# SDR AALA202609292526

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 26, 2026
- Submitted: September 30, 2026
- Operation: Air carrier
- Aircraft: [N820AL](https://openairdocs.org/aircraft/N820AL), registered now
- Make and model: Boeing 787-9
- Registry model: [Boeing 787-9](https://openairdocs.org/model/boeing-787-9) (OpenAirDocs)
- Aircraft serial: 40639
- Aircraft time: 38,166 hours, 4,578 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Acm
- Part number: 7110121H01
- Part serial: 7118968
- Condition: Failed
- Location: Zone 100
- Part time: 35,031 hours, 4,236 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: G, J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202609292526

## Discrepancy

AIRCRAFT WAS NOT GROUNDED: AIR CYCLE MACHINE - PACK R INOP STATUS MESSAGE PACK ACM R CABIN AIR CPRSR R1. ROUGHLY 100 MILES NORTH OF DEN WE HAD A R ACM FAIL, R PACK FAIL, AND R CABIN AIR COMPRESSOR FAIL. WE WERE AT 34,000 FEET AND ATTEMPTED A RESET OF THE R PACK. THE R PACK ESTABLISHED ITSELF AND AFTER 30 SECONDS, FAILED AGAIN. NON-NORMAL CHECKLIST ALLOWS ONE RESET OF PACK. CALLED DISPATCH AND MOC FOR FURTHER INFORMATION REGARDING CONTINUING FLIGHT OVER THE PACIFIC FOR 13 HOURS WITH ONE PACK DECESION MADE TO RETURN TO DFW. EMERGENCY WAS DECLARED AND AIRCRAFT LANDED OVERWEIGHT WITHOUT INCIDENT ARFF WAS ROLLED TO CHECK BRAKES. MAINTENANCE REPLACED RIGHT ACM IAW AMM DMC-B787-A-21-52-02-02A-720A-A.

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