We're getting the message that the likely cause of the San Francisco plane crash was that the pilots failed to properly engage the plane's cruise control.
And now we learn that the likely cause of the much bigger rail disaster in Quebec was that an engineer didn't engage the parking brake so that a 73 car train loaded with flammable oil simply started rolling and picking up speed until it blew up in the middle of that small town.
These were unintentional mistakes. The kind we've all made - forgetting to set the parking brake, pressing the wrong button on the cruise control. Leaving the garage door open, the stove on, the water running.
And every scientist, engineer and do-it-yourselfer will tell you all this is predictable under Murphy's Law - which states anything that CAN go wrong, will go wrong.
So when the stakes are high - as they are with airlines and railroads, you have to take into account the natural human tendency to sometimes forget routine tasks. Which is why you have rules and checklists and procedures and random drug checks and mandatory sleep regulations and thousands of pages of reports documenting the lessons learned.
I'm pretty sure both of these accidents will lead to many more thousands of pages of lessons learned and changes in procedures to make sure nothing like this ever happens again. Because we learn from our mistakes.
Which brings me to the other part of Murphy's Law, which I like to call Ross's Amendment. Every solution works until the day it doesn't. And learning from one's mistakes causes the mistakes to evolve.