On January 1, 2018, about 1725 eastern standard time, a Costruzioni Aeronautiche Tecnam P2006T airplane, N594MA, sustained substantial damage when it was involved in an accident near Lynchburg, Virginia. The flight instructor and the pilot receiving instruction were not injured. The airplane was being operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The instructor reported that the flight was an instructional, cross-country flight with the pilot receiving instruction as the pilot flying. At the conclusion of the flight, the pilot receiving instruction, maintained about a 500-ft per minute descent on final, and verified with the instructor that the airspeed was 70 knots. Immediately after touchdown, the left main landing gear (MLG) assembly separated from the airplane. Subsequently, the airplane skidded for about 100 ft, departed the runway to the left, and then came to rest on grass as shown below in figure 1. The airplane sustained substantial damage to the fuselage. Figure 1. A photograph showing the airplane on grass left of the runway after it came to rest (courtesy of the Federal Aviation Administration) The instructor reported that no wind gusts existed during the approach and landing, that no side loading occurred at touchdown, and that, given his experience, he did not feel the landing would have caused any damage. The Airplane Maintenance Manual (AMM) required that the MLG be replaced every 4,000 landings. The review of the records revealed that several of the previous airplane owners and operators had not tracked the number of the airplane’s landings. After the owner bought the airplane, he worked with the FAA to determine its estimated number of landings and whether it was in compliance with the MLG AMM replacement requirements. At the time of the accident, the estimated number of the airplane’s landings had still not been determined; maintenance records revealed that the MLG had not been replaced at any time. The separated left MLG assembly and the intact right MLG assembly were recovered and transported to the NTSB Materials Laboratory for examination. Figure 2 The outer area of the arm’s fracture surface exhibited a slanted morphology and rough surface texture, consistent with a fracture through the weld filler. The inner area of the arm’s fracture surface was shinier and flatter, consistent with the area not having been welded. Most of the flange’s exterior had not been welded. The flange’s upper area exhibited fracture features consistent with progressive cracking that propagated from the interior unwelded area outward through the weld filler. A complete copy of the NTSB materials laboratory report is included in the public docket for this accident.