I have seen many case studies on Engineering Ethics in which managers have not heeded the device of their underlying engineers, such as the Challenger disaster. I think in order for a manager to really perform their duties well, they need to have performed the same tasks they are asking the people they are managing. It is hard to respect someone who you feel you know more than, as it is difficult communicating your questions and concerns. All of these issues are eliminated when managers are promoted from technical positions, as they are the ones who have been identified as excelling in their expertise and know how to solve problems. If all they know how to do is delegate tasks and balance spreadsheets, then the project is doomed to fail if and when the first hurdle appears.