Toughkenamon, PA, USA
N83547
AERONCA 7AC
The student pilot and flight instructor were practicing takeoffs and landings on grass next to a runway. The pilot reported that, on the downwind leg of the traffic pattern, the instructor directed the student to demonstrate a simulated engine failure, followed by a go-around. When the airplane was about one-quarter of the way down the parallel runway, he told the student to go around. Shortly later, the engine “sputtered” and then lost all power. While attempting to maneuver the airplane during the subsequent forced landing attempt, the airplane struck a hanger. The airplane was substantially damaged, and the student and instructor sustained minor injuries. Following the accident, the student reported that, when he attempted to put the carburetor heat back in, it was possible that he inadvertently closed the fuel shutoff valve. Postaccident examination and a test run of the engine revealed no evidence of any preaccident mechanical failures or malfunctions that would have precluded normal operation. Given this information, it is likely that the loss of engine power was the result of the student pilot’s inadvertent actuation of the fuel shutoff valve instead of the carburetor heat. Postaccident examination of the airplane further revealed that the fuel shutoff valve assembly was missing a grommet. When installed, the grommet provided support to the fuel shutoff rod and resistance to motion. Additionally, the aperture in which the grommet was typically installed was elongated. Examination of the universal joints attached to the fuel shutoff lever and valve revealed that they were worn and moved easily. All these factors resulted in the fuel shutoff lever being allowed to move easily. The airplane’s most recent annual inspection was completed about 3 months before the accident, during which maintenance personnel should have noted the discrepancies with the fuel shutoff system. Additionally, the airplane was not equipped with an optional fuel shutoff valve guard. Had these discrepancies been rectified, and had the optional guard been installed, it is possible that the student pilot might not have inadvertently activated the fuel shutoff valve. The airplane had originally only been equipped with lap belts; however, shoulder harnesses were found installed on both the front and rear seats. The investigation could not determine who manufactured the shoulder harness assembly because it resembled many previously and currently manufactured aftermarket shoulder harness assemblies, and it had no part or serial numbers on it. Review of the airplane’s maintenance records did not reveal when or by whom the shoulder harness assemblies had been installed on the airplane. During the impact sequence, the rear seat shoulder harness assembly pulled loose from its mounting location. Examination of the rear seat shoulder harness assembly revealed that it was not bolted, fastened, or positively secured to the airplane’s tubular structure but was instead clamped over two, 5/8-inch-diameter tubes with upper and lower triangular attachment brackets just forward of where the tubes intersected with the top longeron. Examination of the attachment brackets revealed that, during the impact sequence, the bracket assembly likely either mechanically pulled or slid over the airplane’s structural tubing. It was noted that the back seat occupant was more seriously injured than the front seat occupant, whose shoulder harness did not separate from the structure. On the basis of this evidence, it is likely that the detachment of the rear shoulder harness assembly contributed to the instructor’s injuries because it allowed him to strike the front seatback and his control stick.
On June 1, 2016, about 0854 eastern daylight time, an Aeronca 7AC, N83547, was substantially damaged when it was involved in an accident near Toughkenamon, Pennsylvania. The student pilot and flight instructor sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The student and instructor were conducting takeoffs and landings on grass next to a runway at New Garden Airport (N57), Toughkenamon, Pennsylvania. According to the student, on the downwind leg of the traffic pattern, the instructor directed him to demonstrate a simulated engine failure, followed by a go-around. He then proceeded to conduct the power-off landing. He made a steep turn to base and then a steeper turn to the final approach leg of the traffic pattern. When the airplane was still above the grass and about one-quarter of the way down the parallel runway, the student initiated the go-around and the instructor told him to move the airplane over to above the center of the runway. At this point, the engine “sputtered” and then lost all power. According to the instructor, after the engine lost power when the airplane was about 200 ft above the ground, he began to consider landing options and decided not to continue forward due to many obstacles ahead and subsequently took the controls and turned the airplane left 90°, positioning it over a hangar for a touchdown and rollout on the grass in an uphill direction to dissipate speed and energy. However, as the turn progressed, he realized that the airplane would likely not clear the top of the hangar because it was quickly losing altitude. He pulled the airplane up into a 45° nose-up position so that the engine would penetrate the metal door of the hangar before the fuselage. Subsequently, the airplane penetrated the hangar wall and then came to rest inside the hangar. Although the instructor reported that he checked the magnetos, carburetor heat, and fuel shutoff valve after the loss of engine power and that all appeared to be in their proper positions. The student reported that, when he attempted to put the carburetor heat control back in, it was possible that he closed the fuel shutoff valve instead. The airplane was constructed of welded tubing and a fabric-covered fuselage. The fuel tank was located behind the firewall, which gravity fed the fuel from the fuel tank to a gascolator and then to the carburetor. A float-type fuel gauge was located directly on top of the fuel tank, and the fuel shutoff valve, ignition switch, and carburetor heat control were located on the engine control panel. The accident airplane was not equipped with an optional fuel shutoff valve handle guard. The airplane's most recent annual inspection was completed on March 8, 2016. At the time of the inspection, the airplane had accrued approximately 6,410 total hours of operation. Postaccident examination of the airplane revealed that its fabric covering exhibited multiple tears and punctures. The left main landing gear (MLG) was displaced aft and was collapsed, and the right MLG was displaced forward and was collapsed. Both the left and right wing spars were broken, and the wings had folded aft. The horizontal stabilizers, elevators, vertical stabilizer, and rudder exhibited crushing and compression damage. Flight control continuity was established. The front of the propeller spinner was crushed. One propeller blade was bent back under the engine, and the other blade was straight. Neither propeller blade showed any evidence of S-bending, leading edge gouging, or chordwise scratching. During examination of the engine, the air filter was found clean, the spark plugs appeared normal, the carburetor venturi was found clear, and clean and bright fuel consistent with 100LL aviation gasoline was found in the fuel system. Oil was found in the engine. The engine was test run with no anomalies noted. The examination and test run revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. The engine control panel was missing a grommet, which when installed, provided support to the fuel shutoff rod and resistance to movement. The aperture in which the grommet was typically installed was elongated. The fuel shutoff rod was loose and could be moved easily. The universal joint to which the fuel shutoff rod connected was worn and could be moved easily. The airplane seats were composed primarily of tubing with each seat having both a seat bottom cushion and seat back cushion installed. The seats had originally only been equipped with lap belts; however, at some time afterward, a set of shoulder harnesses had been installed on both the front and rear seats, converting the restraint system into a 4-point design. Review of the airplane’s maintenance records did not reveal when or by whom the shoulder harness assemblies had been installed. Examination of the shoulder harness assemblies revealed that, during the impact sequence, the front seat shoulder harness assembly functioned as designed but that the rear seat shoulder harness assembly had pulled loose from its mounting location, which resulted in the instructor sustaining minor injuries when he struck the front seatback and the control stick. Examination of the front seat shoulder harness assembly revealed that it was secured to the rear spar carry-through with bolts, which passed through a metal reinforcing channel. However, examination of the rear seat shoulder harness assembly revealed that it was not bolted, fastened, or positively secured to the airplane’s tubular structure but that it was instead clamped over two, 5/8-inch-diameter tubes with upper and lower triangular attachment brackets. Examination of the rear seat shoulder harness attachment brackets revealed that the upper attachment bracket exhibited permanent bending deformation of the flat (planar) portion of the bracket from its original shape, and yellow paint transfer marks from the tubing were observed along the edges of the upper and lower attachment brackets’ interior surface. The bending deformation and transfer marks were both consistent with the installed bracket assembly being mechanically pulled or sliding over the structural tubes. The investigation could not determine who manufactured the shoulder harness assembly because it resembled many previously and currently manufactured aftermarket shoulder harness assemblies, and it had no part or serial numbers on it.
The student pilot’s inadvertent actuation of the fuel shutoff valve, which led to a total loss of engine power, forced landing, and impact with a hangar. Contributing to the outcome was maintenance personnel’s inadequate inspection of the fuel shutoff system during the most recent annual inspection. Contributing to the flight instructor’s injuries was the detachment of the rear seat shoulder harness assembly.
Source: NTSB Aviation Accident Database
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