On October 20th approximately 11:13am the operation is TIH with 16” drilling assembly, the Driller was making a connection when a floorman noticed a bolt dropping on the floor near the SmartRacker track. He immediately stops the Driller. The Driller stopped the tripping operation, then inform the Toolpusher. The Toolpusher inform OIM, RSC and, Aramco Foreman. Safety Standdown held. Maintenance crew and Cameron Tech inspected the SmartRacker upper arm and confirm that the bolt fell from it. The dimension of the bolt is 13X55mm weighing 100grams, dropping from a height of 82ft. The nut was located by the chock manifold weighing 30grams. The nordlock washer remained stuck on the side of the bolt hole. All parts were OEM and located. New OEM bolt, nut and washers were replaced. The SmartRacker was inspected and one more bolt was found loose. All bolts were torqued / torqued checked to OEM recommendations. 
No one around the Red Zone. Red zone management protocol was in place. DROPS Calculator potential outcome – First Aid case (FAC)