# SDR SWAA2025063086728

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 29, 2025
- Submitted: June 30, 2025
- Operation: Air carrier
- Aircraft: [N479WN](https://openairdocs.org/aircraft/N479WN), registered now
- Make and model: Boeing 737-7H4
- Registry model: [Boeing 737-7H4](https://openairdocs.org/model/boeing-737-7h4) (OpenAirDocs)
- Aircraft serial: 33990
- Aircraft time: 61,040 hours, 36,798 cycles
- System (JASC): [3610 · Pneumatic Distribution System](https://openairdocs.org/jasc/3610)
- Part: Isolation Valve
- Condition: Faulty
- Location: Zone 400
- Stage of operation: TX
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/SWAA2025063086728

## Discrepancy

DURNING ENGINE #2 START; APU BARELY MADE 22% N2; STARTER LEVER RAISED TO START ENG #2; ENG 2 OVERHEAT LIGHT ILLUMINATED. ABORTED ENGINE START. WHILE PERFORMING CHECKLIST ENG #2 FIRE WARNING ALARM SOUNDED. DISCHARGED BOTH BOTTLES. OVERHEAT LIGHT REMAINED ILLUMINATED. OVERHEAT LIGHT EXTINGUISHED APPROX 5 MINS AFTER ABORTING START. WHEN FIRE ALARM SOUNDED FIRE WARNING LIGHT IN ENG #2 HANDLE ILLUMINATED.<[01] R&R START VALVE REF NONROUTIN TTG8Q013FQ8Q<BR>R&R STARTER REF NONROUTIN TTG8Q013FQ7K<BR>R&R ENGINE ISOLATION VALVE REF NONROUTIN TTG8Q013FQXC<BR>PER AMM 80-11-01 AND AMM 36-11-04

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