Narrative:

The left engine experienced a compressor stall while flying at flight level 450; and traveling at an indicated mach speed of 0.817. We took immediate action by disconnecting the auto-throttles; and slowly retarding the left thrust lever. Compressor stall strengthened in intensity before a red cas message of 'left engine flameout' populated. At this time we [advised] center; squawked 7700 while selecting TA only on the transponder; and requested an immediate lower altitude. We were given flight level 270 and direct to ZZZ. Upon this clearance we started a descent while maintaining the drift down airspeed of 180 KIAS. Pilot in command (PIC) maintained pilot flying; while second in command (sic) maintained pilot not flying and immediately began the checklists as called out by pilot flying. We began with the 'left engine flameout' checklist (em tab 5); and upon completion of the procedure/checklist promptly continued onto the 'inflight engine shut down' checklist (em tab 6) as directed. This checklist was completed by flight level 370; and at the time it was decided that we would not attempt to restart the engine at that time. Once the left engine was secured and procedure/checklist was complete; the sic continued into the 'single engine flight and landing' checklist (ab tab 4) as prompted by the previously completed checklist. At an indicated altitude of 33;560 feet the sic started the APU. The 'single engine flight and landing' checklist was completed up to the approach portion of this checklist. At that time approach advised runway 7 for our landing and the sic briefed the ILS-7 into ZZZ and prepared the landing init for the single engine approach and landing as directed by the checklist. After descending through 14;000 feet it was decided to attempt an in air restart as per maintenance advised. The sic promptly referred to the 'engine airstart' checklist (ab tab 3). This checklist and procedure resulted in a successful airstart and we were then able to continue to ZZZ under power with both engines. At this time all checklists were completed and the sic resumed the running of normal checklists starting with the descent at approximately 13;000 feet. Fire trucks and arff did respond but were not needed. Aircraft X landed without further issues at ZZZ and exited the runway under her own power. Upon parking at [FBO] a member of the airport operations team spoke with the sic regarding airport of departure and original destination. Nothing was signed at this time; and airport operations advised that no further information was required at this time. After engine securing on the ramp the PIC immediately telephoned company and advised them of the situation.

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Original NASA ASRS Text

Title: Corporate jet at high altitude cruise endured a compressor stall followed by a flameout. Crew was able to re-start the engine at a lower altitude. Crew diverted into an en route airport.

Narrative: The Left engine experienced a Compressor Stall while flying at Flight Level 450; and traveling at an indicated Mach speed of 0.817. We took immediate action by disconnecting the Auto-throttles; and slowly retarding the Left Thrust Lever. Compressor stall strengthened in intensity before a red CAS message of 'L ENG FLAMEOUT' populated. At this time we [advised] center; squawked 7700 while selecting TA only on the transponder; and requested an immediate lower altitude. We were given Flight Level 270 and direct to ZZZ. Upon this clearance we started a descent while maintaining the drift down airspeed of 180 KIAS. Pilot In Command (PIC) maintained Pilot Flying; while Second In Command (SIC) maintained Pilot Not Flying and immediately began the checklists as called out by Pilot Flying. We began with the 'L ENG FLAMEOUT' checklist (EM Tab 5); and upon completion of the procedure/checklist promptly continued onto the 'INFLIGHT ENGINE SHUT DOWN' checklist (EM Tab 6) as directed. This checklist was completed by Flight Level 370; and at the time it was decided that we would not attempt to restart the engine at that time. Once the Left engine was secured and procedure/checklist was complete; the SIC continued into the 'SINGLE ENGINE FLIGHT AND LANDING' checklist (AB Tab 4) as prompted by the previously completed checklist. At an indicated altitude of 33;560 feet the SIC started the APU. The 'SINGLE ENGINE FLIGHT AND LANDING' checklist was completed up to the APPROACH portion of this checklist. At that time approach advised runway 7 for our landing and the SIC briefed the ILS-7 into ZZZ and prepared the Landing Init for the Single Engine Approach and Landing as directed by the checklist. After descending through 14;000 feet it was decided to attempt an In Air Restart as per maintenance advised. The SIC promptly referred to the 'ENGINE AIRSTART' checklist (AB Tab 3). This checklist and procedure resulted in a successful AIRSTART and we were then able to continue to ZZZ under power with both engines. At this time all checklists were completed and the SIC resumed the running of normal checklists starting with the Descent at approximately 13;000 feet. Fire trucks and ARFF did respond but were not needed. Aircraft X landed without further issues at ZZZ and exited the runway under her own power. Upon parking at [FBO] a member of the Airport Operations team spoke with the SIC regarding airport of departure and original destination. Nothing was signed at this time; and Airport Operations advised that no further information was required at this time. After engine securing on the ramp the PIC immediately telephoned Company and advised them of the situation.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.