Aging aircraft fleets and recent environmental regulations mandating the use of chromate-free aviation coatings have significantly reduced corrosion protection in modern airframes. These new coating systems, while environmentally compliant, exhibit lower durability in moisture-exposed and chemically aggressive environments. Additionally, aluminium–CFRP joints present in many contemporary aircraft accelerate galvanic interactions, further intensifying structural degradation. Closed and inaccessible zones—particularly under-floor compartments beneath lavatory areas—are highly susceptible to moisture accumulation, condensation, and reagent exposure, making early-stage corrosion difficult to detect and responsible for up to 20–30% of total aircraft maintenance costs. This work presents an advanced Corrosion Health Monitoring (CHM) system tailored for such closed compartments. The system integrates impedance-based and eddy-current sensors with distributed environmental micro-sensors and AI-assisted data analytics. It has been installed and validated on two helicopters, including a transport platform, with sensors deployed across multiple structural zones. As part of a broad research program, the Air Force Institute of Technology (AFIT) conducts large-scale multinational field investigations across several European countries, confirming the system’s robustness and its ability to detect the onset of corrosion under real operating conditions. Building on these results, the next stage involves integration of CHM systems into commercial passenger aircraft, supporting the transition from time-based maintenance to condition-based maintenance (CBM) and enhancing long-term structural integrity, safety, and aviation sustainability.
