HISTORY OF FLIGHT On October 30, 1997, about 0340 central standard time, an Aerospatiale AS350B helicopter, N911RR, was destroyed on impact with the terrain and a post crash fire at the Frankfort Airport, near Frankfort, Illinois. The public use familiarization flight was operated under the provisions of 14 CFR Part 91, and was not operating on a flight plan. Both the civilian contract instructor pilot and the Illinois State Trooper pilot sustained fatal injuries. Witnesses indicated that the helicopter was maneuvering in the vicinity of the airport for about 40 minutes prior to the accident. The flight departed the Chicago Midway Airport at 0244. According to a witness, "At around 3:00 a.m. on 10/30/97 I was working...when other employees who had been on their break had told me a helicopter was flying in the area of Frankfort Airport looking like it was trying to land. Then at around 3:40 a.m. I took my break and was standing next to my car which was parked at the northeast corner of the building. I was watching the helicopter traveling in an easterly direction flying low above the building...when it circled back in a westerly direction some where around the east end of the runway. While heading west above the runway it looked like it was getting ready to land. When the helicopter was about 5 to 10 feet above the ground I turned my back getting into my car when I heard an explosion and then a second explosion and turned around and saw the flames from above the truck which was parked between the airport and my car. I then took a few steps to the east and then saw the helicopter in flames." According to an Illinois State Police report, a Will County Sheriff's Deputy was a witness to the helicopter's activity leading up to the accident. He stated in the police report, "[Sheriff's deputy] (who is a licensed pilot) was on patrol working the midnight shift when at approximately 3:15 a.m. on 10/30/97, he was traveling southbound on Center Road near Frankfort Airport. [Sheriff's deputy] observed a helicopter...approach the airport from the northeast. [Sheriff's deputy] drove into the airport and parked near the last hanger on the east side. [Sheriff's deputy] watched the helicopter make a normal approach and hover stationary near the approach end of the runway. The helicopter was hovering approximately 8 feet off the ground and started to do pedal turns, staying in the same spot and turning 360 degrees. [Sheriff's deputy] advised that the engine sounded like a normal turbine engine. The helicopter completed the pedal turns and then turned sideways with its nose pointing in a northwest direction and began traveling in a westbound direction. The helicopter once again became stationary almost even with [Sheriff's deputy] squad car and proceeded to perform another pedal turn still hovering approximately 8 feet from the ground. After completing the maneuver, the helicopter again turned sideways as it had done previously and traveled westward. The helicopter then became stationary at the east end of the main hangar, whereupon it did another series of pedal turns in both directions. The helicopter rose to approximately 25 to 30 feet and proceeded westward with its nose straight, as if from a normal takeoff. From there, the helicopter started climbing to approximately 1300 feet. The helicopter then started to descend as if it were going to land at Howell Airport in New Lennox, Illinois. At this time (approximately 3:35 a.m.) [Sheriff's deputy] backed his squad car behind the hangar and no longer observed the helicopter." PERSONAL INFORMATION The instructor pilot, born May 30, 1955, was the holder of a commercial pilot's license with privileges in airplane single engine land and helicopters, as well as instrument airplane and helicopter ratings. The pilot held a helicopter instructor rating. Federal Aviation Administration (FAA) records indicate the pilot's last aviation medical examination was performed on September 5, 1997. The pilot held a current second class medical with no limitations at the time of the accident. The second pilot, born February 3, 1963, was the holder of a private pilot certificate with helicopter privileges. FAA records indicate the pilot's last aviation medical examination was performed on May 9, 1997. The pilot held a current second class medical with no limitations at the time of the accident. AIRCRAFT INFORMATION The aircraft was an Aerospatiale AS350B helicopter, serial number 2029. The aircraft could accommodate two pilots and four passengers. The engine was a Turbomeca Arriel series engine. METEOROLOGICAL INFORMATION The reported weather at Midway Airport at 0353 CST was an overcast ceiling of 14,000 feet, 8 miles visibility, and winds were 8 knots from 170 degrees magnetic. Frankfort Airport is about 18 miles southwest of Midway Airport. Moonrise on October 30, 1997 in the Chicago area was not until 0526. WRECKAGE AND IMPACT INFORMATION The wreckage was located east of the main office near runway 09/27 on the airfield. The tail section of the helicopter was on the runway west of the burnt wreckage. The aircraft came to rest facing in a northerly direction. The body of a male (victim #1) was on the west side lying on his back. The second body was under the bucket seat on the ground on its left side. The left and right doors were east of the aircraft as were items such as the searchlight, night vision equipment and both landing skids, which were torn off on impact. Grass located north of the paved runway showed signs that the rear tailskid struck first then the aircraft rolled while westbound. (See attached photographs). A post accident examination of the helicopter disclosed no evidence of any pre-existing anomaly with the helicopter. A post accident examination of the engine revealed engine rotation and continuity. The test showed the main oil filter, main oil chip detector, oil scavenge chip detector, module one magnetic plug, and the module five magnetic plug to be clean. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the instructor pilot at the Silver Cross Hospital, Joliet, Illinois, on October 30, 1997. A Forensic Toxicology Fatal Accident Report was prepared by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma. The test revealed: * 1.100 (ug/ml) Cyanide detected in blood An autopsy was performed on the trooper pilot at the Silver Cross Hospital on October 31, 1997. A Forensic Toxicology Fatal Accident Report was prepared by the FAA Civil Aeromedical Institute. The test revealed: * 28.000 (%) Carboxyhemoglobin detected in blood * 3,070 (ug/ml) Cyanide detected in blood ADDITIONAL INFORMATION FAA inspectors from the DuPage, Illinois Flight Standards District Office joined NTSB investigators on scene of the accident. Other parties to the investigation were Illinois State Police, Turbomeca Engine, and American Eurocopter.