What happened
The pilot was operating a banner flight service, departing from a grass airstrip to fly two separate advertising banners along the beach. After completing the second banner drop, the pilot transitioned into the landing pattern to return to the grass strip.
During the base leg of the approach, the aircraft experienced a stall of the right wing because insufficient airspeed was maintained. This caused the aircraft to bank sharply to the right and enter a nose-down attitude. A witness observed the aircraft on its base-to-final leg transitioning behind the tree line in a 90-degree bank with a 60-degree nose-down pitch. The aircraft subsequently impacted trees while in this nose-down attitude and came to a stop upon hitting the ground. The pilot reported no mechanical problems with the aircraft during the flight.
Findings
The investigation determined that the right wing stalled due to the failure to maintain adequate airspeed during the base leg of the landing pattern.