History of Flight
On September 20, 2013, about 1651 eastern daylight time, an experimental amateur-built Vans RV-7A, registration N174BK, was destroyed during an inflight breakup and subsequent impact with terrain near the Township of Hamilton, New Jersey. The private pilot was fatally injured. Visual meteorological conditions prevailed for the local personal flight conducted under 14 CFR Part 91. The aircraft had departed Cross Keys Airport (17N) in Cross Keys, New Jersey, about 1640.
According to radar data from the Federal Aviation Administration (FAA), the airplane departed 17N at approximately 1640 and turned to a magnetic heading of about 120 degrees, climbing to 6,500 feet above mean sea level (msl). About 13 minutes later, the airplane turned right to a southeasterly heading, then rapidly lost altitude while reversing direction before descending through 300 feet msl, where it was lost from radar coverage.
Witnesses reported observing the airplane traveling in a northwesterly direction at low altitude, almost completely upside down at one point, with pieces falling to the ground. The aircraft then impacted in a wooded area, and a fire ensued.
Pilot Information
According to FAA records, the pilot held a private pilot certificate with a rating for airplane single-engine land. His most recent FAA second-class medical certificate was issued on July 11, 2013. He reported about 400 total hours of flight experience, with 85 hours in the previous six months. NTSB records indicate the pilot was involved in a previous accident on November 21, 2007, in which the probable cause was fuel exhaustion due to inadequate fuel consumption calculations. No injuries occurred in that event.
Aircraft Information
The accident airplane was a two-seat, low-wing, tricycle-gear aircraft of conventional metal construction. It was equipped with a Superior Air Parts IO-360-B1AA3 engine (180 horsepower) and a three-bladed constant-speed MT-Propeller. The airplane was not built by the pilot but by a previous owner. At an aerobatic gross weight of 1,600 pounds, it complied with +6/-3G standards for the aerobatic category, with a maximum maneuvering speed of 142 mph (124 knots) and a never-exceed speed of 230 mph (200 knots). The airplane received its special airworthiness certificate on June 6, 2006, and was purchased by the pilot on March 27, 2011. Its most recent conditional inspection was completed on March 15, 2013. After the inspection, the rudder was damaged while tied down, repaired, and returned to service on April 18, 2013. At the time of the accident, the airplane had about 461 total hours of operation.
Meteorological Conditions
The recorded weather at Atlantic City International Airport (ACY), about 6 nautical miles southeast of the accident site, at 1654 included: winds 200 degrees at 9 knots, visibility 10 miles, clear skies, temperature 22°C, dew point 14°C, and an altimeter setting of 30.05 inches of mercury. Visual meteorological conditions prevailed. Upper air data from a high-resolution weather model indicated that at 1700, at the airplane's initial maneuvering altitude of 6,500 feet, winds were 125 degrees at 3 knots, temperature 10°C, and barometric pressure 23.64 inches of mercury.
Wreckage and Impact
The wreckage path was about half a mile long with three distinct debris areas. The first area contained the lower half of the rudder. The second area contained separated pieces including the vertical stabilizer (found in a tree), rudder balance weight, left horizontal stabilizer, left elevator, left wingtip, left elevator balance weight, and cockpit canopy. The third area contained the main wreckage—fuselage, engine, and wings—which remained attached until striking a tree, then fell inverted and was further damaged by a postcrash fire. Examination showed no evidence of inflight fire, explosion, or bird strike. All major components were recovered. Control continuity was established from cockpit flight controls to breaks showing tensile overload, then to the flight control surfaces. Cockpit switches were found in various positions: both magnetos on, alternator/battery master on, APRS on, throttle full forward, propeller control in fine pitch/high rpm, mixture full rich, and wing flaps up. The engine showed no preimpact malfunction; the propeller hub had separated from the crankshaft with a torsional fracture. The propeller blades exhibited leading edge gouging and chordwise scratching. Oil was present, the oil filter showed no debris, and the fuel system contained trace amounts of fuel. The electronic magnetos were fire-damaged. Spark plugs appeared normal except for oil fouling on the No. 4 top plug and fire damage on the No. 4 bottom plug.
Medical and Pathological Information
An autopsy performed by the State of New Jersey, Office of the State Medical Examiner, listed the cause of death as multiple blunt injuries. Toxicological testing by the FAA Bioaeronautical Sciences Research Laboratory was negative for carbon monoxide, cyanide, and basic, acidic, and neutral drugs.
Tests and Research
A radar performance study showed that the airplane flew southeast for 20 nautical miles before entering a steeply descending, accelerating left turn, during which portions of the empennage separated. The airplane continued descending and turning until impact about 20 seconds later. A performance history derived from radar data, airplane characteristics, and atmospheric data indicated that the airplane was flying south at about 6,500 feet and 130 knots indicated airspeed (KCAS) when it entered a nearly inverted attitude, lost about 3,500 feet, accelerated to about 220 KCAS (253 mph), and reversed direction in 10 seconds. Primary radar returns showed pieces beginning to separate at approximately 1651:17, with separation complete by 1651:20. The airplane continued flying northwest while descending, decelerating, and turning south to the accident site. The data indicated the most efficient way to achieve the maneuver was to roll nearly inverted and pull 2.5 Gs.
A trajectory study evaluated two potential breakup scenarios. The first assumed level flight at 6,500 feet and 140 KCAS before the rapid descent. The second assumed a point during the descent at about 4,500 feet, 220 KCAS, and a 48-degree flight path angle. The best fit was obtained with 220 KCAS and a heading of 000 degrees true, indicating the breakup occurred at lower altitude and higher speed. The trajectory study also showed the breakup likely occurred at the lower altitude during a rapid descent and high airspeed, about 220 KCAS, with a tight grouping of calculated initiation points.
A structures study examined the fractured empennage parts. All fractures exhibited static overload characteristics; no fatigue or preexisting damage was found. Damage to the left horizontal stabilizer was consistent with downloading, and damage to the vertical stabilizer and rudder was consistent with loading to the left (looking forward).
Van's Aircraft Service Bulletins SB 14-01-31 (addressing fatigue cracks in the horizontal stabilizer forward spar area) and SB 14-02-05 (addressing cracking near elevator attach points) were reviewed. Examination of the specified areas on the accident airplane revealed no evidence of fatigue cracking or preexisting damage.
Additional Information
An interview with a friend of the pilot revealed that the pilot had flown a Pitts Special a few times with someone who showed him basic aerobatics. The friend stated that the pilot would sometimes fall out of maneuvers (loops and rolls) and had previously recovered from such events at low altitude. The friend noted that it was not uncommon for the pilot to do so and that there was a possibility the pilot may have fallen out of an aerobatic maneuver on the accident flight. A video from a previous flight showed the pilot performing a left roll during which the nose dropped and the airplane lost about 1,000 feet of altitude.