Summerfield, FL, USA
N57DC
MONROE DENNIS RV-7
The private pilot, who was also the owner/builder of the experimental amateur-built airplane, was assisting with the production of a film throughout the afternoon, and the purpose of the accident flight was to record video footage from the air. After departing from the grass runway, the airplane entered a circular left orbit around a tightly clustered group of actors on the ground at an altitude just above the tops of nearby trees. The airplane had completed three circuits, and during the fourth, it appeared to witnesses to be flying slower than it had during the previous circuits. Analysis of video from onboard the airplane, video taken of the airplane from the ground, and witness statements showed that the airplane banked steeply left and began descending toward the ground at a relatively steep angle, consistent with inadvertent entry into an aerodynamic stall. As the airplane descended, the engine power rapidly increased, and the airplane began banking back toward a wings-level attitude as its pitch attitude increased; these actions are consistent with the pilot recognizing and attempting to recover from the stall. The airplane subsequently impacted the ground in a nearly level and slightly nose-down pitch attitude. Signatures observed on the wreckage were indicative of high engine power at impact, and no evidence of any preimpact mechanical malfunctions or failures were observed on the airframe and engine. Examination of damage to the airplane's horizontal stabilizer revealed that it failed from overstress due to ground impact. The majority of the spar cracks and fracture surfaces exhibited features consistent with overstress failure. The other damage features present on the spar section were consistent with ground impact. Although some fatigue cracks were present in the spar sections, the fatigue crack sizes were small, and crack orientations were inconsistent with the stress direction of the overstress portions of the fracture. These cracks were unlikely to have resulted in an in-flight failure of the horizontal stabilizer. Even if the spar had fractured before impact, the remainder of the part was still riveted to adjacent structural components within the stabilizer.
HISTORY OF FLIGHTOn April 6, 2014, at 1936 eastern daylight time, an experimental amateur-built RV-7, N57DC, was substantially damaged when it impacted terrain while maneuvering near Monroe Airpark (2FA2), Summerfield, Florida. The private pilot and the passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Witnesses reported that the pilot had been assisting with the production of a film throughout the afternoon, and that the purpose of the accident flight was to take video footage from the air. After departing from the grass runway, the airplane entered a circular orbit to the left. The airplane had completed three circuits, when during the fourth, it entered a rapid descent and impacted the ground. One of the witnesses described the airplane's final orbit in detail, stating that it seemed to be flying at a slower speed than it had been during the previous pass. He further described that at the beginning of the pass, the airplane was at an altitude just above the tops of the trees surrounding the area, and it gradually descended to about treetop height as the orbit progressed. He diverted his gaze away from the airplane to the actors on the ground and heard the airplane's engine briefly become "quiet" before it suddenly powered back up. He could not recall any of the events that transpired after that point. Another witness described a similar sequence of events concerning the airplane's final orbit. He recalled that the airplane orbited at a speed relatively slower than the previous passes and that the airplane was at an altitude near the tops of the adjacent trees. He estimated that the airplane was in a shallow left bank as it descended below the height of the trees. The engine sound then rapidly changed before it continued in the left turn, descended, and impacted the ground. PERSONNEL INFORMATIONThe pilot held a private pilot certificate with a rating for airplane single engine land. On his most recent application for a Federal Aviation Administration-issued third-class medical certificate, dated August 21, 2013, the pilot reported 4,189 total hours of flight experience. No flight logs for the pilot were recovered. AIRCRAFT INFORMATIONThe pilot owned and was the builder of the accident airplane. The airplane's airworthiness certificate was issued in August 2005. The pilot completed the most recent condition inspection on January 5, 2014, and on that date the airframe had accumulated 322 total hours of operation. Between the condition inspection and the accident, the airframe accumulated 4 additional flight hours. On February 10, 2014, the pilot made an airframe logbook entry noting compliance with two service bulletins (14-01-31 and 14-02-05) issued by the airframe kit manufacturer, and requiring inspections of structure within the horizontal stabilizer and elevator. According to the entry, "Inspected the areas described in the service bulletins. No cracks found." METEOROLOGICAL INFORMATIONThe 1955 weather conditions reported at The Villages (VVG), Florida, located about 9 nautical miles east of the accident site included calm winds, 10 statute miles visibility, a temperature of 26 degrees C, a dew point of 16 degrees C, and an altimeter setting of 29.95 inches of mercury. Sunset occurred at 1950, and the end of civil twilight was 2014. AIRPORT INFORMATIONThe pilot owned and was the builder of the accident airplane. The airplane's airworthiness certificate was issued in August 2005. The pilot completed the most recent condition inspection on January 5, 2014, and on that date the airframe had accumulated 322 total hours of operation. Between the condition inspection and the accident, the airframe accumulated 4 additional flight hours. On February 10, 2014, the pilot made an airframe logbook entry noting compliance with two service bulletins (14-01-31 and 14-02-05) issued by the airframe kit manufacturer, and requiring inspections of structure within the horizontal stabilizer and elevator. According to the entry, "Inspected the areas described in the service bulletins. No cracks found." WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest upright about 10 ft beyond the initial impact point, and both main landing gear had collapsed. The fuselage displayed significant aft crush damage in the area of the firewall, instrument panel, and cockpit. Control continuity was traced from each flight control surface to the cockpit area. The trailing edge of the electrically-actuated elevator trim tab was deflected 1/2-inch downward from the trailing edge of the elevator and the electrically-driven flap actuator was extended 3 inches, which correlated to a flap extension of 16 degrees. Both fuel tanks were ruptured at the wing root and were found absent of fuel. Continuity of the engine's power- and valvetrain were confirmed through rotation of the propeller, and thumb compression was confirmed on all cylinders. Borescope examination of each cylinder showed no evidence of any abnormal wear or combustion deposits. Each spark plug electrode appeared gray in color and displayed normal wear. Rotation of each magneto's input shaft produced spark at all terminal leads. All four fuel injector nozzles were absent of any obstructions. Disassembly of the fuel system components revealed the presence of fluid consistent in color and odor with 100LL aviation fuel in the fuel lines between the firewall, engine driven fuel pump, and fuel servo, as well as in the fuel distributor valve. Trace carbon deposits were found in the oil suction screen; however, both the suction screen and oil filter were absent of any metallic debris. Both propeller blades displayed s-bending, chord-wise scratching, and burnishing of the blade surface. A damaged section of the airplane's horizontal stabilizer spar was submitted to the NTSB Materials laboratory for further examination. The horizontal stabilizer front spar had fractured on the left side, perpendicular to the orientation of the part. The fracture was located along four rivet holes in the spar, all of which exhibited elongation in the part direction. There was also an "L-shaped" crack on the right side of the assembly, approximately 0.25 inches-long, which had terminated at a rivet hole. There was out-of-plane buckling on the spar outboard of the fracture and a crack on the spar section. This buckling was located at two tears on the lower portion of the right side of spar. This was consistent with damage incurred to the part at ground impact. No indications of wear or corrosion were observed on the spar section. Small portions of the fracture and crack exhibited features consistent with progressive cracking. These thumbnail-shaped areas were generally flat perpendicular to the part direction, and they exhibited crack arrest and ratchet marks. The progressive portion of the right side crack was approximately 0.15 inch-long, and the progressive portion of the left side fracture was approximately 0.25 inch-long. The remaining portions of the fracture and crack exhibited a rougher texture and a general 45-degree slant. These features were consistent with overstress failure. The fractures were examined using a scanning electron microscope. The remainder of the fracture surface exhibited dimple rupture, consistent with failure from overstress. The thumbnail portion of the opened crack also exhibited fatigue striations. The chemical compositions of the part sections were inspected using energy dispersive x-ray spectroscopy and x-ray fluorescence. The chemical compositions were consistent with AA 2024 aluminum alloy. ADDITIONAL INFORMATIONOnboard and Ground Video Recordings A digital video camera and its associated memory cards recovered from the wreckage, along with video and image files recovered from a video camera operated by a ground observer, were forwarded to the NTSB Vehicles Recorder Division for detailed examination. Video and image files were recovered from the onboard camera using normal and forensic methods. The timestamps associated with the creation of the files from both the onboard and ground-based cameras were correlated to local time. An onboard recording began at 1933:09, and showed that the camera operator was seated in the right seat of the airplane, with the camera pointed outside of the airplane through the left rear of its transparent canopy. During the recording, the airplane began its takeoff roll as engine power was increased to a high setting. As airplane rolled down the turf runway, a ground-based recording began and briefly showed the airplane as it became airborne. As the onboard recording continued, the airplane entered a gradual left turn, with the camera positioned to capture events on the ground. At 1933:53, the airplane's wings leveled briefly, and the engine reduced to a lower power setting. About 1934, the airplane re-entered the left banked turn and a group of actors on the ground came into view. About that time, another ground-based recording began showing the airplane in its gradual left bank turn, circling the group of actors. The ground and onboard recordings continued through several starts and stops and throughout showed the airplane in a left bank, slightly nose high pitch attitude. Between 1935:56 and 1936:07, neither the ground nor the onboard camera was recording. At 1936:07, the forensically-recovered onboard video recording began, and initially showed the airplane in a left bank, that returned to a wings level attitude, before returning to the left bank as the camera became trained on a tightly-clustered group of actors on the ground. At 1936:18, the camera's motion became erratic, exhibiting an up and down shaking motion, and about that time, several muffled thumping sounds were present in the background. At 1936:19, the engine sound began changing, slightly decreasing before rapidly advancing toward a maximum over the course of about 2 seconds. Throughout this portion of the recording, the motion of the camera was suggestive that the airplane's flight attitude had become unstable. Through the end of the onboard recording at 1936:22, the camera's motion was erratic, as ground features in the camera's field of view moved upward toward the top of the frame. During this time, the camera never panned forward and did not capture any portion of the cockpit. The movement of the ground features relative to the camera's largely unchanged field of view out of the left rear of the airplane was suggestive that the airplane had rapidly rolled into a steep left bank. Immediately prior to the end of the video a voice exclaimed an expletive phrase. Between 1936:22 and 1936:25, no video was captured. A ground recording began at 1936:25 and captured the final 2 seconds of the flight, and depicted the airplane as it descended toward ground impact. The engine sound from the beginning of the recording through impact was smooth and continuous. Seven frames of this video were extracted and analyzed to determine the airplane's approximate bank and pitch angles for those final moments of the flight. The airplane initially appeared to be in a near 20-degree nose down pitch attitude, with a near 90-degree left wing down bank attitude. The flight path of the airplane steepened until the angle of bank began to decrease, for the first three frames examined. During the final 4 frames, the airplane's flight path angle decreased as the angle of attack increased from an initially calculated value of 5 degrees. The airplane's calculated angle of attack at the time of ground impact had increased 13 degrees, with a nearly wings-level bank attitude. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy was performed on the pilot by the District 5 Medical Examiner's Office, Leesburg, Florida. The medical examiner determined that the cause of death was multiple blunt force injuries. Toxicology testing performed by the FAA's Civil Aerospace Medical Institute found no trace of carbon monoxide or ethanol present in the samples submitted for the pilot. Salicylate (the metabolite of asprin) was detected in samples of urine submitted in a concentration of 105.9 ug/ml.
The pilot's failure to maintain airplane control while maneuvering at a low airspeed, which resulted in an aerodynamic stall, and his decision to maneuver at an altitude that did not allow an adequate margin to recover from a stall.
Source: NTSB Aviation Accident Database
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