Incident Overview
A flight instructor was demonstrating a normal landing to the south in a tailwheel-equipped aircraft. The landing was a 3-point touchdown performed in light crosswind conditions. After touchdown, the airplane rolled approximately 300 to 400 feet down the runway.
Sequence of Events
As the airplane passed abeam a tree line, a gust of wind caused the aircraft to veer toward the right edge of the runway. The flight instructor attempted to correct for the wind gust; however, his heel slid off the heel brake. The instructor stated that he held full rudder and got back on the brake too late.
Runway Excursion
The airplane subsequently exited the right side of the runway and impacted a ditch. The pilot reported that the wind was from the southwest at 10 knots, gusting to 18 knots.