Rockwell North American Civil Twin Jet
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 8; Flight Crew Total 5750; Flight Crew Type 1420
Time Pressure; Training / Qualification
Aircraft Equipment Problem Critical; Ground Event / Encounter Object; Ground Excursion Runway; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Object
Aircraft Aircraft Damaged; Flight Crew Took Evasive Action; General Maintenance Action
Human Factors; Aircraft
After a flight we were instructed to back taxi to general aviation ramp.  When back taxing on runway to general aviation ramp; loss of hydraulic pressure resulted in loss of braking and steering. Emergency braking was applied and felt as though emergency braking was engaging but was not in time to prevent aircraft from going into grass. When aircraft went into grass; the nose gear impacted an above ground concrete [structure] causing the nose gear to collapse.  We shut down and exited the aircraft. If I had a faster response the aircraft would have stopped on pavement. More emergency training.
No injuries and no passengers were aboard. We felt that we could stop the aircraft with emergency braking if we needed; but the emergency brakes were insufficient. We tried to manually boost hydraulic pressure; and we also tried the secondary hydraulic pump; but those systems also failed. Prior to the flight the aircraft had been inactive for an extended time.
A Saberliner 60 hydraulic system failed while back taxiing after takeoff but the emergency braking was insufficient to stop the aircraft which rolled off the runway where the nose gear collapsed damaging it but causing no injuries.