Gulfstream IV / G350 / G450
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Total 9000; Flight Crew Type 3800
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Inflight Shutdown; Flight Crew Landed As Precaution; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification
Aircraft
Shortly after capturing the VNAV for descent into ZZZZ from FL450; when the auto throttles reached idle power; there was a loud bang followed by intense airframe vibration and noise. When I looked at the engine instruments the left Turbine Gas Temperature (TGT) was indicating in the amber arc and bouncing into the red. Based on the fact that the vibration and noise was increasing in intensity I made the decision to shut down the left engine with the fuel cock. After shutting down the engine the noise and vibration stopped; and everything was normal. We ran all pertinent check lists and after [advising ATC] continued on to an uneventful landing in ZZZZ. I feel that I may have acted prematurely in shutting down the engine so quickly but based on the intense noise and vibration; along with elevated TGT I was worried that the engine was going to come apart. I still have no information on the engine as mechanics have not been able to make it here yet.
Captain reported left engine temperatures were fluctuating mostly in the red arc and elected to perform an In Flight Shut Down and continue to destination airport to perform a precautionary landing.