CEN23FA285

The pilot’s visual flight rules flight into instrument meteorological conditions, which resulted in a loss of control in flight and subsequent impact with terrain.

The pilot departed the airport about 1330 local time for an unknown destination in visual flight rules conditions. The accident site was located about 12 nautical miles (nm) from the airport; however, the airplane’s flight path and time of the accident are unknown as there was no flight track or recorded data available; there were no witnesses to the accident. Postaccident examination revealed no preimpact anomalies with the airplane or engines that would have precluded normal operation. Weather conditions after the airplane’s departure suggest the airplane may have encountered an area of deteriorating weather and instrument meteorological conditions (IMC) that reduced visibility and obscured terrain. However, as the accident time is unknown, the investigation was unable to determine if the airplane crashed during a time of deteriorating weather. The pilot was also operating the airplane with an inoperative GPS, which could have decreased the pilot’s ability to maintain situational awareness. The accident site signatures were consistent with a loss of control and impact with terrain. An autopsy was conducted on the pilot; however, due to the condition of the remains, it could not be determined if an impairing condition or natural disease contributed to the accident. An unknown quantity of ethanol detected by toxicological testing may have been from postmortem production; however, the limited results also do not exclude the possibility of ethanol consumption or related impairment.

The accident occurred near Burlington, Colorado, at a field elevation of about 4,275 ft msl. The meteorological investigation was conducted using official National Weather Service (NWS) and National Oceanic and Atmospheric Administration (NOAA) data sources. A surface analysis chart valid at 1200 MDT showed the accident site positioned between a 1023-hectopascals (hPa) high pressure system over Iowa with a ridge extending southwestward over Kansas and a 1018-hPa bubble high over central Colorado. A trough was located between the two high pressure systems extending over eastern Colorado and western Kansas. Wind near the surface were generally from the southeast at 10 knots. Several reporting stations in eastern Colorado, including Burlington (KITR), indicated mist, low visibility, and overcast or obscured skies throughout the morning, with a gradual lifting trend into marginal visual flight rules (MVFR) conditions by early afternoon. The closest official weather reporting station was Kit Carson County Airport (KITR), located about 13 nautical miles north of the accident site. The automated surface observation at 1353 MDT reported wind from 130° at 14 knots, visibility 10 statute miles, few clouds at 1,000 ft above ground level (agl), overcast ceiling at 1,800 ft agl, temperature 19°C, dew point 16°C, and altimeter setting 30.13 inches of mercury. Earlier in the morning, between approximately 0600 and 1200 MDT, low instrument flight rule (LIFR) conditions prevailed, with visibility frequently below one statute mile in fog and vertical visibility as low as 200 ft. These conditions began improving shortly before the accident time window, and transitioned to MVFR. A High-Resolution Rapid Refresh (HRRR) numerical model sounding at 1300 MDT for a grid point near the accident site indicated a saturated atmosphere with a surface temperature of 16°C, dew point 15°C, relative humidity 96 percent, and a calculated density altitude of 5,328 ft. The lifted condensation level (LCL) and level of free convection (LFC) were calculated at 296 ft agl. Cloud ceilings were estimated as broken at 300 ft and overcast at 800 ft agl, with stratiform tops near 10,000 ft. An additional layer of altocumulus clouds was present between 15,600 and 20,000 ft. Precipitable water content was measured at 1.16 inches. The freezing level was identified near 15,500 ft. The HRRR sounding also indicated a high probability of carburetor or induction icing from the surface to 12,000 ft, given the temperature and humidity profile. Winds at the surface were from 120° at 11 knots, veering with altitude and increasing to 20–27 knots by 18,000 ft. No clear air turbulence or mountain wave activity was noted below this level. Satellite imagery from GOES-16 at 1331 MDT revealed widespread low stratiform clouds over eastern Colorado. Cloud top temperatures near the accident site measured 285 Kelvin (approximately 11°C), corresponding to top altitudes around 8,000 ft. Convective clouds associated with dissipating cumulonimbus were observed both west and east of the site. No pilot weather reports (PIREPs) were recorded within 60 nautical miles of the accident site between 1000 and 1800 MDT. The Terminal Aerodrome Forecast (TAF) for Goodland, Kansas (KGLD), approximately 28 miles east of the accident site, issued at 1120 MDT, forecast IFR conditions with wind from 160° at 11 knots, visibility 2 statute miles in mist, overcast ceiling at 800 ft AGL, and showers in the vicinity for the accident time. The Area Forecast Discussion issued by NWS Goodland at 1132 MDT described a saturated near-surface air mass, widespread fog and low ceilings over eastern Colorado, and potential for severe weather development later in the afternoon and evening. Conditions for supercell development were forecasted, with potential hazards including large hail, damaging winds, flash flooding, and tornadoes. Graphical Forecasts for Aviation (GFA) at 1330 MDT depicted low IFR conditions over the accident site, with overcast cloud bases near 4,500 ft msl (approximately 275 ft agl) and tops extending up to 25,000 ft. A Graphic AIRMET for IFR conditions was valid for the region at the time of the accident. Several AIRMETs were in effect over the accident region, including AIRMET Sierra for IFR conditions and mountain obscuration, AIRMET Tango for moderate turbulence below FL180, and AIRMET Zulu for potential icing above the freezing level. No SIGMETs, Convective SIGMETs, or Center Weather Advisories were issued for the area during the relevant time period. A review of FAA Leidos Flight Service and ForeFlight systems indicated that no official weather briefing was obtained by the pilot before departure. It could not be determined what sources, if any, the pilot used to obtain weather information in accordance with Title 14 Code of Federal Regulations Part 91.103. A pilot logbook was not recovered; however, on the pilot’s last application for an FAA medical certificate, he reported his total flight experience of 20,000 hours and 150 hours in the last 6 months. Maintenance records were not located for the airplane. The airplane’s total fuel capacity was 173.5 gallons (165.5 gallons usable); the airplane was equipped with two wing fuel tanks and a fuselage tank. According to fuel receipts, the pilot serviced the airplane with 113.4 gallons of 100 low-lead aviation fuel from the self-serve pumps at ITR before the airplane departed on the flight. An autopsy of the pilot was performed by the Weld County Coroner’s Office, Greeley, Colorado, at the request of the Kit Carson County Coroner. According to the autopsy report the cause of death was multiple blunt force injuries and the manner of death was an accident. Toxicology testing performed on the pilot’s specimens at the FAA Forensic Sciences Laboratory detected ethanol at 0.012 g/hg in liver tissue, at 0.037 g/hg in muscle tissue, at 0.014 g/hg in lung tissue, and at 0.043 g/hg in kidney tissue (in tissue, concentrations in g/hg are approximately equivalent to concentrations in g/dL). Ethanol is a type of alcohol. It is the intoxicating alcohol in beer, wine, and liquor, and, if consumed, can impair judgment, psychomotor performance, cognition, and vigilance. FAA regulation imposes strict limits on flying after consuming ethanol, including prohibiting pilots from flying with a blood ethanol level of 0.04 g/dL or greater. Alcohol consumption is not the only possible source of ethanol in postmortem specimens. Ethanol can sometimes be produced by microbes in a person’s body after death. Postmortem ethanol production is made more likely by extensive traumatic injury. The airplane impacted a fallow cornfield about 11.8 nm southwest of ITR. A 350-ft-long debris path, oriented on a 345° magnetic heading, preceded the location of the main wreckage. The airplane impacted the ground in a near wings-level nose-down attitude. The nose landing gear wheel and fork were found separated from the strut about 325 ft from the initial point of impact. The wing tips were found separated from both wings along the wreckage debris path on their respective sides. Examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. The fuselage was fractured from the wing and the wing spars remained attached as one assembly. Flight control continuity could not be verified because the control push/pull tubes for the ailerons, elevators, and rudder exhibited extensive impact and fire damage. Both ailerons and flaps exhibited impact and fire damage. The hydraulic flap actuators were found retracted, consistent with 0° of flap extension. Both elevators remained attached to the horizontal stabilizer and exhibited impact damage. The elevator trim tabs measured about 10° tab down. The rudder was found about 125 ft from the empennage and the vertical stabilizer was fractured from its mount and crushed. The