# SDR ASAA2018121967447

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 16, 2018
- Submitted: December 20, 2018
- Operation: Air carrier
- Aircraft: [N491AS](https://openairdocs.org/aircraft/N491AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 44109
- Aircraft time: 12,411 hours, 4,168 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Warning Message
- Condition: False Activation
- Location: Lt A/C Pack
- Stage of operation: NR
- How discovered: 9
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2018121967447

## Discrepancy

LEFT PACK LIGHT ILLUMINATED ON MASTER CAUTION RECALL, LIGHT EXTINGUISHED ON MASTER CAUTION RESET. GROUNDED - YES. ACCOMPLISHED LEFT PACK/ZONE TEMPERATURE CONTROLLER BITE TEST, REF 21-61-00-700-806-002. NO ACTIVE FAULTS FOUND. PERFORMED LEFT PACK CABIN TEMPERATURE CONTROL AND INDICATION - OPERATIONAL TEST REF B737-900 AMM 21-61-00-700-807-002 . SYS CHKS NML.

---
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.