PA22 PLT HAND PROPPED ENG WITHOUT TURNING THE MAGNETO SWITCH OFF. THE ENG STARTED WITH NO PLT ABOARD AND WAS DAMAGED.

Narrative

DURING ENG STARTUP; ENG FAILED TO START AFTER NUMEROUS ATTEMPTS. I ALLOWED ENG TO SIT FOR APPROX 2 MIN; THEN APPLIED 2 SHOTS OF PRIMER; AND OPENED THE THROTTLE. I THEN EXITED THE ACFT TO PULL THE PROP THROUGH SEVERAL BLADES TO PRIME THE ENG. ON THE SECOND SLOW PULL; THE ENG FIRED. I RAN TO THE DOOR; ATTEMPTED TO RESTRAIN THE ACFT AND OPEN THE NOW CLOSED DOOR TO STOP THE ENG. THE ACFT DID 2 COMPLETE GND LOOPS IN AN OPEN AREA BEFORE THE L MAIN GEAR COLLAPSED AND THE PROP STRUCK; STOPPING THE ENG. UPON INSPECTION OF THE COCKPIT; I FOUND THAT WHILE I HAD SWITCHED OFF THE MASTER; I HAD NEGLECTED TO SWITCH OFF THE MAGNETOS. PROB ACROSS -- FAILURE OF ENG START AND FAILURE OF PLT TO SWITCH OFF MAGNETOS WHILE MANUALLY PRIMING ENG. CONTRIBUTING FACTORS -- DISTRS INVOLVED IN EXITING COCKPIT TO PRIME ENG. DOING SOMETHING OUT OF YOUR NORMAL ROUTINE/PROCS. HOW IT WAS DISCOVERED -- ENG STARTED. CORRECTIVE ACTION -- ALWAYS TREAT AN ENG AS 'HOT' WHEN TURNING THE PROP. TIE TAIL AND REMOVE KEY. DOUBLE CHK THAT MAGNETOS ARE OFF. EVEN THOUGH YOU ARE NOT ATTEMPTING TO START AN ENG; ASSUME THAT IT WILL START.