# SDR DL764091506

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 14, 2009
- Submitted: September 30, 2009
- Operation: Air carrier
- Aircraft: [N838MH](https://openairdocs.org/aircraft/N838MH), registered now
- Make and model: Boeing 767432ER
- Aircraft serial: 29711
- Aircraft time: 33,369 hours, 8,249 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Valve
- Condition: Intermittent
- Location: Lt Pack
- Stage of operation: TX
- How discovered: O
- Nature of condition: O
- Precautionary procedure: D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/DL764091506

## Discrepancy

RETURN TO BLOCK X2 WITH L PACK INOP.  LT CTC NO EXISTING FAULTS.  SYS TEST FAILED AFT TRIM VLV 21-61130.  REPLACED VLV, LEAK CHECK GOOD.  SYS TEST AND PNEU T/E WITH APU AIR PASS.  NO FAULTS ON ASCTU.  DID OPS TEST ON FL CONT VLVS, ASCTU BACKUP CONTROL.  ASCTU FAILED TO OPERATE B PACKS.  REPLACED ASCTU PER M/M.  NEW ASCTU WILL NOT OPEN FLOW CONTROL VLVS.  ETOPS CATEGORY 'E':  PROBLEMS WITH SYSTEMS CRITICAL TO ETOPS.

---
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.