ALTDEV ALT EXCURSION OCCURS AFTER ATX TWIN EXPERIENCES A DOUBLE ENG STOPPAGE DUE TO INFLT ENCOUNTER WITH SNOW CONDITIONS.

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AT AB55 AM ON JAN/FRI/92; APPROX 25 MI E OF BUFFALO ON A FLT FROM UTICA TO BUFFALO; IFR AT 4000 FT; THE R ENG ON OUR SMT STARTED RUNNING ROUGH. AT THAT TIME; I TURNED ON THE FUEL PUMPS; ENRICHED THE MIXTURES AND BROUGHT THE PROPS FORWARD AND TURNED ON THE ALTERNATE AIRS. 5 MINS LATER THE L ENG QUIT FOLLOWED BY THE R ENG. I DECLARED AN EMER WITH ATC AND STARTED A SPIRALING DSCNT OVER THE AKRON ARPT. AT APPROX 2300 FT MSL; 1500 FT AGL; BOTH ENGS REGAINED FULL PWR AND WE PROCEEDED TO BUFFALO FOR A NORMAL LNDG. AFTER THE ENGS HAD FAILED; I HAD SWITCHED FUEL TANKS AND TURNED ON XFEED WITH NO CHANGE. MAINT BELIEVES THROTTLE BODY ICING WAS THE CAUSE OF THE PWR FAILURE. AFTER THE INCIDENT WHILE REVIEWING THE NUMBERS IT BECAME AWARE TO ME THAT I HAD BEEN OPERATING THE ACFT IN EXCESS OF THE 0 FUEL WT. TO PREVENT THIS FROM HAPPENING AGAIN; I WOULD RECOMMEND HAVING THE ALTERNATE AIR DOORS OPEN BEFORE ENTERING ICING CONDITIONS OF ANY KIND; AND BE AWARE OF ALL WT LIMITS; SUCH AS 0 FUEL WT. CONTRIBUTING FACTORS ARE -8 DEGS C LAKE EFFECT. SNOW LIGHT TO MODERATE INTENSITY. SUPPLEMENTAL INFO FROM ACN 199675: BOTH ENGS STARTED RUNNING AND A CLB WAS STARTED WITH A NORMAL LNDG AT BUFFALO; NY (BUF). FUEL WAS IN ALL TANKS. THE AIR FILTERS WERE CLOGGED WITH SNOW. WE FEEL THE CAUSE WAS BOTH AIR FILTERS CLOGGED WITH SNOW AND THE FUEL INJECTION SYS ICE OR THROTTLE PLATE ICE. THERE WAS NO AIRFRAME ICE.