30 CFR § 250.611
Traveling-block safety device
July 29, 2020
You must equip all units being used for well-workover operations that have both a traveling block and a crown block with a safety device that is designed to prevent the traveling block from striking the crown block. You must check the device for proper operation weekly and after each drill-line slipping operation. You must enter the results of the operational check in the operations log.
[81 FR 36149, June 6, 2016]