Life cycle assessment of an uncrewed military aircraft: a methodological approach for confidentiality-constrained analyses

We present the first comprehensive cradle-to-grave life cycle assessment (LCA) of a military aircraft. We developed a methodological approach for conducting LCA under confidentiality constraints through simplified material allocation, including robust data quality and validation strategies. This provides baseline data for military carbon accounting whilst demonstrating a transferable method for environmental assessment in data-constrained industrial sectors. We conducted a cradle-to-grave LCA for an uncrewed aircraft system. Twenty-five process-based models represented 95% of aircraft mass across material categories (metallics, composites, electrical, electronics, miscellaneous). Primary energy data from power measurements covered 30% of manufacturing emissions, supplemented with validated secondary data. Operational emissions were estimated using business jet parametric analysis supplemented with validated secondary data. Five sensitivity analyses examined operational intensity, material simplification, excluded mass, end-of-life alternatives, and manufacturing energy transitions. Data quality was assessed using pedigree matrix methodology. The ReCiPe 2016 LCIA methodology was applied across all 18 midpoint impact categories. The UAS demonstrates a fundamentally different emissions profile than commercial aircraft. Non-operational phases contributed 56% of total lifecycle emissions compared to <5% in commercial aviation, with operations contributing only 44% versus >95% for commercial aircraft. Sensitivity analyses confirmed this pattern persists across all scenarios, with non-operational phases contributing 32–56% even under wartime assumptions. Carbon fibre composites, aluminium fabrication, and final assembly emerged as the key emission hotspots. Composites represent 17% of aircraft mass but 34% of manufacturing emissions. Normalised impacts revealed Human Toxicity-Cancer exceeds climate change impacts by factor of seven, primarily from coal-based electricity. Military aircraft demonstrate significantly greater non-operational emissions than commercial aviation. The methodological framework – validated through systematic data quality assessment and sensitivity analyses – is transferable to other data-constrained sectors facing security requirements, proprietary restrictions, or supply chain complexity. Future research should focus on composite manufacturing emissions reduction.