Narrative:

While in level cruising flight at 7000 ft, we experienced a sudden partial loss of engine power. Tachometer went from 2500 to 1200 RPM. Immediately applied carburetor heat and adjusted mixture for best RPM. RPM came up to 1500 RPM but continued to run rough. We were losing altitude and advised ZLA that we had experienced a partial loss of power and were reversing course in VMC conditions towards rieder airstrip (private airstrip). Center stated, 'roger, understand that you are canceling IFR, squawk 1200.' I replied, 'no, I am declaring an emergency and am heading towards rieder in visual conditions.' center then handed me back to socal approach. Approach was very helpful and said that they were looking up the airport information for rieder. I told them that I had the airport in sight, was familiar with the runway layout, and knew the length of the runway and the field elevation (all of this was available from the sectional chart). Socal approach then stated that they were trying to call the owner of the airport for notification. At this point, the aircraft was able to maintain altitude and I stated that I would like to try to continue to sdm unless I was unable to maintain altitude in which case I would return to rieder. I also requested that my route take me towards nichols field (private airstrip for parachute jumping). Approach stated that they couldn't find nichols on their sectional chart (it isn't). I stated that I was familiar with its location and that it was marked on my san diego terminal chart. Approach then asked me what troubleshooting measures I had taken, souls onboard, color of aircraft, and fuel remaining. We maintained altitude until over brown field and started a descent over the airport. Engine RPM remained at a constant 1200 RPM. Engine quit upon touchdown. We were able to restart engine after several attempts on the runway and taxied clear. Mechanical inspection by ia revealed stuck valve. Southern california approach control: friendly, relaxed, offering suggestions without impending upon responsibilities of PIC. Controller verifying troubleshooting procedures: nice to have a second set of eyes in that situation. From a legal point of view, it's nice to have it on tape that you did everything you were supposed to do to prevent/minimize an accident.

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Original NASA ASRS Text

Title: SINGLE ENG ACFT DECLARES EMER AND LANDS AT SDM AFTER PWR LOSS.

Narrative: WHILE IN LEVEL CRUISING FLT AT 7000 FT, WE EXPERIENCED A SUDDEN PARTIAL LOSS OF ENG PWR. TACHOMETER WENT FROM 2500 TO 1200 RPM. IMMEDIATELY APPLIED CARB HEAT AND ADJUSTED MIXTURE FOR BEST RPM. RPM CAME UP TO 1500 RPM BUT CONTINUED TO RUN ROUGH. WE WERE LOSING ALT AND ADVISED ZLA THAT WE HAD EXPERIENCED A PARTIAL LOSS OF PWR AND WERE REVERSING COURSE IN VMC CONDITIONS TOWARDS RIEDER AIRSTRIP (PVT AIRSTRIP). CTR STATED, 'ROGER, UNDERSTAND THAT YOU ARE CANCELING IFR, SQUAWK 1200.' I REPLIED, 'NO, I AM DECLARING AN EMER AND AM HEADING TOWARDS RIEDER IN VISUAL CONDITIONS.' CTR THEN HANDED ME BACK TO SOCAL APCH. APCH WAS VERY HELPFUL AND SAID THAT THEY WERE LOOKING UP THE ARPT INFO FOR RIEDER. I TOLD THEM THAT I HAD THE ARPT IN SIGHT, WAS FAMILIAR WITH THE RWY LAYOUT, AND KNEW THE LENGTH OF THE RWY AND THE FIELD ELEVATION (ALL OF THIS WAS AVAILABLE FROM THE SECTIONAL CHART). SOCAL APCH THEN STATED THAT THEY WERE TRYING TO CALL THE OWNER OF THE ARPT FOR NOTIFICATION. AT THIS POINT, THE ACFT WAS ABLE TO MAINTAIN ALT AND I STATED THAT I WOULD LIKE TO TRY TO CONTINUE TO SDM UNLESS I WAS UNABLE TO MAINTAIN ALT IN WHICH CASE I WOULD RETURN TO RIEDER. I ALSO REQUESTED THAT MY RTE TAKE ME TOWARDS NICHOLS FIELD (PVT AIRSTRIP FOR PARACHUTE JUMPING). APCH STATED THAT THEY COULDN'T FIND NICHOLS ON THEIR SECTIONAL CHART (IT ISN'T). I STATED THAT I WAS FAMILIAR WITH ITS LOCATION AND THAT IT WAS MARKED ON MY SAN DIEGO TERMINAL CHART. APCH THEN ASKED ME WHAT TROUBLESHOOTING MEASURES I HAD TAKEN, SOULS ONBOARD, COLOR OF ACFT, AND FUEL REMAINING. WE MAINTAINED ALT UNTIL OVER BROWN FIELD AND STARTED A DSCNT OVER THE ARPT. ENG RPM REMAINED AT A CONSTANT 1200 RPM. ENG QUIT UPON TOUCHDOWN. WE WERE ABLE TO RESTART ENG AFTER SEVERAL ATTEMPTS ON THE RWY AND TAXIED CLR. MECHANICAL INSPECTION BY IA REVEALED STUCK VALVE. SOUTHERN CALIFORNIA APCH CTL: FRIENDLY, RELAXED, OFFERING SUGGESTIONS WITHOUT IMPENDING UPON RESPONSIBILITIES OF PIC. CTLR VERIFYING TROUBLESHOOTING PROCS: NICE TO HAVE A SECOND SET OF EYES IN THAT SIT. FROM A LEGAL POINT OF VIEW, IT'S NICE TO HAVE IT ON TAPE THAT YOU DID EVERYTHING YOU WERE SUPPOSED TO DO TO PREVENT/MINIMIZE AN ACCIDENT.

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.