Erwin, TN, USA
N1058S
COLUMBIA AIRCRAFT MFG LC41 550FG
The instrument-rated private pilot was on an instrument flight rules (IFR) cross-country flight; while en route, the pilot elected to divert to an intermediate airport to "check the weather." The pilot was subsequently provided a weather briefing that described a line of convective weather along the intended route of flight. The airplane departed about 45 minutes later and flew east along the south side of an east-west line of thunderstorms. The pilot was communicating with air traffic control, and when asked by the air traffic controller if he had onboard weather information, the pilot stated that he had NEXRAD. The airplane was equipped with satellite-delivered weather information service that was displayed in the cockpit, and it is likely that the pilot was referring to NEXRAD images provided by that system. The pilot requested and was granted permission to turn north in order to navigate through the line of storms toward his destination. Ground track and weather radar data revealed that the airplane penetrated a thunderstorm cell of strong intensity The pilot subsequently lost control of the airplane before it rapidly descended to ground impact. The wreckage debris path was compact, and examination of the wreckage revealed extensive fragmentation and thermal damage. No preimpact mechanical malfunctions were noted that would have precluded normal operation of the airplane. The impact damage to the engine and propeller were consistent with the engine operating at a high power setting at the time of impact. The satellite-delivered weather information likely being used by the pilot did not provide real-time weather radar images in the cockpit, with a delay between the time the weather was observed and when it was provided. It is likely that the pilot attempted to maneuver through the line of thunderstorms, but the time delay in the satellite-delivered weather data likely resulted in inadvertent penetration of a severe thunderstorm cell. The investigation could not determine the color intensity of the precipitation being displayed to the pilot on cockpit avionics around the time of the accident. However, the most extreme color band that could have been shown would have been dark orange, which was classified as 55 dBZ. On the WSR-88D and satellite-delivered radar images, orange was classified as 40 dBZ. The WSR-88D Level 2 reflectivity product revealed that the weather reflectivity, around the accident location, ranged from 5 dBZ to 55 dBZ. Postaccident toxicology testing revealed the presence of citalopram, an antidepressant medication, and ethanol. Citalopram is one of four medications that has been approved by the FAA for the treatment of depression. Personal medical records documented that the pilot's depression was well controlled with citalopram, and the pilot had no adverse effects from the medication. Therefore, there is no evidence that depression or the citalopram impaired the pilot's decision-making ability or his ability to safely operate the airplane. The ethanol detected was likely from postmortem production. Further, considering that the level of the ethanol was below a level that would be considered impairing, the ethanol detected did not impair the pilot nor contribute to the accident.
HISTORY OF FLIGHTOn October 9, 2015, about 1919 eastern daylight time, a Columbia Aircraft Manufacturing LC41-550FG, N1058S, impacted the ground in an uncontrolled descent after encountering a thunderstorm near Erwin, Tennessee. The private pilot and the passenger were fatally injured, and the airplane was destroyed. The airplane was owned and operated by the pilot. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. The flight originated from the Tyson Airport (TYS) Knoxville, Tennessee, about 1830 and had an intended destination of Monroe County Airport (BMG), Bloomington, Indiana. Night visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed. The flight originated earlier in the day from the Kissimmee Gateway Airport (ISM), Orlando, Florida. Prior to departing ISM, the pilot's login credentials were used to access weather information via DUAT (Direct User Access Terminal). The information provided included weather along the planned route of flight in textual form The terminal area forecasts along the route of flight predicted showers and thunderstorms in the TYS area and north beginning about 1700. The weather report also included a "Severe Weather Outlook," which stated in part "There is a marginal risk of severe thunderstorm from southern New England to the Tennessee Valley. Scattered thunderstorms should occur today in a corridor from New York and parts of New England Southwestward to the Tennessee Valley region. A few of these storms may produce damaging gusts near severe limits and a tornado cannot be ruled out over the northeast." While en route, the pilot diverted to TYS as he wanted to "check the weather." The flight landed at TYS about 1745. DUAT records indicated that about 1750 the pilot's login credentials were used to access the system and obtain a weather briefing. The weather briefing included a textual description of weather reports along the intended route of flight, and spanning as far as Florida and the New England area. About 1830, the airplane departed TYS and was observed on radar climbing to 15,000 ft mean sea level (msl) on an easterly heading, paralleling an east-west line of convective weather to the north. During the flight, the pilot was in communication with air traffic control (ATC) personnel. At 1836:02 the TYS controller contacted an air carrier flight descending into TYS and stated in part, "…i got a Columbia that's trying to get towards uh Bloomington Indiana uh would you say going up to like sixteen thousand uh would be a good idea through that area or should i take him somewhere else." At 1836:13 the air carrier flight stated "absolutely no he needs to go somewhere else." At 1836:21 the accident flight acknowledged the transmission. At 1836:21 the controller stated in part "…if i take you to the north i got some areas of uh some lighter precipitation off to the north uh i can get you that way you might be able to cut through that way would you want to try that." At 1836:37 the controller then stated "that's gonna be my lightest areas i have a few areas of heavy precipitation but it's more scattered and not as uh well us interconnect as the stuff down here towards the uh southwest…" For the next approximate 9 minutes the controller provided clearances for the accident pilot to deviate and turn left and/or right as necessary. At 1845:10 the controller, in communication with another ATC facility stated in part "…he's trying to get through this line that we told him he really shouldn't even have departed cause he can't get through the line." For the next approximate 9 minutes the controller provided deviation clearances and radio frequency change for the accident flight. At 1854:28 the controller stated "…based on the weather i'm showing um do you have any uh nexrad or anything on board." At 1854:36 the pilot replied "i do have nexrad on board" At 1854:41 the controller stated "…just trying to come up with a plan for you here looks like ah right around well let me see here about your ah eleven o'clock position and about forty miles forty one forty two miles um there's an area if you kinda cut north from there looks like you may be able to hang back towards the northwest its (unintelligible) precip that i'm showing but ah just keep me advised as to what youd like to do." At 1855:08 the pilot replied "yeah i think we're looking at the same spot i was looking at either just west or just east of ah is it Greenville." At 1911:09 the pilot requested and received clearance to turn 15° to the left. At 1913:46 the pilot was given permission and acknowledged the clearance to climb from 15,000 ft msl to 17,000 ft msl. At 1918:29 the pilot stated "five eight sierra", which was the last recorded transmission from the accident flight. After the last radio transmission, radar data showed the airplane descending from approximately 17,500 ft to ground level, in approximately one minute, in the vicinity of the accident location. Multiple witnesses observed the airplane descending, turning to the right, and then exploding on ground impact. One witness reported that, at the time of the accident, the area was receiving a "hard rain." PERSONNEL INFORMATIONAccording to Federal Aviation Administration (FAA) records, the pilot, age 45, held a private pilot certificate with airplane single-engine land and instrument airplane ratings, which was issued December 28, 2013. He held an FAA third-class medical certificate, issued April 18, 2014, with a limitation that he "must wear corrective lenses." At the time of the medical examination, the pilot reported 279 total hours of flight experience with 73.9 hours in the previous 6 months. At the time of this writing, no pilot logbooks were provided to the. AIRCRAFT INFORMATIONAccording to FAA records, the airplane was issued an airworthiness certificate in 2007 and registered to the pilot in January 2015. The most recent recorded annual inspection was on April 15, 2015, and, at that time, the airplane had 1,098.7 total flight hours. The most recent maintenance was recorded on June 24, 2015, and, at that time, the airplane had 1,113.1 total flight hours. The airplane was powered by a Continental Motors TSIO-550-C20B engine that, at the time of the airplane's most recent annual inspection, had accrued 37.5 flight hours since major overhaul. The most recent engine maintenance occurred on August 17, 2015, which was an oil change; at that time the engine had accrued 76.3 hours since major overhaul. The airplane was not equipped with on-board weather radar; however, it was equipped to receive XM Satellite Weather. The airplane was also equipped with a Garmin G1000 avionics suite, which was capable of displaying the aviation weather data provided through Sirius XM Satellite Weather services. According to information provided by Sirius XM Satellite Radio, the pilot had established an account for aviator pro aviation weather and Sirius XM Select audio services on July 6, 2011, and the account was current at the time of the accident. According to Sirius' website the aviator pro service provided the following products: High-Resolution NEXRAD Radar, High-Resolution Radar, Severe Weather Storm Tracks, Lightning, Winds Aloft (at Altitude) SPC Aviation Weather Watches, PIREPs, METARs, TAFs, Turbulence, Satellite Mosaic, AIRMETs, SIGMETS, as well as various other aviation weather services. METEOROLOGICAL INFORMATIONThe 1937 special recorded weather observation at Tri-Cities Regional Airport (TRI), Bristol, Tennessee, located about 13 miles to the northwest of the accident location, included variable wind at 3 knots, visibility 6 miles due to thunderstorms and rain, scattered cumulonimbus clouds at 2,300 ft above ground level (agl), broken at 6,000 feet agl, overcast at 11,000 feet agl, temperature 19°C, dew point 17°C, and barometric altimeter 30.05 inches of mercury. The remarks section of the special weather observation stated that a thunderstorm began at 1931 with occasional lighting in cloud and cloud to ground at the airport. The thunderstorms in the vicinity were moving east. The 1915 recorded weather observation at Elizabethton Airport (0A9), Elizabethton, Tennessee, located about 10 miles to the northeast of the accident location, included calm winds, 10 miles visibility, few clouds at 6,000 feet agl, scattered clouds at 7,500 feet agl, broken clouds at 9,000 feet agl, and barometric altimeter 30.03 inches of mercury. Weather radar data indicated that the line of convectively contained cells from 5 dBZ (decibels of equivalent reflectivity) to greater than 55dBZ, and the weather cell around the time and vicinity of the accident indicated greater than 55 dBZ. At 1855, a convective SIGMET was issued advising of a line of thunderstorms 50 miles wide along a line that went through the accident region. The line was reported to be moving from 260° at 30 knots, with cloud tops to FL440 (44,000 feet msl). Lightning data between 1900 and the time of the accident for the area surrounding the accident location showed lightning activity in the area; however, there was no lightning activity associated with the cell that coincided with the location of the airplane at the time of the accident. Figure 1: KRMX Reflectivity Product initiated at 1915, White Line was Accident Flight Path at 1917 Geostationary Operational Environmental Satellite (GOES)-13 infrared cloud-top temperatures varied between about -20°C and -53°C in the accident region, corresponding to heights of about 22,600 ft msl and greater than 35,000 ft msl, respectively. According to the United States Naval Observatory, official sunset was at 1902, and the end of civil twilight was at 1923. Moonset occurred at 1725, and 10% of the moon disc would have been visible had the moon been above the horizon. AIRPORT INFORMATIONAccording to FAA records, the airplane was issued an airworthiness certificate in 2007 and registered to the pilot in January 2015. The most recent recorded annual inspection was on April 15, 2015, and, at that time, the airplane had 1,098.7 total flight hours. The most recent maintenance was recorded on June 24, 2015, and, at that time, the airplane had 1,113.1 total flight hours. The airplane was powered by a Continental Motors TSIO-550-C20B engine that, at the time of the airplane's most recent annual inspection, had accrued 37.5 flight hours since major overhaul. The most recent engine maintenance occurred on August 17, 2015, which was an oil change; at that time the engine had accrued 76.3 hours since major overhaul. The airplane was not equipped with on-board weather radar; however, it was equipped to receive XM Satellite Weather. The airplane was also equipped with a Garmin G1000 avionics suite, which was capable of displaying the aviation weather data provided through Sirius XM Satellite Weather services. According to information provided by Sirius XM Satellite Radio, the pilot had established an account for aviator pro aviation weather and Sirius XM Select audio services on July 6, 2011, and the account was current at the time of the accident. According to Sirius' website the aviator pro service provided the following products: High-Resolution NEXRAD Radar, High-Resolution Radar, Severe Weather Storm Tracks, Lightning, Winds Aloft (at Altitude) SPC Aviation Weather Watches, PIREPs, METARs, TAFs, Turbulence, Satellite Mosaic, AIRMETs, SIGMETS, as well as various other aviation weather services. WRECKAGE AND IMPACT INFORMATIONThe airplane wreckage was found in the Cherokee National Forest, in the vicinity of the accident flight's last radar return, at an elevation of 2,825 ft msl. The slope around the accident site varied between 20° and 30°. The airplane impacted two 27-ft-tall trees. The debris path was fairly compact, and a considerable amount of debris was located within an impact crater that was about the length of the airplane's wingspan. The airframe was impact-damaged, segmented, and thermally destroyed. The engine was found in a 4-ft-deep crater and remained attached to the firewall. The engine mounts were impact-separated and were located with the main wreckage. The propeller was impact-separated at the crankshaft propeller flange. The attitude indicator was located within the debris field; it exhibited impact damage and displayed a nose-down, inverted right-wing-low attitude. No other instruments were readable. The nose landing gear wheel was impact-separated and located about 45 ft downhill from the main wreckage. The nose landing gear strut was impacted-separated and was located in the impact crater. The main wing spar was located in the impact crater. It was composed of composite material, was thermally destroyed, and exhibited some impact splintering. Left Wing The left wing was thermally destroyed. The left wing navigation light was located at one end of the impact crater. The left wing speed brake was found in the stowed position. The left main wheel assembly was impact-separated. The aileron and flap were thermally destroyed, and an accurate flap position could not be conclusively determined. Right Wing The right wing was thermally destroyed. The right wing navigation light was located at the opposite end of the impact crater from the left wing navigation light. The right wing speed brake was found in the stowed position. The right main wheel assembly was thermally destroyed. The aileron and flap were thermally destroyed, and an accurate flap position could not be conclusively determined. Empennage The empennage assembly, which included the vertical and horizontal stabilizers, was thermally damaged. The rudder remained attached to the vertical stabilizer but exhibited thermal damage on its leading edge. The rudder cables remained attached to their respective rudder horns. Engine The engine remained attached to the firewall, which had become impact separated from the airframe. The engine was an TSIO-550- C, 310-hp. The propeller was separated at the propeller flange. The No. 6 cylinder was impact separated from the engine. The oil pan was thermally damaged. The camshaft was visible, and all of the connecting rods were visible and remained attached to the crankshaft. The crankshaft exhibited torsional twist, 45° lip faces, and radial cracking. The fuel pump was thermally destroyed. The fuel manifold valve was impact separated; it was disassembled and found to contain soot and debris but was otherwise unremarkable. The magnetos were impact separated, fragmented, and thermally destroyed. The oil pump was impact damaged. Propeller The Hartzell 3-bladed propeller was impact separated at the propeller crankshaft flange. The spinner was located within the impact crater, exhibited extensive torsional twisting, and was fragmented. All three blades remained attached. Two of the blade tips were impact separated, one about 31 inches from the hub and the other about 31 1/8 inches from the hub. The third blade was intact. All 3 propeller blades were bent aft and formed around the hub. All 3 blades also exhibited leading edge gouging and slight twisting, and the outboard edge of 2 of the blades exhibited forward bending. The damage to the propeller assembly was consistent with it being under power at the time of impact. ADDITIONAL INFORMATIONThe FAA publication "General Aviation Pilot's Guide to Preflight Weather Planning, Weather Self-Briefings, and Weather Decision Making" states, in part: "Datalink does not provide real-time information. Although weather and other navigation displays can give pilots an unprecedented quantity of high quality weather data, their use is safe and appropriate only for strategic decision making (attempting to avoid the hazard altogether). Datalink is not accurate enough or current enough to be safely used for tactical decision making (negotiating a path through a weather hazard area, such as a broken line of thunderstorms). Be aware that onboard weather equipment can inappropriately influence your decision to continue a flight. No matter how "thin" a line of storms appears to be, or how many "holes" you think you see on the display, it is not safe to fly through them." Th
The pilot's decision to fly into a known area of adverse weather, which resulted in the airplane entering a severe thunderstorm and a subsequent loss of control.
Source: NTSB Aviation Accident Database
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