# SDR CALA2026061217044

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 12, 2026
- Submitted: June 18, 2026
- Operation: Air carrier
- Aircraft: [N37274](https://openairdocs.org/aircraft/N37274), registered now
- Make and model: Boeing 737824
- Aircraft serial: 31592
- Aircraft time: 75,063 hours, 26,978 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Door
- Part number: 22156283
- Condition: Missing
- Location: Check Valve
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2026061217044

## Discrepancy

LEFT FAN BYPASS CHECK VALVE DOOR MISSING IN THE PRIMARY PLENUM/DIFFUSER ASSEMBLY. IPC 21-51-03-06A-50.  INSPECTED LT PACK REF. FIM  21-53 TASK 820 FOUND  LEFT FAN BYPASS CHECK VALVE MISSING IN THE PRIMARY PLENUM - DIFFUSER ASSEMBLY. DOOR MISSING,  STARTED TO PERFORMED REMOVAL OF THE HEAT EXCHANGER AND PLENUM - DIFFUSER ASSEMBLY IAW AMM 21-51-03-000-805-002 UP TO G STEP 5. FOR THE LT PACK. CONTINUED REMOVAL OF LT PACK HEAT EXCHANGER AND PLENUM - DIFFUSER ASSEMBLY IAW AMM 21-51-03-000-805-002 STARTING FROM STEP G.(5) TO COMPLETION. INSTALLED NEW PRIMARY HEAT EXCHANGER & PRIMARY DIFFUSER AND PLENUM IAW AMM 21-51-03-400-804-002. CYCLED AND RAN LT PACK FOR SEVERAL MINUTES WITH NO LEAKS OR FURTHER FAULTS DETECTED.

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