Benton, PA, USA
N668CL
Z-HI-MAX 1400
The pilot, who was flying the airplane for the first time, intended to takeoff and perform a teardrop turn, then land on the reciprocal runway. After starting the engine, he taxied to the end of the runway where he paused for some time before takeoff. During the initial climb, about 100 ft above ground level (agl), the airplane made a slow right turn, followed by a left turn that “just kept getting steeper” before the airplane descended and impacted the ground. The pilot did not recall most of the details of the flight; however, he did recall that at some point, the engine ran roughly and then lost power. Several witnesses reported that the engine sounded normal; however, one reported that the engine had briefly “missed” twice during takeoff. One witness reported hearing the engine RPM increase at the time of impact, suggesting that the engine was running at that time. Although a postaccident examination of the engine did not reveal any anomalies that would have precluded normal operation, a review of weather records and a carburetor icing probability chart indicated the potential for serious icing at glide power. While carburetor icing is generally considered to be less likely a factor during takeoff power, the pilot’s pause (presumably at a low power setting) at the end of the runway before departure may have allowed ice to accumulate. Therefore, carburetor icing could not be ruled out as a possible contributing factor. However, based on the pilot’s recollection and the witness’ statements, the investigation was unable to determine if or when a loss of engine power occurred. Based on the witness’ description of the flight, the pilot lost control of the airplane while turning back toward the airport at a relatively low altitude. The wreckage path was confined to an area of about one wingspan, suggesting a near vertical flightpath angle. Given that the turn occurred about 100 ft agl, it is possible that the airplane was also at a relatively slow airspeed when the turn, loss of control, and subsequent aerodynamic stall occurred. Family members described the airplane’s handling characteristics as quick to roll into turns, and slow to roll out of them. A low airspeed may have exacerbated the pilot’s ability to level the wings after initiating the turn.
On October 16, 2021, at 0830 eastern daylight time, an experimental, amateur-built Z-HI-MAX 1400 airplane, N668CL, was substantially damaged when it was involved in an accident near Benton, Pennsylvania. The pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Family members reported that the accident flight was the pilot’s first flight in the airplane. He planned to perform a takeoff, teardrop turn and return to the reciprocal runway. The pilot performed a preflight inspection, started the airplane, and taxied to the runway where he performed an engine run-up and remained for “a while,” according to the pilot’s brother who witnessed the takeoff and subsequent accident sequence. The takeoff and initial climb appeared normal. When the airplane reached about 100 ft agl, it began a slow bank to the right, followed by a bank to the left, which “just kept getting steeper.” The airplane then descended to the ground. One witness reported hearing the engine rpm increase at the time of the impact. Another witness reported that although he heard two “momentary misses” from the engine during takeoff, “the engine was running normally and developing power throughout.” The pilot had limited recollection of accident. He stated that at some time during the flight, the engine “develop(ed) a roughness that occurred twice before it lost power.” He stated that a carburetor heat check is normally performed during engine run-up; however, he did not have any recollection of that portion of the accident flight. The pilot’s brother reported that during previous flights, the airplane was “quick” to roll into turns, and “slow” to roll out of them. He further stated that during stalls, the airplane did not “break” but rather would “mush into a buffet.” Photographs of the accident site provided by a Federal Aviation Administration inspector showed the wreckage was confined to a small area, about the diameter of the airplane’s wingspan, with no ground scars leading to the main wreckage. A subsequent examination of the engine revealed no anomalies that would have precluded normal operation. The 0854 weather conditions reported at Williamsport Regional Airport (IPT), Williamsport, Pennsylvania, located about 24 miles west of the accident site at an elevation of 528 ft msl, included a temperature of 21°C (70° F) and a dew point of 17°C (63° F). Review of a carburetor icing probability chart revealed the potential for serious icing at glide and cruise power.
The pilot’s loss of control and encounter with an aerodynamic stall during a planned low-altitude turn toward the airport after takeoff.
Source: NTSB Aviation Accident Database
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