Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 29; Flight Crew Total 1053
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Equipment Problem Dissipated; Flight Crew Inflight Shutdown; Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
I was sitting in the right front seat of Aircraft X from ZZZ to ZZZ1. Aircraft X was at FL450 and just received instruction to descend at maintain Flight Level 240 over I believe ZZZZZ. As the Captain pulled the thrust levers back approximately 3/4' Aircraft X was vacating Flight Level 450 and started to descend; I watched the number two engine N1 and N2 continue to decrease while the number one engine N1 and N2 remained consistent with the selected thrust lever position. The Captain immediately noticed this at this time and I grabbed the emergency checklist book and opened it up to 'loss of engine at altitude during flight'. I read off the items listed and the Captain completed all the listed tasks. Once those were completed; I read off the items for restarting procedures. Upon reaching Flight Level 250 the engine was restarted and the flight continue to destinations; ZZZ1 and landed without incident or any other anomaly. The take away from this experience was; that in any event such as this; it is extremely important to have the cockpit organized and know where specific checklist items are in case there is a need.
CE525 pilot reported an inflight uncommanded engine shut down and subsequent engine relight; and continued to destination airport.