ST-80 cylinder failure causes lower leg fracture

What happened?

The crew was in the process of pushing liner to bottom. After completing the first connection of heavy weight drill pipe, the Floor Hand was moving the ST-80 (iron roughneck) back to its parked position.

While maneuvering the ST-80, the extend/retract hydraulic duplex cylinder suddenly failed. This caused the unit to fall outward and downward, and the control panel struck the Floor Hand’s lower leg with significant force.

After receiving initial medical care and stabilisation, the Floor Hand was transported to the nearest healthcare facility.

Why did it happen?

The ST-80 extend/retract hydraulic duplex cylinder has a threaded end that connects to a yoke underneath the unit. If the hydraulic duplex cylinder, the threaded connection or the yoke fails, the unit can fall forward and down to the rig floor.

What did they learn?

During routine pre-use checks, the hydraulic duplex cylinder and its threaded connection to the yoke are difficult to inspect properly due to their location.

The Floor Hand was in a line of fire situation while operating the ST-80 using the control panel. When the failure occurred there wasn’t a safe exit path.

The yoke had been installed incorrectly during refurbishment.

There were no fail-safe mechanisms to prevent the unit from falling forward in the event of a hydraulic cylinder or yoke failure. Safety stops have since been installed fleet-wide on all ST-80 units.

Ask yourself or your crew

How could a similar incident occur at your location?

Are your pre-use equipment inspections thorough and focused on the most critical components?

Where in your operations could a single component failure lead to a catastrophic event?

Are you or your crew ever in the line of fire during routine tasks?

What happened?

The crew was in the process of pushing liner to bottom. After completing the first connection of heavy weight drill pipe, the Floor Hand was moving the ST-80 (iron roughneck) back to its parked position.
While maneuvering the ST-80, the extend/retract hydraulic duplex cylinder suddenly failed. This caused the unit to fall outward and downward, and the control panel struck the Floor Hand’s lower leg with significant force.
After receiving initial medical care and stabilisation, the Floor Hand was transported to the nearest healthcare facility.
Why did it happen?

The ST-80 extend/retract hydraulic duplex cylinder has a threaded end that connects to a yoke underneath the unit. If the hydraulic duplex cylinder, the threaded connection or the yoke fails, the unit can fall forward and down to the rig floor.
What did they learn?

During routine pre-use checks, the hydraulic duplex cylinder and its threaded connection to the yoke are difficult to inspect properly due to their location.
The Floor Hand was in a line of fire situation while operating the ST-80 using the control panel. When the failure occurred there wasn’t a safe exit path.
The yoke had been installed incorrectly during refurbishment.
There were no fail-safe mechanisms to prevent the unit from falling forward in the event of a hydraulic cylinder or yoke failure. Safety stops have since been installed fleet-wide on all ST-80 units.
Ask yourself or your crew

How could a similar incident occur at your location?
Are your pre-use equipment inspections thorough and focused on the most critical components?
Where in your operations could a single component failure lead to a catastrophic event?
Are you or your crew ever in the line of fire during routine tasks?