The Importance of Failure
Using what goes wrong in engineering to teach how to do things right
Do engineering students think about failure? Not about failing a test or a course, but about failure as an engineering concept? If they don't, they should. Failure can teach students that yesterday's mistakes can lead to today's solutions and tomorrow's innovations; it can offer them new career options; and it can introduce them to ethics and professional responsibility.
Author, engineer, and educator Henry Petroski is a historian of engineering's negative (and positive) consequences and outcomes, and a believer in the axiom that those who forget the mistakes of the past are doomed to repeat them. He urges engineers and engineering students to look to what's gone wrong before as a way to anticipate what can happen again if they don't take proper precautions.
"Failure is a unifying theme of engineering," Petroski says, yet engineering curricula often focus on successful designs and neglect unsuccessful ones. Ironically, this reliance upon past successes can lead to future failures.
"One of the paradoxes of engineering is that successes don't teach you very much. A successful bridge teaches you that that bridge works," Petroski says. It does not teach you that the same bridge, built at a different location or made longer or taller, will also be successful. "It's all theory until it's completed," he explains.
A case in point is the Tacoma Narrows Bridge, which shook apart in the wind just a few months after opening in 1940. Leon Moisseiff based the bridge design on the designs of several successful bridges, yet at the same time ignored the wind-related problems that had damaged other bridges.
A civil engineer investigating the Tacoma Narrows collapse wrote that the bridge's failure "came as such a shock to the engineering profession that it was surprising to most to learn that failure under wind action was not without precedent," Petroski writes in Design Paradigms: Case Histories of Error and Judgment in Engineering. In fact, "between 1818 and 1889, 10 suspension bridges were severely damaged or destroyed by the wind."
Moisseiff's reliance on engineering successes and exclusion of engineering failures has a modern-day counterpart: computer simulations. "There is clearly no guarantee of success in designing new things on the basis of past successes alone, and this is why artificial intelligence, expert systems, and other computer-based design aids whose logic follows examples of success can only have limited application," Petroski writes.
The initial failure of the Hubble Space Telescope is an example of problems caused by relying on computer simulations. In 1990, when the orbiting telescope sent its first photographs back to Earth, the images were unexpectedly fuzzy and out of focus. NASA determined that the problem was the result of a human error made years before the launch: the telescope's mirror had been ground into the wrong shape. The mirror, tested prior to launch like the telescope's other separate components, functioned properly on its own. However, the manufacturers did not actually test the mirror in conjunction with the other components. The manufacturers relied on computer simulations to determine that the separate components would work together. The simulation didn't take into account the possibility of a misshapen mirror.
Because of the Hubble problems, NASA learned "a great lesson" about "the merits of actually testing a system rather than depending upon theory and simulation," explains Doran Baker, founder and vice-president of Utah State University's Space Dynamics Laboratory.
Relying on computers to predict and counteract failure can cause other problems as well.
Smaller Failures, Bigger Problems
Once again, a single failure had major repercussions. One nonresponsive computer component on Galaxy 4 affected millions of people, and will eventually cost millions of dollars for equipment replacement, customer compensation, and lost revenue. National Public Radio technology commentator Lauren Weinstein says the potential for small failures to cause big problems is increasing. "In a way we're the victims of our own success. As communications technology has rapidly advanced, the ability to concentrate ever-greater amounts of information into single satellites, cables, and other systems has grown enormously," Weinstein explains. "This has brought great economies, but also has geometrically increased the impact of failures."
For example, he explains, years ago a "backhoe slicing a cable might have affected a few hundred simple telephone circuits. Now with that same slice it could potentially terminate massive volumes of voice and data traffic."
"Even backup plans are sometimes thwarted by this fantastic density of communications," he continues. "Back-up circuits sometimes turn out to be feeding through the same satellites or fiber cables as the primary communications channels [which may have been the problem with Galaxy 4's backup unit]. So when a failure occurs, the backup circuits are also kaput."
Weinstein says this failure illustrates that "at the very least we should avoid becoming too complacent and totally dependent upon our modern communications marvels. And that having plans to deal with failures of these systems in a realistic manner is an absolute necessity for governments, business, and citizenry alike."
Many engineers spend their careers doing just the type of failure-related planning Weinstein advocates. The American Society of Safety Engineers has 33,000 members who work in insurance and service industries, construction, and manufacturing, and for consulting firms and government agencies. The society reports that more than 125 colleges and universities offer degrees in safety management, occupational safety, environmental protection, or related fields; and many engineering programs offer safety and failure-related courses and programs. (For a profile of a failure engineer, see "Failure for a Living," right.)
Success from Failure
There are positive aspects of failure. Learning from mistakes, be they your own or someone else's, and overcoming unforeseen obstacles often lead to improved products or processes. Also, the ability to recognize other applications for a failed experiment plays an important role in product development.
Failure for a Living
Shusto loves her job and the intellectual challenges it brings. "Failure analysis is the Sherlock Holmes work of engineering—figuring out what went wrong is exciting and fascinating," she says. "I get to interact with clients instead of sitting in an office or a think tank."
She says her colleagues at Exponent have similar enthusiasm for their work, and there is no "typical day" in the office. On any given day a failure analysis engineer might work on data analysis or a field investigation, write reports for clients, meet with lawyers, prepare exhibits, or testify as an expert witness, she explains.
Exponent experts on structural engineering, chemistry, thermal science, instrumentation and testing, and injury analysis provided plans to stabilize the building for search and rescue operations; assessed injury and damage patterns; tested the explosive properties of the fertilizer used in the bomb; evaluated design guidelines for other government buildings as a precaution against similar attacks; and even provided information used in prosecuting the bombers.
Failure analysis doesn't just take place after something goes wrong. Shusto and her associates evaluate products, devices, and systems to spot potential problems during design and manufacturing, and before the products are released to the public.
A civil engineer by training, Shusto says she entered engineering to build bridges and didn't learn anything about the failure analysis field in college. "Failure wasn't really a concept then," she explains. "It's a field that has really developed in the last 20 years." Failure was only mentioned in relation to building codes, she says.
But while still in college she changed her career path in part due to an article in People magazine about the 1981 Kansas City Hyatt walkway collapse and the firm investigating it: Failure Analysis Associates. Shusto, who always liked puzzles, says she was so intrigued by the company's work that she contacted them about a cooperative education position. That position led to a job right out of college, and she's been with the company ever since.
Shusto says studying failure can benefit students in all engineering disciplines. "Educators can do a lot in helping engineering students learn how to think by giving them examples of failures," she says. "Homework and case studies about failure can intrigue students and keep them interested in and excited about engineering."
And for some, it might lead to a new career.
After receiving those first blurred photos, space system engineers had to devise ways to perform the appropriate failure analysis on the telescope, even though the instrument was only accessible via radio signals from space. Once they analyzed the problem, they had to plan and execute missions in which astronauts could remove and replace the faulty component. The result was that the engineers learned much more from fixing the telescope than they would have had the telescope not needed repairs, Baker says.
The engineers who worked on the Hubble fix encountered problems and learned the solutions as they went along. Sometimes, however, engineers and other inventors encounter problems and turn them into opportunities.
From "Oops" to "Aha!"
That adaptation was not an isolated incident. The Edison Archives include 3,500 handwritten notebooks that trace Edison's inventions from the earliest conception to full-scale development and production. From those notebooks, "Historians have uncovered new evidence of Edison's enormous talent for appropriating techniques that failed in one instance and using them to great effect in another," Sullivan writes.
A generation later a 3M Company engineer used that same spirit of innovation to create the self-attaching, removable bookmark that eventually evolved into the Post-it Note.
During the early 1970s Spence Silver, a chemist in the 3M Company's Central Research Department, was trying to develop a new, stronger adhesive for tape, but instead managed to create a weak one. He mentioned the results of the failed experiment to other 3M researchers, including Arthur Frye, who recounts Post-it Note's history in an article on the 3M Company's Web site.
Frye says he remembered the new, weak adhesive as he was musing about the problem of keeping bookmarks in place in his church hymnal. "This was followed by a dull sermon, and my mind was wandering back to the music problem when I had one of those 'flashes of insight.' Eureka! I think I could make a bookmark, using Dr. Silver's adhesive, that would stick and remove without damaging the book," Frye writes.
Frye helped develop the prototype, and when the new bookmarks were ready, he attached one to a research report, then wrote a note on the blank bookmark. His manager later wrote his answer on the bottom of the bookmark and attached it to an item he was returning to Frye. "It was during a coffee break that afternoon when we both realized that what we had was not just a bookmark, but a new way to communicate or organize information."
The Post-it Note was born, and Silver's failed adhesive became the key ingredient of what today is 3M's best-selling product.
In her books Mistakes That Worked (Doubleday, 1991) and Accidents May Happen: Fifty Inventions Discovered by Mistake (Delacorte Press, 1996), author Charlotte Foltz Jones chronicles dozens of successful failures, including the following:
To Engineer Is Human: The Role of Failure in Successful Design by Henry Petroski, (Vintage Book, 1992).
Set Phasers on Stun and Other True Tales of Design, Technology, and Human Error (2nd edit.)
National Society of Professional Engineers EngineeringEthics page: www.nspe.org/eh-home.htm
Engineering Disasters: Learning from Failure: dol1.eng.sunysb.edu/disaster
Numerical Problems Associated with Ethics Cases (Texas A&M University): ethics.tamu.edu/Nsfcases/
WWW Ethics Center for Engineering and Science at Case Western Reserve University: www.cwru.edu/ affil/wwwethics/
Attitudes About Failure
While engineering failures can result in positive outcomes, such as improved designs and new inventions, many people may only think of engineering failures in negative terms. The idea that "no one thinks of engineering until a bridge collapses" is the oft-repeated lament of engineers trying to improve the profession's image. It's perhaps related to this lament that engineering students can be quite reluctant to address engineering failure, especially when it relates to personal and professional responsibility.
Students just don't want to believe that engineering can have negative consequences, says Arthur Sacks, director of the Liberal Arts and International Studies division at Colorado School of Mines (CSM). Sacks, who teaches the course Nature and Human Values, says many students are not prepared to deal with some of the tough issues, such as pollution and other environmental problems, that can sometimes be the result of engineering "progress" and failure. He attributes much of the students' reluctance to youth and insecurity: "All this can be unsettling to young people, most of whom are just beginning to explore the meaning and implications of their own values and the values of the society in which they hope to be leaders."
Ronald Wiedenhoeft, a CSM liberal arts and international studies professor, also teaches the course and reports the same concern: "The students don't want to upset their view of life."
The course, Sacks explains, is designed to be constructive in the student's process of self-discovery. Sometimes that self-discovery means shaking up students' limited world views and making them tackle tough issues, such as environmental damage caused by the production and utilization of minerals, energy, and materials.
CSM, according to its mission statement, "has dedicated itself to responsible stewardship of the earth and its resources" and its graduates "should, through familiarity with humanities and social sciences, learn the world's complexities beyond their own set of givens, gain an appreciation of other people's values and ways of doing things, think effectively about ethical and social issues, and make conscious choices based on positive values."
CSM sets its students on the path toward those goals by requiring every freshman to take the humanities-based Nature and Human Values course.
Gary Halala, a materials engineering professor at State University of New York at Stony Brook, agrees that getting engineering students to think about consequences is an essential part of a quality education. "I want them to get concerned," he explains. "I don't think they're concerned enough. I want them to know that what they're doing is important."
Some students, Halala explains, particularly those going into computer-related engineering fields, look at engineering as a financially lucrative career without considering the responsibilities that go with it. "They just don't think about programming disasters. If I can communicate anything, it's the question 'Can (the program) handle the unexpected?'"
Raising failure issues is also an important part of exploring engineering ethics, he says. Students in his introduction-to-engineering course study the space shuttle Challenger case as an example of how bad ethics—putting business considerations ahead of safety concerns—lead to disaster.
Halala encourages his students to learn and follow the National Society of Professional Engineers' Code of Ethics, which covers a variety of failure-related issues. Section II of NSPE's Rules of Practice states:
Engineers shall hold paramount the safety, health, and welfare of the public. . . . If engineers' judgment is overruled under circumstances that endanger life or property, they shall notify their employer or client and such other authority as may be appropriate.
Also, NSPE's "Professional Obligations" section states the following:
Engineers shall acknowledge their errors and shall not distort or alter the facts. . . . Engineers shall advise their clients or employers when they believe a project will not be successful.
Halala says he sees his courses as "philosophy of engineering" and that philosophy includes the idea that "any engineering disaster is made up of three parts: unexpected circumstances, poor design, and ethical failure."
He says his students enjoy looking at the tough issues: "Engineering turns out to be much bigger than they thought it was, but it's also more exciting," he says. Students find it so interesting, he says, that he now uses engineering failure examples to interest high school students in engineering and to keep engineering classes interesting and relevant to freshman. "It hits all the aspects of engineering," Halala explains. "It encompasses robust design, ethics, quality control, and failure analysis." It also helps keep engineering relevant by adding current events, which shows students how engineering is a part of their everyday lives.
Vicky Hendley is senior editor of ASEE PRISM.