Narrative:

Roughly about 1.5 hours from the intended initial destination; we had a combined hydraulic fail cas message. We immediately checked the quantity on the systems page and determined that we lost not only the combined hydraulic pump; but also the combined hydraulic fluid. We consulted the appropriate checklist and checked the auxiliary hydraulic system for pressure as outlined in the checklist. We turned the auxiliary hydraulic pump on for at least 30 seconds as per checklist and it indicated 3;000 psi of pressure. At this time we were assured of auxiliary hydraulic pressure for brakes and flaps for landing as per checklist. We did not declare an emergency at this time. After further consultation between the crew and checking various information such as weather etc.; we decided that it would be safer to land on a longer runway and initially planned to use an enroute airport; because of the long runway; just in case and to be on the safe side. The stronger than expected crosswind at our divert airport however made that airport not suitable for landing and we decided that another nearby airport would be the safest choice for many reasons. Primarily; it offered a very long 12;000 ft runway as well as a 200 ft wide runway and the wind condition favored the best runway; considering the associated failure of our nosewheel steering unit. We consulted the checklist many times and checked/briefed each other of all the possible scenarios that we might encounter. We initiated our decent into the divert airport and started our initial approach. As instructed by the checklist; we turned the auxiliary hydraulic pump on and to our dismay auxiliary hydraulic pressure indicated 0 pressure. At this time; we broke off our initial approach to deal with our new situation and the real possibility of only having the parking brake available for stopping the aircraft. At this time; we declared an emergency in order to have all the available safety resources available at the airport. Landing on a long and wide runway became even more important than before! We asked approach control for a vector so we could consult with the checklist as well as with each other. The vector took roughly about 20 minutes and after that time we checked the auxiliary pump again by turning it on and we had pressure. We immediately asked for a vector onto final approach and commenced with the checklist and the approach. We landed and used differential braking for keeping the aircraft on the center line. Given all the information available to us at the time; weather; length and width of runway; landing into the wind and safety equipment available at the airport; I believed then and I still believe now; that the chosen destination was the safest and most suitable airport for us to use considering all the circumstances. The passengers were briefed and kept informed at all times! My colleague was the pilot in command on the flight plan for this leg and occupied the left seat. The trip was conducted under part 91 of the far's.

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Original NASA ASRS Text

Title: A G-IV CAS alerted COMBINED HYDRAULIC FAIL while at cruise. A diversion airport was selected but abandoned because of winds. A safe landing was made at a nearby airport after declaring an emergency and using AUX Hydraulic system pressure.

Narrative: Roughly about 1.5 hours from the intended initial destination; we had a Combined Hydraulic Fail CAS message. We immediately checked the Quantity on the Systems page and determined that we lost not only the Combined Hydraulic Pump; but also the Combined Hydraulic Fluid. We consulted the appropriate checklist and checked the Auxiliary Hydraulic System for pressure as outlined in the checklist. We turned the Auxiliary Hydraulic Pump on for at least 30 seconds as per checklist and it indicated 3;000 PSI of pressure. At this time we were assured of Auxiliary Hydraulic Pressure for brakes and flaps for landing as per checklist. We did not declare an emergency at this time. After further consultation between the crew and checking various information such as weather etc.; we decided that it would be safer to land on a longer runway and initially planned to use an enroute airport; because of the long runway; just in case and to be on the safe side. The stronger than expected crosswind at our divert airport however made that airport not suitable for landing and we decided that another nearby airport would be the safest choice for many reasons. Primarily; it offered a very long 12;000 FT runway as well as a 200 FT wide runway and the wind condition favored the best runway; considering the associated failure of our nosewheel steering unit. We consulted the checklist many times and checked/briefed each other of all the possible scenarios that we might encounter. We initiated our decent into the divert airport and started our initial approach. As instructed by the checklist; we turned the Auxiliary Hydraulic Pump on and to our dismay Auxiliary Hydraulic Pressure indicated 0 pressure. At this time; we broke off our initial approach to deal with our new situation and the real possibility of only having the Parking Brake available for stopping the aircraft. At this time; we declared an emergency in order to have all the available safety resources available at the airport. Landing on a long and wide runway became even more important than before! We asked Approach Control for a vector so we could consult with the checklist as well as with each other. The vector took roughly about 20 minutes and after that time we checked the Auxiliary Pump again by turning it on and we had pressure. We immediately asked for a vector onto final approach and commenced with the checklist and the approach. We landed and used differential braking for keeping the aircraft on the center line. Given all the information available to us at the time; weather; length and width of runway; landing into the wind and safety equipment available at the airport; I believed then and I still believe now; that the chosen destination was the safest and most suitable airport for us to use considering all the circumstances. The passengers were briefed and kept informed at all times! My colleague was the pilot in command on the flight plan for this leg and occupied the left seat. The trip was conducted under Part 91 of the FAR's.

Data retrieved from NASA's ASRS site as of April 2012 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.