Narrative:

Cleared for initial descent from cruise altitude. Engine began to surge. Power erratic. Immediately contacted ATC and declared an emergency, requesting vectors to closest airport. ATC responded with airport 10 mi ahead on present heading. Began to troubleshoot problem, engine continued to surge. Located field ahead for straight in landing. Continued to troubleshoot. Isolated 1 fuel tank and surge seemed to clear. May have been contaminant in 1 fuel tank. Proceeded to make precautionary landing. Drained fuel from both tanks. Conducted run-ups, and proceeded on trip. Cancelled IFR clearance with ATC through land to air relay with a citation that was monitoring emergency for ATC after descending below radio coverage.

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Original NASA ASRS Text

Title: A C-182 SINGLE PLT DECLARED AN EMER WITH ZMP WHEN HIS ENG BEGAN TO SURGE AND HE MADE AN UNPLANNED LNDG AT GLR.

Narrative: CLRED FOR INITIAL DSCNT FROM CRUISE ALT. ENG BEGAN TO SURGE. PWR ERRATIC. IMMEDIATELY CONTACTED ATC AND DECLARED AN EMER, REQUESTING VECTORS TO CLOSEST ARPT. ATC RESPONDED WITH ARPT 10 MI AHEAD ON PRESENT HDG. BEGAN TO TROUBLESHOOT PROB, ENG CONTINUED TO SURGE. LOCATED FIELD AHEAD FOR STRAIGHT IN LNDG. CONTINUED TO TROUBLESHOOT. ISOLATED 1 FUEL TANK AND SURGE SEEMED TO CLR. MAY HAVE BEEN CONTAMINANT IN 1 FUEL TANK. PROCEEDED TO MAKE PRECAUTIONARY LNDG. DRAINED FUEL FROM BOTH TANKS. CONDUCTED RUN-UPS, AND PROCEEDED ON TRIP. CANCELLED IFR CLRNC WITH ATC THROUGH LAND TO AIR RELAY WITH A CITATION THAT WAS MONITORING EMER FOR ATC AFTER DSNDING BELOW RADIO COVERAGE.

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.