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On Thursday, June 17, 1993, at 0935 eastern daylight time, an Enstrom F28C, N200NH, piloted by Mr. Vernard O. Whitaker, of Whitesburg, Kentucky, struck a static wire, in Gordon, Kentucky. The main rotor and tail boom separated from the helicopter and it was destroyed by the ground impact and post crash fire. The pilot was fatally injured. Visual meteorological conditions prevailed and no flight plan had been filed for the business flight operating under 14 CFR 91.
The pilot was flying between a private heliport in Whitesburg, Kentucky, and a private heliport in Harlan, Kentucky.
A witness, Mr. Hughie King, observed the helicopter from Creech Lookout, in Kingdom Come State Park, approximately 1.3 miles east of, and 1,000 feet above the accident site.
Mr. King said he worked for the park. He was at Creech Lookout picking up litter when he heard the helicopter. He watched the helicopter enter the valley and it appeared to be about 200 feet above the trees on the side of the road. As it passed over a dirt road, it looked like it descended a little and was about 150 to 200 feet above the trees and going faster. The helicopter was down in the valley, the whole time he saw it. It flew toward the power lines, and then the helicopter lurched, papers flew out of the helicopter and the rotor blades rolled left and flew off. He said he thought the helicopter then caught on fire. When it hit the ground there was a big explosion. He said there was no change in engine or rotor noise prior to the accident, and the did not turn or do anything else prior to hitting the wires. The sky was clear, there was no haze and the winds were calm. After the helicopter hit the ground, the smoke went straight up.
The accident occurred during the hours of daylight at location 37 degrees, 00 minutes, 19 seconds North and 82 degrees, 59 minutes, 50 seconds West.
On June 18, 1993, Mr. David McGeorge, of Kentucky Utilities Company, if Cumberland, Kentucky told the investigative team the two static wires were 7/16 inch in diameter and the main transmission lines were 1 3/4 inch in diameter. He also said that they had the main transmission and static lines observed by a crew in a helicopter. The crew reported that above the accident site, one strand on the western static wire was broken. In addition, they reported a dark mark on the eastern static wire. No marks or broken strands were found on the main transmission lines.
The 34 year old pilot in command was the holder of a commercial certificate for rotorcraft - helicopter and private pilot certificate for airplane single engine land. In addition, he held an instrument rating for airplane single engine land. He was issued a 2nd class FAA airman medical certificate with no limitations, on August 4, 1992.
According to the pilot's personal flying log book for helicopters, which had entries through March 26, 1993, the pilot had logged a total of 357.4 hours in helicopters and had logged 320 hours as pilot in command. No flight records were available for flight taken after March 26, 1993. Based upon previous flying records, the pilot is estimated to have logged an additional 28 hours as pilot-in-command in helicopters between March 26, 1993, and the date of the accident.
Due to impact and post crash fire damage, the recording hour meter was not recovered and the time from the last inspection to the accident was not determined. Based upon the pilot's flight time records, the helicopter is estimated to have flown an additional 72 hours since the last inspection.
WRECKAGE AND IMPACT INFORMATION
The wreckage was examined at the accident site on June 18, 1993, and again on July 7th, and 8th, after the wreckage had been removed to a hangar.
The accident site was on the side of a wooded hill. The terrain sloped upward approximately 30 degree. Small pieces of fiberglass and plexiglass, were found under the power lines. The debris path continued in the general direction of 250 degrees magnetic for 350 feet and terminated with the cabin and engine. The main rotor head with the blades still attached was found 275 feet to the south of the main wreckage.
The pitch link control rods for the tail rotor were intact, and the blades were free of leading edge impact damage. The 90 degree gearbox rotated freely with no binding.
There was no evidence of wire contact to the main rotor head, or main rotor drive shaft. The main rotor head separated at the base of the head. According to NTSB Metallurgical Factual Report No. 93-114,
...The fracture of the main rotor drive shaft and associated deformation was typical of a bending overstress separation....
The fracture surfaces for the yellow blade pitch link control rod were granular in appearance, when viewed with a 10 power hand lens. There was no evidence of fatigue striations. The blade gripe with the yellow blade attached had rotated 90 degrees, to a leading edge up position.
The lag stops on the main rotor head were broken. The lead stops were in place. There was no evidence of blade flapping. The push pull tubes had pulled out of the walking beams at the rotor head.
The red and blue blades had wire marks on the leading edge that matched the diameter of the tail rotor pitch link control cable. The red blade was bent upward and the blue and yellow blades were bent rearward. Most of the trailing edge tab on the red blade was torn off. The blue blade had a cut on the underside of the blade that appears to visually match the bearing housing of the tail rotor drive shaft.
The yellow blade had wire rub marks on the upper surface of the blade between 10 and 11 feet from the tip which appear similar in size to the static wire.
There was no evidence of metallic wear on the transmission, or bearing surfaces from the clutch or transmission. The clutch sprages were found in the correct position. The push pull control rod ends were still attached to the lower swash plate.
The cooling fan was crushed onto the engine with no evidence of rotation at impact. The fuel control unit finger screen was clean. The engine was torn down on August 20, 1993. According to the FAA report,
...Summary: There were no indication of any failure or internal problems with the engine. All wear appeared to be normal....
The aft portion of the tail boom was bent right, aft of the 3rd bulkhead, with blade scrape marks on the tail boom. The forward end of the tail boom, between the fuselage and the aft portion of the tail boom, had a blade strike mark on the left side.
According to Mr. William Taylor, an accident investigator, with Enstrom Helicopters, the trim positions correspond to full forward trim, and right lateral trim of 56 to 57 percent, which are consistent with cruise flight.
The fiberglass nose of the helicopter in the vicinity of the nose landing light was broken up. One piece near the nose landing light had a scrap mark similar to a wire rub mark. The backing for the nose landing light had a gouge similar in diameter to the static wire moving in a rearward direction. Metal on the back side of the radio rack (toward the front of the helicopter), in line with the nose landing light was deformed on both sides.
MEDICAL AND PATHOLOGICAL INFORMATION
An autopsy was conducted by Dr. John Hunsacker, of Lexington, Kentucky. According to the autopsy report, the pilot died of injuries incurred from the accident. A toxicological examination conducted by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma, and the Commonwealth of Kentucky was negative for drugs and alcohol.
When tested for carbon monoxide, the FAA Civil Aeromedical Institute reported a level of less than 10 percent. According to the autopsy report from the Commonwealth of Kentucky, the carboxyhemoglobin saturation was estimated at 25 percent, however, this was attributed to a post accident condition.
At 0930 on June 17, 1993, the sun was approximately 37 degrees above the horizon, and the magnetic bearing to the sun was 91 degrees (east).
The power lines were suspended between two towers located 3345 feet apart, with the towers located on each side of a valley. The transmission lines were approximately 450 feet above the road and the static wires were approximately 600 feet above the road in the bottom of the valley. In the area of the accident, the terrain sloped upward at approximately a 30 degree angle, while the power lines and static wires slope upward at a shallower angle. The static wire was estimated to be approximately 450 feet above the ground, in the vicinity of the accident site. The trees in the accident site were estimated to be between 50 and 100 feet high above the ground.
According to 14 CFR 77, OBJECTS AFFECTING NAVIGABLE AIRSPACE, powerlines are not required to be marked if they are more than five miles from an airport. Examination of the Cincinnati sectional chart found in the wreckage showed the power line was depicted, and there was no airport within five miles. In addition, the chart was folded to show the accident area, including the power line.
Mr. Chad Anderson, of Whitesburg, Kentucky, and Mr. Tim Lucas, of the Kentucky State Police, said they had flown in the helicopter with Mr. Whitaker. They said Mr. Whitaker was aware of power lines in the area and the need for continued vigilance.
The pilot had mounted a video camera externally on the helicopter. Mr. Chad Anderson said the accident flight was the first flight the pilot made with the camera attached. There was a monitor hooked up to the camera to display in the cockpit. The monitor and camera were thrown free in the accident. The camera was damaged, however, the tape was recovered. The tape was jammed inside the cassette. When played, the tape showed the takeoff and the helicopter flying low over terrain. The tape ran for 9 minutes, 14 seconds minutes after which it stopped.
The accident site was 11.3 nautical miles from the departure heliport. According to Mr. Taylor, of Enstrom Helicopter, the F28C will normally cruise between 80 and 85 knots.
The wreckage was verbally released to the Kentucky State Police on June 18, 1993.