Narrative:

The primary aircraft involved is a 1939 luscombe 8A (certified without an electrical starting system). The normal start procedure involves chocking the wheels, opening the throttle approximately 1/4 inch or less, priming the engine 2-3 strokes, setting the magnetos to the 'both' position and then hand propping the engine. I did all of the above and the engine seemed to be starting normally. As I quickly left the front of the aircraft and made my way to the left side pilot's door, the engine went from a coughing idle to a short burst of power. I had not yet reached the cockpit but did have my hand on the left strut when the 'burst' occurred. The aircraft jumped the chocks and spun to the left hitting a nearby C170's wingtip. The luscombe's propeller made a number of slices into the wingtip prior to returning to a slower idle and stopping. A contributing factor could have been an overly rich initial mixture. Although the above start sequence is commonly accomplished without incident, it would always be best to have a second person in the aircraft at the controls in case there was a run away such as this.

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Original NASA ASRS Text

Title: PLT OF VINTAGE SMA REQUIRING MANUAL START PROC (HAND PROPPING) IS UNABLE TO RESTRAIN THE ACFT AFTER START. ACFT COLLIDES WITH A C170 PARKED NEARBY.

Narrative: THE PRIMARY ACFT INVOLVED IS A 1939 LUSCOMBE 8A (CERTIFIED WITHOUT AN ELECTRICAL STARTING SYS). THE NORMAL START PROC INVOLVES CHOCKING THE WHEELS, OPENING THE THROTTLE APPROX 1/4 INCH OR LESS, PRIMING THE ENG 2-3 STROKES, SETTING THE MAGNETOS TO THE 'BOTH' POS AND THEN HAND PROPPING THE ENG. I DID ALL OF THE ABOVE AND THE ENG SEEMED TO BE STARTING NORMALLY. AS I QUICKLY LEFT THE FRONT OF THE ACFT AND MADE MY WAY TO THE L SIDE PLT'S DOOR, THE ENG WENT FROM A COUGHING IDLE TO A SHORT BURST OF PWR. I HAD NOT YET REACHED THE COCKPIT BUT DID HAVE MY HAND ON THE L STRUT WHEN THE 'BURST' OCCURRED. THE ACFT JUMPED THE CHOCKS AND SPUN TO THE L HITTING A NEARBY C170'S WINGTIP. THE LUSCOMBE'S PROP MADE A NUMBER OF SLICES INTO THE WINGTIP PRIOR TO RETURNING TO A SLOWER IDLE AND STOPPING. A CONTRIBUTING FACTOR COULD HAVE BEEN AN OVERLY RICH INITIAL MIXTURE. ALTHOUGH THE ABOVE START SEQUENCE IS COMMONLY ACCOMPLISHED WITHOUT INCIDENT, IT WOULD ALWAYS BE BEST TO HAVE A SECOND PERSON IN THE ACFT AT THE CTLS IN CASE THERE WAS A RUN AWAY SUCH AS THIS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.