HISTORY OF FLIGHT
On August 30, 2009, about 0950 eastern daylight time, a Bond S-9, N463NB, was substantially damaged after an in-flight structural failure near Saylorsburg, Pennsylvania. The experimental, amateur-built airplane was owned and operated by the pilot. The certificated sport pilot was killed. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. The flight originated at Pegasus Air Park, Stroudsburg, Pennsylvania, at 0945.
A friend of the pilot, who also witnessed the accident, reported speaking with the pilot about 0920. The pilot performed his preflight inspection and planned to fly locally for about 40 minutes to perform slow flight and turns at altitude. The friend agreed to communicate via hand-held radio. About 0940, the pilot reported being at 4,000 feet and 70 mph. The pilot made a left clearing turn, then a right turn. During the right turn, the nose dropped and the airplane completed one turn of a spiral or spin. The friend called the pilot, asking what he was doing and telling him to raise the nose. The observer noted the spiral ceased and the nose came up, but not sufficiently. As the nose rose, the friend saw something red and silver separate from the airplane, believed to be the right elevator and a wing strut. The nose dropped again, and the airplane spiraled. As it descended, the friend observed the wing break and instructed the pilot to bail out.
Another witness heard a loud noise and saw a small airplane flying without a wing before it descended and crashed. A third witness walking his dog observed the pilot appear to pull up when the wing came off, then the airplane spiraled down.
PERSONNEL INFORMATION
The pilot held a sport pilot certificate issued July 11, 2006, and an experimental aircraft builder and repairman certificate limited to the S-9. His logbook showed 315.4 total hours, including 4.3 hours in the S-9, through March 15, 2009. A friend indicated the pilot flew about 52 additional hours in the S-9 after that date.
AIRCRAFT INFORMATION
The airplane, serial number 0493121, was originally sold as a kit on May 17, 1993. A spiral notebook chronicled its inspection and building. On March 29, 2005, an inventory of parts was performed. Construction continued from April 1, 2005, until March 5, 2009, when a condition inspection by the pilot passed all items with no defects. A friend who assisted in building recalled the pilot purchased the S-9 about five years earlier, partially assembled. The tail section was assembled, skinned, and painted red. There were 73.8 Hobbs hours on the airplane at the time of the accident. The friend stated neither he nor the pilot performed any welding; they purchased hardware from a vendor.
METEOROLOGICAL INFORMATION
The 0951 weather observation at Allentown, Pennsylvania, 18 nautical miles south, reported sky clear, calm surface winds, 10 statute miles visibility, temperature 22°C, dew point 17°C, and altimeter 29.91 inHg.
WRECKAGE AND IMPACT INFORMATION
An FAA inspector examined the wreckage. The airplane crashed in a residential area. The right elevator was found about 0.25 miles from the fuselage. The left wing had separated at its attachment points and was located 75 to 80 feet from the fuselage. After recovery to a barn, an NTSB senior air safety investigator examined the wreckage on October 8, 2009. The right wing remained attached with impact damage; the right flap and aileron were attached. The left wing separated at the root with overstress features; left flap and aileron remained attached. The propeller, engine, and forward section were intact with little damage. The cockpit was intact with some deformation. The upper empennage was crushed; vertical stabilizer and rudder attached. Left horizontal stabilizer and elevator partially attached; right horizontal stabilizer partially attached but right elevator separated.
MEDICAL AND PATHOLOGICAL INFORMATION
Postmortem examination listed cause of death as massive traumatic injury due to fall from plane. The pilot self-ejected but at low altitude, and the parachute opened but did not effectively slow his descent. He was wearing a National 360 parachute, which was open with the pull cord in his left hand. Forensic toxicology was negative for carbon monoxide and drugs; testing for carbon monoxide and cyanide was not performed.
TESTS AND RESEARCH
Two guy wires from the right horizontal stabilizer and the right elevator outboard hinge were examined at the NTSB Materials Laboratory. Magnified optical examinations of the fractured cable ends revealed yielding and necking or slant fractures consistent with overstress. No progressing cracking or corrosion was found. The elevator hinge, a steel tube welded to adjacent structure, showed fractures through the structure adjacent to the weld with overstress features. Lack of weld fusion was visible in portions of the welds at the ends of the barrel. The NTSB Chief Scientist examined the wreckage and reported all evidence consistent with a static, aerodynamic overload starting in the right elevator due to flight control inputs. No substandard structure or fatigue was found. Bowing of the right stabilizer and elevator indicated a large downward aerodynamic load. The torque from bowing caused fracture and separation of the hinge. The left wing and strut failed in down bending from high negative air loads.