What was found
NOTE: THIS AIRCRAFT WAS BUILT UNDER FAA EXPERIMENTAL AMATURE BUILT GUIDANCE. THIS AIRCRAFT IS NOT A LIGHT SPORT AIRCRAFT. IT WAS BUILT FROM A KIT AND CERTIFIED AS AN EXPERIMENTAL AMATURE BUILT AIRCRAFT. LOST ENGINE POWER AFTER TAKE-OFF AND MADE EMERGENCY LANDING WITH EXPERIMENTAL AMATURE BUILT AIRCRAFT: (HORNET)DETAILS: 2 CYLINDER,2 CYCLE ENGINE. 2 SPARK PLUGS IN EACH CYLINDER. AFT SPARK PLUG SEPARATED FROM AFT CYLINDER. THREADS THAT WERE MILLED INTO CYLINDER HEAD FAILED TO HOLD SPARK PLUG CAUSING DEPARTURE OF PLUG, LOSS OF COMPRESSION AND POWER LOSS CAUSING AN EMERGENCY LANDING. REPAIR WAS MADE BY INSTALLING A HELI-COIL INTO CYLINDER HEAD & REINSTALLING A SPARK PLUG.