Challenger 300
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft
Left engine failure climbing through 18;000. Crew disengaged autopilot; leveled off and notified ATC and started diversion.  PM (pilot monitoring) executed the engine failure and shut down checklists; and PF (pilot flying) took over the radios while PM was doing the checklists and programming FMS for arrival. ATC vectored us for a 15 mile visual approach for [Runway] XXL.  Approach and landing were performed as normal as possible and without further incident. Crew felt heavy vibrations in airframe; ailerons; elevator and rudder and received 'L Engine Vibration' CAS. Felt it was a catastrophic engine failure so elected to perform engine shut down checklist. We also received 'L Engine Flameout' and 'L FADEC FAIL' CAS Messages. In flight: 'L & R AUX Bus Fail' CAS Messages (normal ops single engine) During descent; crew saw LH Engine N1 indications between 10-15% N1. But no ITT (interstage turbine temperature) indication (not sure if that is normal ops after engine failure) We elected not to start APU airborne or on the ground and upon parking on ramp did a full aircraft shutdown. No visual indication of external engine or cowling damage. No evidence of oil leaks from cowling.
Climbing through approximately 18;000 feet the left engine failed. 'L Eng Flameout' and 'L Eng Fail' CAS posted. 'L Engine Vibration' posted and it was causing the entire airplane; including all flight controls; to vibrate severely. The pilot flying disengaged the autopilot and began hand flying. I notified ATC and asked for vectors and a new; lower altitude to be assigned. After a short discussion we agreed diverting would be the safest course of action. I asked for vectors. Executed the engine failure in flight and engine securing checklists from the QRH. ATC vectored us for the visual approach to [Runway] XXL. The subsequent approach and landing was completed without further incident. ATC called the emergency vehicles to be ready at our landing runway. Unknown reason why the engine failed.  Unsure how to prevent this. A catastrophic engine failure is outside of our control.
CL-300 flight crew reported left engine failure with heavy vibration resulted in divert.