Abstract:

With the global transition of civil aviation navigation systems from magnetic north to true north reference, a dynamic risk assessment model integrating STPA and FBN was proposed to quantify, identify, and effectively control systemic risks induced by the navigation reference transition. A four-level control structure-covering strategic, regional, organizational, and equipment layers-was established to identify seven categories of system-level hazards and twelve types of unsafe control actions. Expert uncertainty was quantified via fuzzy sets, and a Bayesian network (BN) was constructed using the Leaky Noisy-or Gate model. Furthermore, a dynamic Bayesian network (DBN) was developed to simulate risk evolution across five phases (t₀ to t₀+28 years). The results show that technological lag and insufficient policy coordination are the major risk drivers in the early stage (e.g., airspace conflict probability up to 0.852). However, through phased implementation of technology upgrades, policy alignment, and redundancy design, key risks can be reduced to below 0.01 by t₀+28. This study proposes an original strategy integrating the 'phased compliance-fund disbursement' policy linkage mechanism, aircraft service life-based technical iteration path, and the 'inertial navigation + low-orbit satellite' dual-redundancy artificial intelligence (AI) governance system, to systematically resolve policy delays, intergenerational equipment conflicts and operational risks in the true north transition.

Key words: system-theoretic process analysis(STPA), fuzzy Bayesian network(FBN), true north navigation, risk assessment, unsafe control action(UCA), transition process, risk mitigation