Gulfstream IV / G350 / G450
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 20; Flight Crew Total 9700; Flight Crew Type 4500
Workload; Troubleshooting; Time Pressure; Confusion; Distraction
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Weather; Human Factors; Aircraft
We were at FL450 topping and maneuvering for clearing a line of thunderstorms stretching hundreds of miles to the north and south. We were in visual conditions clearing the tops by about 1;000 feet at Mach -0.80 with the when we experienced a spike in airspeed and associated moderate to severe turbulence. As the airspeed abruptly climbed due to updraft; I disengaged the auto-throttles then manually and slowly reduced the throttles to avoid an over-speed. A few moments later we experience a strong downdraft and were 'pulled' into the cell while initiating a smooth advance in power. The crew quickly observed all gauges on the right engine indicating an engine failure and subsequently heard the associated CAS messages. ATC was advised and we continued to descend as required by performance. Upon stabilizing the engine failure an exceedance occurred on the 'good' right engine. LP 100.2 for 6 second according to the Exceedance page (see picture).We did not officially [request priority handling] due to task demands; however ATC was advised of the situation of an engine failure necessitating a lower altitude and cleared us as such and we were getting the priority we needed to handle the event. We were cleared for lower altitudes.We asked ATC for a lower altitude (FL250) and initiated the Quick Reference Handbook Engine Failure Checklist. Upon reaching FL250 we initiated the Air-start Normal Checklist.Upon reaching FL250 we restarted the right engine. After stabilization we advised ATC of nominal condition and as such we climbed back up to FL400. The remainder of the flight was normal and uneventful.Upon landing chief pilot was contacted as required and requested reports were filed in accordance with company reporting protocols.Corrective action: Have Igniters ON (as long as they have continuous capability) anywhere near thunderstorms even if on top of a 'blown out' layer.
Gulfstream IV First Officer reported that turbulence from a thunderstorm caused a momentary engine flameout.