Narrative:

We were cruising at FL410 and saw some thunderstorms building up in the distance. We decided to climb up to FL430. We received clearance to climb to FL430. The first officer increased power to climb and initiated the climb. We barely left FL410 when the left engine flamed out, followed +/-5 seconds later followed by the right engine. Both pilots then donned oxygen masks. I asked for and received a clearance to descend. The initial clearance was for FL330, this because of traffic. Being unable to maintain altitude, we declared an emergency and received further clearance to FL240 and a turn for the descent to 090 degrees. This was for traffic avoidance. Meanwhile the first officer remained in control of the airplane while I ran the checklist. Descending out of FL250, using the airstart checklist, I managed to restart the right engine, followed within 2 mins by the left engine. Both engines ran normal after the airstart. We never did descend below our clearance limit of FL240. After about 5 mins at FL240 we determined all engine parameters were within normal operating range. We canceled the emergency and asked for and received a clearance to FL330. The engines continued to operate normally and we climbed to FL370 and got cleared direct to our destination, followed by a normal descent and landing. A visual check of the engines revealed nothing. The cause of the flameout remains unknown. It might have been windshear/turbulence associated with the presence of cumulus clouds. The engine power settings were within normal parameters. I believe there was no way to avoid this occurrence. The occurrence was solved by using crew coordination and the learjet checklist. There was no damage visible to the engines and no fluid leaks were present.

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Original NASA ASRS Text

Title: AN LJ24 FLC ATTEMPTING TO CLB FROM FL410 TO FL430 FOR WX AVOIDANCE NEAR SAT EXPERIENCED A DUAL ENG FLAMEOUT.

Narrative: WE WERE CRUISING AT FL410 AND SAW SOME TSTMS BUILDING UP IN THE DISTANCE. WE DECIDED TO CLB UP TO FL430. WE RECEIVED CLRNC TO CLB TO FL430. THE FO INCREASED PWR TO CLB AND INITIATED THE CLB. WE BARELY LEFT FL410 WHEN THE L ENG FLAMED OUT, FOLLOWED +/-5 SECONDS LATER FOLLOWED BY THE R ENG. BOTH PLTS THEN DONNED OXYGEN MASKS. I ASKED FOR AND RECEIVED A CLRNC TO DSND. THE INITIAL CLRNC WAS FOR FL330, THIS BECAUSE OF TFC. BEING UNABLE TO MAINTAIN ALT, WE DECLARED AN EMER AND RECEIVED FURTHER CLRNC TO FL240 AND A TURN FOR THE DSCNT TO 090 DEGS. THIS WAS FOR TFC AVOIDANCE. MEANWHILE THE FO REMAINED IN CTL OF THE AIRPLANE WHILE I RAN THE CHKLIST. DSNDING OUT OF FL250, USING THE AIRSTART CHKLIST, I MANAGED TO RESTART THE R ENG, FOLLOWED WITHIN 2 MINS BY THE L ENG. BOTH ENGS RAN NORMAL AFTER THE AIRSTART. WE NEVER DID DSND BELOW OUR CLRNC LIMIT OF FL240. AFTER ABOUT 5 MINS AT FL240 WE DETERMINED ALL ENG PARAMETERS WERE WITHIN NORMAL OPERATING RANGE. WE CANCELED THE EMER AND ASKED FOR AND RECEIVED A CLRNC TO FL330. THE ENGS CONTINUED TO OPERATE NORMALLY AND WE CLBED TO FL370 AND GOT CLRED DIRECT TO OUR DEST, FOLLOWED BY A NORMAL DSCNT AND LNDG. A VISUAL CHK OF THE ENGS REVEALED NOTHING. THE CAUSE OF THE FLAMEOUT REMAINS UNKNOWN. IT MIGHT HAVE BEEN WINDSHEAR/TURB ASSOCIATED WITH THE PRESENCE OF CUMULUS CLOUDS. THE ENG PWR SETTINGS WERE WITHIN NORMAL PARAMETERS. I BELIEVE THERE WAS NO WAY TO AVOID THIS OCCURRENCE. THE OCCURRENCE WAS SOLVED BY USING CREW COORD AND THE LEARJET CHKLIST. THERE WAS NO DAMAGE VISIBLE TO THE ENGS AND NO FLUID LEAKS WERE PRESENT.

Data retrieved from NASA's ASRS site as of July 2007 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.