2009-12-04 Positioning Grapple Yarder on Lowbed - Pass Chain connecting the haulback to the base of the boom failed - Driver Hit

Safety Alert Type: 
Heavy Equipment
Port McNeill Forest Operation
Date of Incident / Close Call: 
Company Name: 
Western Forest Products
Details of Incident / Close Call: 

The crew was loading a grapple yarder onto the lowbed which was designed with a folding gooseneck. The haulback was secured to the base of the yarder boom using a pass chain, which kept the grapple tight to the boom. The crew had put the grapple yarder on the lowbed and the truck had been re-connected to the gooseneck. The grapple yarder had moved ahead on the lowbed and was in the process of booming down to lower the grapple onto the gooseneck when a link of the pass chain failed.

The Lowbed Driver was standing on the truck’s deck behind the water tank. He was facing the grapple yarder observing to see if the machine was positioned correctly for travel. The Driver was in the process of getting off the truck while the grapple yarder started booming down. As the boom was lowered, the haulback became tight and excess tension was put on the pass chain causing it to fail. The grapple swung ahead (like a pendulum) grazing the Driver on the right elbow and forearm, then struck and damaged the water tank of the truck.

After he was grazed the Driver went off the deck landing on his feet on the ground; he could not remember if he jumped or if he was knocked off. The Driver had pain in his hip from jump or possible contact with the fender. The Operator got out of the cab and found the Driver on the driver’s side of the truck favouring his right arm. First Aid Attendant responded.

Bruises and soreness to forearm, elbow and hip.

Learnings and Suggestions: 
  1. When loading any machine on the lowbed, there must be clear communication between the Ground Person (signaler) and the Operator.  There must be a failsafe plan - the Operator does not proceed if the Ground Person is in the bight and the Ground Person must not leave the Safe Zone and enter the machine Danger Zone without clearance.  Look out for one another and intervene where necessary!
  2. Ensure a pre-determined Safe Zone is established, communicated and adhered to while loading equipment.  If the plan changes for any reason, the STOP, re-assess, and identify any new hazards.  Re-establish the Safe Zone if required.
  3. Ensure the haulback is sufficiently secured to the base of the boom.  Shackled to a flange (lug) is the preferred method.
  4. Inspect similar pieces of equipment to ensure flanges are available to tailhold the haulback to the base of the boom and area of sufficient strenth.
  5. Discuss with crew and observe machines on extended walks or lowbed moves to ensure the haulback is properly secured.

For more information contact:

Brian Smith - Port McNeill General Foreman 250-956-5215

Vince Devlin - Timberlands EHS Advisor 250-230-2173

Incident #: PMO-2009-12-02-4162


File attachments
2009-12-04 Positioning Grapple Yarder on Lowbed - Pass Chain connecting the haulback to the base of the boom failed - Driver Hit.pdf
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