On March 16, 1999, about 1001 central standard time, a Fairchild Hiller FH-1100 helicopter, N547FH, operated by Ward Aviation Inc., lost power during liftoff and collided with the cab of a truck near Opp, Alabama. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the 14 CFR Part 137 aerial application flight. The helicopter was substantially damaged. The commercial-rated pilot reported no injuries. The flight was originating at the time. The helicopter had completed a 2-hour aerial application flight and returned to the helipad to refuel and reload. The helipad was a flatbed trailer attached to a truck. After refueling and taking on more chemicals, the pilot reported that when he lifted off the trailer, the helicopter's engine lost power, causing the helicopter to settle downward, resulting in the main rotor blades striking the cab of the truck. According to the FAA inspector's statement, "...inspection of the helicopter...revealed failure of the engine to transmission drive shaft flex coupling...physical breakup of the flex coupling with metal particles present. Both flex coupling components were covered with rust. Failure prior to ground impact was evident due to the extensive surface abrasions caused by the failure of the coupling and countinued operation of the engine."