Primary finding
Probable cause
a fatigue failure of the tailwheel spring.
Investigator assessment
Analysis narrative
The pilot lost control of the airplane when the tailwheel spring failed during landing roll. Metallurgical examination of the fracture surface determined the failure was from fatigue.
Source record
Factual narrative
On September 18, 1993, at 1315 central daylight time, a Luscombe 8F, N840B, sustained substantial damage when it departed the runway and ground-looped during landing rollout at the Festus Memorial Airport, Festus, Missouri. The private pilot was not injured. No flight plan was filed, and visual meteorological conditions prevailed for the personal flight which originated at the St. Clair Regional Airport, St. Clair, Missouri. The pilot reported the tail wheel spring broke during landing roll, and that he lost directional control when the rudder became ineffective. The tail wheel spring was examined at the NTSB Materials Laboratory. The report described the fracture as containing features indicative of fatigue cracking. -