On August 19, 2002, about 0745 Alaska daylight time, a float-equipped deHavilland Beaver DHC-2 airplane, N64393, and a float-equipped deHavilland DHC-3 Turbine Otter airplane, N409PA, collided in midair about 12 miles north of Ketchikan, Alaska. The DHC-3 Turbine Otter sustained substantial damage to both wings, fuselage, and vertical stabilizer. The DHC-2 Beaver sustained minor damage to the floats. Both airplanes were operated by Promech, Inc., of Ketchikan. The certificated airline transport pilot and four passengers aboard the DHC-2 Beaver were not injured. The certificated airline transport pilot of the DHC-3 Turbine Otter and the ten passengers aboard were not injured. Both aircraft were being operated under Title 14, CFR Part 135, as on-demand air taxi flights in visual meteorological conditions. Both airplanes departed the Ketchikan Harbor Seaplane Base between 0730 and 0735, en route to Neets Bay. Both airplanes were carrying cruise ship passengers en route to a bear viewing area located within Neets Bay. During telephone interviews with the National Transportation Safety Board investigator-in-charge on August 19, the pilots of the two airplanes disclosed the following information: The pilot of the DHC-2 Beaver stated that his airplane was the first of three company airplanes to depart from the Ketchikan Harbor Seaplane Base, en route to Neets Bay. He said that once he was airborne, and clear of the class E airspace to the north, he changed radio frequencies to monitor the common traffic advisory frequency, 122.9. He added that the second company airplane, the DHC-3 Turbine Otter, departed about 3 minutes after his departure. The pilot reported that about 15 minutes after departure, while on a northerly heading in level cruise flight at 2,000 feet msl over Behm Channel, he felt a sudden thump, followed by a pronounced airframe shudder. He said that he originally thought this was just the airplane flying through turbulence, but immediately observed the top of the left wing of the DHC-3 Turbine Otter to his left side, just under the floats of his airplane. He said that just after the two airplanes collided, the DHC-3 Turbine Otter made a left, descending turn, away from his airplane. The pilot said that after determining that he still had full flight control, he elected to return to Ketchikan. He added that he tried to contact the pilot of the DHC-3 Turbine Otter, but did not receive a response. The pilot said that a postaccident inspection of his airplane disclosed minor damage to the underside of both floats. The pilot of the DHC-3 Turbine Otter said that his airplane was the second of three airplanes en route to Neets Bay. He said that after an uneventful takeoff from the Ketchikan Harbor Seaplane Base, about 5 minutes after the DHC-2 Beaver, he proceeded on a northerly heading, about 2,200 feet above the waters of Behm Channel. He said that just before the impact, he heard one of the passengers seated in the rear of the airplane yell "airplane." About two seconds later, the pilot heard a loud scrape on the top portion of the airplane. He then started a descending left turn, while attempting to transmit a "mayday" radio call on the common traffic advisory frequency, 122.9. The pilot said that just after the impact, he experienced some difficulty in controlling the airplane, but was soon able to regain partial control, and subsequently made an emergency landing in the ocean waters of Behm Channel. After assessing the damage to the airplane, he elected to step-taxi the airplane back to Ketchikan. A postaccident inspection revealed substantial damage to the top portions of both wings, fuselage, and vertical stabilizer. All of the airplane's communications antennas that were mounted on top of the wings and fuselage were destroyed during the collision. The pilot of the DHC-3 Turbine Otter reported that his airplane was about 10 knots faster than the DHC-2 Beaver.