Virtual items are a way to simplify a large assembly through abstraction. An example is the Landing Gear of an airplane. This subsystem has a parts-list of items that have physical forms:

• Front landing gear assembly
• Rear landing gear assemblies
• Cover panels/hatche assemblies
• Fasteners
• Cables
• Hydraulic lines

RELATED PAGE Hardware System Interfaces

Many of these components are not colocated, so can not form an assembly that can be placed in inventory. Instead, these items are inventoried as a build kit. The Virtual Item abstaraction allows a system designer to simplify the set of constraints and requirements related to that aspect of the system. This also benefits the designer, as they can create drawings, technical writing documents, and interface control documents to state how the subsystem functions. These drawings show the Virtual Item's parts with solid lines, and then show other reference components in phantom lines.

Some common names for Virtual Items are:

• Subsystem
• Installation
• Upgrade Kit