On July 15, 2004, at 1600 Hawaiian standard time, a McDonnell Douglas 369FF, N530RL, contacted a tree with the main rotor blades during firefighting operations near the Lihue Airport, Lihue, Hawaii. The pilot completed an emergency landing, and the helicopter rolled onto its side. The commercial pilot, the sole occupant, was not injured; the helicopter sustained substantial damage. The helicopter was registered to Smokey Mountain Helicopters, Inc., and being operated by Inter Island Helicopters under the provisions of 14 CFR Part 133. Visual meteorological conditions prevailed, and no flight plan had been filed. The helicopter departed from the Port Allen Airport, Hanapepe, Hawaii, at 1400. According to the pilot, he was performing fire suppression on a fire burning near the Lihue airport. He dropped 60 buckets of water over the course of 2 hours. The helicopter was slow and nearly in a hover. He had his attention focused on the bambi bucket attached to the helicopter, and the clearance between it and the trees. As he initiated the water release, he heard a loud noise and suspected that the main rotor blades impacted a tree. The helicopter impacted the ground and rolled onto its right side. Because of his focused attention on the bucket, he did not see the limited clearance and angle between the tree and the main rotor blades. The pilot did not report any mechanical malfunctions with the helicopter. His total time of bambi bucket experience was 10 hours. The Federal Aviation Administration (FAA) inspector examined the helicopter on July 16, 2004. The inspector did not find any preimpact mechanical anomalies with the helicopter during the examination.