Cessna Citation Sovereign (C680)
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Ground Event / Encounter Loss Of Aircraft Control
Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Regained Aircraft Control; Flight Crew Landed in Emergency Condition
Aircraft
Upon taking off from ZZZ; aircraft would not trim nose down and took both crew members to control the pitch of the aircraft.  Retarding power still would not stop the aggressive climb based on the trim failure.  We received a primary trim fail CAS (Crew Alerting System) message.  At this point in time; it was not possible to maintain an assigned altitude and we [advised ATC] and requested a block altitude and requested a return to the airport.  Selecting secondary trim worked and we were able to trim the aircraft properly.  We elected to do a flaps 15 landing to minimize excessive trim requirements.  We landed safely on Runway XXR and taxied uneventfully to the FBO.
On climbout; aircraft experienced a pitch trim fail. It took both crew members to force the nose down initially. Crew activated secondary pitch trim which worked properly. Although in IMC; crew remained below clouds to maintain visual with the runway. We flew a normal pattern; entering a left downwind for [Runway] XXR. Crew [advised ATC] and elected to land flap 15 to negate possible pitch abnormalities. Crash/Fire rescue followed us to the FBO ramp as a precaution.
CE-680 flight crew encountered Trim Failure after takeoff; advised ATC; returned to departure airport; and landed uneventfully.