Crews were preparing to move a rig and, at the time of the incident, the blocks were near the rig floor. This rig’s configuration was such that the drawworks were below floor level and a brake tube connects the brake handle at the driller’s console to the drawworks below. The crew was performing a variety of rigging down activities and a mechanic’s helper was assigned the job of disconnecting the brake tube. No one noticed his activity or assessed the dangers involved. When the tube was disassembled, the
drawworks brakes loosened, allowing the blocks to fall onto the rig floor. There were no injuries or damage to equipment.