Aviation Accident Summaries

Aviation Accident Summary CHI03FA179

Boonville, MO, USA

Aircraft #1

N298HS

Eurocopter EC120B

Analysis

The helicopter impacted terrain during cruise flight in night instrument meteorological conditions. The pilot had previously landed due to deteriorating weather encountered along his route of flight. Thunderstorms with heavy rain and reduced visibilities were passing through the accident area. After landing, the pilot evaluated the weather and elected to continue onto his planned destination. The pilot did not obtain a FAA weather briefing prior to departing on the accident flight. The helicopter encountered instrument meteorological conditions during the accident flight. The helicopter impacted terrain while attempting to return to the departure airport. The wreckage was located 10.1nm south of the departure airport. The pilot was not instrument rated and had not logged any instrument flight time. The pilot had accumulated 8.5 hours of night experience and his last logged night flight was 10 months prior to the accident. Inspection of the wreckage did not exhibit any evidence of pre-impact malfunction that would have prevented normal operation.

Factual Information

HISTORY OF FLIGHT On June 25, 2003, about 2245 central daylight time, a Eurocopter EC120B, N298HS, was destroyed during impact with terrain near Boonville, Missouri. The helicopter was operating at night in instrument meteorological conditions (IMC). The personal flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The private pilot was fatally injured. The flight departed Jesse Viertel Memorial Airport (VER), Boonville, Missouri, around 2230 with the intended destination of Grand Glaize/Osage Beach Airport (K15), Osage Beach, Missouri. The pilot had several telephone conversations with his wife and son prior to departing on the accident flight, according to the pilot's wife. At 2050, the pilot left his wife two phone messages stating that he landed at VER due to deteriorating weather conditions encountered along his route of flight. At 2100 and 2113, the pilot spoke with his son concerning the weather radar and a possible "clean break" between two lines of thunderstorms. At 2125, the pilot spoke with his wife and reiterated that he landed at VER due to deteriorating weather conditions and that he was watching the weather radar. At 2210, the pilot told his wife that he thought there was a possible "clean break" between the two lines of thunderstorms. At 2224, the pilot told his wife that he had been watching the weather radar with the airport manager and it appeared there was a "window" in the weather. The airport manager and the pilot both agreed that there was a suitable opening between the two lines of thunderstorms, according to the pilot's wife. The pilot stated that he was going to depart VER and continue to K15. There were no witnesses to the accident. Local law enforcement was notified that the helicopter was overdue on June 26, 2003, at 0113. At 1213, the accident site was located 10.1 nautical miles (nm) south of the departure airport. PERSONNEL INFORMATION The pilot held a private pilot certificate with a rotorcraft/helicopter rating. The pilot certificate was issued by the Federal Aviation Administration (FAA) on June 1, 2000. The pilot was not instrument rated. FAA records indicated that his last airman medical examination was completed on January 29, 2002, when he was issued a third-class medical certificate with no restrictions or limitations. The following flight times were calculated from the pilot's flight logbook and the accident helicopter's airframe logbook: The pilot had a total flight time of 664.1 hours, of which 612.4 hours were as pilot-in-command (PIC). He had accumulated 85.9 hours in a Eurocopter EC120B helicopter. His last flight review, as required by 14 CFR Part 61.56, was completed on May 31, 2002. The pilot accumulated 170.1 flight hours in the past year, 96.6 hours during the prior 6 months, 38.3 hours during the past 90 days, and 16.6 hours during the previous 30 days. The last flight logbook entry was dated June 20, 2003. The pilot's wife reported that he flew the helicopter on June 22, 2003, from Lee C Fine Memorial Airport (AIZ) to the helicopter's home base in New Sharon, Iowa. This was a routine flight that typically took about 2.0 hours to complete. The pilot logbook did not list any flight hours in actual or simulated instrument conditions. He had accumulated 8.5 hours during night conditions and his last logged night flight was completed on August 19, 2002. The pilot completed 50.5 hours of flight training in the Eurocopter EC120B helicopter, which included 3.0 hours provided by a Eurocopter flight instructor. AIRCRAFT INFORMATION The accident helicopter, a Eurocopter EC120B (Colibri), serial number 1149, was issued a FAA standard airworthiness certificate on November 1, 2000. The helicopter was powered by a Turbomeca Arrius 2F engine, serial number 34168. The last airframe examination was completed on December 20, 2002, at 140.8 hours total time. The last logbook entry was on June 20, 2003, at 235.65 hours total time. A review of the daily usage logs for the helicopter indicated that there were no unresolved maintenance discrepancies. METEOROLOGICAL INFORMATION The automated surface observing system (ASOS) at Jefferson City Memorial Airport (JEF), Jefferson City, Missouri, recorded the following information at 2234: Wind 350 degrees true at 8 knots gusting to 18 knots; 3/4 statute mile visibility; heavy thunderstorms with rain and mist; broken clouds at 300 and 900 feet agl, overcast cloud layer at 3,100 feet agl; temperature 22 degrees Celsius; dew point of 21 degrees Celsius; altimeter 29.98 inches of mercury. The National Weather Service (NWS) Surface Analysis Chart issued at 2200 showed a cold front crossing the northwestern portion of Missouri. There was a line of thunderstorms (squall line) just preceding this cold front, which ran through the area in which the accident occurred. A central Missouri station surface model, positioned between the cold front and squall line, indicated slight to moderate thunderstorms in the area. The NWS radar summary chart issued at 2215 indicated an elongated area of precipitation extending from the Great Lakes to the Texas panhandle. Specifically, the contours on the chart showed there was intense precipitation embedded within the line of thunderstorms. The thunderstorms had cloud tops of approximately 54,000 feet near the accident location. Weather radar images recorded between 2243 and 2258 show the general storm movement was to the northeast, with the most intense storm cells located to the east and northwest of the accident site. At the time of the accident, light to moderate precipitation returns encompassed the accident site. There were strong to very strong precipitation returns recorded at the flight's purposed destination (K15). Infrared satellite data taken at 2245 indicated there were clouds throughout central Missouri. At the accident location, the cloud top temperatures were approximately -60 degrees Celsius, corresponding to a cloud top height of about 43,000 feet. Prior to the accident, there were two Convective SIGMETs issued for the accident area. Both advisories noted that there were severe thunderstorms near the accident location, and the thunderstorms were moving to the east at 25 knots. The thunderstorm cloud tops were forecasted to be greater than 45,000 feet, with the possibility of 2-inch hail and wind gusts of 60 knots. The accident occurred at night with the moon below the horizon, according to data supplied by the U.S. Naval Observatory. The pilot did not obtain a FAA weather briefing prior to the accident flight, according to Automated Flight Service Station (AFSS) data. As previously mentioned, the pilot had landed at the departure airport after encountering deteriorating weather along the route of flight. The pilot had reportedly reviewed local weather radar images prior to departing on the accident flight. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board's (NTSB) on-scene investigation began on June 27, 2003. The wreckage was in a cornfield located about 10.1 nm south of the departure airport. A global positioning system (GSP) receiver recorded the location of the initial impact as 38-degrees 46.63-minutes north latitude, 92-degrees 41.75-minutes west longitude. The wreckage debris path was distributed in a straight line, over approximately 400 feet on a 345 degree magnetic heading. There were several fragmented portions of the main rotor system near the initial impact point. The tailboom and shrouded tail rotor were located 321 feet and 328 feet from the initial impact point, respectively. The main cabin was located 340 feet from the initial impact point. The main transmission, engine, mast and rotor head were located 392 feet from the initial impact point. The wreckage was recovered and a layout determined that all primary airframe structural components, flight control systems, rotor systems, transmissions, and powerplant components were present. The main cabin and cockpit were damaged and fragmented. A majority of the flight control system was damaged. The fractured portions of the flight control system exhibited fracture features consistent with overload. The flight controls located above the transmission deck remained intact and were continuous. Collective control continuity was established between the cockpit and the mixing-unit. Rotational continuity was established throughout the main transmission and mast. The tail rotor driveshaft was found fractured in several pieces, consistent with overload. No anomalies were found with the shrouded tail rotor or its related control systems. The main rotor system was destroyed. A layout of the fragmented main rotor system confirmed that all blades were accounted for. Inspection of the recovered flight control components did not exhibit any evidence of pre-impact malfunction. The engine was examined and no discrepancies were noted that could be associated with any pre-impact condition or malfunction. Both the compressor and turbine sections of the engine rotated freely, and mechanical continuity was confirmed to the main transmission drive shaft. The main transmission drive shaft was twisted and fractured. The power turbine blades had leading edge damage, consistent with foreign object ingestion. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot on June 27, 2003, at the Boone/Callaway Medical Examiner's Office, Columbia, Missouri. Toxicology samples for the pilot were submitted to the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma. The toxicology results indicated Fluconazole was detected in blood, kidney, and liver samples. Fluconazole is an oral antifungal medication used for the treatment of Onychomycosis, a fungal infection of the fingernails or toenails. On April 8, 2003, the pilot was prescribed Fluconazole to treat a nail infection, according to his wife. ADDITIONAL INFORMATION The wreckage was released to a representative of the owner on June 30, 2003. Parties to the investigation included American Eurocopter Corporation, Turbomeca Engine Corporation, and the FAA.

Probable Cause and Findings

The pilot's inadequate weather evaluation which resulted in his inadvertent flight into instrument meteorological conditions. An additional cause was the pilot's failure to maintain clearance from the terrain. The dark night, thunderstorms, rain and lack of instrument rating were contributing factors.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports