A methodology to assess the re-purposing of manned aircraft airworthiness standards for unmanned aircraft

As unmanned aircraft systems (UASs) become more common in civilian and military applications, certifying agencies must ensure the safety of third parties on the ground. In order to leverage existing knowledge, approaches based on re-purposing manned aircraft airworthiness standards have been proposed. Standards for manned aircraft often ensure safety of third parties indirectly by instead ensuring the safety of persons on-board the aircraft. Thus, approaches that simply ignore or remove airworthiness requirements that address the pilot or the crew may not ensure the safety of persons and properties on the ground. In this paper, we present a methodology to assess the re-purposing of manned aircraft airworthiness standards for UAS that is grounded on principles from requirements engineering and functional analysis. We identify three main categories of manned aircraft airworthiness standards: (1) those that are directly applicable to UAS, (2) those that can be ignored when considering UAS with no reduction in safety, and (3) those for which functional and safety analyses must be performed to assess if they can be ignored or converted into a new set of safety requirements specific for UAS.