Analysis code for "The Volumetric Blind Spot: How the Reference Geometric Factor in the ICAO CO2 Standard Mis-Specifies Efficiency for Mid-Size Freighters" (The Aeronautical Journal, manuscript AeroJ-2026-0336, revised manuscript under review)

Analysis code accompanying the revised manuscript AeroJ-2026-0336. It covers: the codified ICAO CO2 limit lines L_NT(M) and L_InP(M) (40 CFR 1030.30); the structural (empty-weight) model; the transpose-pair arithmetic and the analytic induced-drag carry-over derivation; the OpenVSP/VSPAERO comparison model in its two releasedconfigurations (the forward reconstruction and the equalised-exposed-span configuration on which the Section 4.4 comparison is stated); the Monte Carlo propagation of Experiment A and the Section 4.5 mission model; the clean-sheet placement analysis; the Section 5 remedy benchmark; and the generation of Figures 1-5 with Table 4. The OpenVSP scripts generate their .vsp3 model files on run. Figure 1's freighter points are illustrative only, exactly as the figure caption states (anchored centrals, not estimator outputs, no uncertainty bands). The estimator predictions of Appendix A are not covered by this release; their record is Appendix A of the paper. The data underlying the study are the public sources cited in the paper's reference list. Requirements: Python 3.10+, NumPy, Matplotlib (figure images only); SciPy optional (pure-Python fallbacks included); OpenVSP 3.x with its Python module for the two OpenVSP scripts only.