Narrative:

On departure climb at approximately 9000 feet MSL; intermittent hydraulic flow low annunciator began to appear in conjunction with moderate to severe turbulence. On notification to ATC; we began a turn north to return to ZZZ. Following a direct path for the extended final; when speed was reduced to configure for landing it was confirmed that there was insufficient hydraulic pressure to extend the flaps and landing gear normally.an overhead; upwind pattern entry was made with the assistance of tower vectors and the gear was extended using the manufacturer abnormal checklist. Approach speeds were also increased to account for the no flap landing. Winds at the time were approximately 210 at 27 gust 35. A shallow approach was conducted to a smooth landing.to preclude any hydraulic system damage; it was requested to exit the runway and shutdown the engines on the taxiway. This was accomplished and the aircraft was towed to the ramp without incident.on initial maintenance inspection by the [company] service unit; it was discovered that a pinhole leak in the pressure line located aft belly section was the cause of the leak and loss of pressure. No visible source of abrasion or external cause for this leak was found. A failure in the metallurgy or design of the line is the only viable cause. Images of the failed line can be provided for reference.

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Original NASA ASRS Text

Title: CE-525 pilot reported a loss of hydraulic pressure due to a leak in a pressure line; which resulted in a return to the departure airport.

Narrative: On departure climb at approximately 9000 feet MSL; intermittent hydraulic flow low annunciator began to appear in conjunction with moderate to severe turbulence. On notification to ATC; we began a turn north to return to ZZZ. Following a direct path for the extended final; when speed was reduced to configure for landing it was confirmed that there was insufficient hydraulic pressure to extend the flaps and landing gear normally.An overhead; upwind pattern entry was made with the assistance of Tower vectors and the gear was extended using the manufacturer abnormal checklist. Approach speeds were also increased to account for the no flap landing. Winds at the time were approximately 210 at 27 gust 35. A shallow approach was conducted to a smooth landing.To preclude any hydraulic system damage; it was requested to exit the runway and shutdown the engines on the taxiway. This was accomplished and the aircraft was towed to the ramp without incident.On initial Maintenance inspection by the [Company] service unit; it was discovered that a pinhole leak in the pressure line located aft belly section was the cause of the leak and loss of pressure. No visible source of abrasion or external cause for this leak was found. A failure in the metallurgy or design of the line is the only viable cause. Images of the failed line can be provided for reference.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.