N769R

HISTORY OF FLIGHT

On September 14, 2007, at 1030 mountain daylight time, a special light sport airplane (S-LSA) Skykits Savannah ADV airplane, N769R, came to rest inverted after landing at Lava Hot Springs Airport (00E), Lava Hot Springs, Idaho. The pilot/owner operated the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The airplane sustained substantial damage. The private pilot and one passenger (a safety pilot) were not injured. Visual meteorological conditions prevailed for the local area flight that departed about 1012. No flight plan had been filed.

In a written report, the pilot stated that he had recently obtained certification as a light sport instructor. He reported that the purpose of the flight was to become proficient with crosswind landings while flying in the right front seat. He reported that there were no toe brakes installed on the right side of the airplane, so a safety pilot seated in the left seat would assist with braking. The first takeoff and landing occurred without incident. The pilot noted that there was a moderate, variable crosswind with bumpy conditions, so he was landing and taking off at a speed about 5 knots faster than he would have if there were calm wind conditions. During the flare for the second landing, there was ground level turbulence, and the airplane floated. The pilot stated that the nose of the airplane unexpectedly dipped and the nose gear hit the ground and collapsed. The nose of the airplane contacted the ground and the airplane nosed over, resulting in structural damage to the fuselage.

The pilot and a Federal Aviation Administration (FAA) investigator inspected the airplane and noted a broken trim control rod in the horizontal stabilizer.

The pilot stated that the airplane is to be trimmed with "a significant nose-high attitude" during landing. A representative from Skykits Corporation provided a typed copy of text from the section titled "Normal Landing," (pages 7-16), of the Pilot's Information Handbook for the accident airplane type. The following is stated in the description of a normal approach and landing: "…At approximately 500 feet altitude above the ground, apply 20 degrees of flap, full up trim, and slow to 50 mph IAS..."

The representative also noted that the accident pilot had received 5 hours of flight familiarization from the manufacturer when the airplane was purchased.

TESTS AND RESEARCH

The elevator trim aft control rod and elevator and horizontal stabilizer tip fairings were examined by a National Transportation Safety Board metallurgist. The FAA inspector provided a picture of the trim assembly taken after the airplane was recovered from the runway to a hangar, still in an inverted position. The metallurgist reported that based on a provided manufacturer’s illustration, the positions of the pivot plate and hinge point indicated that the airplane was in a full nose down trim position in the picture.

The metallurgist examined the control rod and noted that it was fractured about 1.5 inches from the aft end fitting centerline. The bearing in the end fittings moved freely, and the rod had local downward bending deformation at the fracture location, consistent with overstress fracture under compression loading.

The metallurgist observed circumferential scoring marks on the rod surface aft of the fracture location, but they did not intersect the fracture surface. There was a series of five, regularly spaced, rectangular marks near each end of the control tube in four quadrants of the tube, totaling 20 marks at each end. Longitudinal depressions were observed near the ends of the aluminum tube on opposing sides, consistent with contact with a gripping tool. The metallurgist noted slight bulging deformation on the lower side of the control rod. The metallurgist removed the aft piece of the control rod from the end fitting and cut it to expose the internal threads; no anomalies were noted. Dimensional checks of the control rod were consistent with the control rod engineering drawing provided by the manufacturer. Hardness of the control rod was measured to be consistent with the hardness value in the material inspection certificate provided by the manufacturer. The metallurgist analyzed the chemical composition of the control rod and found it consistent with the composition shown in the material inspection certificate.