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Two injured in an explosion, Woodbridge manufacturer fined $135,000

Fully pressurized shock strut from an aircraft exploded during disassembly.

December 16, 2019   by PLANT STAFF

NEWMARKET, Ont. — A manufacturer of structural landing gear components for aircraft has been fined $135,000 as a result of an explosion at its Woodbridge, Ont. plant that injured two workers.

Noranco Inc. pleaded guilty in the Newmarket, Ont. provincial court and was fined for failing to ensure internal pressures of a drum, tank, pipeline or other container were adjusted to atmospheric pressure before any fastening was removed.

On May 3, 2018, two workers were attempting to disassemble a landing gear sub-assembly called a shock strut that had been returned to Noranco by a customer for a retrofit upgrade.

The shock strut was suspended from an overhead crane, and unknown to the two workers, it had been returned fully pressurized with nitrogen.

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The strut exploded during disassembly, separating the piston from the cylinder. The piston was moving upward with such force that it struck the overhead crane and dislodged it from its mooring, forcing it to the ground. The piston and other components struck both workers who sustained critical injuries.

Noranco’s quality control department reviews returned items before releasing them for work and tags the part to indicate any special warnings to workers. No tag was attached to the shock strut to indicate it was pressurized.

This disassembly process for a returned, pressurized part had never been done before at Noranco, so there were no written procedures for the task. Noranco now has a policy to ensure all shock struts returned by a customer are depressurized. A procedure is in place to ensure any residual pressure is released prior to disassembly. And a secondary restraint cable is to remain in place until a strut unit is fully depressurized to atmospheric pressure.