Often project managers will face a merry-go-round of evolving requirements that will drive the most sane among us crazy. Decisions are made in midstream, sometimes at odds with the project's objectives, that require a project team to quickly change priorities and direction. This is the unpredicable world of project management.
In order to succeed, a project manager must be able to play in an ambiguous sand box. It requires creativity and a single minded focus on the end game. Our tendency is to try to solve problems with more control and complexity; however, the best solutions are generally the simplest solutions - there is an elegance in simplicity. Even the most elaborate endeavors benefit from simplicity born of a clear mission.
Case in point:
These engineers were free to make decisions on the ground based on the circumstances facing them. They were well aware of what success looked like, but diverged from common methods without fear of compromising the project. By the way, their solution was far less expensive and took less time. This simple solution can be a touchstone for project managers.
Always go back to the restraint and rhythm of simplicity.