Grand Prairie, TX, USA
N4YJ
Bell 206B
After departing their home base, the flight reported on the traffic and news for a local television and radio station for 42 minutes. While the helicopter was transiting from another location for an upcoming news story, the helicopter experienced a loss of engine power while in cruise flight at 800-feet above ground level. The pilot reported that he initiated a left 180-degree turn to a clear area. The autorotation was terminated over tall grass and during touchdown the helicopter rolled over and came to rest on its right side. The accident site was a wooded area with soft soil on rough and uneven terrain. The 8,000-hour helicopter pilot reported having accumulated approximately 7,000-hours in the Bell 206 helicopter, with 200-hours within the last 90 days and 50 hours in the last 30 days. The pilot reported that he did not perceive any anomalies or engine warnings prior to the loss of engine power. A preliminary examination of the helicopter was conducted under the supervision and control of the NTSB Investigator-in-Charge. Initial examination of the engine revealed that the compressor (N1) would not rotate. The engine was subsequently removed from the airframe and shipped to the engine manufacturer's facilities for further evaluation and teardown examination. The engine examination revealed that all of the blade airfoils for the 5th stage compressor had separated from the wheel, with no signs of distress on the first 4 stages of the compressor. Damage to the 6th stage of the compressor and compressor case assembly were considered to be secondary. A detailed metallurgical examination of the compressor revealed that the compressor failure was result of the separation of one or more of the 5th stage compressor blades. Some of the blade fragments were recovered during the engine examination; however they were heavily damaged precluding further analysis. The reason for the failure of the compressor blade(s) could not be determined due to the extensive secondary damage of the components involved.
On July 30, 2007, at 0643 central daylight time, a single-engine Bell 206B helicopter, N4YJ, was substantially damaged during a forced landing following a reported loss of engine power while in cruise flight near Grand Prairie, Texas. The commercial pilot and one passenger were not injured. A second passenger was seriously injured. The helicopter was registered to Helicopters Inc., of Linden, New Jersey and was being operated by a local television station in Dallas, Texas. No flight plan was filed and visual meteorological conditions prevailed for the traffic and news gathering flight conducted under 14 Code of Federal Regulations Part 91. The local flight originated from the Dallas Love Field (DAL), near Dallas, Texas, at approximately 0600. After departing DAL, the flight reported on the traffic and news for a local television and radio station in the Dallas-Fort Worth metropolitan area for about 42 minutes. While the helicopter was transiting from another location for an upcoming news story, the helicopter experienced a loss of engine power while in cruise flight at 800-feet above ground level. The pilot reported that he initiated a left 180-degree turn to a clear area. The autorotation was terminated over tall grass and during touchdown the helicopter rolled over and came to rest on its right side. The pilot and the two passengers (news reporters) were able to egress the aircraft through the left side doors. Damage was sustained to the helicopter's blades, skids, tail boom, undercarriage, and cockpit. The accident site was a wooded area with soft soil on rough and uneven terrain. There were no reported eyewitness to the mishap on the ground. The 8,000-hour helicopter pilot reported having accumulated approximately 7,000-hours in the Bell 206 helicopter, with 200-hours within the last 90 days and 50 hours in the last 30 days. The pilot reported that he did not perceive any anomalies or engine warnings prior to the loss of engine power. The 1997-model helicopter, serial number 4463, was recovered to a secured location for a detailed examination. On July 31, 2007, a preliminary examination of the helicopter was conducted under the supervision and control of the NTSB Investigator-in-Charge. No evidence of an in-flight fire or post-impact fire was found. Aircraft control system and drive train continuity was confirmed and no airframe anomalies were identified. Examination of the fuel system revealed that the fuel cell was not breached and more than 15-gallons of fuel were removed from the fuel cell. Engine control continuity was established and there was no evidence of an uncontained engine failure. Initial examination of the engine revealed that the compressor (N1) would not rotate. The engine, a 420-horsepower Rolls Royce Model 250-C20J gas turbine engine, serial number CAE 272756, was subsequently removed from the from the airframe and shipped to the engine manufacturer's facility in Indianapolis, Indiana, for further evaluation and teardown examination. Examination of the maintenance records for the engine revealed that the engine had been installed on the helicopter for 297.2 hours and had accumulated a total of 5,566.4 hours. Additionally, it was determined that the last 100 and 300 hour inspections on the engine were completed at 5,565.6 hours. The engine inspection and teardown examination was completed at the engine manufacturer's facilities on 7 September 2007. The examination revealed that all of the blade airfoils for the 5th stage compressor were found separated from the wheel. No signs of distress were found on the first 4 stages of the compressor. A detailed metallurgical examination of the compressor revealed that the compressor failure was result of the separation of one or more of the 5th stage compressor blades. Damage to the 6th stage of the compressor and compressor case assembly were considered to be secondary. Some of the blade fragments were recovered during the engine examination; however they were heavily damaged precluding further analysis. The reason for the failure of the compressor blade(s) could not be determined due to the extensive secondary damage of the components involved. At 650 local, the automated weather reporting facility at the Grand Prairie Airport (GPM), located approximately 4-nautical miles northwest from the accident site, reported calm winds, 10 statue miles visibility, few clouds at 13,000 feet, temperature 75 degrees, dew point 73 degrees, and barometric pressure of 29.91 inches of Mercury.
The loss of engine power as result of the failure of one or more of the compressor blades for the 5th stage compressor for undetermined reasons. A contributing factor was the lack of suitable terrain for the pilot to execute a successful autorotation.
Source: NTSB Aviation Accident Database
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