Pilot of ct flight design experiences partial engine failure at 9000 feet. After setting up for a pr...

Narrative:

About 15 mi south of ZZZ I had experienced a loss of engine power. At the same time ZZZ approach asked if I had some local traffic in sight. I responded by saying that I didn't have traffic in sight and that I was experiencing a loss of engine power. They asked if I would like to declare an emergency and if there was anything they could do to help. I informed them that I would not like to declare an emergency. At this point the power was in and out. Going from what would seem like idle to about half throttle. As all of this was happening I double-check what fuel/air/spark variables inside the cockpit that may help aid this situation. Only things that were available were full shut off 'valve' which was on; throttle about half to full; choke which I left alone; and magnetos on both. At this point I had lost enough altitude and had picked numerous off airport landing spots. I was 50 ft from my off field landing (about 8-10 mi south now) and the throttle kicked from idle back up to about 80-90%. I proceeded to climb back up still keeping off field landing ahead in case it were to quit again. Approach picked me back up on radar. They said they thought they lost me and that they had declared an emergency for me. I was cleared to land any runway at ZZZ and was asked if I had the airport in sight. I informed them that I had the runway in sight. I kept climbing until I knew I was power off gliding distance from the runway. At that point I closed the throttle again and the engine not only lost power but came to a complete stop. (Not wind-milling anymore.) I proceeded to land; got off at the first taxiway where I was greeted by 4 fire trucks and 2 ambulances. I then tried to start the aircraft after I landed and got it started after about 2 or 3 cranks. I taxied up to the hangar. We immediately checked the fuel tanks to begin our troubleshooting. Left tank of the flight design was empty. Right tank had 8 gals. This is a 31.5 gal system so we are saying that one quarter of the total fuel was still on board the aircraft. The ct flight design burns 4-5 gph. So I should have been good for at least another hour and a half. Also there is no option for switching tanks with a fuel selector and there is no auxiliary fuel pump like you have on most other GA aircraft. The only conclusion we could come up with logically was fuel starvation in the left tank and no options to access the fuel in the right tank. Maybe as I was banking to land off field it helped some of the fuel from the other tank get to the engine. Callback conversation with reporter revealed the following information: the reporter did notice that one tank was being used more rapidly than the other by looking at the fuel sight gauges on each side of the aircraft but didn't think much of it until the engine begin to run rough. In hindsight he would now assume that there is a problem if the tanks do not remain nearly even. It is the nature of rotax 912 engine to stop turning in flight when the fuel or ignition is cut off. The reporter left the company before any definitive cause for this incident was found.

Original NASA ASRS Text

Title: PILOT OF CT FLIGHT DESIGN EXPERIENCES PARTIAL ENGINE FAILURE AT 9000 FEET. AFTER SETTING UP FOR A PRECAUTIONARY EMERGENCY LANDING AND CLOSING THE THROTTLE THE ENGINE STOPS COMPLETELY.

Narrative: ABOUT 15 MI S OF ZZZ I HAD EXPERIENCED A LOSS OF ENG PWR. AT THE SAME TIME ZZZ APCH ASKED IF I HAD SOME LCL TFC IN SIGHT. I RESPONDED BY SAYING THAT I DIDN'T HAVE TFC IN SIGHT AND THAT I WAS EXPERIENCING A LOSS OF ENG PWR. THEY ASKED IF I WOULD LIKE TO DECLARE AN EMER AND IF THERE WAS ANYTHING THEY COULD DO TO HELP. I INFORMED THEM THAT I WOULD NOT LIKE TO DECLARE AN EMER. AT THIS POINT THE PWR WAS IN AND OUT. GOING FROM WHAT WOULD SEEM LIKE IDLE TO ABOUT HALF THROTTLE. AS ALL OF THIS WAS HAPPENING I DOUBLE-CHK WHAT FUEL/AIR/SPARK VARIABLES INSIDE THE COCKPIT THAT MAY HELP AID THIS SITUATION. ONLY THINGS THAT WERE AVAILABLE WERE FULL SHUT OFF 'VALVE' WHICH WAS ON; THROTTLE ABOUT HALF TO FULL; CHOKE WHICH I LEFT ALONE; AND MAGNETOS ON BOTH. AT THIS POINT I HAD LOST ENOUGH ALT AND HAD PICKED NUMEROUS OFF ARPT LNDG SPOTS. I WAS 50 FT FROM MY OFF FIELD LNDG (ABOUT 8-10 MI S NOW) AND THE THROTTLE KICKED FROM IDLE BACK UP TO ABOUT 80-90%. I PROCEEDED TO CLB BACK UP STILL KEEPING OFF FIELD LNDG AHEAD IN CASE IT WERE TO QUIT AGAIN. APCH PICKED ME BACK UP ON RADAR. THEY SAID THEY THOUGHT THEY LOST ME AND THAT THEY HAD DECLARED AN EMER FOR ME. I WAS CLRED TO LAND ANY RWY AT ZZZ AND WAS ASKED IF I HAD THE ARPT IN SIGHT. I INFORMED THEM THAT I HAD THE RWY IN SIGHT. I KEPT CLBING UNTIL I KNEW I WAS PWR OFF GLIDING DISTANCE FROM THE RWY. AT THAT POINT I CLOSED THE THROTTLE AGAIN AND THE ENG NOT ONLY LOST PWR BUT CAME TO A COMPLETE STOP. (NOT WIND-MILLING ANYMORE.) I PROCEEDED TO LAND; GOT OFF AT THE FIRST TXWY WHERE I WAS GREETED BY 4 FIRE TRUCKS AND 2 AMBULANCES. I THEN TRIED TO START THE ACFT AFTER I LANDED AND GOT IT STARTED AFTER ABOUT 2 OR 3 CRANKS. I TAXIED UP TO THE HANGAR. WE IMMEDIATELY CHKED THE FUEL TANKS TO BEGIN OUR TROUBLESHOOTING. L TANK OF THE FLT DESIGN WAS EMPTY. R TANK HAD 8 GALS. THIS IS A 31.5 GAL SYS SO WE ARE SAYING THAT ONE QUARTER OF THE TOTAL FUEL WAS STILL ON BOARD THE ACFT. THE CT FLT DESIGN BURNS 4-5 GPH. SO I SHOULD HAVE BEEN GOOD FOR AT LEAST ANOTHER HR AND A HALF. ALSO THERE IS NO OPTION FOR SWITCHING TANKS WITH A FUEL SELECTOR AND THERE IS NO AUX FUEL PUMP LIKE YOU HAVE ON MOST OTHER GA ACFT. THE ONLY CONCLUSION WE COULD COME UP WITH LOGICALLY WAS FUEL STARVATION IN THE L TANK AND NO OPTIONS TO ACCESS THE FUEL IN THE R TANK. MAYBE AS I WAS BANKING TO LAND OFF FIELD IT HELPED SOME OF THE FUEL FROM THE OTHER TANK GET TO THE ENG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER DID NOTICE THAT ONE TANK WAS BEING USED MORE RAPIDLY THAN THE OTHER BY LOOKING AT THE FUEL SIGHT GAUGES ON EACH SIDE OF THE ACFT BUT DIDN'T THINK MUCH OF IT UNTIL THE ENGINE BEGIN TO RUN ROUGH. IN HINDSIGHT HE WOULD NOW ASSUME THAT THERE IS A PROBLEM IF THE TANKS DO NOT REMAIN NEARLY EVEN. IT IS THE NATURE OF ROTAX 912 ENGINE TO STOP TURNING IN FLIGHT WHEN THE FUEL OR IGNITION IS CUT OFF. THE REPORTER LEFT THE COMPANY BEFORE ANY DEFINITIVE CAUSE FOR THIS INCIDENT WAS FOUND.

Data retrieved from NASA's ASRS site as of January 2009 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.

Attributes
ACN	739488
Time
Date	200705
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	general aviation : personal
Make Model Name	Light Sport Aircraft
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	VFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : multi engine pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 60 flight time total : 750 flight time type : 40
ASRS Report	739488
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	controller : provided flight assist flight crew : declared emergency flight crew : diverted to another airport flight crew : landed in emergency condition
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Pilot of ct flight design experiences partial engine failure at 9000 feet. After setting up for a precautionary emergency landing and closing the throttle the engine stops completely.