Accident Details
A float-equipped de Havilland DHC-6, registration N235SA, was moored at a dock. Passengers had boarded the aircraft, and the two pilots were completing preflight duties. The engines of N235SA were not running. Moored at the same dock, approximately four feet behind N235SA, was another float-equipped DHC-6, registration N353PM. Both aircraft were being operated as sightseeing flights. The pilots of N353PM had completed their pretaxi checks, and its engines were running. The pilot in command of N353PM signaled the dockhand to disconnect the shore power. The dockhand disconnected the shore power and, without direction to do so, released the mooring ropes. N353PM, under idle power, surged forward and struck the tail of N235SA.
Damage
Both aircraft sustained substantial damage as a result of the collision.
Procedural Changes
At the time of the accident, company procedures directed the dockhand to wait for a signal from the pilot before releasing the mooring ropes. Following the accident, the operation was relocated to a longer dock to provide greater distance between aircraft. Additionally, the procedure was changed: the first officer is now responsible for releasing the mooring ropes at the direction of the pilot.