Cessna Citation Sovereign (C680)
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Confusion; Training / Qualification
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; Flight Crew Regained Aircraft Control
Aircraft; Manuals; Procedure
At approximately 20 minutes after departure while climbing to FL290 we received a CAS message 'Hydraulic Pressure Low R'. The autopilot was engaged at the time and did not disengage initially. We advised ATC of the situation and immediately began searching for suitable airports to divert. I quickly picked up the QRH and found the appropriate checklist. After several minutes a second CAS message appeared 'Hydraulic Volume Low'. We [notified ATC] and told them about our intentions to divert. ATC recommended ZZZ1 since it was at our 12 o'clock position. We completed the QRH checklist and we initially chose ZZZ2 as our intended landing airport. I advised the passengers that we were going to divert into ZZZ2. After performing a preliminary landing performance assessment we determined that ZZZ2 may not be suitable with its 9400 foot runway so we decided to return to ZZZ. We reviewed the checklist once more to determine if further corrective action was needed. We then discussed what should occur if we were required to make a ground evacuation by reviewing the QRC. After proceeding direct to ZZZ3 as per ATC instructions we were given vectors to intercept the ILS for RWY 25L. We then commenced configuring the aircraft for landing. We used the gear blow down procedure to extend the landing gear and observed 3 green lights. On final approach the Captain called for flaps 35. When the flaps were moving into position the aircraft rolled abruptly right and pitched nose down. I immediately retracted the flaps and we regained control of the aircraft and continued the approach. Upon landing I controlled the yoke and the PIC maintained directional control on the runway centerline with the tiller and operated the emergency brake. We managed to stop the aircraft on the runway and completed the After Landing checklist from the QRH. We were then towed to [FBO] where everyone deplaned safely. Upon post-flight inspection we observed hydraulic fluid dripping from beneath the aircraft rear-center fuselage then later from the right engine. Two spoiler panels on the right wing were deployed. It would be advisable to include in the QRH procedure a caution detailing a potential loss of control when adding flaps due to potential asymmetric lift from floating spoilers.
Citation First Officer reported a hydraulic problem after takeoff and a rolling and pitching anomaly when extending the flaps.