Narrative:

Events leading to engine stoppage: 3 days prior to forced landing, there were extremes in ambient temperature (20-70 degrees F). I noticed increased moisture when sumping wing tanks. The morning of flight ambient temperature was 25 degrees and fuel selector was frozen. As this is the low spot in the system, heat was applied to the aircraft belly until fuel flowed through gascolator. Fuel sumping was done again and no water or ice crystals were noticed. A 45 min local flight was taken close to the airport. Aircraft was flown in 270 degree turns at 45 degree right and left banks using right and left tanks. Straight ahead flight was performed with +2 G and 0 6 maneuvers. No abnormal engine power surges were noted. After landing, gascolator drain was clamped open and 3 gals of gas were drained. No moisture or ice were noted. 2 hours later after preflting plane again, a 45 min flight was taken to a distant airport. While on approach to that airport and at low cruise setting of 19 in mp, the mixture was moved full rich, the engine made a slight shudder and stopped. 4 hours after off-airport landing was made,the engine was started and run up, and was normal. I believe the engine stoppage was caused by ice remaining in the fuel selector valve which broke loose and blocked the mixture metering valve. Corrective action is difficult due to low wind dihedral, and fuel bladders that trap moisture that is produced by normal condensation. Poor design of the fuel system makes checking for contamination ineffective. Effective and reasonably priced fuel additives are needed. Callback conversation with reporter revealed the following: reporter said engine stopped when he was about 4 mi north of chx while over water. He did a right 180 degree turn to get nearer shore, then saw a beach area (north ave beach) and succeeded in landing west/O damage to aircraft or anything else. He had already checked in with dgx tower and was in communication with them throughout the emergency landing. He said FAA has made a 'thorough' investigation and concluded that the problem was carburetor ice. They have a previous record of this occurring int his type aircraft when flying at low altitude over-water in the kind of ambient conditions existing at the time of this incident. The FAA has concluded that no enforcement action is needed or appropriate in this case. Reporter said that the very thorough precautionary actions he took before this flight with respect to fuel ice were not take because he had had previous difficulties of this nature. He was simply carrying out recommended winter flying procedures.

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Original NASA ASRS Text

Title: SMA HAS ENGINE FAILURE DURING EARLY STAGE OF APCH TO DESTINATION ARPT AND MAKES OFF-ARPT LNDG.

Narrative: EVENTS LEADING TO ENG STOPPAGE: 3 DAYS PRIOR TO FORCED LNDG, THERE WERE EXTREMES IN AMBIENT TEMP (20-70 DEGS F). I NOTICED INCREASED MOISTURE WHEN SUMPING WING TANKS. THE MORNING OF FLT AMBIENT TEMP WAS 25 DEGS AND FUEL SELECTOR WAS FROZEN. AS THIS IS THE LOW SPOT IN THE SYS, HEAT WAS APPLIED TO THE ACFT BELLY UNTIL FUEL FLOWED THROUGH GASCOLATOR. FUEL SUMPING WAS DONE AGAIN AND NO WATER OR ICE CRYSTALS WERE NOTICED. A 45 MIN LCL FLT WAS TAKEN CLOSE TO THE ARPT. ACFT WAS FLOWN IN 270 DEG TURNS AT 45 DEG RIGHT AND LEFT BANKS USING RIGHT AND LEFT TANKS. STRAIGHT AHEAD FLT WAS PERFORMED WITH +2 G AND 0 6 MANEUVERS. NO ABNORMAL ENG PWR SURGES WERE NOTED. AFTER LNDG, GASCOLATOR DRAIN WAS CLAMPED OPEN AND 3 GALS OF GAS WERE DRAINED. NO MOISTURE OR ICE WERE NOTED. 2 HRS LATER AFTER PREFLTING PLANE AGAIN, A 45 MIN FLT WAS TAKEN TO A DISTANT ARPT. WHILE ON APCH TO THAT ARPT AND AT LOW CRUISE SETTING OF 19 IN MP, THE MIXTURE WAS MOVED FULL RICH, THE ENG MADE A SLIGHT SHUDDER AND STOPPED. 4 HRS AFTER OFF-ARPT LNDG WAS MADE,THE ENG WAS STARTED AND RUN UP, AND WAS NORMAL. I BELIEVE THE ENG STOPPAGE WAS CAUSED BY ICE REMAINING IN THE FUEL SELECTOR VALVE WHICH BROKE LOOSE AND BLOCKED THE MIXTURE METERING VALVE. CORRECTIVE ACTION IS DIFFICULT DUE TO LOW WIND DIHEDRAL, AND FUEL BLADDERS THAT TRAP MOISTURE THAT IS PRODUCED BY NORMAL CONDENSATION. POOR DESIGN OF THE FUEL SYS MAKES CHKING FOR CONTAMINATION INEFFECTIVE. EFFECTIVE AND REASONABLY PRICED FUEL ADDITIVES ARE NEEDED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR SAID ENG STOPPED WHEN HE WAS ABOUT 4 MI N OF CHX WHILE OVER WATER. HE DID A RIGHT 180 DEG TURN TO GET NEARER SHORE, THEN SAW A BEACH AREA (N AVE BEACH) AND SUCCEEDED IN LNDG W/O DAMAGE TO ACFT OR ANYTHING ELSE. HE HAD ALREADY CHKED IN WITH DGX TWR AND WAS IN COM WITH THEM THROUGHOUT THE EMER LNDG. HE SAID FAA HAS MADE A 'THOROUGH' INVESTIGATION AND CONCLUDED THAT THE PROB WAS CARB ICE. THEY HAVE A PREVIOUS RECORD OF THIS OCCURRING INT HIS TYPE ACFT WHEN FLYING AT LOW ALT OVER-WATER IN THE KIND OF AMBIENT CONDITIONS EXISTING AT THE TIME OF THIS INCIDENT. THE FAA HAS CONCLUDED THAT NO ENFORCEMENT ACTION IS NEEDED OR APPROPRIATE IN THIS CASE. RPTR SAID THAT THE VERY THOROUGH PRECAUTIONARY ACTIONS HE TOOK BEFORE THIS FLT WITH RESPECT TO FUEL ICE WERE NOT TAKE BECAUSE HE HAD HAD PREVIOUS DIFFICULTIES OF THIS NATURE. HE WAS SIMPLY CARRYING OUT RECOMMENDED WINTER FLYING PROCS.

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.