It becomes apparent to me that there’s much commonplace thinking about accidents. What I mean by this is that there’s simple mental models of how events happen that we all share. These simple models are often not all that helpful. Commonplace in that journalists and commentators use them as a default. It’s a way of communicating.
Don’t worry I’m not going on a tirade of how complex the world happens to be, with a dig in the ribs for anyone who tries to oversimplify it. We need simple mental models. Answering questions and explaining as if everything is an academic paper doesn’t help most of us.
I talk of no less than the causal chain. That’s a love of putting the details of events into a chronological sequence. For an aviation accident it might go like this – fuel gets contaminated, fuel is loaded onto aircraft, engine stops, pilot makes an emergency landing, aircraft ends up in a field and an investigation starts. The headline is dominated by the scariest part of the sequence of events. Key words like “emergency” are going to command the readers attention.
In my example above it’s reasonable to assume that there’s a relationship between each link in the chain. The sequence seems obvious. It’s easy to assume that’s the way the situation developed and thus made the accident or incident. However, it doesn’t have to be so. Let’s say there was contaminated fuel but not sufficient to stop an engine. Let’s say for entirely unrelated reasons (past events) the spluttering of the engine led the pilot to think that there was a fire on-board. Fuel was shut down. Thus, events took a different sequence.
Anyway, my point is an ancient maximum. Question what you first hear (or see). The recent tragic fatal accident in India is an example of much speculation often based on a proposed orderly sequence of events. Many commentators have lined them up as, this happened, and then that happened and then something else happened. QED.
What I’ve learned from reading and analysing accident reports over the years is that such major accidents are rarely, if ever, a simple sequence or only a couple of factors combined.
Yes, adding circumstantial factors to a causal chain adds realism. Even that is not so easy given that each factor has a different potential influence on the outcome. Atypical circumstantial factors are time of day or night, weather, atmosphere conditions and the human and organisational cultural ones.
To make sense of the need to put events in an order a more sophisticated model is the fishbone diagram[1]. The basic theme is the same. A core causal chain. What’s better is the injection of multiple factors to make a more authentic accident model.
Although, we do think in a cause-and-effect way about the world, if there are more than 4 or 5 factors combined in a random manner these models are far from authentic. My message is not so sophisticated, beware of simple sequences as being definitive.
John Vincent 