# SDR 2026FA0000904

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 24, 2026
- Submitted: October 26, 2026
- Operation: General aviation
- Aircraft: N9YTKD
- Make and model: Agusta AW139
- Registry model: [Agusta AW139](https://openairdocs.org/model/agustawestland-philadelphia-aw139) (OpenAirDocs)
- Aircraft serial: 41398
- Aircraft time: 9,219 hours, 20,453 cycles
- Engine: Pwc PT6C67C
- System (JASC): [2910 · Hydraulic System, Main](https://openairdocs.org/jasc/2910)
- Part: Hydraulic Line
- Part number: 3G2910V00551
- Condition: Ruptured
- Location: Zone 200
- Part time: 9,219 hours, 20,446 cycles
- Stage of operation: TX
- How discovered: O
- Nature of condition: K, J
- Precautionary procedure: E
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2026FA0000904

## Discrepancy

DURING A START SEQUENCE FOR A MAINTENANCE/ AIRCRAFT GROUND RUN A COMPLETE #2 HYDRAULIC SYSTEM FAILURE OCCURRED.  CREW NOTED AFTER ENGINE MODE SWITCHES WAS PLACED INTO 'FLIGHT' #2 HYDRAULIC PRESSURE DROPPED RAPIDLY, ACCOMPANIED BY CAS MESSAGES ILLUMINATING AND OIL (HYDRAULIC FLUID) WAS OBSERVED EMANATING TO BE SPRAYING OUT FROM THE UPPER DECK.  CAS MESSAGES "HYD UTIL PRESS, 2 HYD OIL PRESS, 2-4 HYD PUMP, 2 HYD MIN AND 2 SERVO SEEN ILLUMINATED.  AIRCRAFT WAS SHUT DOWN IMMEDIATELY.  NR 2 SERVO CONTROL (PRESSURE) LINE  WAS SEEN TO BE RUPTURED.  NR 2 SERVO CONTROL (RETURN) LINE BECAME DAMAGED AS A RESULT OF THE HIGH-PRESSURE FLUID DISCHARGE FROM THE RUPTURED SERVO CONTROL (PRESSURE) LINE PIERCING THROUGH ITS INSULATION. THE INTERNAL WIRE BRAID COULD BE SEEN.  MAINTENANCE CARRIED OUT REPLACEMENT OF ALL DAMAGED LINES.  NR 2 POWER CONTROL MODULE WAS SERVICED.  NR 2 MAIN HYDRAULIC SYSTEM BLED.  OPS CHKS WERE CARRIED OUT TO ASCERTAIN FUNCTIONALITY OF SYS.  HYDRAULIC SYS LINES WERE LEAK CHECKED CARRIED OUT VIA GROUND RUN - ALL FOUND TO BE SATISFACTORY.  ENVIRONMENTAL CONDITIONS AT THE TIME OF THE OCCURRENCE WERE SUNNY AND CLEAR.  OUTSIDE AIR TEMPERATURE WAS QUOTED TO BE 32 DEGREES CELSIUS.  A FLEET CHECK WAS CONDUCTED TO ATTEMPT AS BEST TO ASCERTAIN ANY EVIDENCE OF DAMAGES TO OTHER SERVO CONTROL LINES. REF MADE TO PSE/TQ/2026/263265 AND PSE/TQ/2025/191136.  NR 1 SERVO CONTROL LINE  RUPTURE OCCURRENCES ON 07 OCTOBER 2026 AND 22ND MARCH 2025 RESPECTIVELY. THE OEM WAS INFORMED OF THE INCIDENT BY TECHNICAL QUERY - REPORTING OCCURRENCE. REFERENCE PSE/TQ/2026/265820 FOR FURTHER DETAILS.

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