Narrative:

The unusual sequence of events that led to this propeller strike problem are: 1) I normally preflight the airplane after it's pulled out of the hangar. This is for better light, easier access to walk around the airplane, and confirming that there are no towbars attached, open baggage doors, or anything else that could be detrimental. My normal procedure is to make the preflight the last event before flight, so if I go straight from preflight to flight, it eliminates any negative intervening factors. However, on this occasion, another pilot had pulled his grumman tiger from the hangar and was doing an extraordinarily long engine warm-up before taxiing. I altered my normal procedure and did a preflight inside the hangar. 2) in moving the rudder through its free motion with my hand, it seemed to have more play than normal, and didn't feel quite right. I made a mental note to put it through a lot of taxiing and high speed taxiing before considering taking off. 3) due to snow and ice on the entire hangar row taxiway, it was a struggle to get the airplane out of the hangar. I had to use the electric towbar with a drive wheel to eventually get it out. The electric towbar is normally reserved for pushing the airplane back into the hangar. I can't recall ever having to use it to get the airplane out of the hangar. 4) due to this same snow and ice, I was unable to make the normal 90 degree turn to line it up in the center and parallel with the hangar row taxiway. The slipping tire on the electric towbar was barely able to get the airplane out of the hangar. The airplane was now turned only at a 45 degrees angle to the hangar. 5) I unplugged the cord from the electric towbar and walked the cord back into the hangar. In the past, whenever I return to the hangar after pulling out the airplane, it's to return the hand towbar. I then lowered the electric bi-fold hangar door. It's a slow process during which I started thinking of something else, and forgot that I had used the electric towbar, which was still attached to the airplane. 6) the airplane was not at the usual 90 degree angle where I would have had the normal clear view of its profile, including the attached electric towbar. Instead, it was at a 45 degree angle, which I approached from the airplane's rear. This resulted in the towbar being hidden behind the nosewheel and nose cone. 7) I started the airplane and began to taxi. The rudder pedals didn't feel quite right, which agreed with my earlier preflight, so I didn't suspect anything else. I decided to continue the taxi to gather more input to provide to the mechanic about it. 8) after a short taxi, the electric towbar came unhooked, swung off to the side, where the left propeller struck it. I then notified ground control of the problem.

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Original NASA ASRS Text

Title: A LIGHT TWIN ATP PLT STARTS HIS TAXI WITH THE ELECTRIC TOWBAR STILL ATTACHED TO THE NOSE GEAR AND SUFFERS A L PROP STRIKE AT TVC, MI.

Narrative: THE UNUSUAL SEQUENCE OF EVENTS THAT LED TO THIS PROP STRIKE PROB ARE: 1) I NORMALLY PREFLT THE AIRPLANE AFTER IT'S PULLED OUT OF THE HANGAR. THIS IS FOR BETTER LIGHT, EASIER ACCESS TO WALK AROUND THE AIRPLANE, AND CONFIRMING THAT THERE ARE NO TOWBARS ATTACHED, OPEN BAGGAGE DOORS, OR ANYTHING ELSE THAT COULD BE DETRIMENTAL. MY NORMAL PROC IS TO MAKE THE PREFLT THE LAST EVENT BEFORE FLT, SO IF I GO STRAIGHT FROM PREFLT TO FLT, IT ELIMINATES ANY NEGATIVE INTERVENING FACTORS. HOWEVER, ON THIS OCCASION, ANOTHER PLT HAD PULLED HIS GRUMMAN TIGER FROM THE HANGAR AND WAS DOING AN EXTRAORDINARILY LONG ENG WARM-UP BEFORE TAXIING. I ALTERED MY NORMAL PROC AND DID A PREFLT INSIDE THE HANGAR. 2) IN MOVING THE RUDDER THROUGH ITS FREE MOTION WITH MY HAND, IT SEEMED TO HAVE MORE PLAY THAN NORMAL, AND DIDN'T FEEL QUITE RIGHT. I MADE A MENTAL NOTE TO PUT IT THROUGH A LOT OF TAXIING AND HIGH SPD TAXIING BEFORE CONSIDERING TAKING OFF. 3) DUE TO SNOW AND ICE ON THE ENTIRE HANGAR ROW TXWY, IT WAS A STRUGGLE TO GET THE AIRPLANE OUT OF THE HANGAR. I HAD TO USE THE ELECTRIC TOWBAR WITH A DRIVE WHEEL TO EVENTUALLY GET IT OUT. THE ELECTRIC TOWBAR IS NORMALLY RESERVED FOR PUSHING THE AIRPLANE BACK INTO THE HANGAR. I CAN'T RECALL EVER HAVING TO USE IT TO GET THE AIRPLANE OUT OF THE HANGAR. 4) DUE TO THIS SAME SNOW AND ICE, I WAS UNABLE TO MAKE THE NORMAL 90 DEG TURN TO LINE IT UP IN THE CTR AND PARALLEL WITH THE HANGAR ROW TXWY. THE SLIPPING TIRE ON THE ELECTRIC TOWBAR WAS BARELY ABLE TO GET THE AIRPLANE OUT OF THE HANGAR. THE AIRPLANE WAS NOW TURNED ONLY AT A 45 DEGS ANGLE TO THE HANGAR. 5) I UNPLUGGED THE CORD FROM THE ELECTRIC TOWBAR AND WALKED THE CORD BACK INTO THE HANGAR. IN THE PAST, WHENEVER I RETURN TO THE HANGAR AFTER PULLING OUT THE AIRPLANE, IT'S TO RETURN THE HAND TOWBAR. I THEN LOWERED THE ELECTRIC BI-FOLD HANGAR DOOR. IT'S A SLOW PROCESS DURING WHICH I STARTED THINKING OF SOMETHING ELSE, AND FORGOT THAT I HAD USED THE ELECTRIC TOWBAR, WHICH WAS STILL ATTACHED TO THE AIRPLANE. 6) THE AIRPLANE WAS NOT AT THE USUAL 90 DEG ANGLE WHERE I WOULD HAVE HAD THE NORMAL CLR VIEW OF ITS PROFILE, INCLUDING THE ATTACHED ELECTRIC TOWBAR. INSTEAD, IT WAS AT A 45 DEG ANGLE, WHICH I APCHED FROM THE AIRPLANE'S REAR. THIS RESULTED IN THE TOWBAR BEING HIDDEN BEHIND THE NOSEWHEEL AND NOSE CONE. 7) I STARTED THE AIRPLANE AND BEGAN TO TAXI. THE RUDDER PEDALS DIDN'T FEEL QUITE RIGHT, WHICH AGREED WITH MY EARLIER PREFLT, SO I DIDN'T SUSPECT ANYTHING ELSE. I DECIDED TO CONTINUE THE TAXI TO GATHER MORE INPUT TO PROVIDE TO THE MECH ABOUT IT. 8) AFTER A SHORT TAXI, THE ELECTRIC TOWBAR CAME UNHOOKED, SWUNG OFF TO THE SIDE, WHERE THE L PROP STRUCK IT. I THEN NOTIFIED GND CTL OF THE PROB.

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.