On August 11, 1996, about 1115 eastern daylight time, a Bell 47G-4A, N9472G, registered to Coker Helicopter, Inc., collided with a television antenna near Adel, Georgia, while workers were attempting to hook an external line to the antenna to remove it from the tower. Visual meteorological conditions prevailed at the time. No flight plan was filed for the Title 14 CFR Part 91 external lift flight. The helicopter was destroyed and the commercial-rated pilot was fatally injured. One worker on the tower received serious injuries and one worker was not injured. The flight originated from the base of the tower a few minutes before the accident. A worker who was located on the tower stated he and another worker had been lifted to the top of the tower by a 50-foot line connected to the bottom of the helicopter. They had partially unbolted the antenna at the top of the tower. The other worker was on the antenna and was attempting to connect the 50-foot line from the helicopter to the antenna, so it could be lifted from the tower. This worker had the line wrapped around the antenna. As the helicopter maneuvered above the tower, it settled down and the main rotor blades collided with the antenna and mounting pole. The main rotor separated from the helicopter and it descended uncontrolled until ground impact. The other worker's left ankle was broken when the helicopter hit the antenna. The winds were blowing steady at about 15 mph at the time of the accident and there were no gusts. Postmortem examination of the pilot was performed by Dr. Carol A. Terry, Georgia Division of Forensic Sciences, Decatur, Georgia. The cause of death was attributed to multiple blunt force injuries. No findings which could be considered causal to the accident were reported. Postmortem toxicology tests on specimens obtained from the pilot were performed by Georgia Division of Forensic Sciences and Dr. Dennis V. Canfield, Manager FAA Toxicology Laboratory, Oklahoma City, Oklahoma. The tests were negative for carbon monoxide, ethanol alcohol, basic, acidic, and neutral drugs. The tests were positive for .241 ug/ml Diphenhydramine in blood, .597 ug/ml Diphenhydramine in liver fluid, and a detection of Diphenhydramine in urine See attached toxicology reports. The Physicians' Desk Reference (PDR) identifies Diphenhydramine as an antihistamine drug. The PDR states patients taking Diphenhydramine should be advised that this drug may cause drowsiness and has an additive effect with alcohol. Patients should be warned about engaging in activities requiring mental alertness such as driving a car or operating appliances, machinery, ect. See attached pages from the PDR. Federal Aviation Administration records shows the helicopter operator, Coker Helicopter, Inc., holds a Title 14 CFR Part 137 Aerial Application certificate. There was no record that the operator held a 14 CFR Part 133 External Load certificate. Additionally, aircraft logbook records showed no FAA Form 337, Major Repair and Alteration, for installation of the external load hook, which was reported by the pilot's family to have been installed by the pilot a week before the accident.