Henry Petroski Quotes

Engineering is achieving function while avoiding failure.

Failure is central to engineering. Every single calculation that an engineer makes is a failure calculation. Successful engineering is all about understanding how things break or fail.

Case studies of failure should be made a part of the vocabulary of every engineer so that he or she can recall or recite them when something in a new design or design process is suggestive of what went wrong in the case study.

Any design, whether it's for a ship or an airplane, must be done in anticipation of potential failures.

The fact that it wasn't tells me that we've got a much more fundamental problem of understanding what went wrong, and we've got to figure out what was there. And that's what I call fundamental fault analysis.

Finding out exactly what went wrong is key toward preventing future debacles.

In computing, the mean time to failure keeps getting shorter.

Failure is Central to engineering. Every single calculation that an engineer makes is a failure calculation.

(Technology reliability) x (Human reliability) = (System reliability)

When you want to know how things really work, study them when they're coming apart.

There's no worse feeling than seeing my buildings and realizing the mistakes.

It is in Toyota's DNA that mistakes made once will not be repeated.

In a previous life I wrote the software that controlled my physics experiments. That software had to deal with all kinds of possible failures in equipment. That is probably where I learned to rely on multiple safety nets inside and around my systems.

Just because nobody complains doesn't mean all parachutes are perfect.

My first book, 'To Engineer Is Human,' was prompted by nonengineer friends asking me why so many technological accidents and failures were occurring. If engineers knew what they were doing, why did bridges and buildings fall down? It was a question that I had often asked myself, and I had no easy answer.

Every time I make a mistake with a company, I write it out and try to figure out why it happened.

Now, therefore, the Directors of the company are hereby ordered to see that precautions are taken to make travel on said railroad perfectly safe by using a screw with at least twenty-four inches diameter.

I emphasize that virtually every engineering calculation is ultimately a failure calculation, because without a failure criterion against which to measure the calculated result, it is a meaningless number.

There are people who design buildings that are not technically and financially good, and there are those who do. Two categories - simple.

As a rule, software systems do not work well until they have been used, and have failed repeatedly, in real applications.

We call the fates of the Titanic and the Concordia - as well as those of the space shuttles Challenger and Columbia - 'accidents.' Foreseeing such undesirable events is what engineers are expected to do. However, design trade-offs leave technological systems open to failings once predicted, but later forgotten.

After the Challenger accident, NASA put in a lot of time to improve the safety of the space shuttle to fix the things that had gone wrong.

The Corps of Engineers Analyses are fraught with errors, mistakes and miscalculations, and used invalid assumptions and outdated data.

Processes break in two ways. They break because they don't have the right checks and balances and because they don't have the right execution.

In any endeavor, you have to understand your tolerance for risk. What's a failure you can afford?