Challenger 300
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 130; Flight Crew Total 11275; Flight Crew Type 3220
Time Pressure; Workload
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed in Emergency Condition; Flight Crew Inflight Shutdown
Aircraft
Descending through FL300 speed was M.80 transitioning to 300 knots. Thrust levers were matched at approximately 75% N1. We started to feel a heavy vibration but could not determine which engine was causing the vibration. All engine indicators appeared normal. However; we noticed the LH (left hand) engine ITT (Interstage Turbine Temperature) was reading higher than the RH ITT. Initially; the LH ITT was 100 degrees higher than the RH ITT. While we weren't positive which indication was normal the LH engine was suspected as being abnormal. The LH oil pressure was lower than the RH oil pressure.The vibration was continuous and at a constant level. N1 and N2 indicators were stable and matched. As I retarded the Thrust Levers to about 60% N1 the vibration increased in intensity. As I was retarding the Thrust Levers to slow the aircraft down we noticed the LH ITT split with the RH ITT was increasing to about 200 degrees hotter at about 750 degrees LH ITT. LH oil psi was 40 psi while RH oil psi was 80 psi. LH fuel flow was also higher than RH fuel flow indications.Sky conditions were clear during the descent when the vibration event began so Icing was not suspected.The MDC (Main Data Computer) time stamped an amber LH Vibration CAS which finally confirmed which engine was having problems. Checklist was pulled to follow Engine Vibration procedures but the MDC time stamped a red LH Engine Exceedance CAS message at which point the engine sounded like it was experiencing compressor stall and LH engine N1 indicator showed an erratic spike. Per checklist memory item for Engine Exceedance the thrust lever was retarded and we agreed to immediately shutdown the LH engine at which time vibration levels ceased. Engine Exceedance checklist and Engine Shutdown in Flight checklist procedures were followed. Approach control [was notified].Continuing on our descent with the LH engine shut down; I noticed LH N1 wind milling at about 11% but 0 N2 rotation. LH oil psi never dropped to 0.On base leg and on final approach with the LH engine shut down; we felt about 3 times a small vibration. On short final we saw an amber VIB under the LH N1 indicator. Not sure if that remained from the event before engine shutdown or if it came on again due to N1 still wind milling but N2 still at 0.Final descent and landing were uneventful. Touchdown occurred 15 minutes later. Emergency services with BFI Tower were cancelled upon touchdown.On pilot post-flight walk-around inspection of the LH engine; there was nothing obvious: No oil or fluids dripping from the engine; no obvious damage externally.Maintenance Tech on preliminary post-flight inspection confirms LH engine oil level still at full; FAN is locked with no evidence of FOD on blades or stators; N2 blades bent or missing; no evidence of Airframe FOD from debris exiting tailpipe; and no evidence of engine containment breech.
CL30 First Officer reported an inflight shutdown of the left engine due to vibrations.