On February 2, 2014, about 2230 eastern standard time, a Gates Learjet Corporation L35A, N979RF, sustained minor damage while taxiing in preparation for a flight at Fort Lauderdale International Airport (FLL), Fort Lauderdale, Florida. The pilot, copilot, and two additional crewmembers were not injured. A lineman sustained serious injuries. The airplane was owned and operated JEDAMI Air, LLC, under 14 Code of Federal Regulations Part 135, as a medical transport flight. Night visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the flight that was destined for Owen Roberts International Airport (MWCR), Cayman Islands. According to the pilot, he occupied the left seat and the copilot occupied the right seat. The copilot was at the controls of the airplane. During engine start, the copilot observed one of the two linemen depart the ramp area, leaving one lineman remaining to assist the airplane with ground operations. After completion of the engine start, the copilot gave the disconnect ground power hand signal to the lineman. The lineman moved to the left and rear of the airplane to disconnect the ground power unit (GPU). The pilot monitored the airplane's voltmeter to verify disconnect by observing a drop in the voltage current. After placing the airplane's two generators on line, the pilot looked up and outside to find that the airplane was rolling forward at idle power. The pilot applied the brakes and set the parking brake. After about 5 minutes, the flight crew still did not have visual contact with the lineman; however, the additional crewmembers seated in the cabin observed the lineman standing next to the GPU. The pilot took controls of the airplane and began a right turn to taxi in the ramp area. The copilot glanced out of the right cockpit window and notified the pilot that the lineman was lying on the ground. The pilot stopped the airplane and shut down the engines. When the occupants exited the airplane, they observed that the GPU was lying on top of the lineman, and were able to move lift it off of him. According to a statement provided to police, the lineman gave the pilot the "HOLD" signal and proceeded to the GPU that was still connected to the airplane. The lineman stated that as he attempted to disconnect the GPU from the airplane, the airplane began moving forward, pulling the GPU over, and knocking him down to the ground. The GPU came to rest on his right leg. Examination of the airplane did revealed minor damage to the GPU connector points and to the airplane skin. The lineman was transported to the hospital for further treatment. According to the manager of the operator, normal ground servicing operations were conducted utilizing either one or two lineman depending on availability. In the NTSB Pilot/Operator Accident Report Form, the operator noted that an observed drop in voltage confirmed that the GPU was no longer supplying power to the airplane; however, it would not confirm that the GPU cable had been disconnected.