On August 10, 1999, at 1138 central daylight time, a Bell 206L, N810F, operated by Saint Louis Helicopter Airways Incorporated, impacted terrain during takeoff from a helicopter pad located on top of a hospital. The auxiliary power unit (APU) cord was attached to the helicopter during the helicopter's takeoff attempt. Visual meteorological conditions prevailed at the time of the accident. The commercial rated pilot received no injuries and one passenger received minor injuries. The 14 CFR Part 91 flight was not operating on a flight plan. The flight was originating from the Southeast Hospital, Cape Girardeau, en route to Poplar Bluff, Missouri. In a written statement, the pilot reported the following: "...On August 6, 1999 the operational BO-105 was replaced with a Bell 206 in order to conduct some scheduled maintenance on the BO-105. I was given a check ride in the Bell 206 and signed off to conduct normal EMS operations. I have over 2,000 hours in the Bell 206. On August 10, 1999 we received a call to transport a patient from a hospital in Poplar Bluff, Missouri to a Hospital in St. Louis, Missouri. I went outside and unplugged one medical chord used to charge medical equipment, completed my 'walk around' inspection of aircraft condition and then plugged in the APU for the starting sequence. I began starting the aircraft as the medical crew began to approach the aircraft. They approached the aircraft from the front where coincidentally the APU chord is attached. After I completed the start and some checklist items I noticed that both of the medical crew elected to sit in the back seat. (In the BO-105 one of them always sits up in the front seat.) The medical crew on this day consisted of one experienced crew member and one that was new to the aviation environment. I asked the crew if they were ready to go and they both responded, "O.K. in the back, were ready to go." I completed my last before take-off items which included making sure no caution or advisory lights were illuminated and picked up to a hover to check my hover power. (This particular Bell 206 did not have an APU advisory light.) What occurred next happened in only seconds and my recovery of the aircraft was instinctive and immediate. I took off in a north direction and everything appeared normal until the aircraft reached the edge of the roof that surrounds the fourth floor helipad. The aircraft did an abrupt and violet yaw to [the] left, the nose tucked downward and the aircraft started loosing the roof clearance that we had. I initially pulled power to clear the roof, then corrected the yaw with pedal inputs. At this time I wasn't sure what was going on but elected to fly the aircraft as if an engine failure had occurred, thus conserving vital rotor RPM and avoiding a hard landing. I reduced collective some, flared and drifted right to avoid a telephone pole and land perpendicular on a two lane street. My options to recover at a hover were gone since there was no time to discern if I had engine power or not and to hesitate for a short time could mean a far worse consequence. The aircraft landing smoothly on the paved street however the tailboom landed on a brick wall that paralleled the street..." Following the accident, the chief pilot reported that the length of the APU cable has been shorthened to ensure the entire unit must be pushed up the ramp and onto the deck where it would be visible to the pilot. Also, a new policy was written stating that the designated fire guard remain outside and at the nose of the aircraft until the engines are started and will conduct a quick "walk around" before getting in the aircraft.