Aviation Accident Summaries

Aviation Accident Summary CHI02FA049

Waukesha, WI, USA

Aircraft #1

N7007F

Robinson R44

Analysis

The helicopter, while in cruise flight, was destroyed when it impacted a static powerline, a vehicle and terrain . The pilot asked local ATC to fly in controlled airspace and was told to remain outside due to present IFR conditions. Those weather conditions were 1 1/2 statute miles visibility, drizzle, and overcast skies at 400 feet. A witness stated that he "was driving and saw a red light over what seemed like the median a few 100 ft. in the air. The light rose almost straight upward maybe another 200 ft and then began corkscrewing downward." The helicopter is placarded, "THIS ROTOCRAFT APPROVED FOR DAY AND NIGHT VFR [visual flight rules] OPERATIONS." An on-scene investigation revealed no pre-impact anomalies. The fiberglass chin portion of the front right side of the cabin had a linear tear. The right side forward and aft cabin doors had a linear scratch across them. The helicopter color scheme was blue, white, and red. A power line contractor stated, "I inspected the helicopter crash site at I-43, on December 14, 2001. I inspected the static wire span, hands on, and found some plastic and fiberglass shavings. I also found three different color paints, mainly blue, very little yellow and a tiny bit of red. ... The locations of apparent contact points on the shield wire was an area 35 - 40 feet just North of mid-span." A power line employee calculated the wire was about "146' over the roadway." Robinson Safety Notice SN-26 stated, "NIGHT FLIGHT PLUS BAD WEATHER CAN BE DEADLY ... When it is dark, the pilot cannot see wires or the bottom of clouds, nor low hanging scud or fog." A Flight For Life Pilot stated that a request was received for "Aeromedical transport from an accident on [Highway] 164 and [Interstate] -43 by the Waukesha Co. Sheriff's Dept. I determined weather conditions were not acceptable so the flight request was denied."

Factual Information

HISTORY OF FLIGHT On December 12, 2001, about 1822 central standard time, a Robinson R44 helicopter, N7007F, was destroyed when it impacted power lines and impacted Interstate Highway 43 near Waukesha, Wisconsin. Four motor vehicles were damaged. The helicopter impacted one of the motor vehicles and the remaining three motor vehicles sustained minor damage. The helicopter was piloted by an airline transport pilot. The flight was operating under 14 CFR Part 91. Night visual to instrument meteorological conditions prevailed in the area at the time of the accident. No flight plan was on file. The pilot was fatally injured, one motor vehicle occupant sustained serious injury, and one motor vehicle occupant sustained minor injury. The positioning flight originated about 1810 from the Lawrence J. Timmerman Airport (MWC), near Milwaukee, Wisconsin, and was destined for East Troy Municipal Airport, near East Troy, Wisconsin. A witness, who had been a passenger on the flight immediately prior to the accident flight, stated: At approx. 4:40 pm we launched from MWC after taking on fuel. We flew to a tannery fire at 3rd [and] Oregon approx 5 mi. north of MKE [General Mitchell International Airport]. We orbited the fire taking pictures until approx 6 pm. We then returned to MWC. I exited the aircraft at approx. 6:10 pm and the pilot told me he was going back to the East Troy airport to hangar the aircraft. At the time it was dark [and] cloudy with drizzle. The pilot requested to transition through the Waukesha County Airport (UES), near Waukesha, Wisconsin, airspace. The air traffic controller on duty at UES stated the following. Chopper 12 called Waukesha tower and requested to transition from the northeast to the southwest. I instructed him Chopper 12 to remain outside of the airspace and that he would have to circumnavigate due to the fact that Waukesha was in IMC [instrument meteorological condition] conditions. Chopper 12 acknowledged and stated that he would remain approximately 5 - 5 1/2 miles east southeast. This was the last contact with Chopper 12 by Waukesha tower. UES weather - 130000Z 12005kt 1 1/2 SM DZ OVC004 07/07 A2989. A witness who had been driving in a motor vehicle stated the following. We were the third vehicle directly in the path of the helicopter, approx 1/4 mi. in front of our vehicle. I, ..., was driving and saw a red light over what seemed like the median a few 100 ft. in the air. The light rose almost straight upward maybe another 200 ft and then began corkscrewing downward. It was very foggy and difficult to see anything. We stopped, turned on our yellow strobe and hazard flashers, and went up to check the pilot. My wife telephoned 911 for help. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate with an airplane multiengine land rating and DC-9 type rating. He held commercial privileges for airplane single-engine land, rotorcraft-helicopter, and instrument helicopter. He held a flight instructor certificate for airplane single and multiengine, rotorcraft-helicopter, instrument flight instructor airplane and helicopter ratings. He held a Federal Aviation Administration (FAA) first-class medical certificate issued on July 24, 2001, with no restrictions. At the time of that medical, he reported 12,000 hours total flight time. He held a statement of demonstrated ability for defective color vision dated March 13, 1985. The operator reported the pilot had 14,351.4 hours total time, 2,291.2 hours in rotorcraft, and 250.7 hours in this make and model aircraft. AIRCRAFT INFORMATION The accident helicopter, N7007F, serial number 0508, was a Robinson R44, four-place, single main rotor, single-engine helicopter, with a spring and yield skid type landing gear. The primary structure of its fuselage was welded steel tubing and riveted aluminum sheet. The tailcone was a monocoque structure consisting of an aluminum skin. Fiberglass and thermoplastics were used in the secondary structure of the cabin, engine-cooling system, and in other ducts and fairings. The doors were constructed of fiberglass and thermoplastics. A 260 horsepower Lycoming O-540-F1B5 engine, serial number L-25207-40A, powered the helicopter. The helicopter contained a standard airworthiness certificate dated September 11, 1998 and a registration certificate dated September 19, 2000. The pilot's operating handbook stated that "THIS ROTOCRAFT APPROVED FOR DAY AND NIGHT VFR [visual flight rules] OPERATIONS" and is to be placarded as such in "clear view of pilot." A review of the helicopter's maintenance logbooks revealed that an annual inspection was completed on October 7, 2001 and that a 100-hour inspection was completed on December 5, 2001. The 100-hour inspection entry noted the Hobbs meter read 2837.1 hours. METEOROLOGICAL INFORMATION At 1745, the MWC weather, about 15 miles northwest of the accident site, was recorded as: Wind 150 degrees at 5 knots; visibility 4 statute miles; present weather mist; sky condition overcast 1,400 feet; temperature 7 degrees C; dew point missing; altimeter 29.94 inches of mercury. At 1845, the MWC weather was recorded as: Wind 150 degrees at 5 knots; visibility 3 statute miles; present weather mist; sky condition overcast 800 feet; temperature 6 degrees C; dew point missing; altimeter 29.90 inches of mercury. At 1745, the Waukesha County Airport (UES), near Waukesha, Wisconsin, weather, about 10 miles north of the accident site, was recorded as: Wind calm; visibility 2 statute miles; present weather mist; sky condition overcast 600 feet; temperature 7 degrees C; dew point 7 degrees C; altimeter 29.91 inches of mercury. At 1845, the UES weather was recorded as: Wind 120 degrees at 5 knots; visibility 1 statute miles; present weather drizzle; sky condition overcast 400 feet; temperature 7 degrees C; dew point 7 degrees C; altimeter 29.87 inches of mercury. At 1815, the Burlington Municipal Airport (BUU), near Burlington, Wisconsin, weather, about 15 miles south of the accident site, was recorded as: Wind calm; visibility 1 1/4 statute mile; sky condition overcast 300 feet; temperature 7 degrees C; dew point 7 degrees C; altimeter 29.89 inches of mercury. At 1835, the BUU weather was recorded as: Wind 110 degrees at 3 knots; visibility 1 statute mile; sky condition overcast 300 feet; temperature 7 degrees C; dew point 7 degrees C; altimeter 29.88 inches of mercury. WRECKAGE AND IMPACT INFORMATION The helicopter came to rest on the northbound lanes of Interstate Highway 43 about 200 feet southwest of power lines that cross the highway near its intersection with State Highway 164. The area was photographed and the helicopter wreckage was relocated to a hangar. An on-scene investigation was conducted. Waukesha County Sheriff's photographs revealed the tailcone's skin was separated at a riveted splice joint. The photographs show the skid's struts were hinged upward and outward. A forward section of the right skid was torn from the right skid at the point where it is attached to its strut. The right side landing gear strut and strut fairings exhibited serrated cutting and scoring on their outboard surfaces. The ground handling wheel support brackets on the right landing gear skid were deformed in an outboard direction. A center section of a main rotor blade was separated from its leading edge and was retained to the blade's trailing edge. The engine's cowling was detached from the right side of the helicopter and was retained to the fuselage on the left side. The engine cooling fan exhibited scoring and folding in a direction parallel to its rotational direction. The upper drive belt sheave exhibited circumferential scoring on its forward and aft surfaces. The upper sheave exhibited a semicircular gouge on the belt pulley surface adjacent starter's ring gear. The carburetor was found detached from the engine. Throttle, mixture, and carburetor heat control continuity was traced from the cockpit to the engine. Control continuity was traced to all flight control surfaces. The engine rotated and produced a thumb compression at all cylinders. A magneto produced spark at five of its six leads. The remaining lead was found torn and a spark was observed at the torn section. Removed spark plugs exhibited a gray color. The Hobbs meter read 2864.4 hours on-scene. The fiberglass chin portion of the front right side of the cabin exhibited a linear tear. The right side forward and aft cabin doors exhibited a linear scratch across them. The right navigation light assembly was found with a semicircular deformation. The tailskid exhibited a semicircular deformation on its surface. The red navigation light filament was found stretched. The helicopter's color scheme contained blue, white, and red colors. The helicopter main rotor's had yellow as one of the colors in its scheme. No pre-impact anomalies were found. A power line maintenance helicopter examined the power lines that crossed the highway. A maintenance crewmember reported the following. I inspected the helicopter crash site at I-43, on December 14, 2001. I inspected the static wire span, hands on, and found some plastic and fiberglass shavings. I also found three different color paints, mainly blue, very little yellow and a tiny bit of red. The static wire did not have any broken strands at all. The static shoes were pulled toward the contact paint. I also found one broken damper and two knotted-up armor rods. The locations of apparent contact points on the shield wire was an area 35 - 40 feet just North of mid-span. A power line employee reviewed sag, tension, and clearance data. He calculated that the wire was about "146' over the roadway." MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by the Waukesha County Coroner's Office. The FAA Civil Aeromedical Institute prepared a Final Forensic Toxicology Accident Report. The report was negative for all tests performed. ADDITIONAL INFORMATION The parties to the investigation included the FAA, Robinson Helicopter Company, and Textron Lycoming. The aircraft wreckage was released to a representative of the operator. Robinson issued Safety Notice SN-26 January 1987 and revised it June 1994. That notice stated: NIGHT FLIGHT PLUS BAD WEATHER CAN BE DEADLY Many fatal accidents have occurred at night when the pilot attempted to fly in marginal weather after dark. The fatal accident rate during night flight is many times higher than during daylight hours. When it is dark, the pilot cannot see wires or the bottom of clouds, nor low hanging scud or fog. Even when he does see it, he is unable to judge its altitude because there is no horizon for reference. He doesn't realize it is there until he has actually flown into it and suddenly loses the outside visual references and his ability to control the attitude of the helicopter. As helicopters are not inherently stable and have high roll rates, the aircraft will quickly go out of control, resulting in a high velocity crash which is usually fatal. A Flight For Life Pilot stated, "On December 12th, 2001[,] at 1832 CST[,] a request was received for Aeromedical transport from an accident on [Highway] 164 and [Interstate] -43 by the Waukesha Co. Sheriff's Dept. I determined weather conditions were not acceptable so the flight request was denied."

Probable Cause and Findings

The pilot's continued flight into adverse weather and not maintaining altitude/clearance from the static line during cruise flight. Factors were the static wire, the darkness of night, the low ceiling, and the vehicle.

 

Source: NTSB Aviation Accident Database

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