Narrative:

On climb out to cruising altitude of FL400; hydraulic level low light illuminated and stayed on during flight. At cruise altitude; right pump low pressure light illuminated every 30 seconds along with master caution. Reviewed checklist and advised if pump pressure in the green to continue flight. During descent; rh/lh pump lo press and master caution illuminated together along with the already illuminated hydraulic low level light. The hydraulic system pressure dropped from 1400 to 500 and fluctuated between 500 and 1400 the remainder of flight. Consulted checklist which told me to prepare for no flap approach and alternate emergency gear extension. When it was time to blow gear down and elected to wait to see if pressure would go back to 1400 psi or so. When it did; I instructed the PF to slow to below 200 knots and dropped the gear to avoid emergency gear extension. The gear did not deploy and per the checklist we ran the alternate gear extension procedure and prepared for a no flap approach. Requested runway xx at ZZZ. I told ATC I was on emergency brake only and have equipment standing by just in case there was a problem stopping. PF flew approach to landing and I applied emergency brake on touchdown and stopped. ATC asked if I had enough braking power to taxi off at the end and I said I would see; started taxing and brakes were mushy; used emergency braking and taxied off on taxiway D; shutdown and requested a tug from the FBO to tow us to the FBO. I was busy with checklist and coordinating with ATC and elected not to brief passengers that we may see emergency vehicle around the plane upon landing. He stated he knew something was up when I reached over and applied the emergency brake after landing. Post flight revealed no hydraulic fluid in reservoir. This airplane had the right hydraulic o-ring replaced the night before after suffering a hydraulic leak.

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Original NASA ASRS Text

Title: Hawker 400XP flight crew reported a loss of hydraulic system fluid and pressure which necessitated an emergency extension of the landing gear and a loss of normal braking capability. A landing was safely accomplished and the aircraft was stopped using emergency braking.

Narrative: On climb out to cruising altitude of FL400; hydraulic level low light illuminated and stayed on during flight. At cruise altitude; right pump low pressure light illuminated every 30 seconds along with master caution. Reviewed checklist and advised if pump pressure in the green to continue flight. During descent; RH/LH pump lo press and master caution illuminated together along with the already illuminated hydraulic low level light. The hydraulic system pressure dropped from 1400 to 500 and fluctuated between 500 and 1400 the remainder of flight. Consulted checklist which told me to prepare for no flap approach and alternate emergency gear extension. When it was time to blow gear down and elected to wait to see if pressure would go back to 1400 psi or so. When it did; I instructed the PF to slow to below 200 knots and dropped the gear to avoid emergency gear extension. The gear did not deploy and per the checklist we ran the alternate gear extension procedure and prepared for a no flap approach. Requested Runway XX at ZZZ. I told ATC I was on emergency brake only and have equipment standing by just in case there was a problem stopping. PF flew approach to landing and I applied emergency brake on touchdown and stopped. ATC asked if I had enough braking power to taxi off at the end and I said I would see; started taxing and brakes were mushy; used emergency braking and taxied off on taxiway D; shutdown and requested a tug from the FBO to tow us to the FBO. I was busy with checklist and coordinating with ATC and elected not to brief passengers that we may see emergency vehicle around the plane upon landing. He stated he knew something was up when I reached over and applied the emergency brake after landing. Post flight revealed no hydraulic fluid in reservoir. This airplane had the right hydraulic O-ring replaced the night before after suffering a hydraulic leak.

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.