Narrative:

Engine quit on takeoff 100 ft above ground. Instructor on board managed to coax enough power from engine by jiggling with throttle to make 180 degree turn and land. Student and instructor taxied back to maintenance hangar. Fuel was observed dripping from gascolator drain valve on left lower side of bottom cowl. There was also a large blue fuel stain trailing aft from fuel drain valve along cowl and on top and bottom of left wing root. The fuel drain valve Y was found locked in the open position, allowing suction of fuel away from the carburetor and subsequent loss of power. Manufacturer of drain valve offers, among its various products, a locking drain valve, Y, with a 90 degree locking feature, and in a similar size the X with a nonlocking spiral feature for opening the valve. A look at the manufacturer parts manual for the small aircraft model showed the following on 7 492-312 valve Y drain X. All other single engine small aircraft parts manuals show only the Y valve for the gascolator drain. Based upon the above described near accident, I believe that only the X should be installed on gascolators on which drain valves are installed. Also, manufacturer aircraft corp, should clarify the small aircraft parts manual to show which drain valve is required to be installed in the gascolator. I recommend that manufacturer should change its parts manuals to show the X drain valve in all gascolators to prevent accidents that could result from improper securing of the Y drain valves. Callback conversation with reporter revealed the following information. Reporter states problem developed because student forgot the engine drain. Instructor said get out and check it. Instructor not there to make sure valve closed. Reporter said if there had been an accident no one would have known why as the valve would most likely have popped closed. He is replacing valves with those that automatic close on all FBO aircraft.

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Original NASA ASRS Text

Title: GASCOLATOR DRAIN LOCKED OPEN. ENG QUIT AT 100 FT.

Narrative: ENG QUIT ON TKOF 100 FT ABOVE GND. INSTRUCTOR ON BOARD MANAGED TO COAX ENOUGH PWR FROM ENG BY JIGGLING WITH THROTTLE TO MAKE 180 DEG TURN AND LAND. STUDENT AND INSTRUCTOR TAXIED BACK TO MAINT HANGAR. FUEL WAS OBSERVED DRIPPING FROM GASCOLATOR DRAIN VALVE ON L LOWER SIDE OF BOTTOM COWL. THERE WAS ALSO A LARGE BLUE FUEL STAIN TRAILING AFT FROM FUEL DRAIN VALVE ALONG COWL AND ON TOP AND BOTTOM OF L WING ROOT. THE FUEL DRAIN VALVE Y WAS FOUND LOCKED IN THE OPEN POS, ALLOWING SUCTION OF FUEL AWAY FROM THE CARB AND SUBSEQUENT LOSS OF PWR. MANUFACTURER OF DRAIN VALVE OFFERS, AMONG ITS VARIOUS PRODUCTS, A LOCKING DRAIN VALVE, Y, WITH A 90 DEG LOCKING FEATURE, AND IN A SIMILAR SIZE THE X WITH A NONLOCKING SPIRAL FEATURE FOR OPENING THE VALVE. A LOOK AT THE MANUFACTURER PARTS MANUAL FOR THE SMA MODEL SHOWED THE FOLLOWING ON 7 492-312 VALVE Y DRAIN X. ALL OTHER SINGLE ENG SMA PARTS MANUALS SHOW ONLY THE Y VALVE FOR THE GASCOLATOR DRAIN. BASED UPON THE ABOVE DESCRIBED NEAR ACCIDENT, I BELIEVE THAT ONLY THE X SHOULD BE INSTALLED ON GASCOLATORS ON WHICH DRAIN VALVES ARE INSTALLED. ALSO, MANUFACTURER ACFT CORP, SHOULD CLARIFY THE SMA PARTS MANUAL TO SHOW WHICH DRAIN VALVE IS REQUIRED TO BE INSTALLED IN THE GASCOLATOR. I RECOMMEND THAT MANUFACTURER SHOULD CHANGE ITS PARTS MANUALS TO SHOW THE X DRAIN VALVE IN ALL GASCOLATORS TO PREVENT ACCIDENTS THAT COULD RESULT FROM IMPROPER SECURING OF THE Y DRAIN VALVES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. RPTR STATES PROBLEM DEVELOPED BECAUSE STUDENT FORGOT THE ENG DRAIN. INSTRUCTOR SAID GET OUT AND CHK IT. INSTRUCTOR NOT THERE TO MAKE SURE VALVE CLOSED. RPTR SAID IF THERE HAD BEEN AN ACCIDENT NO ONE WOULD HAVE KNOWN WHY AS THE VALVE WOULD MOST LIKELY HAVE POPPED CLOSED. HE IS REPLACING VALVES WITH THOSE THAT AUTO CLOSE ON ALL FBO ACFT.

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.