The objective of this research project is to attain Industry 4.0 capability for small- and medium-sized enterprises (SME) in the n-tier supply chain and for Maintenance, Repair and Overhaul (MRO) processes within aviation industry. 
Challenges in digitization in aviation industry cannot be met solely top down by Original Equipment Manufacturers (OEMs). Instead, Industry 4.0 capabilities must be developed along the whole supply chain for mutual benefit. Cyber-physical enterprise processes are therefore developed in the research project KMUDigital (english: SMEDigital) for two SME representing different supply chain links in order to develop Industry 4.0 capabilities in a bottom up approach. Conditions for SME 4.0 capabilities are analyzed for a second-tier and a first-tier supplier (supplier for parts and appliances). Current physical and information processes for development, production, and MRO processes are documented with a focus on production control, procurement, product certification, and MRO approval. Present interfaces between other supply chain links and legacy SME IT systems are analyzed with respect to digitization potentials. Industry 4.0 capable development, production, and information management processes using cyber-physical systems, e.g. aviation compliant eID technology are developed based on the previous process analysis. The SME and other supply chain links benefit from general multi use concepts that can be applied to other SMEs.