A question about pad switches...

[Al Kraft]

You guys wonder where the urban myths come from? This is a good example because there is some truth in how some manufacturer's products (especially legacy products) do this BUT it doesn't have to be this way, and in fact much of the industry has moved away from it.

...and this is the difference between actual technical understanding and the obvious logical flaw in the staement, "I saw a brown dog, so I can safely conclude all dogs are brown".

 

[agedhorse]

...and this is the difference between actual technical understanding and the obvious logical flaw in the staement, "I saw a brown dog, so I can safely conclude all dogs are brown".

In your business, following urban myths gets people killed.

 

[Al Kraft]

In your business, following urban myths gets people killed.

Accurately and completely understanding why something happens/happened and being able to establish a consistent, precise cause and effect chain is essential to meet safety requirements. The bar is appropriately set very high and it's why every aviation mishap/accident is thoroughly investigated to ensure failure modes/mechanisms, effects, and time sequenced interrelationships are clearly understood. Only then do we truly have the knowledge and insight to take some properly vetted, value-added action.

It's something easily appreciated when you compare the early/preliminary findings and theories about an aviation mishap/accident with the final report. I'm always puzzled by the lack of patience to get to real ground truth. I'm even more amazed at the willingness to demand action and assign blame based only on nascent and uncorrelated data supplied by media reports when there is virtually nothing accurately known other than the physical location of a smoking in the hole in ground.

An unfortunate example of seat of the pants/folklore decision making and the associated consequences that most will be familiar with was the Challenger disaster. IMO it was a culture of complacency that erroneously relied on past success to justify an assumption of risk that was not supportable through rigorous engineering analysis. I'm sure some will disagree with that characterization, but from my study of the official report, it was an inescapable conclusion.

Sorry to get somewhat off topic...but it does go to how folklore and assumptions are more rampant than we may recognize, and how that becomes a greater and greater risk as we become increasingly dependent on technologies we may not always fully understand.