CHI99FA285

The helicopter impacted trees and terrain while maneuvering during a sightseeing flight over a national park. The helicopter was in a descending left turn and a high angle of bank with decreasing main rotor rpm. A low rpm warning horn was heard several seconds prior to impact with the trees. An acoustical analysis of a video tape taken by a passenger shows a decrease in the engine gear box and planetary speeds along with a steady state engine speed several seconds prior to the end of the video tape. The end of the video tape recorded the initial impact with the trees. Examination of the engine and airframe revealed no anomalies.

History of flight

On August 10, 1999, at 1730 mountain daylight time, a Bell 206B, N67JJ, operated by Rapid Helicopters Incorporated, was destroyed on impact with trees and terrain while maneuvering over Custer State Park, South Dakota. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 sightseeing flight was not operating on a flight plan. The pilot and one passenger sustained fatal injuries; two of the passengers sustained serious injuries, and the remaining passenger sustained minor injuries. The flight originated, at approximately 1715, from a private heliport located approximately 6 miles southwest of the accident site.

A police report documented the interview of two of the passengers. The report states the following:

"They stated the pilot had been flying for approximately 7 hours today while they were in the air. He made a sweep over Mt. Rushmore and turned the helicopter on it's side to get a better view of the sights. They said he did this at the Needles Eye to get another view. [One of the passengers] stated the Helicopter made the same maneuver as at Mt. Rushmore but then felt as if the helicopter went into a power slide. [The passenger] also stated the pilot went too far in trying to make the maneuver. The helicopter hit the trees and rocks and then crashed. [The other passenger] stated the helicopter started vibrating real bad before the crash. He stated the vibrating occurred during the sweeping maneuver..."

A copy of a video tape taken by a passenger during the accident flight along with a map of the accident area is included in this report. The video tape shows the helicopter in a descending left turn and a high angle of bank prior to impact.

Personnel information

The pilot was 28 years old and held a commercial pilot certificate with airplane single engine land, airplane multiengine land, rotorcraft-helicopter and instrument airplane and helicopter ratings. The pilot received a first class medical certificate on December 11, 1998. He had accumulated a total airplane flight time of 316 hours and a total helicopter flight time of 1,300 hours.

Aircraft information

The 1989 Bell 206B, serial number 4062, was powered by a Rolls-Royce Allison 250-C20B turboshaft engine, serial number CAE 270448, rated at 420 shaft horse power (SHP). The helicopter accumulated a total airframe and engine time of 2,720.5 hours. A 100-hour inspection of the airframe and engine was completed on July 31, 1999 at a total airframe and engine time of 2,675.6 hours.

The helicopter has a total fuel capacity of 84.1 gallons with a usable fuel capacity of 82.6 gallons. Examination of the helicopter's annuciator panel revealed that it was not equipped with a "fuel low" annunciator light.

Wreckage and impact information

The main wreckage was located at 43 degrees 50 minutes 476 seconds North and 103 degrees 32 minutes 820 seconds West and within a wooded area of trees which were estimated to be 50 feet in height. The elevation of the accident site was approximately 6,500 feet msl. The fuselage was resting on its left side and on a westerly heading as viewed from tail to the nose of the helicopter toward the bottom of a 30 degree slope at the top of which was Highway 87 or Needles Highway. The tail boom was resting approximately 15 feet from the main wreckage.

Flight control continuity from both pedals and both stick controls was established. Engine control continuity from the cockpit to the engine was also established. Continuity of the main rotor transmission was established. Approximately 6 gallons of liquid consistent with Jet A aviation fuel was drained from the helicopter's fuel tank. Approximately 5 cc of liquid consistent with Jet A was drained from the fuel line leading to the fuel nozzle. The airframe fuel filter was unobstructed and contained approximately 11 oz of liquid consistent with Jet A. The engine was removed and shipped to Rolls-Royce Allison for testing.

Medical and pathological information

The FAA toxicological test of the pilot were positive for dextromethorphan, dextrorphan, ephedrine, pseudoephedrine, and phenylpropanolamine. Pseudoephedrine is a common decongestant with a trade name Sudafed that is found in many over-the-counter cold and allergy preparations. Ephedrine is sold as an asthama medication with a trade name Primatene available over-the counter in tablet form. Ephedrine and pseudoephedrine are often found together in the herbal supplement "Ma Huang" also known as "ephedera". "Ma Huang" is used as an "energy booster", stimulant, weight loss product, or decongestant in many nutritional supplements. Phenylpropanolamine is an over-the-counter decongestant, also marketed as a weight loss product. It is also a metabolite of ephedrine and pseudoephedrine. Dextromethorphan is an over-the-counter cough suppressant, available in a large number of preparations, including many multi-symptom cold relievers.

The left front passenger's FAA toxicological test results were negative for all substances tested.

An autopsy of the pilot was conducted by the Clinical Laboratory of the Black Hills, Rapid City, South Dakota.

Tests and research

According to the Rolls-Royce Accident Investigation and Engine Test Run Report, which is included in this report, the percent shaft horsepower for 6 data points ranged from 18.125 - 35.978 percent shaft horsepower below rated power during the test run.

Additional information

The Federal Aviation Administration, Bell Helicopter and Roll-Royce Allison were parties to the investigation.

The wreckage was released to the registered owner.