Interfaces and Interface Control Documents
ICDSection 11: Aircraft & Avionics Architecture
Definition
An Interface Control Document (ICD) formally defines the physical, electrical, logical, and data characteristics of the interface between two or more systems, subsystems, or components. ICDs specify connector types and pin assignments, signal characteristics (voltage levels, timing, protocols), data formats and message definitions, and the responsibilities of each side of the interface.
Where This Shows Up
ICDs are critical certification artifacts because interfaces are a primary source of integration problems and potential failure modes. Each interface must be fully defined, agreed upon by both sides, and verified during integration testing. In avionics, ICDs typically cover power interfaces, data bus interfaces (ARINC 429, ARINC 664, discrete signals, analog signals), mechanical/mounting interfaces, and cooling interfaces. The ICD is controlled under configuration management and must be updated whenever interface changes occur. Uncontrolled or ambiguous interfaces are a frequent finding during certification audits and can result in system integration failures and schedule delays.
Primary Sources
Addresses interface definition as part of the system architecture development process.
Artifacts Produced
Formal document defining all physical, electrical, logical, and data characteristics of an interface between two or more items, controlled under configuration management.
Related Terms
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