Madill 071 Guywinch Inspection

Safety Alert Type: 
Heavy Equipment
Date of Incident / Close Call: 
Details of Incident / Close Call: 

A recent guywinch failure on a Madill 071 yarder resulted in collapse of the tower. This is an area on machines of this type which will require closer scrutiny during Annual Yarder Tower Inspections.

Learnings and Suggestions: 

Photos of the particular guywinch assembly are shown below. The problem area is where you can see the shiny new bush. The top of the bush supporting the left mounted winch spindle broke out allowing the spindle to bend and fail (at a fatigue crack at the end of the keyway); drum came loose, shock load caused adjacent guyline shackle to fail; tower fell over.

This failure has been discussed with the manufacturer and their advice is as follows:
1. This bush (item 43 on Madill Drawing No D1521 - attached) is to be closely inspected at least annually on machines of this type and age. (Practically, this requires removal of the winch drum and spindle).
2. Guy winch spindles should be removed annually and inspected using non-destructive testing (NDT) methods as they are subject to fatigue cracking.

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