# SDR ASAA2019011127748

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 11, 2019
- Submitted: January 15, 2019
- Operation: Air carrier
- Aircraft: [N478AS](https://openairdocs.org/aircraft/N478AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 44105
- Aircraft time: 14,023 hours, 4,684 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Warning System
- Condition: False Activation
- Location: Cockpit
- Stage of operation: NR
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2019011127748

## Discrepancy

ON MASTER CAUTION RECALL LEFT PACK LT ILLUMINATES PACK LT. EXTINGUISHES WITH MASTER CAUTION RESET. GROUNDED - YES. PERFORMED BITE TEST OF PZTC 1, FOUND SRADA EXIT FAULT, RESET PZTC 1 SRADA EXIT FAULT CLEARED, BITE TEST PZTC 2 FOUND NO FAULT, REF FIM 21-62 TASK 801, PZTC 1 ALSO LOGGED LEFT TCV FAULT, REF FIM 21-62 TASK 830, RECYCLED 3 CIRCUIT BREAKERS PROCEDURE, LEFT TCV FAULT CLEARED, RAN BOTH PACKS FOR 30 MINUTES, RECALL TEST SHOWN LEFT PACK LIGHT NOT ILLUMINATED, NO FAULT NOTED ON BOTH PZTC 1 & 2.

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