At 00:40hrs on the 20 Oct 2018, The operation was Nipple up BOP in the cellar and simultaneously the Driller was trying to setup the BOP Control panel in place behind the drillers console. At this time the travelling block started descending uncontrolled coming into contact with the BOP (hit the oil tray on top of the annular) due to the hoist floor not being installed yet. The complete drilling line came out from Draw Works, all the way up passing the first sheave. As soon the block landed on ground, the remaining drilling line stayed on crown sheave. Due to the slow descend of the travelling block there was no damage to the equipment.