Primary finding
Probable cause
The pilot's loss of airplane control due to spatial disorientation while flying in instrument meteorological conditions in the vicinity of adverse weather conditions.
Investigator assessment
Analysis narrative
Before departing on the instrument flight rules cross-country flight, the instrument-rated private pilot received an official weather briefing which included the latest Significant Meteorological Information (SIGMET) valid along the proposed route of flight. While en route at 8,000 ft mean sea level (msl), the controller provided a vector to the pilot to deviate around weather. The pilot accepted the deviation and turned the airplane; shortly thereafter, he reported that the airplane was in an area of moderate-to-heavy precipitation. Several minutes later, the pilot reported that the airplane was clear of the precipitation; he requested and was cleared to resume the on-course heading. The controller subsequently observed the radar return associated with the airplane descending rapidly from 8,000 ft to 5,000 ft before radar contact was lost. Review of the airplane's flight track data showed the airplane descending in a left turn, then making a sharp right turn followed by a sharp left turn; there were no further communications received from the pilot. The wreckage was significantly fragmented, consistent with a high-energy impact and trees in the vicinity of the accident site displayed angular cuts consistent with propeller contact. There was no evidence of mechanical malfunctions or anomalies that would have precluded normal operation. A cold frontal boundary just west of the accident site provided a moderately unstable environment for the formation of thunderstorms along the route of flight. Review of weather information indicated that the pilot was operating in instrument meteorological conditions and likely turbulence associated with the thunderstorm activity. These conditions are known to be conducive to the development of spatial disorientation. Additionally, the airplane's series of descents and changes in direction before being lost from radar and the evidence of a high-energy impact are consistent with the known effects of spatial disorientation and a subsequent loss of control.
Source record
Factual narrative
Pilot Weather Briefing The accident pilot received an official weather briefing from Leidos Flight Service at 0825. The Leidos briefing included the latest Significant Meteorological Information (SIGMET) valid along the proposed route of flight, METARs, TAFs, Graphical Forecast for Aviation (GFA), PIREPs, AIRMETs, and Winds Aloft Forecast valid along the proposed route of flight. While the GFA information was available to the pilot in graphical format, the briefer also described the GFA images to the pilot as part of the briefing. SIGMET Advisories A SIGMET 29E was valid for the area around the accident site at the time of the accident time and warned of an area of thunderstorms with tops to FL450. The SIGMET was forecast to move from 270° at 45 knots. Two SIGMETs were valid along the proposed route of flight before departure and at the time the accident pilot received Leidos weather briefing. Figure 2 is an aviation weather center (AWC) graphic which depicts SIGMETs, center weather advisories (CWA) and AIRMETS valid at 1100 in relation to the accident site. Figure 2. AWC graphic with SIGMETs, CWAs, and AIRMETs valid at 1100 EDT Surface Analysis Chart The mid-Atlantic section of the National Weather Service (NWS) Surface Analysis Chart identified a cold front located just west of the accident site, stretching from central New York southwestward through southern Ohio and into central Tennessee. A surface trough was located east of the accident site stretching north to south from central Maryland into central South Carolina. A surface low pressure center with a pressure of 1010-hectopascals (hPa) was located in western Ohio. The station models around the accident site depicted air temperatures from mid-60°F to low 70°F, dew point temperatures from low to mid 60°F with temperature-dew point spreads of 5°F or less, a south to southwest wind of 5 to 10 knots, and cloudy skies with areas of fog reported at the two closest station models north and west of the accident site. Surface Observations North Central West Virginia Airport (CKB), Clarksburg, West Virginia, was located 21 miles southeast of the accident site at an elevation of 1,224 ft. The CKB automated weather observation at 1053 included wind from 190° at 8 knots, 10 miles visibility or greater, a broken ceiling at 2,600 ft above ground level (agl), broken skies at 3,200 ft agl, overcast skies at 4,000 ft agl, temperature 20°C, dew point temperature 18°C, and an altimeter setting of 29.83 inches of mercury. Remarks included distant lightning 6 miles west through north, rain ended at 1050. The 1153 observation included wind from 210° at 12 knots, 10 miles visibility, thunderstorms in the vicinity, broken ceiling at 1,800 ft agl, broken skies at 2,300 ft agl, broken skies at 9,500 ft agl, temperature 22°C, dew point 18°C, and an altimeter setting of 29.82 inches of mercury. Base Reflectivity and Lightning Data The accident flight track depicted the flight in an area of echoes of 30 to 45 dBZ between 1139 and 1147. The pilot reported to the controller that the airplane had exited the precipitation by 1145. There were no echoes located above the accident site at 1147, and there were no lightning flashes or strikes located within 10 miles of the accident flight track between 1139 and 1151. Figure 3 depicts the reflectivity for the 0.5° elevation scan initiated at 1139 with the ATC flight track (pink line) and black arrow pointing in the direction of travel. Figure 3. Reflectivity for the 0.5° elevation scan initiated at 1139 with the ATC flight track (pink line) and black arrow pointing in direction of travel The pilot held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. His most recent FAA third-class medical certificate was issued on February 24, 2016. A review of the pilot's logbooks revealed 1,077 total hours of flight experience, which included 92 hours in the SR20 as of July 29, 2017. In addition, the pilot had accumulated 37.6 total hours of actual instrument time, of which 24.9 hours were logged in the SR20. The pilot accumulated 14.6 hours of instrument time as of July 29, 2017. No other flight time entries were entered into the pilot's logbook. The pilot's logbook revealed that he did meet the requirements to act as pilot in command under IFR or weather conditions less than the minimums prescribed for visual flight rules (VFR) only. The single-engine airplane was manufactured in 2000 and was powered by a Continental IO-360-ES6B, 215-horsepower engine equipped with a Hartzell three-bladed, controllable-pitch propeller. The airplane was also equipped with an Aspen Pro EFD 1000, dash mounted Garmin 696, XM weather/audio, JP Instruments EDM-730 engine temperature monitor, Garmin 430, Garmin420, S-tec systems auto pilot, Garmin GTX 327 transponder. All of the instruments were destroyed and no significant information could be recovered from their remains. The airplane's most recent annual inspection was completed on October 14, 2016, at a Hobbs time of 1,141.3 hours. The Hobbs meter was destroyed during the accident and the current airframe and engine total times could not be determined. Review of the maintenance logbooks revealed that the most recent altimeter/pitot-static system inspection and transponder test was performed on August 26, 2015. The last update on the cockpit electronic flight display (EFD) and primary flight display (PFD) was performed on January 7, 2013. On September 5, 2017, about 1148 eastern daylight time, a Cirrus SR20, N135CD, was destroyed when it collided with terrain in Jacksonburg, West Virginia. The private pilot and passenger were fatally injured. The airplane was privately owned and was being operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Instrument meteorological conditions prevailed at the time of the accident, and an instrument flight rules flight plan was filed for the flight, which originated at Delaware Coastal Airport (GED), Georgetown, Delaware, and was destined for Fleming-Mason Airport (FGX), Flemingsburg, Kentucky. According to Federal Aviation Administration (FAA) air traffic control (ATC) radar and voice communication information, the pilot checked in with the Clarksburg, West Virginia, approach control facility at 1106 at an altitude of 7,000 ft mean sea level (msl). About 1114, the pilot requested an alternate course to the Parkersburg VOR (JPU) in order to avoid weather and was cleared direct to the JPU VOR. About 1115, the controller instructed the pilot to climb to 8,000 ft. About 1129, the controller advised the pilot that another aircraft on his same route was deviating due to weather and asked the accident pilot if he also wanted to deviate. The pilot advised the controller that he would deviate and the controller subsequently issued the pilot a heading east of his current heading to clear the weather. About 1142, the controller asked the pilot about the flight conditions, and the pilot reported that he was in the clouds, level at 8,000 ft, and was "almost past" thunderstorms. The controller told the pilot to expect a clearance direct to JPU VOR in about 8 miles, and the pilot acknowledged. Shortly thereafter, the pilot reported that the airplane was in an area of moderate-to-heavy precipitation. The controller offered the pilot a heading to exit the precipitation; however, the pilot declined the heading change and said that he was "okay." About 1146, the pilot reported clear of the precipitation and requested and was subsequently cleared direct to the JPU VOR. Shortly thereafter, the airplane made a rapid descent from 8,000 ft to 5,000 ft before radar and radio contact were lost (see figure 1). Figure 1. NTSB accident flight track radar data plot An alert notice (ALNOT) was issued after the controller was unable to establish contact with the airplane.