Incident Overview
A banner towing aircraft experienced a throttle malfunction during a routine operation, leading to a ditching near a beach. The pilot had descended from 1200 feet to 500 feet to position the aircraft over water for banner towing. When the pilot attempted to level off by advancing the throttle, there was no response to throttle movement. The engine continued operating at approximately 1500 RPM, rather than increasing power as expected.
Sequence of Events
Unable to regain normal throttle control, the pilot executed a ditching maneuver, landing the aircraft in the water about 80 yards from the shore. The aircraft was subsequently recovered and examined.
Investigation Findings
An investigation into the incident revealed that a clamp securing the mechanical linkage to the throttle had come loose. This allowed the linkage to disengage or slip, preventing the throttle from responding to pilot inputs.