What happened
A pilot operating a Stinson 108-2 was taxiing toward runway 19 for departure. During the taxi, the aircraft was following an ultralight aircraft that had decided to perform an intersection departure from runway 25. The pilot of the ultralight transmitted his intention to depart via the intersection and subsequently stopped his aircraft at the point where the taxiway leading to runway 19 crossed runway 25.
The pilot of the Stinson heard the radio call regarding the departure but failed to realize that the ultralight was positioned at the intersection. Consequently, the Stinson pilot continued to taxi across runway 25. Upon entering the runway, the pilot observed the ultralight directly in front of him and applied the brakes forcefully. This sudden braking caused the Stinson 108-2 to tip forward onto its nose, resulting in the aircraft's right wing impacting the ultralight.