Jetstream 31
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 25; Flight Crew Total 2900; Flight Crew Type 900
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Aircraft
While at cruise at 25;000 the Captain noticed the left power lever was unresponsive.  The crew discussed the issue and decided the power lever may have frozen due to the cold temperature.  We then requested a descent to a lower (warmer) altitude and vectors to our home base at a nearby airport.Once the descent was initiated we began to troubleshoot and all appropriate checklists were accomplished. After flying at 2;000 MSL and extensive troubleshooting we decided the engine would need to be shut down in order to land safely.After climbing to 5;000 MSL and reviewing the engine shut down procedures the First Officer flew the airplane while I shut down the left engine. At this point we were within a few miles of the diversion airport and I then flew a visual pattern and landed on Runway XX.  Once clear of the runway we finished the checklists and taxied in to the ramp for maintenance.
When the left power lever became unresponsive while at cruise thrust; possibly due to frigid operating conditions; the flight crew of a JS31 (Jetsream) opted to perform an inflight shutdown prior to landing.