Incident Overview
A Cessna 172N, rented by the FAA and operated by two aviation operations inspectors, experienced a left flap malfunction during a go-around. The pilot-in-command had performed a simulated forced landing using flaps and was instructed to go around at about 400 feet. During the climbout after flap retraction, the left flap was observed to be bent and extended approximately 30 degrees at the inboard end and 10 degrees at the outboard end. The right flap was fully retracted, and the flap lever was in the retracted position. The flight returned to the airport for an uneventful landing.
Inspection Findings
During taxi after landing, it was found that the left aileron was binding on the bent left flap. Postflight examination of the left flap determined that the inboard roller was jammed in the track. When pressure was applied to the flap, the roller became free and the flap retracted rapidly. After removal of the inboard roller, it was found to contain very little lubrication and to have rust on the roller surface.
Maintenance Requirements
The Cessna Aircraft Company maintenance manual for the 172N requires inspection and lubrication of the flap rollers and tracks every 100 flight hours.