Narrative:

While in level cruise flight at FL200 left engine stopped producing power and began to surge. Pilot activated low boost pumps. Condition continued for another 15 seconds. Pilot initiated failed engine restart procedure. Pilot disengaged autopilot; changed fuel tanks; selected high boost momentarily to determine if a primary engine pump had failed. Condition continued. Engine continued to surge for another 5-10 seconds; and then began producing power again. Pilot had lost 400 ft of altitude. Engine began to run normally; pilot initialed climb. Controlled asked to confirm altitude. Pilot responded that he was dealing with an engine problem. Controller queried if the pilot needed assistance. At this point engine was running normally; all cockpit engine indications were normal; pilot declined assistance and reestablished cruise flight at FL200 and reengaged the autopilot. Pilot elected to land short of original destination. Controller questioned the reason for the diversion. Entire event lasted 30-45 seconds. Altitude lost; 400 ft; reason for engine power loss; undetermined. Fuel quantity indicators showed fuel in tanks. All other engine indicators were normal. Pilot; who is an a&P and has owned that aircraft suspects trapped water in fuel bladders; aircraft was parked outside the night before and it had rained. Pilot had double sumped all drains specifically because of that fact. Pilot sumped tanks after landing; no contaminants were found. Pilot took fresh fuel; re sumped tanks; no contaminants found; and continued to destination without incident.

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Original NASA ASRS Text

Title: A C414's left engine quit at FL200 apparently because of water in the tank but after a restart it ran normally so the pilot diverted to a nearby airport for an inspection and fresh fuel.

Narrative: While in level cruise flight at FL200 left engine stopped producing power and began to surge. Pilot activated low boost pumps. Condition continued for another 15 seconds. Pilot initiated failed engine restart procedure. Pilot disengaged autopilot; changed fuel tanks; selected high boost momentarily to determine if a primary engine pump had failed. Condition continued. Engine continued to surge for another 5-10 seconds; and then began producing power again. Pilot had lost 400 FT of altitude. Engine began to run normally; pilot initialed climb. Controlled asked to confirm altitude. Pilot responded that he was dealing with an engine problem. Controller queried if the pilot needed assistance. At this point engine was running normally; all cockpit engine indications were normal; pilot declined assistance and reestablished cruise flight at FL200 and reengaged the autopilot. Pilot elected to land short of original destination. Controller questioned the reason for the diversion. Entire event lasted 30-45 seconds. Altitude lost; 400 FT; reason for engine power loss; undetermined. Fuel quantity indicators showed fuel in tanks. All other engine indicators were normal. Pilot; who is an A&P and has owned that aircraft suspects trapped water in fuel bladders; aircraft was parked outside the night before and it had rained. Pilot had double sumped all drains specifically because of that fact. Pilot sumped tanks after landing; no contaminants were found. Pilot took fresh fuel; re sumped tanks; no contaminants found; and continued to destination without incident.

Data retrieved from NASA's ASRS site as of July 2013 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.