N174BK

HISTORY OF FLIGHTOn September 20, 2013, about 1651 eastern daylight time, an experimental amateur built Vans RV-7A, N174BK, was destroyed during an inflight breakup and impact with terrain after a rapid loss of altitude and increase in airspeed near the Township of Hamilton, New Jersey. The private pilot was fatally injured. Visual meteorological conditions prevailed for the local personal flight conducted under Title 14 Code of Federal Regulations (CFR) Part 91, which departed Cross Keys Airport (17N), Cross Keys, New Jersey about 1640.

According to radar data provided by the Federal Aviation Administration (FAA), the airplane departed 17N at approximately 1640. Turn to an approximate magnetic heading of 120 degrees and climb to an altitude of 6,500 feet above mean sea level (msl). Approximately 13 minutes later, the airplane turned right to a southeasterly heading. It then rapidly lost altitude while reversing direction before descending through 300 feet msl where it was lost from radar as it descended below the floor of radar coverage.

According to witnesses, moments later the airplane was observed traveling in a northwesterly direction at low altitude, almost completely upside down at one point, and "pieces" of the airplane were observed falling to the ground. It then impacted in a wooded area and a fire ensued

PERSONNEL INFORMATION

According to NTSB records, the pilot had been involved in a previous accident in the Township of Hamilton, New Jersey (NYC08CA042) on November 21, 2007, while flying a Cessna 172N, N172MG when the engine sputtered while in cruise flight and stopped producing power. The pilot then performed a forced landing to trees, resulting in substantial damage. Neither he nor his two passengers were injured. Examination of the fuel tanks by a FAA inspector revealed they were intact, and no evidence of fuel, fuel spillage, or fuel odor was identified at the scene. The pilot stated that he departed his home airport with full tanks earlier in the day and recorded 3.2 hours on the Hobbs meter. Several stops were made during the day, which involved six takeoffs and climbs to altitude. The Safety Board determined that the probable cause of that accident was the pilot's inadequate fuel consumption calculations which resulted in fuel exhaustion.

According to FAA records, the pilot held a private pilot certificate with ratings for airplane single-engine land. His most recent FAA second-class medical certificate was issued on July 11, 2013. He reported that he had accrued approximately 400 hours of total flight experience on that date, 85 hours of which was in the previous six months.

AIRCRAFT INFORMATION

The accident aircraft was a tricycle landing gear equipped, two seat, low wing airplane of conventional metal construction. It was equipped with a Superior Air Parts IO-360-B1AA3, horizontally opposed, 4-cylinder, air cooled engine which produced 180 horsepower, and a MTV-A5-B, three bladed constant speed MT-Propeller.

The airplane had not been built by the pilot but had been built by a previous owner.

At an aerobatic gross weight of 1,600 pounds, the airplane complied with the +6/-3G standards of the FAA's aerobatic category. It had a maximum maneuvering speed of 142 mph (124 knots), and a never exceed speed of 230 mph (200 knots).

The maximum maneuvering speed of 142 mph (124 knots) was the maximum permissible speed at which full and abrupt control inputs could be applied. Any speed in excess of the maximum maneuvering speed with full control application could result in G-loads in excess of design limits.

The never exceed speed of 230 mph (200 knots) was the maximum permissible speed under any condition. Any speed in excess of this could result in structural damage. Full control application at the never exceed speed would produce a load of approximately +15.0 G.

According to FAA and maintenance records, the airplane had received its special airworthiness certificate on June 6, 2006. The airplane was purchased by the pilot on March 27, 2011.

The airplane's most recent conditional inspection was completed on March 15, 2013. Shortly afterwards, the rudder on the airplane was damaged while the airplane was tied down on a parking ramp when the rudder came into contact with a rudder stop which punctured the right lower, side of the rudder. The damaged rudder was removed by the owner and reskinned in accordance with FAA Advisory Circular 43.13-1B and Van's Aircraft design drawings, and was returned to service on April 18, 2013.

At the time of the accident, the airplane had accrued approximately 461 total hours of operation.

METEOROLOGICAL INFORMATION

The recorded weather at Atlantic City International Airport (ACY), Atlantic City, New Jersey, located approximately 6 nautical miles southeast of the accident site, at 1654, included: winds 200 degrees at 9 knots, visibility 10 miles; clear skies, temperature 22 degrees C, dew point 14 degrees C, and an altimeter setting of 30.05 inches of mercury.

Visual meteorological conditions prevailed along the route of flight and atmospheric data for use in determining the upper air profile in the area of the accident site was gathered on behalf of the NTSB by the United States Army Aberdeen Test Center from a high resolution weather forecast model (4DWx), developed by the National Center for Atmospheric Research (NCAR) that the Army Test and Evaluation Center (ATEC) Meteorology Teams use on a daily basis.

The model continuously merges data gathered from the Army's ranges as well as from sources such as FAA aircraft reports, air traffic control radar, satellites, National Weather Service weather radar, and upper-air and surface observations. Since data continues to be assimilated, when a new forecast is being developed, 4DWx "compares" its previous forecast with the observations and adjusts or "nudges" its forecast towards the observations. So, although the data provided by the program was model data, it included observations to produce and interpolate the upper air profile over a given point.

This data was generated from an altitude of 10,504 feet msl down to 66 feet msl at a point above the geographic location of the accident site. This data along with recorded radar data, and airplane characteristics, was later used to develop an airplane performance history for the accident and indicated that at 1700, at the airplanes initial maneuvering altitude of 6,500 feet, the weather conditions included: winds 125 degrees at 3 knots, temperature 10 degrees C, and a barometric pressure of 23.64 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

Examination of the wreckage path revealed that it was approximately 1/2 mile long and contained three distinct areas of debris.

The first area contained the lower half of the rudder.

The second area contained numerous pieces all of which were separated from their mounting locations. This included the vertical stabilizer (which was found in the top of a tree), the rudder balance weight, the left horizontal stabilizer, the left elevator, the left wingtip, the left elevator balance weight, and the cockpit canopy.

The third area contained the main wreckage (the fuselage, engine, and wings), which had remained attached to each other until striking the top of a tree, falling to the forest floor and coming to rest inverted, where they were further damaged by exposure to a postcrash fire.

Examination of the debris fields and main wreckage revealed no evidence of an inflight fire, explosion, or bird strike, and all of the major components of the airplane were recovered.

After collection and examination of the flight control system components, control continuity was established from the flight controls in the cockpit to the breaks in the system which displayed evidence of tensile overload and from the breaks in the system to the flight control surfaces.

Examination of the cockpit revealed that both magneto switches were in the on position, the alternator/battery master switch was on, the Automatic Packet Reporting System (APRS) Switch was on, the throttle was full forward, the propeller control was in the fine pitch/high rpm position, the mixture was full rich, and the wing flaps were in the up (zero degree) position.

Examination of the engine did not reveal any evidence of any preimpact malfunction or failure. The propeller hub had separated from the crankshaft during the impact sequence and the face of the fracture on the crankshaft flange displayed a 45-degree cupped shear lip and evidence of torsional rotation.

One propeller blade had remained attached to the hub, and the other had separated from its mounting location. Both propeller blades displayed leading edge gouging and chordwise scratching, and the separated blade also displayed S-bending. The propeller governor was impact damaged but remained attached to the engine.

Drive train continuity was established from the back of the engine to the front of the engine, and all of the valves were observed to be functional.

Oil was present in the rocker boxes and in the galleries of the engine. The oil pump displayed impact damage but could be operated by hand. Examination of the inside of the oil filter revealed no evidence of debris.

The engine driven fuel pump was functional and the fuel manifold valve contained trace amounts of fuel. The throttle body injector was intact, its throat was unobstructed, and the diaphragm assembly was undamaged.

The electronic magnetos were still attached to the engine however they were fire damaged and were unable to be operated. The electrodes on all of the spark plugs were intact, and appeared normal and gray in color with the exception of the No. 4 cylinder's top spark plug which was oil fouled and the No. 4 cylinder's bottom sparkplug which was fire damaged.

The fractured pieces of the empennage and aft fuselage were examined on scene without any evidence of prebreakup or preexisting damage being discovered. They were l...