# SDR DALA2026041302321

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 9, 2026
- Submitted: April 13, 2026
- Operation: Air carrier
- Aircraft: [N3765](https://openairdocs.org/aircraft/N3765), registered now
- Make and model: Boeing 737832
- Aircraft serial: 30819
- Aircraft time: 78,459 hours, 29,757 cycles
- System (JASC): [2130 · Cabin Pressure Control System](https://openairdocs.org/jasc/2130)
- Part: Heat Exchanger
- Part number: 1828203
- Condition: Inoperative
- Location: Zone 100
- Part time: 8,879 hours, 29,744 cycles
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/DALA2026041302321

## Discrepancy

RETURNED ORD DUE TO AIRCRAFT WOULD NOT MAINTAIN CABIN PRESSURIZATION. RIGHT PACK ON MEL.   MAINTENANCE FOUND GROUND AIR CHECK VALVE OBSTRUCTED. RESEATED CLAMPS ON CHECK VALVE. REPLACED DAMAGED PLENUM AND SECONDARY HEAT EXCHANGER, REPLACED 4 MISSING FUSELAGE DRAINS AND RIGHT FLOW CONTROL VALVE. REFER TO B737 AMM 21-51 AND AMM 51-41. (LOG 7604038 - AIRCRAFT WAS GROUNDED).

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