFFICULTY PRESSURIZING THE AIRCRAFT IN AUTO AND A BURNING SMELL EMITTED FROM ROW 24.  CABIN PRESSURIZATION WAS CONTROLLED MANUALLY AND AIRCRAFT RETURNED TO HNL AND LANDED WITHOUT FURTHER INCIDENT.  REPLACED ZONE 3 TRIM AIR DUCT UNDER FLOOR AT ROW 24 RIGHT, CABIN PRESSURE CONTROLLER, AND NR 2 AIR CYCLE MACHINE TURBINE BYPASS VALVE.  OPERATIONAL CHECK GOOD.

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