MODERN AIRCRAFT SYSTEMS HAVE SLOWLY EVOLVED TOWARDS INTEGRATED MODULAR COMPUTING ARCHITECTURES THAT ARE LINKED TO MULTIPLE EXTERNAL NETWORKS. THESE DEVELOPMENTS HAVE INTRODUCED CYBER-ATTACK VULNERABILITIES WHICH DID NOT EXIST IN OLDER-GENERATION AVIONICS SYSTEMS. TO COUNTER THE EMERGING THREATS AND INCREASED VULNERABILITIES, AN ABILITY TO COMPREHENSIVELY AND SYSTEMATICALLY ASSESS AVIATION CYBERSECURITY RISKS IS NEEDED. TOOLS ARE NEEDED TO SUPPORT THE DESIGN OF NEW AIRCRAFT SYSTEMS AS WELL AS TOOLS THAT CAN SUPPORT ROUTINE INSPECTIONS ON AN AIRFRAME-BY-AIRFRAME BASIS. ATC-NY PROPOSES SILVERLINEAN, AN ASSESSMENT MANAGEMENT PLATFORM FOR AVIATION SYSTEMLEVEL CYBERSECURITY. SILVERLINEAN PROVIDES A PRINCIPLED, MACHINE-READABLE RECORD OF BOTH MANUAL AND AUTOMATED CYBERSECURITY RISK ASSESSMENT PROCEDURES AND RESULTS FOR INDIVIDUAL COMPONENTS/SUBSYSTEMS, COMPUTES SYSTEM-LEVEL METRICS, AND FACILITATES REEVALUATION THROUGHOUT THE SYSTEM S LIFECYCLE. SILVERLINEAN AGGREGATES INDIVIDUAL COMPONENT/SUBSYSTEM RESULTS INTO A LARGER ATTACK MODEL, WHICH CAN BE USED TO ASSESS SYSTEM-LEVEL RISK. THE SILVERLINEAN TOOL CAN SERVE BOTH AS DEVELOPMENT TOOL AND IN A MAINTENANCE CAPACITY. FOR EXAMPLE, DURING THE DEVELOPMENT OF A NEW AVIONICS COMPONENT UNDER A SUPPLEMENTAL TYPE CERTIFICATE (STC), THE DEVELOPING ORGANIZATION COULD TEST THE THE COMPONENT FOR CYBER-VULNERABILITIES USING THE SILVERLINEAN TOOL. IN A MAINTENANCE CAPACITY, AN AMT (AVIATION MAINTENANCE TECHNICIAN) MIGHT USE SILVERLINEAN TO VERIFY THAT AN AVIONICS INSTALLATION OR UPDATE ON A PARTICULAR AIRFRAME HAS NOT INTRODUCED ANY CYBER-VULNERABILITIES