MAKING A MILLION DECISIONS
Myriad initial design considerations have far-reaching consequences By Warren Hoburg
Today’s aircraft are some of the most complex engineering systems ever conceived and built.
For example, a Boeing 777-300ER comprises approximately three million parts, provided by 500 suppliers worldwide. Designing, testing, certifying, and producing such a system is a monumental undertaking representing millions of decisions and years of effort. For aircraft manufacturers, airlines, government operators, regulatory agencies, or investors, the stakes are high — decisions made early in the design process lock in operational and manufacturing costs, marketability, and mission constraints for years to come. While design programs once focused heavily on vehicle performance (“further, faster, higher”), today’s design considerations stretch far beyond vehicle systems to production systems, supply chains, manufacturing processes, and operations. This complex web of interactions and tradeoffs drives hundreds of billions of dollars in annual economic activity. There is substantial industrial and academic interest in optimization models that can improve solutions, and enable more informed decisions earlier in the design process. Just as computation and simulation have pervaded all aspects of engineering, numerical optimization is becoming a widely used tool, now embedded in many analysis routines and software packages. This brings great opportunity, but also introduces unique challenges. Currently, starting with a clean sheet of paper, it takes approximately one decade to design a new commercial aircraft. To put this in perspective, Donald Douglas’ (an MIT alumnus and aeronautics assistant professor) 1933 DC-1 was designed and placed in service in fewer than two years. For today’s more complex systems, non-recurring design costs constitute a significant portion of most program budgets. Production tooling requires long lead times, forcing designs to be fixed
Myriad initial design considerations have far-reaching consequences