Stoneville, NC, USA
N831HC
MARK COBY EARLY BIRD JENNY
The pilot, who was the co-owner/co-builder of the experimental amateur-built airplane, was departing on a local flight. The other co-owner/co-builder of the airplane witnessed the accident takeoff and stated that the airplane’s pitch attitude was “a little steep” and that the airplane looked slow as it approached 150 ft above ground level in the climb. Both the co-owner and another witness stated that the airplane’s wings were rocking before one wing dropped and the airplane entered a nose-down descent. The airplane impacted terrain about halfway down the 5,200-ft-long runway, and a postimpact fire ensued. Postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or anomalies that would have precluded normal operation. Review of the pilot’s logbook indicated that the accident flight was his third flight in the accident airplane and that he had recorded a total of 0.8 hours of flight experience. The co-owner stated that he and the accident pilot took turns flying the airplane and that the day of the accident was the warmest day on which they had flown the airplane. The co-owner had flown the airplane earlier on the day of the accident and stated that, although the airplane’s takeoff profile was “flatter than usual,” the airplane otherwise performed well and handled as expected. The co-owner also stated that neither he nor the accident pilot had conducted any aerodynamic stalls in the airplane, which was not equipped with a stall warning system. The extent to which the accident pilot had explored the airplane’s low-speed handling characteristics during flight could not be determined based on the available evidence for this accident. Review of the atmospheric conditions about the time of the accident indicated a density altitude of about 2,400 ft. Weight and balance documents for the airplane were not located, and the airplane’s weight and balance condition at the time of the accident was not determined. Autopsy and toxicology results for the pilot revealed evidence of an enlarged heart, anthracosis of the lungs, a carboxyhemoglobin saturation between 11% and 13%, and medications to treat high blood pressure. Minimal soot deposits were found in the trachea. Given the available evidence for this accident investigation, it is unlikely that the pilot’s cardiac condition was a factor in this accident. His carboxyhemoglobin saturation was not likely associated with impairment and was most likely the result of postcrash exposure to carbon monoxide. The circumstances of the accident are consistent with the pilot’s exceedance of the airplane’s critical angle of attack during takeoff, which resulted in an aerodynamic stall and a loss of control. It is likely that the density altitude conditions at the time of the accident degraded the airplane’s takeoff performance and that the pilot’s unfamiliarity with the airplane’s handling characteristics (especially in higher-density-altitude conditions) and with low speed/aerodynamic stalls contributed to his failure to recognize and correct the airplane’s angle of attack before the stall occurred.
HISTORY OF FLIGHTOn May 27, 2021, about 1835 eastern daylight time, an experimental amateur-built Early Bird Jenny, N831HC, was destroyed when it was involved in an accident near Stoneville, North Carolina. The private pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The co-owner/co-builder of the airplane stated that he flew the airplane on the morning of the accident, returning to the airport after about 30 minutes due to rain. The co-owner reported that the flight was uneventful and that the airplane performed well and handled as expected, even though the takeoff profile was “flatter than usual” due to the warmer temperature. He and the accident pilot, who was the other owner/builder of the airplane, moved the airplane into their hangar, where they waited for the rain to move through the area. Later that afternoon, the accident pilot departed on runway 31 for his flight. The co-owner reported that the pilot’s taxi to runway 31 was normal and that the engine was producing power, but the takeoff did not “look right.” He described the airplane’s pitch attitude as “a little steep” and stated that the airplane looked slow. He saw the wings rock left and right and the airplane “buffet” before the right wing dropped and the airplane impacted terrain. Another witness to the accident reported that the airplane appeared to be “hanging off the prop” during the initial climb and that its wings were “rocking.” About 150 ft above ground level, the airplane entered an abrupt turn and “dropped” to the ground and that a “big ball of flame” ensued. He reported that the engine did not sputter and sounded as if it had been producing full power until impact. PERSONNEL INFORMATIONReview of excerpts from the pilot’s logbook dated from July 3, 2019, to May 11, 2021, indicated that he had a total of about 755 hours of flight experience. The excerpts contained two flights in the accident airplane; the first, dated September 8, 2019, had a duration of 0.4 hours, and contained an annotation indicating, “first flight of N831HC.” The second flight in the accident airplane, dated November 29, 2020, was also 0.4 hours in duration. The entries for these flights did not annotate the maneuvers performed. AIRCRAFT INFORMATIONThe airplane’s experimental amateur-built airworthiness certificate was issued on August 4, 2019. Review of excerpts from the airplane’s maintenance log indicated that the most recent condition inspection was completed by the accident pilot on August 15, 2020, at which time the airplane had 7.6 hours of operation. The co-owner of the airplane reported that he and the accident pilot took turns flying the airplane and were working through the 40-hour Phase 1 requirement. He stated that the airplane was “very docile” but that they were still getting comfortable in it and “stayed in the middle of the envelope.” The co-owner also reported that neither he nor the accident pilot had conducted any aerodynamic stalls at altitude. The airplane was not equipped with a stall warning system. The co-owner reported that he and the accident pilot were initially concerned with weight and balance limitations because of the accident pilot’s weight (about 300 pounds based on his most recent medical certificate), but they were careful not to exceed aft center-of-gravity limitations. Weight and balance limitations for the airplane were not located, so the weight and balance condition at the time of the accident was not determined. The co-owner reported that, on the day of the accident, the airplane was fueled to capacity with automotive gas kept in cans in his and the accident pilot’s hangar and that the airplane likely consumed about 2 gallons during his flight. The airplane was not refueled before the accident flight. Before the day of the accident, the airplane’s most recent flight was in January 2021. The day of the accident was both pilots’ first time flying the airplane in warmer weather. METEOROLOGICAL INFORMATIONReported weather conditions at the airport about the time of the accident included calm wind, temperature 27°C, dew point 18°C, and an altimeter setting of 29.97 inches of mercury. The calculated density altitude was about 2,446 ft. AIRPORT INFORMATIONThe airplane’s experimental amateur-built airworthiness certificate was issued on August 4, 2019. Review of excerpts from the airplane’s maintenance log indicated that the most recent condition inspection was completed by the accident pilot on August 15, 2020, at which time the airplane had 7.6 hours of operation. The co-owner of the airplane reported that he and the accident pilot took turns flying the airplane and were working through the 40-hour Phase 1 requirement. He stated that the airplane was “very docile” but that they were still getting comfortable in it and “stayed in the middle of the envelope.” The co-owner also reported that neither he nor the accident pilot had conducted any aerodynamic stalls at altitude. The airplane was not equipped with a stall warning system. The co-owner reported that he and the accident pilot were initially concerned with weight and balance limitations because of the accident pilot’s weight (about 300 pounds based on his most recent medical certificate), but they were careful not to exceed aft center-of-gravity limitations. Weight and balance limitations for the airplane were not located, so the weight and balance condition at the time of the accident was not determined. The co-owner reported that, on the day of the accident, the airplane was fueled to capacity with automotive gas kept in cans in his and the accident pilot’s hangar and that the airplane likely consumed about 2 gallons during his flight. The airplane was not refueled before the accident flight. Before the day of the accident, the airplane’s most recent flight was in January 2021. The day of the accident was both pilots’ first time flying the airplane in warmer weather. WRECKAGE AND IMPACT INFORMATIONThe accident site was located about 175 ft north of the runway 13/31 centerline and about 2,500 ft from the runway 31 threshold. The airplane came to rest on a southerly heading and was destroyed by the postimpact fire. All major components of the airplane were accounted for at the site, and flight control continuity was established from the flight control surfaces to the cockpit area. The wooden propeller, which had separated from the engine, was highly fragmented. The engine displayed extensive thermal damage. The crankshaft could not be rotated by hand, but valve train continuity was achieved upon rotation of the camshaft. The throttle control cable was continuous from the carburetor to the cockpit area. ADDITIONAL INFORMATIONFederal Aviation Administration (FAA) Advisory Circular 90-89C, Amateur-Built Aircraft and Ultralight Flight Testing Handbook, recommended establishing an airplane’s preliminary stall speed and low-speed handling characteristics during the first flight at a safe altitude of 5,000 ft above ground level. The AC also stated the following: Note: In an effort to reduce maneuvering accidents in all aircraft the FAA and the EAA [Experimental Aircraft Association] strongly urge all amateur builders to install an AOAI [angle of attack indicator] or lift reserve indicator in their aircraft and learn how to use it effectively. Since most experimental amateur-built aircraft do not have any stall warning device installed, the AOAI can fulfill the need to serve that safety function…The potential life- saving benefit of those devices should not be underestimated. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was performed at the Office of the Chief Medical Examiner, Raleigh, North Carolina. His cause of death was multiple blunt force injury. The autopsy revealed that the pilot had an enlarged heart with left ventricular wall thickening. The pilot’s lungs had anthracosis (black pigment often seen with heavy cigarette smoking) and minimal soot deposits in the trachea. Toxicology testing revealed a carboxyhemoglobin saturation of 13%. Toxicology testing performed by the FAA Forensic Sciences Laboratory revealed salicylic acid (commonly known as aspirin) and the high blood pressure medications amlodipine, metoprolol, and valsartan in the pilot’s blood and urine. His carboxyhemoglobin saturation was measured at 11%.
The pilot’s exceedance of the airplane’s critical angle of attack during the takeoff initial climb, which resulted in an aerodynamic stall and a loss of control.
Source: NTSB Aviation Accident Database
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