“…As highlighted by Aalmoes et al, 6 given that unmanned systems are in their early development stages, operational data needed to populate third party casualty models are lacking. Consequently, the data necessary to drive numerous risk models were approximated through various sources such as numerical distributions, 6, 23 manned aircraft failure rates, 4,6,11 and/or military unmanned or manned operational data. 10 The authors believe that, although such assumptions might be suitable for approximations or comparative studies of various future operational concepts, reliability data from manned aircraft operations do not provide an adequate baseline due to vast redundancy and configuration differences between manned and unmanned aircraft as well as the varying operational context (military vs. civilian aircraft).…”