Incident Overview
During a banner pickup operation, the pilot of a Bellanca aircraft had just initiated the approach when the engine began running roughly. Despite the abnormal engine behavior, the pilot proceeded with the banner pickup. A witness reported that when power was applied, the engine ran extremely roughly and emitted black smoke. Ground personnel instructed the pilot to release the banner, which the pilot did, before starting a shallow right turn. The aircraft then dropped out of sight behind a line of trees and impacted the ground. Examination of the accident site indicated that the aircraft had crashed in a steep nose-down attitude.
Post-Crash Examination
An inspection of the aircraft revealed an ample fuel supply onboard. Investigators replaced several damaged engine components and performed an operational check. The engine started and ran normally up to approximately 1300 to 1400 RPM. However, due to a bent crankshaft flange, the engine could not be tested at higher RPM.
Investigative Findings
The source did not state a probable cause for the accident. The engine's rough running and subsequent failure were examined, but the bent crankshaft flange prevented a full power assessment. No further analysis or conclusions were provided in the source material.