Accident Overview
On July 25, 2012, at 0930 central daylight time, a Flight Design GmbH model CTLS light-sport airplane, registration N930SA, was substantially damaged during landing at Dennis F Cantrell Field Airport (CWS) in Conway, Arkansas. The commercial pilot and passenger were not injured. The airplane was registered to and operated by Sparrow Aviation Group, LLC under 14 Code of Federal Regulations Part 91, operating without a flight plan. Day visual meteorological conditions prevailed for the personal flight, which originated from Searcy Municipal Airport (SRC) in Searcy, Arkansas, at about 0900.
Landing and Damage Sequence
The pilot reported completing an uneventful straight-in approach to runway 26 (4,875 feet by 100 feet, asphalt). Upon touchdown, the right main landing gear collapsed. The airplane subsequently swerved to the right, departing the right side of the runway. It came to a stop aligned about 180 degrees from the original runway heading. The fuselage, firewall, empennage, and right wing sustained substantial damage during the accident sequence.
Weather Conditions
The closest aviation weather reporting facility was at Little Rock Air Force Base (LRF), about 17 miles southeast of the accident site. At 0955, the LRF automated surface observing system reported wind 220 degrees at 10 knots with gusts to 16 knots, surface visibility 10 miles, clear sky, temperature 33°C, dew point 21°C, and an altimeter setting of 29.97 inches of mercury.
Aircraft Information
The accident airplane, serial number 08-02-05, was manufactured by Flight Design GmbH of Leinfelden-Echterdingen, Germany, and imported into the United States by Airtime Aviation Inc. of Tulsa, Oklahoma. It received a special airworthiness certificate from the Federal Aviation Administration on May 24, 2008, and was sold to the owner-of-record on June 4, 2008. At the time of the accident, the airplane had accumulated 1,149.9 hours since new. Maintenance records showed that the main landing gear legs had never been repaired or replaced. On December 2, 2011, at 1,025 hours total service time, the fuselage structure was reinforced in the landing gear attachment area per Flight Design GmbH Service Instruction SI-ASTM-CTLS-07.
Landing Gear Examination
The main landing gear legs were sent to the National Transportation Safety Board's (NTSB) Materials Laboratory Division for examination. The right main landing gear leg had a longitudinal crack along the leading edge and a transverse fracture near the intersection with the fuselage. The left main landing gear leg remained intact. The NTSB laboratory examination confirmed that the fiber reinforcements in the composite construction included unidirectional glass fibers, glass fiber fabric, basalt fiber fabric, and basalt/aramid fiber fabric. According to the manufacturer, the landing gear was designed per ASTM Standard F2245-06, and compliance was shown through drop tests.
Detailed examination of the right leg revealed that the upper surface was bent upward between the fracture and the fuselage intersection. Fiber pullout was observed, greatest at the lower side of the transverse fracture. Parallel transverse cracks in the paint adjacent to the fracture were consistent with a bending load with the lower surface in tension and upper surface in compression. The longitudinal crack at the leading edge had a jagged appearance. Paint cracks emanating from the longitudinal crack were consistent with shear stress where the outboard end was loaded upward relative to the inboard end. Cross-section examination showed an additional layer each of 0/90-degree glass fabric, 45-degree basalt fabric, and 0-degree glass fiber bundles beyond the specified layup. No preexisting damage or manufacturing anomalies were noted that would have reduced design strength.
Probable Cause
No probable cause was determined in the source material.