Yes. A single control (for example, a technical safeguard or a procedural requirement) can legitimately map to multiple control families, especially in cybersecurity and quality frameworks. This overlap is normal but must be handled with clear scoping, traceable mappings, and documented ownership to avoid double-counting, gaps, or confusion during audits.

Small plants do not need a large, enterprise-grade configuration management system (CMS) to start benefiting from IEC 62443. However, they do need a minimum level of disciplined configuration control, documentation, and change tracking. The right approach depends on plant complexity, legacy systems, validation needs, and audit expectations.

In aerospace, IEC 62443 typically applies to most networked shopfloor control and monitoring assets: machine controllers, SCADA, historians, OT networks, and supporting infrastructure. Exact scope depends on network segmentation, data flows, safety links, and how systems are classified in your cybersecurity/OT asset inventory and risk assessment.

Integrating ISO 27001 with AS9100 in aerospace and other regulated manufacturing environments is feasible but not trivial. The main challenges are aligning risk and control frameworks, handling overlapping documentation and audits, reconciling product quality vs. information security priorities, and adapting controls to brownfield plants, legacy systems, and long equipment lifecycles without implying any compliance guarantees.

ISO 27001 costs vary widely for industrial companies and depend on size, scope, current maturity, and how much is done internally. Expect a multi‑year spend: internal effort (people time) usually dominates, with external costs for consulting, tooling, and certification audits ranging roughly from tens of thousands to low hundreds of thousands of USD, not counting ongoing maintenance.