Cessna 152 N48259 accident near Carlsbad, California

Probable cause

A partial loss of engine power during takeoff due to carbon fouling of a spark plug.

NTSB analysis

The pilot reported that he had been practicing touch-and-go takeoffs and landings for about an hour. On the accident takeoff, he noted a rough running engine. The airplane had already attained traffic pattern altitude, therefore the pilot continued the flight and declared an emergency on downwind. The pilot stated that he trimmed the airplane for best glide, and as he turned onto final approach, there was a further reduction in engine rpm and an increase in engine roughness. Unable to reach the runway, the airplane landed on its nose short of the runway threshold. Both the wings and fuselage were substantially damaged. An inspection of the engine revealed that the bottom spark plug of the number 2 cylinder was carbon fouled, which could have resulted in a partial loss of engine rpm and a rough running engine. No other mechanical anomalies were noted with the engine inspection.

Text from the NTSB. Open the NTSB docket for WPR09LA205 for the full record.