A McDonnell Douglas MD-81 passenger plane, registered JA8297, sustained substantial damage in a landing gear collapsed accident at Tokunoshima Airport (TKN), Japan. There were 163 passengers and six crew members on board. Three passengers were slightly injured. JAS Flight 979 took off from Kagoshima Airport at 15:35 and flew to Tokunoshima Airport. On landing at Tokunoshima Airport runway 01, the aircraft’s left main landing gear (MLG) collapsed during rollout and its left wing tip contacted the ground. The aircraft came to a stop on the runway. PROBABLE CAUSE: In this accident, it is estimated that due to the left main landing gear cylinder collapsed immediately after the aircraft landed at Tokunoshima Airport, the fuselage inclined to the left and the aircraft traveled with its left wing in contact with the runway surface, resulting substantial damage. With respect to the collapse of the MLG cylinder, it is considered that Gear Walks which experienced before the restrictor was installed generated large stresses on the fuse section of the cylinder surface and caused micro cracks. The micro cracks are considered to grow during normal operation and eventually lead to the fracture. Further, it is considered that the presence of surface flaw on the cylinder caused by grit-blast contributed to the crack generation. And the contributing factor to the fact that the company could not detect the cracks on the cylinder by the scheduled maintenance, etc. is considered to be that the manufacturer had not established appropriate inspection intervals or inspection times to detect fatigue cracking.