Narrative:

On the morning of jun/89, I was en route from L26 to apv flying a ult (experimental aircraft). The aircraft is of high wing parasol type, with the main fuel tank in the center of the wing. The wing tank feeds the nose tank that is just behind the firewall. On preflight inspection, checking the fuel for contamination, there was none. En route from hesperia airport (L26), to apple valley airport (apv), I turned the valve which allows the fuel from the wing tank to fill the nose tank. The nose tank became about 3/4 full, and I turned the valve off. On final approach to runway 18, at apv, the engine quit running and I landed short of the runway in the open desert. Upon inspection, it was found that no structural damage had occurred, however, the bolt holding the tail wheel onto the tail spring had broke. The reason for the engine stopping was determined when the carburetor was drained, and it was found to be full of water. The problem with the fuel system seems to be that the wing tank on the ult isn't equipped with a fuel sump drain. This causes difficulties when, even after a thorough preflight inspection, where the nose tank sump is flushed, any condensation in the wing tank is still remaining, with no way of being flushed. Later, when the nose tank requires refilling, the fuel and any water that has settled in the wing tank is transferred directly into the nose tank. This was the particular problem that I experienced. I felt it only prudent to write to inform your organization of this situation. I have also enclosed a similar letter to the association of ult builders and owners.

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Original NASA ASRS Text

Title: PLT OF ULTRA LIGHT EXECUTES FORCED LNDG DUE TO ENGINE FAILURE. REPORTER ALERTS BUILDERS OPERATORS OF THIS SPECIFIC ULTRA LIGHT OF THE PROBLEM AND RECOMMENDS SOLUTION IN OPERATOR NEWSLETTER.

Narrative: ON THE MORNING OF JUN/89, I WAS ENRTE FROM L26 TO APV FLYING A ULT (EXPERIMENTAL ACFT). THE ACFT IS OF HIGH WING PARASOL TYPE, WITH THE MAIN FUEL TANK IN THE CENTER OF THE WING. THE WING TANK FEEDS THE NOSE TANK THAT IS JUST BEHIND THE FIREWALL. ON PREFLT INSPECTION, CHECKING THE FUEL FOR CONTAMINATION, THERE WAS NONE. ENRTE FROM HESPERIA ARPT (L26), TO APPLE VALLEY ARPT (APV), I TURNED THE VALVE WHICH ALLOWS THE FUEL FROM THE WING TANK TO FILL THE NOSE TANK. THE NOSE TANK BECAME ABOUT 3/4 FULL, AND I TURNED THE VALVE OFF. ON FINAL APCH TO RWY 18, AT APV, THE ENGINE QUIT RUNNING AND I LANDED SHORT OF THE RWY IN THE OPEN DESERT. UPON INSPECTION, IT WAS FOUND THAT NO STRUCTURAL DAMAGE HAD OCCURRED, HOWEVER, THE BOLT HOLDING THE TAIL WHEEL ONTO THE TAIL SPRING HAD BROKE. THE REASON FOR THE ENGINE STOPPING WAS DETERMINED WHEN THE CARBURETOR WAS DRAINED, AND IT WAS FOUND TO BE FULL OF WATER. THE PROBLEM WITH THE FUEL SYSTEM SEEMS TO BE THAT THE WING TANK ON THE ULT ISN'T EQUIPPED WITH A FUEL SUMP DRAIN. THIS CAUSES DIFFICULTIES WHEN, EVEN AFTER A THOROUGH PREFLT INSPECTION, WHERE THE NOSE TANK SUMP IS FLUSHED, ANY CONDENSATION IN THE WING TANK IS STILL REMAINING, WITH NO WAY OF BEING FLUSHED. LATER, WHEN THE NOSE TANK REQUIRES REFILLING, THE FUEL AND ANY WATER THAT HAS SETTLED IN THE WING TANK IS TRANSFERRED DIRECTLY INTO THE NOSE TANK. THIS WAS THE PARTICULAR PROBLEM THAT I EXPERIENCED. I FELT IT ONLY PRUDENT TO WRITE TO INFORM YOUR ORGANIZATION OF THIS SITUATION. I HAVE ALSO ENCLOSED A SIMILAR LETTER TO THE ASSOCIATION OF ULT BUILDERS AND OWNERS.

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.