Alert 99 – 09 Brake Linkage Failure

Alert 99 – 09 Brake Linkage Failure


The drill crew was preparing to pull the drill string from the well to log it. The drill string was hoisted and the kelly was broken off and racked back. Than the first stand of drill pipe was hoisted. When the driller applied the brakes, the brake handle fell to the floor. The driller immediately secured the drill string in a stationary position by engaging the drawworks clutch. He instructed the floorhands to inspect the brake linkage, assuming that a pin had come out of the brake lever linkage upstream of the
crown saver-actuating device. While this task was underway, the driller instructed the motorman to engage the crown saver. Engaging the crown saver automatically releases the drawworks hoisting clutch and engages the drum brakes, as this mechanism is designed to prevent the traveling blocks from hitting the derrick mast crown (sheaves). The driller was trying to engage the drum brakes in order to release the drawworks hoisting clutch to prevent friction on this clutch. With the clutch released, the traveling blocks fell free to the drill floor. The crew was not able to set the slips as the drill pipe was not centered and this could have decreased the distance that the traveling blocks would have fallen.

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