Narrative:

I was on an IFR flight in VMC conditions from greeley, co to centennial, co, flying the aircraft from the right seat. As first officer shortly after takeoff (5 min) we had a fuel flow interruption on the right engine and the captain enriched the mixtures, brought both the propellers and throttles forward and verified that the fuel pumps were in the 'on' position. I continued to fly the aircraft while the captain worked on the problem. After several power surges, normal power indications were observed. After power was restored the captain commented the fuel selector did not appear to be completely on the right main, that it was in between (right side) the right main and right auxiliary settings. The captain then advised denver center that we had an emergency situation, but not fully declaring an emergency or squawking 7700. Because we did not know the exact nature of the problem, we thought it prudent to do a 180 and return to greeley. Denver center also asked us the exact nature of the problem, to which the captain replied 'possible fuel contamination'. We then returned to greeley and made a normal approach and landing. After shutting down in the ramp area, investigating the problem, sufficient fuel was found for the return trip to centennial. Because we were still not certain of the exact nature of the problem, fuel was added to the right main. After letting the fuel settle, we took fuel samples from all drains and found small amounts of sediment from both sides of the fuel system. Before departing greeley, a high power run-up was performed and the aircraft was run for several minutes and all indications and performance were normal. We took off from greeley and flew to centennial VFR without further incident. Both the captain and I believe that the right fuel selector was displaced, either by vibration or was accidentally kicked, due to lack of a positive detent. That being the cause of the problem, letting the right fuel selector move to the auxiliary position and consuming what little fuel was in that tank, or using what little fuel was left in the lines. Also the fuel selectors not being covered and in the entry way to the cockpit allows for the possibility for the selectors to be bumped by persons leaving or entering the cockpit. Pilot actions under the circumstances I feel were good, because we got the engine back in service in a short period of time. However the mention of an emergency situation on board, whether that constitutes a declaration or not, I feel was a little premature. The decision to return to greeley was a good one because we did not know exactly what we were dealing with at the time.

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Original NASA ASRS Text

Title: AFTER EXPERIENCING SOME ENGINE SURGING WHICH WAS CORRECTED, FLT RETURNED TO DEP ARPT TO CONDUCT INVESTIGATION.

Narrative: I WAS ON AN IFR FLT IN VMC CONDITIONS FROM GREELEY, CO TO CENTENNIAL, CO, FLYING THE ACFT FROM THE RIGHT SEAT. AS F/O SHORTLY AFTER TKOF (5 MIN) WE HAD A FUEL FLOW INTERRUPTION ON THE RIGHT ENGINE AND THE CAPT ENRICHED THE MIXTURES, BROUGHT BOTH THE PROPS AND THROTTLES FORWARD AND VERIFIED THAT THE FUEL PUMPS WERE IN THE 'ON' POSITION. I CONTINUED TO FLY THE ACFT WHILE THE CAPT WORKED ON THE PROBLEM. AFTER SEVERAL POWER SURGES, NORMAL POWER INDICATIONS WERE OBSERVED. AFTER POWER WAS RESTORED THE CAPT COMMENTED THE FUEL SELECTOR DID NOT APPEAR TO BE COMPLETELY ON THE RIGHT MAIN, THAT IT WAS IN BETWEEN (RIGHT SIDE) THE RIGHT MAIN AND RIGHT AUX SETTINGS. THE CAPT THEN ADVISED DENVER CENTER THAT WE HAD AN EMER SITUATION, BUT NOT FULLY DECLARING AN EMER OR SQUAWKING 7700. BECAUSE WE DID NOT KNOW THE EXACT NATURE OF THE PROBLEM, WE THOUGHT IT PRUDENT TO DO A 180 AND RETURN TO GREELEY. DENVER CENTER ALSO ASKED US THE EXACT NATURE OF THE PROBLEM, TO WHICH THE CAPT REPLIED 'POSSIBLE FUEL CONTAMINATION'. WE THEN RETURNED TO GREELEY AND MADE A NORMAL APCH AND LNDG. AFTER SHUTTING DOWN IN THE RAMP AREA, INVESTIGATING THE PROBLEM, SUFFICIENT FUEL WAS FOUND FOR THE RETURN TRIP TO CENTENNIAL. BECAUSE WE WERE STILL NOT CERTAIN OF THE EXACT NATURE OF THE PROBLEM, FUEL WAS ADDED TO THE RIGHT MAIN. AFTER LETTING THE FUEL SETTLE, WE TOOK FUEL SAMPLES FROM ALL DRAINS AND FOUND SMALL AMOUNTS OF SEDIMENT FROM BOTH SIDES OF THE FUEL SYSTEM. BEFORE DEPARTING GREELEY, A HIGH POWER RUN-UP WAS PERFORMED AND THE ACFT WAS RUN FOR SEVERAL MINUTES AND ALL INDICATIONS AND PERFORMANCE WERE NORMAL. WE TOOK OFF FROM GREELEY AND FLEW TO CENTENNIAL VFR WITHOUT FURTHER INCIDENT. BOTH THE CAPT AND I BELIEVE THAT THE RIGHT FUEL SELECTOR WAS DISPLACED, EITHER BY VIBRATION OR WAS ACCIDENTALLY KICKED, DUE TO LACK OF A POSITIVE DETENT. THAT BEING THE CAUSE OF THE PROBLEM, LETTING THE RIGHT FUEL SELECTOR MOVE TO THE AUX POSITION AND CONSUMING WHAT LITTLE FUEL WAS IN THAT TANK, OR USING WHAT LITTLE FUEL WAS LEFT IN THE LINES. ALSO THE FUEL SELECTORS NOT BEING COVERED AND IN THE ENTRY WAY TO THE COCKPIT ALLOWS FOR THE POSSIBILITY FOR THE SELECTORS TO BE BUMPED BY PERSONS LEAVING OR ENTERING THE COCKPIT. PLT ACTIONS UNDER THE CIRCUMSTANCES I FEEL WERE GOOD, BECAUSE WE GOT THE ENGINE BACK IN SERVICE IN A SHORT PERIOD OF TIME. HOWEVER THE MENTION OF AN EMER SITUATION ON BOARD, WHETHER THAT CONSTITUTES A DECLARATION OR NOT, I FEEL WAS A LITTLE PREMATURE. THE DECISION TO RETURN TO GREELEY WAS A GOOD ONE BECAUSE WE DID NOT KNOW EXACTLY WHAT WE WERE DEALING WITH AT THE TIME.

Data retrieved from NASA's ASRS site as of August 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.