MKC86FCA01

Factual narrative

THE OWNER/BUILDER HAD HIRED THE PLT TO TEST FLY THE ACFT ON ITS INITIAL FLT. SHORTLY AFTER TAKEOFF, THE PLT TRANSMITTED THAT HE HAD AN ENG PROBLEM. HE WAS CLEARED FOR AN IMMEDIATE LANDING & ENTERED A DOWNWIND FOR RWY 28. AS HE CONTINUED & WAS TURNING FROM A BASE TO FINAL APCH, THE ACFT ENTERED A SPIN IN THE OPPOSITE DIRECTION. THE ACFT IMPACTED ON THE EDGE OF AN INTERSTATE HIGHWAY WHILE IN A STEEP NOSE-DOWN ATTITUDE. AN EXAM OF THE ENG REVEALED THE #1 CYCLINDER SPARK PLUG WIRE WAS COMPLETELY DETACHED; THE #2 CYLINDER WIRE WAS DETACHED FROM THE SPARK PLUG (ALTHO ITS DUST BOOT WAS STILL CONNECTED); & THE #4 SPARK PLUG WIRE DUST BOOT SHOWED EVIDENCE OF HAVING COME IN CONTACT WITH AN ADJACENT EXHAUST STACK & WAS BURNED UNTIL THERE WAS SEPARATION AT THE BOOT'S MIDPOINT. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12