SAFETY
Rules and checklists by themselves do not make us safe; they require great effort and attention to detail to make them have the desired effect.
SYSTEM SAFETY System safety (the precursor to SMS) has been part of aviation since the mid-1940s. Department of Defense (DOD) MIL spec (MIL-STD-882E) details how a systems safety program should be configured for DOD projects. If you read this document and then read an article by Fred A. Manuele (in “Professional Safety,” Oct. 2011) you will understand why the DOD specification only gives you part of the solution. Manuele makes the point that it is a myth that the principal cause of occupational accidents is unsafe acts by individuals. His point is made in saying, “the emphasis is now properly placed on improving the work system, rather than on worker behavior.” The implication is that worker behavior will change for the better if the institution promotes it. Systems safety, as detailed in MIL-STD-882E, is an engineering approach that is data based and can leave you looking for answers to the question of what to actually do with all the data your safety program collects and how you interpret it. We are always quick to say “be safe” at the end of a message, but we don’t spend enough time telling people HOW to be safe. Rules and checklists by themselves do not make us safe; they require great effort and attention to detail to make them have the desired effect. It takes much more continuing effort to make an SMS program work than it does to write one. Looking back at errors is the easy part. The past is
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relatively easy to talk about; it is fixed. The future is blurred and hopelessly complex with many possible outcomes. We pick apart our errors well, but how do we prevent them from happening again? The older I get, the more I use a mini-checklist by asking, “What is the worst that could happen?” when I start or finish a task. Even so, I sometimes find myself saying, “Well, I didn’t see that coming.” For example, I have found that using chainsaws and ladders at the same time is a good time to ask that question (but that’s another story).
B-52 JACK SCREW ASSEMBLIES In one of the most interesting aviation maintenance errors I have read about, a B-52 lost both of the inboard flap panels after takeoff. The flap jack screw assemblies had been overhauled and parts were left out. One interesting thing is that in the opinion summary of this report, the root cause is stated to be the fact that an individual failed to install two retaining caps and that the ancillary causes had to do with failure to provide sufficient oversight on various levels. Although it might just be semantics, I would state the root cause as lack of oversight and that failure to install all the parts was the result of this problem. The institution set up the technician to fall into this trap. Amazingly, nobody got hurt. The
aircraft damage was to the tune of $1.8 million dollars. No matter what we do, we will find a way to circumvent our precautions. If
you take away nothing more from what I’m writing, it should be that no individual and no procedure we devise will keep us free of maintenance errors. The Unpredictability of Human
Behavior Our efforts might be relentless, but
they will never make us 100-percent effective/safe because human behavior is too hard to predict for the narrow stream of events that lead up to a maintenance error. Acknowledging our failure to achieve the goal of 100-percent safety is a first step in trying to see the root causes of errors to come. We know the next maintenance error is around the corner despite our rules and checklists. Any time a technology change happens is the time to be extra careful. In 1935, the Boeing 299 (B-17 prototype) took off on a demonstration flight with the empennage control locks engaged. It crashed and burned because the crew had no checklist. It was perhaps the first aircraft of its size that had control locks that could be disengaged from the cockpit. That’s from where checklists came. We still fail to use them as often as we should. Pilots need to know some things by rote because of the brief time they might have to deal with a problem. Mechanics need to be more introspective, almost as if they need to be able to watch themselves work, and try to see how the links in the chain of events get laid out before
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