An AHP-fuzzy FMEA and bow-tie barrier approach for maintenance risk assessment of outdoor-parked general aviation aircraft

Purpose This study aims to evaluate a maintenance risk-prioritization and barrier-mapping workflow for outdoor-parked general aviation aircraft. Design/methodology/approach Six failure scenarios were identified from 220 anonymized records covering 23 long-parking episodes and assessed by 12 qualified experts. Eleven consistent analytic hierarchy process (AHP) matrices yielded severity, occurrence and detection weights of 0.7572, 0.1224 and 0.1204. Median ratings were evaluated by fuzzy failure mode and effects analysis (FMEA) and mapped to Bow-tie task-card requirements. Robustness was tested across 27 weight combinations; record burden was reported as finding density over 9,225 aircraft-parking days, and rating dispersion and agreement were assessed. Findings Landing-gear/brake corrosion and engine-intake contamination ranked first and second. Three middle scenarios were borderline high because their classifications changed underweight or quartile perturbation; lower-fuselage water ingress remained medium. Conventional risk priority number produced the same ranking (Spearman rho = 1.00), so the integration did not improve ordinal discrimination. Average-measures intraclass correlation coefficient (ICC)(2,12) ranged from 0.954 to 0.973. Research limitations/implications The single-organization, Cessna 172/525, humid-inland case limits generalization. Because the retained index lacks aircraft and parking-episode identifiers, episode-level incidence and cluster-adjusted intervals cannot be estimated. The workflow requires local recalibration and prospective multi-site operational validation. Practical implications The workflow can support inspection and task-card planning after local recalibration; operational benefits require prospective validation. Originality/value The contribution is an auditable applied workflow linking established AHP-fuzzy FMEA methods to explicit Bow-tie-derived maintenance actions, not a new risk-analysis method.