Who Leads System Design?

8.5 Design Oversight Responsibility

Although it is not the intent of this book to describe systems engineering management processes it is helpful to briefly describe how roles and responsibilities change during the system development phases. The first change in responsibility takes place when the baseline design is refined through trade studies to be the preferred design, e.g. a best value design, and the design requirements database is complete. The system development work is then at the end of the define requirements phase and ready to enter the design phase. This means the design requirements are complete to the level of responsibility of each of the lowest level IPTs, assuming the work is organized so that the lowest level IPT leaders are able to work in the “craftsman” model, i.e. the leader has the knowledge and experience to make all the design decisions for the work assigned to his/her IPT. At this point the individual IPTs take leadership responsibility from the SEIT or systems engineering and lead in determining how the system is designed and any prototypes built.

During the design phase systems engineering watches over the design to ensure requirements compliance, testability and producibility and monitors MOEs, progress on “ilities” and risk management. In addition, systems engineering is responsibility to manage any specification changes. If designers encounter difficulties in meeting an allocated requirement then systems engineers should take responsibility for determining if and how the requirement in question can be modified without jeopardizing overall requirements compliance. The systems engineering role during the design phase can be summarized as supporting the designers to ensure that a balanced and compliant design is achieved that is testable, producible and maintainable.

The transition from the system definition phase to the design phase is typically gated with a design review, e.g. a System Design Review (SDR). Program managers often wish to move systems engineers off a development project when the actions items from a SDR are complete. Although this is a time to increase the design specialty engineers and decrease the systems engineers on the IPTs removing too many systems engineers can leave the designers without adequate systems engineering support and cause other necessary tasks to be understaffed. It is better to assign the systems engineers to tasks like preparing system and subsystem integration and test plans and completing and maintaining the system design documentation.

When the design phase is compete and any prototypes are fabricated then systems resumes lead responsibility during test even though other specialty engineers may conduct the testing. Typically this change in leadership occurs sometime during integration and subsystem testing of an engineering model or prototype. These leadership responsibility transitions should occur naturally for IPTs with experienced systems and design engineers.