Drilling Rig Crowned Out-Blocks Dropped
Traveling Blocks move drill pipe in and out of the hole during drilling operations. When a Driller losses concentration and strikes the top of the rig with the blocks it's known as "Crowning Out". What usually follows after crowning out is breakage of the drilling line resulting in the traveling blocks, drilling line, parts of the rig crown & 100+ feet of drill pipe crashing to the floor.The traveling blocks alone often weigh 50,000 lbs.
You can see "crowning out" caught in this video on a derrick cam. Although not shown, the results are fatal to crew members. Drillers should check the proper setting and function of a fail-safe device known as a "crown-o-matic" at the start of every tour to avoid this type of catastrophe.