19990807041892A

Seaborne aviation air taxi (float plane) was parked at the dock when it was struck by N224SA, another seaborne aviation DH6 air taxi (float plane), which was starting its engines while parked at the dock, N288SA sustained substantial damage, N224SA has minor damage, no injuries were reported, other circumstances are unknown. (.4)a pair of float equipped, twin engine airplanes were each parked parallel to a dock. The airplanes were separated by about eight feet, one in front of the other. Both airplanes, operated by the same company, were preparing to depart on sightseeing flights. The crew of first airplane, N288SA, was beginning a passenger briefing. The passengers were on board the airplane, but the engines had not been started. The crew of the second airplane, N224SA, had completed a briefing to their passengers, and had started the engines. N224SA was tethered to the dock by ropes attached to the floats at the forward and aft end of the airplane. Each rope was tended by a company dock handler. Due to a slight change in the manner the passengers arrived from a cruise ship, the passengers had not received a briefing booklet b efore boarding the airplane crew. The aft dock handler observed this activity and mistook its meaning as a 'thumbs up' signal. He released the docking rope, allowing N224SA to being moving forward under idle power. The nose of N224SA collided with the tail of N288SA. N288SA received damage to the rudder and trim tab assembly. N224SA received minor damage to the left pitot tube, and the elft side of the nose. (-23) while tied to the dock, engines not running, N288AS was struck from behind by N288, sustained substantial damage to the rudder and elevator. No injuries.