CEN15FA240

The pilot’s failure to maintain airplane control while maneuvering at low altitude, which resulted in the airplane’s wing exceeding its critical angle-of-attack and a subsequent aerodynamic stall .

The private pilot/owner was conducting a local personal flight. GPS data from a handheld device recovered from the airplane revealed that, after takeoff, the pilot maneuvered in the vicinity of the airport. About 22 minutes after takeoff, the pilot twice overflew a residence located about 0.25 mile northeast of the accident site; both overflights were made from east to west, and the pilot flew a left racetrack pattern between the overflights. Immediately after the second overflight, the pilot entered a left turn. A witness observed the airplane turning left when its nose dropped, and it "fell straight down." The final GPS data point was recorded after the airplane had completed about 90 degrees of heading change to the south and was about 500 ft above ground level. The accident site was located about 400 ft east of the final data point, indicating the airplane completed about a further 90 degrees of heading change before ground impact. Examination of the accident site indicated that the airplane impacted an open field in a nose down attitude and came to rest upright. A postaccident examination of the airframe and engine did not reveal any anomalies consistent with a preimpact failure or malfunction. The GPS data indicated that the pilot maneuvered extensively during the flight; however, it did not indicate that he was performing aerobatic maneuvers at any point. The data suggest that the final left turn was flown with a gradually decreasing turn radius consistent with an increasing angle of bank. The abrupt departure from controlled flight as depicted in the GPS data and described by the witness is consistent with the wing's angle-of-attack exceeding its critical angle-of-attack during the turn, resulting in an aerodynamic stall. The stall occurred at an altitude that was too low for recovery. A review of medical and pathological information related to the pilot indicated that a sudden incapacitation or significant cardiac event precipitating the accident was unlikely. Diphenhydramine, a sedating antihistamine, was detected in the pilot's blood. However, the level of the medication in the pilot's system at the time of the accident could not be accurately determined from the available toxicological data. Therefore, the extent of any impairment due to diphenhydramine at the time of the accident could not be determined.

HISTORY OF FLIGHT On May 25, 2015, at 0818 mountain daylight time, a Yakovlev Yak 52 airplane, N124FS, was substantially damaged during an in-flight collision terrain near Syracuse, Kansas. The pilot was fatally injured. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from the Syracuse-Hamilton County Municipal Airport (3K3), Syracuse, Kansas about 0755. A friend of the accident pilot, who also owned a Yak 52, stated that they had planned to meet at the airport about 1000 to conduct a fly-by in conjunction with the local Memorial Day events. When he arrived at the airport about 0900, the accident pilot's car was there, but his airplane was gone. He noted that the accident pilot commonly used his airplane to check on his cattle. He attempted to contact the accident pilot over the radio without success. He subsequently took off about 1000 and held north of town. When the accident pilot did not arrive, he conducted a single airplane fly-by. He was notified of the accident after returning from the flight. A witness reported that the airplane was initially eastbound. She observed it make a right 180-degree turn to a west course. The airplane then "dipped down" (descended) until she lost sight of it momentarily, before it climbed back up. She noted that the airplane banked again and she was able to see both wings. She added that the wings were red, while the body of the airplane was white. The airplane leveled off and then "dipped" again, causing her to momentarily lose sight of it again until it climbed up. The airplane then began what appeared to be a normal turn to the left toward the south when it "fell straight down." She explained that it did not appear to bank, but that it nosed down. The airplane descended below her line of sight and she heard a "funny" sound. When the airplane did not climb back up again, she thought that it had crashed. She notified the local authorities at that time. Authorities received a call regarding a possible airplane crash at 0819. The accident site was located about 1130 after an extensive search of the local area. PERSONNEL INFORMATION The pilot held a private pilot certificate with single-engine land airplane rating. He was issued a third class airman medical certificate with a limitation for near and distant vision corrective lenses on September 12, 2013. On his medical certificate application, the pilot noted a total flight time of 1,000 hours, with no flight time within the preceding six month time period. The pilot's logbook was reviewed by the NTSB. According to the logbook, the pilot had accumulated a total flight time of about 656 hours in single-engine land airplanes, 541 hours as pilot-in-command, 99 hours dual instruction received, and 31 hours night flight time. The initial logbook entry was dated October 25, 1994, and appeared to correspond to the accident pilot's initial flight lesson. Three entries corresponding to the accident airplane were dated November 6, 2011; November 27, 2011; and November 28, 2011. These entries totaled 5.1 hours. The next and final logbook entry was dated November 27, 2014. According to the entry, this flight was conducted in a Beech V35A airplane. This entry also included a remark, "Flight Review." However, a complete flight review endorsement was not located in the logbook. The logbook did include an endorsement for the operation of high-performance airplanes. With respect to recording flight time, pilots are required to document the flight training and aeronautical experience used to meet the requirements for a rating, certificate, flight review, or recent flight experience as specified by the regulations. (Ref: 14 CFR 61.51) However, pilots are not required to document all flight time. AIRCRAFT INFORMATION The accident airplane was a 1981 Yakovlev Yak-52, serial number 811614. It was a two-place, tandem seating, single-engine airplane, with a retractable tricycle landing gear configuration. The airplane was powered by a 360-horsepower, nine-cylinder Vendeneyev M14P radial engine, serial number KR032039. The accident airplane was issued an FAA experimental category, exhibition airworthiness certificate in May 1993. The accident pilot purchased the airplane in October 2011. According to the airplane maintenance records, the most recent condition inspection was completed on May 1, 2014. At the time of that inspection, the airframe and engine had accumulated 2,661.3 hours and 947.2 hours total time, respectively. The recording hour (Hobbs) meter indicated 1,174.4 hours at that time. No subsequent maintenance entries were recorded in either the airframe or the engine logbook. The recording hour (Hobbs) meter was damaged and a definitive reading could not be obtained. METEOROLOGICAL INFORMATION Weather conditions recorded by the 3K3 Automated Weather Observing System, at 0815, were: wind from 280 degrees at 3 knots, 10 miles visibility, clear sky, temperature 13 degrees Celsius, dew point 11 degrees Celsius, and an altimeter setting of 29.84 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane impacted an open field about 3 miles southeast of 3K3. The fuselage was oriented on an approximate 230-degree magnetic heading. A ground impact mark was located about 21 feet west of the main wreckage. The impact mark was about 31 feet long and up to about 1.75 feet deep. The initial portion of the impact mark was oriented on an approximate 090-degree bearing, while the final portion was oriented about 110-degrees. The outboard portion of the right wing, about 5 feet in length, and the right main wheel assembly were located adjacent to and in the impact mark, respectively. Local authorities reported a small fuel spill at the accident site. A wetted area of ground with a faint fuel odor was observed adjacent to the left wing fuel tank during the on-scene examination. The main wreckage consisted of the remainder of the airplane; specifically, the cowling, engine, propeller, fuselage, remaining portion of the right wing, the entire left wing, and the empennage. The engine cowling was deformed and partially separated. The engine was dislocated aft and to the right, with corresponding damage to the engine mount. The fuselage was deformed along its entire length. The forward and aft cockpit areas were deformed and compromised. The left wing was dislocated relative to the fuselage, but remained attached. The wing exhibited leading edge crushing over the inboard and outboard portions. The inboard portion of the wing spar was bent forward, with corresponding deformation and tearing of the inboard closure rib. The lower-forward spar attachment lug was bent forward and partially separated; appearance of the fracture surface was consistent with overstress failure. The left wing attachment lugs on the fuselage carry-through spar were intact. The wing attachment bolts were securely installed. The left main fuel tank was deformed and breached within the wing structure. The left main landing gear assembly remained attached to the wing and was in the up and locked position when observed during the on-scene examination. The left aileron and flap remained attached to the wing; however, the aileron was dislocated outboard. Aileron control continuity was confirmed to the wing root. The aileron push-pull control tube was separated at the wing root consistent with an overstress failure. The flap push-pull control tube was dislocated inboard. The connecting links between the control tube and flap had separated from the flap, remaining attached to the control tube. The fracture surfaces appeared consistent with overstress failures. The flap connecting rod linkage remained attached to the fuselage actuator and w