# SDR ASAA2021030434246

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 4, 2021
- Submitted: March 9, 2021
- Operation: Air carrier
- Aircraft: [N579AS](https://openairdocs.org/aircraft/N579AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35187
- Aircraft time: 50,986 hours, 15,092 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Control Valve
- Part number: 3989085
- Part serial: 25499
- Condition: Faulted
- Location: Rt A/C Pack
- Part time: 18,081 hours, 5,833 cycles
- Stage of operation: NR
- 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/ASAA2021030434246

## Discrepancy

RIGHT PACK LIGHT ILLUMINATED. GROUNDED - YES. PERFORMED BIT PER B737-800 FIM 21-62 TASK 801. INITIALLY NO FAULTS NOTED. NOTED TCV FAULT ON LATER BIT CHECK. TCV FAULT CLEARED PACK OPERATED NORMALLY AT THAT TIME. SUSPECT FAULTY RH TCV. REMOVED AND REPLACED #2 PACK TCV PRECAUTIONARY REF B737-800 AMM 21-51-10-400-801. PERFORMED PZTC BITE REF AMM 21-61-00-700-806-002, OP CHECK GOOD. LEAK CHECK GOOD. ETOPS GROUND VERIFICATION SUCCESSFUL.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.