CEDAR RAPIDS, IA, USA
N1020U
Hughes 269A-1
After refueling, the pilot departed north from a helipad with an observer aboard. The helicopter overflew a 50 foot building located 141 feet from the pad. The helicopter started to shudder over the building and shuddered again when it crossed a powerline located 292 feet from the pad. The observer reported the helicopter did a right, flat turn. The helicopter impacted the top crossbeam of a powerline pole, then impacted the ground in a right skid down, nose low attitude. A fire erupted. The pilot was initially pinned in the wreckage, but the observer & a truck driver, who arrived at the scene, were able to extricate the pilot. Investigation revealed evidence of continuity in the flight controls and engine, but the magnetos were fire damaged & could not be tested. Performance calculations indicated that power required for a 50' hover out of ground effect (HOGE) would have been 154 HP; power available should have been 173 HP. The local airport's (Aviation Routine Weather Report) METAR winds indicated 100 degrees at 7 knots. The wind sock at the helicopter pad was not functional. For takeoff, the pilot also had the option to depart the helipad on a heading of 140 degrees, or to depart on a heading of 320 degrees after back taxiing about 150 feet for additional takeoff distance. The pilot received serious burns & head injuries. He was wearing a polyester based police uniform & no flight helmet or gloves. The observer was wearing a Nomex flight suit and boots, but no helmet or gloves.
History of Flight On June 11, 1997, at 2105 central daylight time (CDT), a Hughes 269 A-1, N1020U, operated by the City of Cedar Rapids, Iowa, was destroyed when it struck powerlines and impacted the ground shortly after takeoff. The commercial pilot and observer, who both were police officers of Cedar Rapids, Iowa, received serious injuries. After impacting the ground, the observer was able to extract the pilot from the helicopter before the helicopter burst into flames and was destroyed by fire. The 14 CFR Part 91 flight had departed from a helicopter landing zone after refueling to continue a local patrol flight. Visual meteorological conditions prevailed and no flight plan was filed. The observer who was in the left seat of the accident helicopter was interviewed two days after in accident. The observer was a member of the Cedar Rapids Police Department and was in the process of being trained to work as a pilot in the Aviation Department. He had worked in the Aviation Department about 10 months. He had recently received airplane flight instruction and had logged about 40 hours of flight time as an airplane student pilot. He had not received any flight instruction in helicopters, but he had flown about five hours as an observer in the helicopter. The observer and pilot reported for duty at the Air Support Office located at the Cedar Rapids Municipal Airport where the helicopter was hangared and maintained. The observer was wearing a Nomex flight suit, flight boots, but no flight helmet or flight gloves. The pilot was wearing his standard police uniform including shoes, but no helmet or flight gloves. The helicopter was fueled and they departed on an aerial patrol mission. The observer reported that the helicopter experienced no abnormalities during the flight. The observer reported that they went to refuel at the helicopter pad, IA 80. The observer reported that the pilot landed the helicopter to the north. The nose of the helicopter was facing the river (320 degrees) while sitting on the pad. The fuel pumps were on the left side of the helicopter. The pilot remained on the controls during the "hot refueling" while the observer fueled the aircraft so that a total of 20 gallons were on board. The helicopter held 25 gallons. The observer reported that after refueling the aircraft he got back in the left seat of the helicopter. He reported that the pilot departed the pad to the north (about 360 degrees) and flew over the western end of the steel building that was to the north of the helicopter pad. He reported that he was attempting to strap on his knee board when he felt the aircraft shudder. He observed that the helicopter was at a low airspeed. The observer reported the helicopter was over the roof of the steel building when it shuddered. He reported that the helicopter lost lift over the building, and then regained lift for about a half second as the pilot lowered the nose. It "bogged" down again when the helicopter crossed over the wires. He reported the second shudder over the wires was not as pronounced as when the aircraft was over the building. He reported that the helicopter shuddered and banked right in a flat turn. He reported he thought the pilot might be attempting to turn toward an open area to land it on a gravel road. The observer further described the shudders as a change of sound pitch. He said the helicopter felt and sounded different. He described the change in sound as, "...like a semi [truck] in high gear bogged down." He reported it sounded bogged down with the exact same sound over the building as over the wires. He reported the helicopter settled over the building and also settled over the wires. He reported the helicopter hit something and he saw a flash of "pure white light." The helicopter nosed over and impacted a gravel road in a right, nose low attitude. The observer was conscious and realized that fuel was streaming into the cockpit. He tried to extricate the pilot, but the pilot's lower legs were pinned in the wreckage. A truck driver rendered assistance and lifted up on the main rotor mast which allowed the observer to pull the pilot from the wreckage. The observer and truck driver assisted the pilot in getting away from the helicopter. The helicopter continued to burn and was destroyed by the fire. Wreckage and Impact Information The examination of the accident site revealed the steel building was 50 feet high and on a course of 002 degrees and 141 feet from the helicopter pad. The powerline pole was about 292 feet from the helicopter pad on a course of about 360 degrees from the helicopter pad. The helicopter wreckage was about 51 feet from the powerline pole, and on a heading of about 090 degrees from the powerline pole. The elevation at the helicopter pad was 720 feet mean sea level (msl). The elevation of the gravel road where the helicopter impacted was 700 feet msl. The height of the top of the steel building was 770 feet msl, and the height at the top of the powerline pole impacted by the helicopter was 740 feet msl. The upper crossbeam on the powerline pole had two sets of impact marks that were about 6 feet 6 inches apart. Two powerline electrical wires were broken and bent in about 90 degree angles. A wooden crossbeam support brace on the powerline pole was fractured. The upper four wires of the pole were separated from the pole and were laying near the adjacent pole to the northeast of the helicopter wreckage. Electrical arcing was evident on the skids and tailboom support, and on one main rotor blade. The aircraft wreckage indicated that the right front skid collapsed and sheared away from the right skid. The remaining right skid then sheared away from the helicopter's crosstubes. Five strike marks were located on the gravel road west of the wreckage. The tail rotor boom had a black strike mark at the location where it had been severed. The three main rotor blades had leading edge damage to the blades and backwards buckling of all three blades at the blade root. The outboard ends of the blades were also buckled backwards opposite the direction of travel. The examination of the wreckage revealed the following: Fuel tank shut off valve: open Mixture: full rich Throttle linkage at fuel control: melted connector 7/8 open (full open) Rotor engage: fully engaged Linear actuator: fully engaged Idler pulley: Turns freely The main rotor and tail rotor flight controls were checked for continuity. Due to the fire damage to the cabin area of the helicopter some of the control components had been destroyed. The controls and fittings aft of the cabin demonstrated continuity to the main rotor and tail rotor. The engine examination revealed continuity. The starter gear turned the crank and cam, and all pistons and rods moved. The spark plugs electrodes indicated normal wear. Thumb compression was evident on # 1 and #3 cylinders. No thumb compression was evident on cylinders #2 and #4. The #2 and #4 cylinders received extensive fire damage. The magneto gears rotated. The magnetos could not be checked due to melted cam followers and cracked distributor blocks. A fuel sample from the fuel tank at the helicopter pad was taken and it was free of contamination. Additional Information The helicopter pad was located along the river in Cedar Rapids about six miles from the airport. The landing and takeoff direction at the helicopter pad was oriented 320/140 degrees. There were two approaches into the helicopter pad. If winds were from the south an approach to the pad was made over the river and into the pad. If winds were from the north, an approach was made from around the east side of the landfill located south of the helicopter pad. Takeoffs from the helicopter pad when the winds were from the north or west were normally accomplished by flying straight out from the pad on a northwesterly heading. The takeoff could be accomplished by lifting off from the helicopter pad and proceeding with the takeoff. A second technique involved back taxiing about 150 feet before departing on a 320 degree heading in order to increase airspeed and altitude during climbout for obstacle clearance. The primary obstacle for a takeoff to the northwest was a powerline running east and west about 128 feet from the helicopter pad. The height of the transmission wires presented a 20 feet obstacle. If the winds were from the south or east, a 140 degree departure was normally accomplished by lifting off the pad and departing. After the initial climb, a turn to the east was required to avoid a hill located to the south of the pad. The observer reported that he could not remember any discussions with the pilot concerning the direction of the wind. The wind sock on top of the building located east of the helicopter pad was not operational since the fabric of the wind sock was tattered and/or missing. A new helicopter pad located at the police station was nearing completion and the helicopter pad, IA 80, was scheduled to be deactivated once the new pad was operational. A tall smokestack across the river to the north of the helicopter pad provided pilots with an indication of wind direction. The Cedar Rapids Municipal Airport METAR weather observation at 2052 was: Winds from 100 degrees at 7 knots, visibility 4 statute miles, haze, temperature 19 degrees centigrade, dewpoint 16 degrees centigrade, altimeter 29.82. The pilot was interviewed on August 11, 1997. During the interview, the pilot reported he had flown about 2 to 2.5 hours of aerial patrol before landing at the helicopter pad for refueling. He reported that the helicopter operated normally during the flight. He reported that he did not recall the wind direction, but that he generally listened to ATIS information and used the exhaust from a smoke stack across the river to determine wind direction. He reported that he could not remember in which direction he landed at the pad, but the tail of the helicopter was pointing to the river after landing. Initially he reported that he took off to the south and then did a 180 degree turn to fly out over the river. Then he reported that he could not remember if he took off to the north or south. He reported that his normal departure to the north requires an initial climb toward the Mercy Hospital which was to the northwest and he generally stayed left of the shed since flying over it required a steeper climb. He reported that his normal technique for takeoff when winds were from the north was to back taxi to the south side of the pad before departing. The pilot made a drawing depicting the flight path of the helicopter during the accident flight. The drawing indicated that the helicopter departed to the northwest. The drawing indicated the helicopter passed over the powerline pole that was about 40 to 50 yards west of the steel building. It indicated that the helicopter flew about half way over the river (about 100 yards) before turning 180 degrees. It indicated the helicopter impacted the powerline pole located west of the steel building, and impacted the gravel road west of the steel building. The pilot reported on December 19, 1997, that the helicopter experienced a "major RPM drop" as it was crossing the river. He reported that the RPM's dropped from 2700 RPM's to 1500 RPM's. He made a decision to turn back to the helicopter pad. He reported that as he was approaching the river bank, the helicopter experienced another power loss. He reported that he could not make it back to the pad and tried to land on the gravel road. He reported that he saw the electrical wires but could not avoid them, because, "I was now committed to a landing with no engine power left and losing altitude rapidly. There was no way of making it over the lines now to the pad." He reported that the helicopter impacted the top of the pole. He reported that he "...was knocked unconscious, and do [did] not remember anything for the next 6 or so days." In both his August 11, 1997, interview and in the December 19, 1997 report, the pilot reported that he had not flown over the steel building during the accident flight, and that the location of the steel building was to the left (east) of the powerline pole which the helicopter had impacted The wreckage at the accident site revealed that the helicopter impacted the adjacent powerline pole located about 100 yards east of the pole that the pilot had indicated in his drawing. The wreckage of the helicopter was also located about 100 yards east of the site indicated by the pilot's drawing. The Director of Aviation for the Cedar Rapids Police Department reported that normally a pilot would not fly over the steel building when departing to the north. He reported that he had not departed over the building and was uncertain why the pilot had flown over it. He reported that the pilot might have flown over the building because of the winds. He reported that wind is critical during takeoff. He reported that back taxiing prior to departing to the north was an option but not required. The helicopter was within weight and balance calculations. The total weight of the helicopter was 1,601 pounds and the Design Gross Weight of the helicopter was 1,670 pounds. The Hughes helicopter, Model 269 A1, used by the Cedar Rapids Police Department, was the same model helicopter as the United States Army's Model TH-55A Primary Trainer. The United States Army produced a TH-55A Primary Trainer Owner's Manual, TM 55-1520-233-10, revised 30 September 1976. Section 7 of the manual contains Performance Data. The Performance Charts from Section 7 of the manual indicated the following calculated performance characteristics: Elevation at helicopter pad: 720 feet msl Temperature: 19 degrees C Gross Weight: 1,601 pounds Winds: Calm (Assumed) Rotor RPM: 483 RPM (Assumed) Engine RPM: 2900 RPM (Assumed) Calculated Performance Data Max Horsepower Available: Hover In Ground Effect - 169 HP Max Horsepower Available: Hover Out of Ground Effect - 173 HP Max Horsepower Available: Max Power Forward Flight - 164 HP Horsepower Required: Hover 3 foot skid height - 138 HP Horsepower Required: Hover Out of Ground Effect 50' - 154 HP Obstacle Height: 50 feet Distance to Obstacle: 141 feet The Performance Charts in Section 7 did not include a chart that calculated the effects of headwinds, crosswinds, or quartering tailwinds on aircraft performance. The Director of the Aviation Department reported that the flight manuals used by the police department pilots were the authorized manuals that were available through the helicopter manufacturer and approved by the Federal Aviation Administration. The manuals used by the aviation department did not contain the Performance Charts that were contained in the Army's flight manuals. Survival Aspects The observer reported that an electrical spark ignited the fuel. He reported that the pilot's police uniform and the his Nomex flight suit started on fire. After the pilot was pulled from the wreckage, the observer was able to put out the fire to his Nomex flight suit and sustained no burn damage to his body. The truck driver tried to put out the pilot's uniform fire. The polyester based uniform had burned and melted to portions of the pilot's lower torso and legs. The pilot was wearing standard police shoes and received burns to his ankles. The pilot was not wearing a helmet and received serious injuries to his head. The pilot reported receiving injuries that included eight skull fractures, third degree burns to both legs requiring skin grafts, and a broken back in two places. The observer injured his back. The Air Support Operating Manual dated May 9, 1996, did not specifically prescribe a uniform for flight operations other than the following statement: "At all times, crew members will properly utilize safety equipment assigned to them." The Air Support Operating Manual was revised on June 11, 1997. The revision added the following requirements: 9-2 The prescribed uniform for fl
loss of engine power due to undetermined reason(s). Related factors included the obstructions (building, utility pole, and transmission wires); and the lack of a functional windsock, due to inadequate facility maintenance by the operator.
Source: NTSB Aviation Accident Database
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