On June 2, 2021, about 2050 central daylight time, a Piper PA-28-161 airplane, N2120J, was substantially damaged when it was involved in an accident near San Angelo, Texas. The flight instructor and student pilot were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The instructor stated that, during the landing roll, he noticed the left wing lower as if the tire was flat. The airplane subsequently veered left, which resulted in substantial damage to the left wing. Postaccident examination revealed a hole on top of the left wing where the left main landing gear strut assembly had broken loose from the upper left wing spar cap. Several mounting holes in the left main landing gear strut were elongated, consistent with wear over an extended period of time. Several landing gear strut mounting bolts were loose, and all bolts were missing from the lower strut assembly mount. During removal of the left main landing gear strut assembly from the left wing, only the brake line remained attached, with no other hardware securing the left main landing gear strut to the left wing. The airplane’s maintenance records were not made available for review, and the maintenance history of the landing gear could not be determined.