Date of incident: January 2016
Notice of incident number: 2016161980003
Employer: Log hauling company

Incident summary
Two workers, a driver and a backup driver, were travelling in a tractor unit when the air brake system air pressure dropped and a hazard warning activated. The driver stopped the tractor on a sloped and icy road. The parking brakes were applied. Both workers climbed under the tractor to determine the location of the air brake system leak. The tractor began sliding backward and downhill on the icy road. One worker was fatally injured when he was struck by components underneath the truck. The other worker was not injured.

Investigation conclusions

Cause

• Failure to adequately secure tractor on icy slope. The tractor was not effectively secured from inadvertent movement. Two workers went under the vehicle to locate the air leak. Ice had built up on the air line between the third and fourth axle, causing the quick connector fitting on the line to separate enough for the air to escape the line and the air pressure to drop. With the workers underneath, the tractor began to slide on the road due to the slope and icy conditions of the road.

Contributing factors

• Failure to recognize potential hazards. The slope in the road and the icy surface were not recognized as hazards before the two workers went underneath the tractor to locate and repair the leak in the air brake system. Additionally, they did not recognize that they did not need to crawl under the tractor to locate the leak and that precautions needed to be put in place to prevent the inadvertent movement of the tractor.
• Failure to control kinetic energy. The use of wheel chocks or comparable blocking was necessary to prevent the tractor from sliding. However, the tractor was not equipped with chocks and nothing was placed behind any wheels on the tractor, allowing the tractor to slide on the sloped and icy surface. Another means to prevent movement was also not used. For example, turning off the engine and placing the transmission in reverse or low gear might have assisted in preventing the inadvertent movement of the tractor.

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