On September 3, 1999, about 1930 Alaska daylight time, a Cessna 207 airplane, N800DF, sustained substantial damage when it collided with a tree stump during the takeoff roll from a beach on Chinitna Bay, at 59 degrees 40 minutes north latitude, 153 degrees 10 minutes west longitude, about 25 miles southwest of Ninilchik, Alaska. The commercial pilot and three of the passengers were not injured. The remaining two passengers sustained minor injuries. The flight was being conducted under 14 CFR Part 135 by Clearwater Air, Inc., of Soldotna, Alaska, as an on-demand air taxi flight, returning the five passengers to Soldotna from a fishing charter. Visual meteorological conditions prevailed at the time of the accident, and a company VFR flight plan was filed. During a telephone interview with the NTSB investigator-in-charge (IIC) on September 3, the pilot stated that during the takeoff roll from the packed sand beach, the left wing contacted a tree stump, resulting in substantial damage to the left wing, nose gear, and engine. He said the load included the five passengers, their fishing gear, and two hours of fuel. He described the winds to be from the southwest at 10 knots, and he was taking off to the west. The airplane was modified with a Horton Short Take Off and Landing (STOL) kit. The NTSB IIC held telephone interviews with, and received written statements from, the passengers. They indicated that the flight was about one hour later than planned, and the tide was coming in, reducing the size of the beach available for takeoff. The passengers said the pilot was in a hurry because of the incoming tide, and the late schedule. The pilot was taking off into the setting sun, and was not wearing sunglasses. According to the passengers, the pilot said he would wait for the sun to pass behind a cloud, but decided to depart. They related that the incoming tide forced the pilot to takeoff close to brush at the upper side of the beach. During the takeoff roll the left wingtip struck a tree stump, and about four feet of the left wing and the left aileron separated.