Accident Overview
On April 6, 2014, at 1936 eastern daylight time, an experimental amateur-built RV-7, registration N57DC, was substantially damaged when it impacted terrain while maneuvering near Monroe Airpark (2FA2) in 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, which was conducted under Part 91.
Witness Reports
Witnesses reported that the pilot had been assisting with a film production throughout the afternoon, and the purpose of the accident flight was to take aerial video footage. After departing from the grass runway, the airplane entered a circular orbit to the left. After completing three circuits, during the fourth orbit, it entered a rapid descent and impacted the ground.
One witness described the final orbit in detail, noting the airplane seemed to fly at a slower speed than previous passes. It began at an altitude just above treetops and gradually descended to about treetop height. The witness diverted his gaze to actors on the ground and heard the engine briefly become "quiet" before suddenly powering back up. Another witness recalled a similar sequence: slower speed, altitude near treetops, shallow left bank descent below treetops, then an abrupt change in engine sound before impact.
Aircraft Information
The pilot owned and built the airplane. Its airworthiness certificate was issued in August 2005. The most recent condition inspection was completed on January 5, 2014, at which time the airframe had 322 total hours of operation; an additional 4 hours were flown before the accident. On February 10, 2014, the pilot made a logbook entry noting compliance with two service bulletins (14-01-31 and 14-02-05) requiring inspections of structure within the horizontal stabilizer and elevator; the entry stated, "Inspected the areas described in the service bulletins. No cracks found."
Wreckage Examination
The airplane came to rest upright about 10 ft beyond the initial impact point, with both main landing gear collapsed. The fuselage had significant aft crush damage at the firewall, instrument panel, and cockpit. Control continuity was established from each flight control surface to the cockpit. The trailing edge of the electrically-actuated elevator trim tab was deflected 1/2-inch downward, and the electrically-driven flap actuator was extended 3 inches, correlating to a flap extension of 16 degrees. Both fuel tanks were ruptured at the wing root and contained no fuel.
Engine continuity was confirmed by rotating the propeller; thumb compression was obtained on all cylinders. Borescope inspection showed no abnormal wear or combustion deposits. Spark plugs appeared gray with normal wear. Magnetos produced spark at all leads. Fuel injector nozzles were unobstructed, and fuel lines contained fluid consistent with 100LL aviation fuel. Trace carbon deposits were found in the oil suction screen, but no metallic debris was present. Both propeller blades exhibited s-bending, chord-wise scratching, and burnishing.
A damaged section of the horizontal stabilizer front spar was examined. The left side had fractured perpendicular to the part orientation along four rivet holes, all showing elongation. An L-shaped crack about 0.25 inches long was found on the right side, terminating at a rivet hole. Out-of-plane buckling was present on the spar outboard of the fracture, consistent with ground impact damage. No wear or corrosion was observed. Small portions of the fracture and crack exhibited progressive cracking features (thumbnail-shaped, flat, with crack arrest and ratchet marks). The progressive portion on the left side was about 0.25 inches long; on the right side, about 0.15 inches. The remaining fracture areas showed 45-degree slant features consistent with overstress failure. SEM revealed fatigue striations in the thumbnail portions and dimple rupture in the overstress areas. Chemical composition matched AA 2024 aluminum alloy.
Video Analysis
Video from an onboard camera and ground-based cameras was examined. The onboard recording began at 1933:09, showing the takeoff roll and a left turn. The airplane entered a left banked orbit around actors on the ground. At 1936:07, the forensically recovered onboard video showed the airplane in a left bank leveling briefly then returning to left bank. At 1936:18, camera motion became erratic with muffled thumping sounds; the engine sound decreased then rapidly advanced to maximum over 2 seconds. The camera's motion indicated unstable flight attitude. At 1936:22, a voice exclaimed an expletive. A ground recording from 1936:25 captured the descent; analysis of seven frames showed the airplane initially at a near 20-degree nose-down pitch and near 90-degree left bank, then the bank decreased and angle of attack increased from 5 degrees to 13 degrees at impact, with nearly wings-level attitude.
Medical and Toxicological Findings
An autopsy determined the cause of death as multiple blunt force injuries. Toxicology testing by the FAA's Civil Aerospace Medical Institute found no carbon monoxide or ethanol. Salicylate (a metabolite of aspirin) was detected in urine at a concentration of 105.9 ug/ml.