# SDR CWQA20260627001

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 27, 2026
- Submitted: July 2, 2026
- Operation: Air carrier
- Aircraft: [N421QS](https://openairdocs.org/aircraft/N421QS), registered now
- Make and model: Gulstm GIVXG450
- Aircraft serial: 4114
- Aircraft time: 12,636 hours, 6,267 cycles
- System (JASC): [3220 · Nose/Tail Landing Gear](https://openairdocs.org/jasc/3220)
- Part: Dump Valve
- Part number: 1159SCH51219
- Part serial: EFS0495A
- Condition: Malfunctioned
- Location: Zone 700
- Stage of operation: AP
- How discovered: O
- Nature of condition: J
- Precautionary procedure: L
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CWQA20260627001

## Discrepancy

ON APPROACH TO KAPF AND UPON SELECTING GEAR DOWN, CREW RECEIVED 'NOSE GEAR NOT DOWN' AND 'L-R MAIN GEAR NOT DOWN CAS' MESSAGE, FOLLOWED BY A 'L HYDRAULIC QUANTITY LOW CAS' MESSAGE. COMPLETED THE LANDING GEAR FAILED TO EXTEND CHECKLIST, THAT INSTRUCTED TO USE THE EMERGENCY GEAR EXTENSION PROCEDURE, AND RECEIVED A SUCCESSFUL GEAR EXTENSION INDICATION. CREW DECLARED AN EMERGENCY AND PERFORMED AN UNEVENTFUL LANDING. MAINTENANCE EVALUATION FOUND FAILED LANDING GEAR SELECTOR/DUMP VALVE.

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