NTSB Factual Report

On March 30, 1997, at 1520 eastern standard time, a homebuilt airplane, N4424V, was substantially damaged when it struck the ground during a descending spin, about 1 mile east of a private airstrip in Perry Township, Pennsylvania. The certificate commercial pilot and passenger were fatally injured. Visual meteorological conditions prevailed for the personal flight that originated at the private strip, about 1500. No flight plan had been filed for the local flight conducted under 14 CFR Part 91.

According to a witness, he observed the pilot perform takeoffs and landings at the private strip, prior to the accident flight. After the last landing, the pilot appeared to refuel the airplane, and then departed with a passenger. About 20 minutes later, the witness heard an airplane's engine "power up," and turned to observe the airplane in a descending spin, about 2,000 feet above the ground. After about two to three spins, the engine sound decreased, and the airplane continued to spin until it struck the ground.

Another witness outside of his home stated that he heard an airplane flying over. When he heard a "sharp snap," he looked in the direction of the airplane. He estimated that the airplane was about 1,500 to 2,500 feet above the ground, and descending in a wide, "swirling" motion, counter clockwise. The airplane came to rest about 2,000 feet from his residence.

According to a Federal Aviation Administration (FAA) Inspector's report, examination of the airplane's engine revealed clean spark plugs, and compression in both cylinders when the propeller was rotated. Fuel was observed in the fuel tank and both carburetors. The carburetor fuel filter inlet screens were absent of debris. Examination of the fuselage revealed control continuity from the pilot's controls to the airplane's rudder, elevator, and ailerons. The right rear jury strut was found "broken" from the rear spar attaching point, with the jury base plate still intact.

The FAA Inspector's report also stated:

"It was discovered that the two self locking nuts and bolts holding the base plate to the spar were only finger tight. Further inspection revealed no threads in the plastic feature of the self locking nuts. The fabric cover surrounding the hole was worn and tattered."

In a written statement and during an interview, the owner of the airplane stated that he had purchased the airplane in Florida, during July, 1995. The airplane had not been flown, although the construction had been completed. The wings were not installed on the airplane when he purchased it, but strapped in saddles on the inside of the airplane's trailer. He then drove the trailer to Pennsylvania, where he and the accident pilot installed the wings. During the previous year, the airplane had undergone about 40 hours of flight testing, by the accident pilot and the owner.

In a written statement, the owner stated that during the assembly in Pennsylvania, the airplane had been examined by a FAA Inspector. The owner stated, "...the FAA made the first inspection and gave us more suggestions to make the plane safer and to comply with regulations, such as safety wiring the rigging and installing placards..."

The owner also stated that after the 40 hours of required flight testing, the airplane was due for an annual inspection, which was accomplished by a FAA certificated airframe and powerplant mechanic, at the Deck Airport, Myerstown, Pennsylvania. At the completion of the annual inspection, the airplane received its final inspection by the FAA Inspector, who issued the airworthiness certificate. About 4 to 5 flight hours after the inspection, the accident occurred.

The owner further stated that during the inspections, covers had been removed from the inspections holes on the bottom of the wings, and that:

"...I don't think the connection for the jury struts are visible from the inspection holes. Also, when the wings are mounted on the plane, it seems like the weight of the wing combined with the interconnection of the struts would put forces on the struts that would make it seem like all the strut connections were tight. From what the FAA Inspectors showed me, after the crash, it looks like the connections for the jury strut inside the wing was never tightened..."

A letter from an aviation consultant that examined the wreckage stated:

"Reviewing the wreckage of the Super Koala, N4424V, it was very evident to see that the wood parts had not been properly glued. There were many areas where the sanding marks were not even covered with glue, as well as, areas where the glue had been spread, but allowed to dry too much before clamping or insufficient glue to penetrate both surfaces of the wood parts..."

Toxicology testing was conducted on the pilot by the FAA Toxicology and Accident Research Laboratory, Oklahoma City, Oklahoma.

An autopsy was performed on the pilot by Malcolm L. Cowen, M.D., forensic Pathologist, for the Lehigh County Coroner's Office, Allentown, Pennsylvania, on March 31, 1997.

NTSB Probable Cause

improper construction by the builder which led to the failure of the strut and wing assembly.