Flight Worthiness Evaluation of Small Unmanned Aircraft Using Acoustic Testing

A study on the ability to evaluate flight worthiness of a popular small unmanned aircraft systems (sUAS) using acoustic methods is presented. The ability to detect propeller and other potential damage that may be present in an autonomous operations environment is of great interest. SUAS are increasingly being designed to operate autonomously, however prior to flight there must be a flight worthiness evaluation to help ensure safe operations. To accomplish this, an evaluation of the effects of prop damage in the acoustic signature provides meaningful insight using a noninvasive evaluation tool. This study provides data obtained by experimentally measuring the acoustic noise levels produced, as well as the vibration levels on the host airframe and at the base. The data are analyzed to gain further understanding of the acoustic and vibration responses to accurately make predictions on flight worthiness. The experiments utilize an airframe that is commonly used in the UAS community with props with and without damage. The data are obtained from an aircraft powered in a stowed configuration, as would be occurring at a remote UAS launch station. This detailed study on the acoustic responses help enable the development of noninvasive damage detection algorithms. These systems would be part of robust and economical safety assessment procedures and protocols for preflight testing to ensure flight worthiness of remote autonomous sUAS operations that are planned.