On April 19, 2022, about 1538 Pacific daylight time, a Diamond Aircraft Inc. DA-42 airplane, N822SA, was substantially damaged when it was involved in an accident at Long Beach Airport (Daugherty Field), Long Beach, California. The flight instructor and the pilot receiving instruction were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The pilot receiving instruction reported that he was conducting a multiengine training flight and had performed multiple maneuvers before the accident. During the rollout after a short-field landing, about 750 ft from the touchdown point, the right main landing gear collapsed, and the right wing contacted the ground, which substantially damaged the right aileron. According to the flight instructor, the approach was normal, and the touchdown occurred with no sideloading. The flight instructor also stated that he checked the gear three times; the pilot receiving instruction checked it twice; and the gear appeared to be in the down and locked position, as indicated by the three green landing gear lights. A representative from the Federal Aviation Administration (FAA), along with maintenance personnel from the operator, examined the airplane at the accident site and observed the composite right landing gear brace rib had separated from the wing structure. Further examination of the airframe revealed the right main landing gear brace rib had separated from its attachment points at the spar and upper wing skin. The bonding paste material was still adhered to both the brace rib and the spar/wing skin attachment points, consistent with correct adhesion of the components. There was no evidence of faulty adhesion from the original installation. The examination also revealed an 8- to 10-inch crack between the upper and lower wing skin bonds to the airplane’s center section spar. A coin tap test and a visual examination revealed no cracks on the left main landing gear brace. A review of maintenance documents revealed that the latest service bulletins and airworthiness directives had been performed on the airplane. Also, the airplane had recently completed a 100-hour/annual inspection about 3 weeks before the accident, with no report of damaged or faulty components related to the landing gear. The airplane had been flown for about 35 hours since the annual inspection by multiple pilots.