Narrative:

After executing a 3 point landing at plk a slight vibration was experienced in the tailwheel. Vibration increased and aircraft made a short yaw to the left. After approximately 30 degree yaw the right landing gear attach bracket bolts sheared and right wing contacted the runway. Aircraft then skidded to the right and exited runway tail first. The yaw experienced was not controllable. No injury to occupants or property damage incurred. Inspection of tailwheel by ia revealed right control arm on tailwheel broke clean with evidence of corrosion at break. Tailwheel assembly is lang P/north D-501A with 8 hours and 14 lndgs since new. NTSB form 6120-1/2 filed. Aircraft involved was american yankee aa-1TW. WX was not a factor. Installation of manual locking tailwheel would eliminate problem. Callback conversation with reporter revealed the following information: reporter states that the control arm had been on the aircraft only 2 1/2 weeks. There is speculation that the part might be faulty since the mechanic on site indicated it had been broken prior to the incident. It was a stress problem that caused the break. Since it took 6 months on back order to receive the part, reporter speculates that this was a new batch of parts. He has requested the old part from the insurance company and will match this with the specification sheets to evaluate the problem.

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Original NASA ASRS Text

Title: PLT OF AMERICAN YANKEE WITH TAILWHEEL CONVERSION HAS RWY EXCURSION ON LNDG DUE TO BROKEN TAILWHEEL CTL ARM.

Narrative: AFTER EXECUTING A 3 POINT LNDG AT PLK A SLIGHT VIBRATION WAS EXPERIENCED IN THE TAILWHEEL. VIBRATION INCREASED AND ACFT MADE A SHORT YAW TO THE L. AFTER APPROX 30 DEG YAW THE R LNDG GEAR ATTACH BRACKET BOLTS SHEARED AND R WING CONTACTED THE RWY. ACFT THEN SKIDDED TO THE R AND EXITED RWY TAIL FIRST. THE YAW EXPERIENCED WAS NOT CONTROLLABLE. NO INJURY TO OCCUPANTS OR PROPERTY DAMAGE INCURRED. INSPECTION OF TAILWHEEL BY IA REVEALED R CTL ARM ON TAILWHEEL BROKE CLEAN WITH EVIDENCE OF CORROSION AT BREAK. TAILWHEEL ASSEMBLY IS LANG P/N D-501A WITH 8 HRS AND 14 LNDGS SINCE NEW. NTSB FORM 6120-1/2 FILED. ACFT INVOLVED WAS AMERICAN YANKEE AA-1TW. WX WAS NOT A FACTOR. INSTALLATION OF MANUAL LOCKING TAILWHEEL WOULD ELIMINATE PROB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT THE CTL ARM HAD BEEN ON THE ACFT ONLY 2 1/2 WKS. THERE IS SPECULATION THAT THE PART MIGHT BE FAULTY SINCE THE MECH ON SITE INDICATED IT HAD BEEN BROKEN PRIOR TO THE INCIDENT. IT WAS A STRESS PROB THAT CAUSED THE BREAK. SINCE IT TOOK 6 MONTHS ON BACK ORDER TO RECEIVE THE PART, RPTR SPECULATES THAT THIS WAS A NEW BATCH OF PARTS. HE HAS REQUESTED THE OLD PART FROM THE INSURANCE COMPANY AND WILL MATCH THIS WITH THE SPEC SHEETS TO EVALUATE 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.