On September 10, 1995, about 1545 Alaska daylight time, a Bell 206B helicopter, N84TA, crashed while conducting a rescue operation on Tazlina Lake, about 20 miles southwest of Glennallen, Alaska. The helicopter was being operated as a visual flight rules (VFR) local area flight under Title 14 CFR Part 91 when the accident occurred. The helicopter, registered to Trans Alaska Helicopters Inc., Anchorage, Alaska, and operated by the U.S. Department of Interior, was destroyed. The certificated commercial pilot received minor injuries. A Bureau of Land Management employee, the sole passenger, was not injured. A stranded pilot, the subject of the rescue, received serious injuries. Visual meteorological conditions prevailed. The flight originated at the Gulkana airport, Gulkana, Alaska, at 1520. The operator reported that the helicopter was conducting survey operations and the pilot overheard radio transmissions about a float equipped airplane that had inverted on Tazlina Lake. A military rescue helicopter was reported to have an estimated time of arrival (ETA) at the scene of about 2 hours. The pilot and passenger volunteered to attempt a rescue of the stranded pilot who was reported to be sitting on the inverted floats of the airplane for about 5 hours. The helicopter arrived at the scene and the pilot hovered next to the airplane. The pilot of the airplane displayed symptoms of hypothermia and was unresponsive to the rescuers. The passenger of the helicopter partially stepped into an external load basket on the right side of the helicopter and attempted to assist the stranded pilot into the right side of the helicopter. This placed a lateral weight change on the right side of the helicopter. The helicopter pilot displaced the cyclic control to the left to maintain a level hover. The helicopter continued tilting to the right and the main rotor blades struck the surface of the lake. The helicopter crashed into the lake and sank. The two occupants of the helicopter escaped from the helicopter and swam to the stranded pilot who had been thrown into the water. The pilot of a float equipped airplane observed the events and elected to land on the lake. A passenger in the airplane assisted in rescuing the occupants of the helicopter and in getting the stranded pilot onto a float and eventually into the cabin of the airplane. The pilot taxied to the shore of the lake where the military rescue helicopter arrived to transport the victims. The stranded pilot reported that he was struck by the helicopter's landing gear skid tube during the crash. The pilot's physician reported that he received a bilateral pneumothorax and anterior and posterior rib trauma with flail segments consistent with a heavy crush injury. The initial accident involving the stranded airplane is ANC-95-L-A164.