Event Description
On December 10, 2014, at approximately 1440 central standard time, a Cessna 182S, registration N661SP, experienced a flap malfunction that interfered with the aileron while operating near Springfield, Illinois. The aircraft was being used for a public use flight by the Illinois State Police, with commercial pilots performing a proficiency check. Weather conditions were visual meteorological conditions.
During a slow flight recovery demonstration, the aircraft was configured with flaps fully extended. As power was added and the flaps were retracted, at about 80 knots indicated airspeed with the flaps moving from 10 degrees to fully retracted, the pilot felt the control yoke being pushed to the right. The pilot confirmed that the other pilot was not on the controls and that the autopilot was off. As more control authority was needed to maintain level flight, both pilots heard a popping sound, after which the uncommanded right yoke movement ceased. The pilot assessed the airplane and noted that the right flap was buckled. A precautionary landing was performed without incident. Neither pilot was injured, and the airplane sustained minor damage.
Postaccident Inspection
A subsequent inspection of the airplane found that the inboard portion of the right flap had become dislodged from its track, shifting outboard and contacting the aileron. Cracks were found in both the inboard and outboard brackets surrounding the inboard flap track, with the inboard bracket being completely fractured. Both brackets were bent downward. Paint abrasions consistent with contact from the flap roller support arm were found on the brackets.
Prior to the accident, doubler patches had been added to the lower trailing edge skin to repair cracks where rivets were attached. These doublers flattened the curve of the lower trailing edge skin. A review of other agency-maintained airplanes found similar discrepancies regarding the curvature of the lower trailing edge skin and bracket damage.
No probable cause was stated in the source.