On 30th May at around 7:30 PM, After crane operators crew change, the night crane operator carried out pre-shift daily crane inspection which was stationed at parking area. He observed wire overlapped on wire drum. He decided to reeve the wire line in correct position. In this process he called night forklift operator to help him observe the drum and gave verbal signal. During the reeving process, he extended the boom without extracting the outriggers. Once wire was back in place, he tried to retract the boom which was unsuccessful. After several attempts, he asked night forklift operator to report the case to the tool pusher. Day crane operator (IP) was called to analyze the situation. Once IP reached the site. TP asked him to carefully just do visual inspection. However, IP entered cabin and decided to start the engine in his own judgment. The crane started to swing by itself and shifted the load on left hand side, which led the crane toppling to the left side. During this time, IP remained inside the crane’s cabin. After the impact, he was helped to leave the cabin and sent to hospital for further medical examination.