The Operator Did It

What do an overwhelming majority of accidents and errors have in common? All too often, operator error is identified as the causal factor.

In fact, operators are identified as the culprits in 80 percent of all accidents. Doesn't this seem odd in this day and age of automation and complex systems? Doesn't this seem like an easy out on the part of investigators? Rather than play the blame game for whatever reason, organizations should focus on causal factors and address the real issues.

Complexity

It's no secret that our world is becoming more complex. Not only does everything from stoves to air conditioners to the space shuttle have electronics and computers, but now they are becoming increasingly integrated into a web of connections creating dependencies and interactions never before dreamed of. However, with all of these interconnections and dependencies come the potential for some serious headaches.

We like to think of ourselves as rational people who live by causality. Simple causality is very straightforward and we cling to it. Simple causality deals with cause and effect -- the system overheated and failed. We view this as "because it overheated, the system failed." This seems easy enough. The truth is that problems aren't always this simple.

When multiple things fail and interact in ways that, combined, cause the system to fail, this is known as systemic causality. The trick here is that systemic causality does not necessarily need to follow a linear path. Instead, it depends on the failure of multiple components, or subsystems, to interact and fail.

For example, a power failure causing systems to crash seems easy. But, when we dig in we find that there was a UPS (uninterruptible power supply) and generator. The systems should have been protected.

However, we find out that the UPS died earlier than expected due to a couple of space heaters being plugged in on the UPS circuit because an electrician accidentally connected an outlet to the protected power circuit and the heaters only ran during business hours when the staff was present, hence the load was never noticed during regular weekend testing.

To make matters worse, the generator hadn't been exercised for a long time due to a failure of an electronic remote starter and, hence, the fuel had evaporated and clogged the fuel injection system. Operations didn't notice because the generator's monitoring circuit had been erroneous for quite some time and operators discounted what the logs said. To make matters worse, the second generator was down having preventive maintenance performed.