Narrative:

I was departing on runway 26L at atl airport, on the takeoff roll, when at the point of rotation I got a very violent shimmy in the aircraft. My initial response was to lift the nosewheel off the ground, fearing the shimmy dampener was not working properly at that point. The nose and aircraft lifted off the ground, the shimmy subsided, but was still apparent. I thought that I had lost a nosewheel tire and continued the departure straight out. The controller gave me a heading to turn to and I told him to stand by, I had a bad shimmy after takeoff. He asked if I needed any assistance and I stated no, but I would like to return for landing. He acknowledged and gave me a heading. At this point I had determined that the right engine was not functioning properly and decided to pull back most of the power on that engine to slow the shimmy and proceeded to land uneventfully. Upon arrival, I had still not determined what the problem was, so I landed very smoothly and as slow as possible -- everything appeared fine. After shutdown, a postflt inspection showed that a recap had come off the tire, hit the gear door and went into the propeller, bending 2 propeller blades. I then called the tower and advised that I had lost the retread on the tire and that an operations check of that runway would be needed. They did so returning with the retread and a retainer for the gear door that had also been broken off when the tread separated from the tire.

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Original NASA ASRS Text

Title: AN MU2B-36A ON TKOF ROLL AT POINT OF ROTATION DECLARED AN EMER AND DIVERTED DUE TO SEVERE NOSE GEAR VIBRATION AND PWR FLUCTUATION ON THE R ENG CAUSED BY A NOSE TIRE THROWN TREAD WHICH BENT THE R PROP.

Narrative: I WAS DEPARTING ON RWY 26L AT ATL ARPT, ON THE TKOF ROLL, WHEN AT THE POINT OF ROTATION I GOT A VERY VIOLENT SHIMMY IN THE ACFT. MY INITIAL RESPONSE WAS TO LIFT THE NOSEWHEEL OFF THE GND, FEARING THE SHIMMY DAMPENER WAS NOT WORKING PROPERLY AT THAT POINT. THE NOSE AND ACFT LIFTED OFF THE GND, THE SHIMMY SUBSIDED, BUT WAS STILL APPARENT. I THOUGHT THAT I HAD LOST A NOSEWHEEL TIRE AND CONTINUED THE DEP STRAIGHT OUT. THE CTLR GAVE ME A HDG TO TURN TO AND I TOLD HIM TO STAND BY, I HAD A BAD SHIMMY AFTER TKOF. HE ASKED IF I NEEDED ANY ASSISTANCE AND I STATED NO, BUT I WOULD LIKE TO RETURN FOR LNDG. HE ACKNOWLEDGED AND GAVE ME A HDG. AT THIS POINT I HAD DETERMINED THAT THE R ENG WAS NOT FUNCTIONING PROPERLY AND DECIDED TO PULL BACK MOST OF THE PWR ON THAT ENG TO SLOW THE SHIMMY AND PROCEEDED TO LAND UNEVENTFULLY. UPON ARR, I HAD STILL NOT DETERMINED WHAT THE PROB WAS, SO I LANDED VERY SMOOTHLY AND AS SLOW AS POSSIBLE -- EVERYTHING APPEARED FINE. AFTER SHUTDOWN, A POSTFLT INSPECTION SHOWED THAT A RECAP HAD COME OFF THE TIRE, HIT THE GEAR DOOR AND WENT INTO THE PROP, BENDING 2 PROP BLADES. I THEN CALLED THE TWR AND ADVISED THAT I HAD LOST THE RETREAD ON THE TIRE AND THAT AN OPS CHK OF THAT RWY WOULD BE NEEDED. THEY DID SO RETURNING WITH THE RETREAD AND A RETAINER FOR THE GEAR DOOR THAT HAD ALSO BEEN BROKEN OFF WHEN THE TREAD SEPARATED FROM THE TIRE.

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.