On April 9, 2023, at 0845 central daylight time, a Helicopteres Guimbal Cabri G2, N372PA, was involved in an accident near Cahokia, Illinois. The helicopter sustained substantial damage. The flight instructor received minor injuries and the student pilot was uninjured. The helicopter was operated under Title 14 Code of Federal Regulations Part 91 as an instructional flight. The flight instructor stated that during the approach for landing at the departure airport, his left cyclic had “a little bit of play,” and the helicopter was not responding fully to his control inputs. He then completely lost cyclic control upon lining up with the taxiway of intended landing site. He stated that he still had collective and rudder control. The student pilot’s cyclic controls continued to function, and the flight instructor coached him on cyclic control inputs to maintain control of the helicopter, but the student pilot’s cyclic control then ceased to function. The helicopter impacted the ground during the attempted landing and sustained substantial damage to the main rotor blades. Postaccident examination of the flight control system revealed that the helicopter’s Illustrated Parts Catalog part #34 (Reference HG17-0545) - Pin and part #36 (Reference HG21-0803) – Safety Pin were found not inplace on the left cyclic control. Part #43.0 (Reference G41-41-300) – Pin Locker, part # 44 (Reference HG20-2036) – Bolt and part #7 (Reference HG12-0332) – Nut were not installed. Ideal Aviation was unable to a date when these parts were removed. There was no evidence indicating these parts were impacted by the crash. The left cyclic control did not have any deformation/damage.