Event Description
On approach, as the aircraft proceeded over the outer marker, the captain selected flaps to 50 degrees. During the extension, when the flaps passed 35 degrees, the airplane began to roll to the left. The crew immediately retracted the flaps to the 35-degree position and initiated a go-around. Subsequently, the flaps were set to 22 degrees and the aircraft landed without further incident.
Examination Findings
A post-flight examination of the airplane uncovered that approximately 20 feet of the left outboard trailing edge flap vane was missing. Inspection of the remaining flap vane sections revealed that the attachment nut at track number two was severely corroded. The corresponding bolt was not recovered.
Actions Taken
The missing flap vane and corroded nut were documented. No further operational issues were reported, and the aircraft was taken out of service for maintenance review. The specific cause of the roll was not stated in the source.