On November 14, 2001, at 0033 mountain standard time, a Messerschmitt-Bolkow-Blohm, BO 105 LS helicopter, was destroyed when it collided with terrain in a rural area near Mud Lake, Idaho. The helicopter is owned by Bannock Medical Center, Pocatello, Idaho, and was being operated as a visual flight rules (VFR) repositioning flight under the provisions of Title 14 CFR Part 91. No flight plan was filed. The commercial pilot-in-command, the sole occupant, sustained serious injuries. The flight originated from an area near Mud Lake, with a planned destination of Pocatello, Idaho. In a written statement, the pilot reported that during a medical transport flight, with a patient and medical crew aboard, he performed a precautionary off airport landing (approximately 30-40 minutes after departure) due to a problem with the helicopter's fuel transfer pumps. Upon landing, the patient and medical crew were offloaded and transported to the destination hospital via ground ambulance. Approximately five hours after the unscheduled landing, a mechanic employed by the operator arrived to make appropriate repairs to the helicopter. The pilot reported that while the mechanic worked on the aircraft, he slept in the mechanic's vehicle for approximately 1.5 hours. After the repairs were made to the helicopter, the pilot conducted a post-maintenance ground run that lasted approximately 10 minutes. At the conclusion of the ground run, the pilot initiated a normal departure, under dark night conditions, with an intended destination of Pocatello. The pilot reported to the FAA Principal Operations Inspector that shortly after departure he recalled seeing the silhouette of mountains, and the stars were visible, but fuzzy looking. In a written statement, the pilot reported, "I decided to take off and head back towards Bannock. I was trying to stay with the road but shortly after takeoff, I lost visual sight of the road. I could no longer make out the ridgeline. I tried to cross-scan between inside and outside the aircraft and all of a sudden I was disoriented. I couldn't tell which way was up or down. Then came impact". The pilot further stated that he came to rest upside down, released his seat belt and pulled himself away from the helicopter wreckage. The mechanic reported that he had driven to the helicopter to repair the fuel system problem. He stated to the FAA Principal Operations Inspector that he replaced the number one and number two fuel transfer pumps, filled the main tanks with 20 gallons of fuel, and checked the operation of the pumps. He stated that the pilot warmed up the aircraft for approximately 10 minutes, and then he observed the helicopter take off. He stated "I started forward on the highway when off to the left I saw a very bright glow reflected in the air above the foothills that got quite intense". The mechanic reported that he then drove towards the glow, found the wreckage and the pilot, put out a small fire, disconnected the aircraft's battery, and called for help. The pilot reported to the FAA Principal Operations Inspector that he noted no mechanical failures or malfunctions with the helicopter during the accident flight.