Under 1919.15(a), how often must derricks, winches, cranes and other hoisting machines be tested and thoroughly examined?
They must be tested and thoroughly examined every 5 years. 1919.15(a) requires that derricks with their winches and accessory gear, and cranes and other hoisting machines with their accessory gear, be tested and thoroughly examined as a unit every 5 years in the manner set forth in subpart E of Part 1919.