Accident Details
On September 19, 2023, at about 0830 mountain standard time, a Champion 7KCAB, registration N998B, was substantially damaged in an accident near Benson, Arizona. The aircraft was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor and the pilot receiving instruction were not injured.
Flight Sequence
The flight instructor reported that the plan was to fly for about an hour to practice basic maneuvers and then return to the traffic pattern at Benson Municipal Airport (E95). The pilot receiving instruction conducted an engine run-up and a full-deflection flight control check before departure. Shortly after departing the runway, while approximately 50 ft above ground level, the tailwheel-equipped airplane began to drift right and then suddenly rolled sharply to the right. The airplane's attitude was held briefly before the flight instructor took over the controls. The instructor found the aileron controls unresponsive. He added left rudder, and the wings leveled off. The airplane then started a left roll followed by a right roll. Pitch control was normal, but ailerons had no effect on roll attitude. The instructor continued to control the airplane with elevator and rudder inputs. The airplane lost altitude and impacted the ground with wings level. It bounced along the ground and came to rest on the runway. The pilot reported that the inflight event felt like wake turbulence from a mountain rotor or vortex, or a dust devil.
Postaccident Examination
A postaccident examination of the airplane's flight control system revealed aileron control cable continuity, and the ailerons moved freely from both cockpit positions. Both aileron bellcranks, pushrods, turnbuckles, pulleys, and cables were examined, and no anomalies were noted. The left aileron bellcrank cover plate was removed; the bellcrank and control stick linkage were intact and operated normally. The right aileron bellcrank and control stick linkage were intact and operated with no restrictions. During left banking movement of the control stick, the right aileron cable contacted a fuselage longitudinal wood stringer near the aileron bellcrank. The ELT antenna cable was twisted and routed between the right aileron bellcrank and the bellcrank cover plate. The cable was worn on the inboard side and the internal metal cable core was visible. However, there were no restrictions of movement of the bellcrank during the examination.
Weather Information
Weather data from the Tucson International Airport (TUS) Automated Surface Observing System, located about 50 miles west-northwest of the accident location, indicated winds between 0800 and 0900 varied between 4 and 6 knots. Longline automated observations from Bisbee Douglas International Airport (DUG), about 50 miles southeast, reported winds between 0556 and 0956 varying between 3 and 5 knots.