Design Interface, as defined in the IPS Element Guidebook, is the activity of “participating in the systems engineering process to impact the system design for maximum availability and effectiveness at lowest cost.” During system development, Design Interface is a “leading activity,” in that design decisions not only have implications across the life cycle, but also play a central role, along with Product Support Management, in impacting the other 10 Integrated Product Support (IPS) Elements, as shown in Fig. 21 of the DoD PSM Guidebook. For this reason, PSMs should pay close attention to Design Interface activities.

Design decisions made early in the life cycle tend to “lock in” sustainment costs, which make up 60-70% of Life Cycle Costs for a weapon system, and are often difficult and/or costly to change once a system is fielded. For example, a design decision on where to position an aircraft’s main battery can have maintenance implications for decades of service. In the case of the F-4 Phantom II, a design decision likely driven by considerations other than product support required raising or removing part of the ejection seat to replace the battery. Conversely, the aircraft that replaced the F-4, the F-16 Fighting Falcon, has its battery in the wheel well, much more accessible and efficient to maintain.

To promote effective and efficient supportability, the PSM should assign logistician(s) to the Reliability and Maintainability (R&M) Working Group or equivalent Integrated Product Team (IPT) to collaborate with systems engineering (and other specialty engineering, such as Human Systems Integration (HSI)) and maintenance SMEs to analyze, evaluate, and influence system and support design. This includes participation in supportability analysis activities, such as Fault Tree Analysis (FTA); Failure Mode, Effects, and Criticality Analysis (FMECA); Reliability-Centered Maintenance Analysis (RCMA); Maintenance Task Analysis (MTA); and Level of Repair Analyses (LORA).

For digital programs, the PSM’s Design Interface responsibilities are enhanced through use of a model-based Human Engineering Design Approach Document-Maintenance (HEDAD-M) and model-based systems engineering and technical reviews (such as Preliminary Design Review and Critical Design Review), which assist in visualizing and evaluating system and support designs.

To explore Design Interface further, consider DAU’s online training course LOG 0080, Designing for Supportability in DoD Systems; CLCL 005, Supportability & Design Interface Credential; or CLCL 006, Designing Supportable Systems Credential.