Abstract: At approximately 1:00 p.m. on July 24, 1997, Employee #1 was working on rig #41 under FWA's drilling lease PSU 4159A. At the time of the accident, circulation in the hole had been lost for about three to hour hours. The crew had just obtained the correct volume in the hole and had run 10 to 12 stands of pipe back into the hole. As this was being done, the travelling block was moving up and down, traversing approximately 110 ft with each motion. A 3 to 5 lb pin in the traveling block fell 90 to 100 ft and struck Employee #1 on the head. He was wearing a hard hat, but was killed. The pin that fell was in the locking mechanism of the travelling block latch. When strands of pipe were being lifted, the swivel was attached to the top of the stand. It was then attached to the travelling block by inserting the travelling block latch through the eye of the swivel. The swivel moved within the latch as it moved up and down. According to the rig crew and the tool pusher on the rig, the latch pin had already been fixed twice at this location. During rig up on July 8, 1997, the tool pusher saw that the pin was jammed into place, and that the spring and the washer that the pin should go through had been displaced. He used a hammer to push the pin into place. A week later, the pin came loose again. The tool pusher thought the cotter pin had sheared off, and he again used force to push the pin into place. The derrickhand stated that he had worked on this rig at its previous location and had experienced the same problems with the pin. The pin was a recurring problem with this rig that had not been corrected except for an occasional quick fix. Improper maintenance on the latch to correct the problem led to the pin dislodging again in this accident. Rig #41 had been in service since 1992. Rig components were purchased from around the area and assembled at the FWA yard. Rig inspections in the field were accomplished according to the availability of the safety manager, who indicated that he tried to do at least one inspection per day.