Quicksilver GT-400 R503 N415HC accident near New Braunfels, Texas

Probable cause

The partial loss of engine power due to a loose spark plug. Contributing to the accident was the pilot's improper preflight inspection of the airplane.

NTSB analysis

The sport pilot reported that, about 15 minutes into the pleasure flight, the engine began "sputtering" and losing power. The pilot attempted to correct the problem by adjusting the throttle and applying the engine primer without success. The pilot then selected a field for a forced landing, during which the right main landing gear struck a power line. The airplane then flipped over and subsequently impacted a carport rooftop.

Examination of the engine revealed that one of the four spark plugs was loose in the cylinder, which led to a loss of compression and partial loss of engine power. The pilot's safety recommendation stated, "closer inspection of checking spark plugs before flight."

Text from the NTSB. Open the NTSB docket for CEN17LA079 for the full record.