# SDR CALA2024110501019

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 2, 2024
- Submitted: November 5, 2024
- Operation: Air carrier
- Aircraft: [N27274](https://openairdocs.org/aircraft/N27274), registered now
- Make and model: Boeing 737-8
- Registry model: [Boeing 737-8](https://openairdocs.org/model/boeing-737-8) (OpenAirDocs)
- Aircraft serial: 67529
- Aircraft time: 7,377 hours, 2,634 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Controller
- Part number: 51090322002
- Part serial: 51090322026
- Condition: Faulty
- Location: Zone 100
- Part time: 7,352 hours, 2,627 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/CALA2024110501019

## Discrepancy

PACK LIGHT COMES ON DURING FLIGHT  LEFT PACK LIGHTFOUND WOW/AG DISCRETE FAULTS ALONG WITH  MAINTENANCE MESSAGE 21-55340. PERFORMED RAM AIR DOOR SIMULATION IN AIR MODE FOUND THAT LEFT PACK RAM AIR DOOR WAS NOT WORKING, INTERMITANT CYCLE AIRMODE SIM WORKED INTERMITANT. SWAPPED ACAU NO CHANGE. SWAPPED ISSAC NOTICED RIGHT RAM DOOR WAS SLOW ONCE TO CLOSE. BUT COULD NOT DUPLICATE. RETURNED BOXES TO ORIG POSITION. SUGGEST REPLACING LEFT IASC M2939 AND PSEU M2061. REF FIM 21-51 TASK 834. FOUND WOW/AG DISCRETE FAULTS ALONG WITH  MMSG 21-55340. PERFORMED RAM AIR DOOR SIMULATION IN AIR MODE FOUND THAT LEFT PACK RAM AIR DOOR WAS NOT WORKING, INTERMITANT CYCLED AIRMODE SIM WORKED INTERMITANT. RAM AIR ACTUATOR SHOWS GREEN ON BITE. SWAPPED ACAU NO CHANGE. SWAPPED ISSAC NOTICED RIGHT RAM DOOR WAS SLOW ONCE TO CLOSE. BUT COULD NOT DUPLICATE. RETURNED BOXES TO ORIG POSITION. SUGGEST REPLACING LEFT IASC M2939 AND PSEU M2061. REF FIM 21-51 TASK 834. UPLOADED FAULTS PIC UPLOADED PIC REMOVED AND REPLACED PROXIMITY SWITCH ELECTRONIC UNIT. COMPLETED LRU REPLACEMENT TEST, TEST PASSED. REF AMM 32-09-10 PARTS UREMOVED AND REPLACED LEFT INTEGRATED AIR SYSTEM CONTROLLER REF AMM 21-61-22-400-801 AIR CONDITIONING IBIT AND LRU TEST PASSED. ALSO OPERATED THE PACK FOR LONG PERIOD OF TIME PACK LIGHT OFF ALL THE TIME.

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