Unmanned Systems Technology 013 | AutonomouStuff Lincoln MKZ | AI systems | Unmanned Underwater Vehicles | Cosworth AG2 UAV twin | AceCore Neo | Maintenance | IDEX 2017 Show report

69 Regulations, Part 107, on standards and operations for small UASs weighing less than 55 lb. Unfortunately, these guidelines remain vague, beyond requiring the proper working condition of control links, sufficient power, and security and safety of any payload. Official advisory circulars have since pointed towards more specific tasks, including visually inspecting constituents of the airframe structure, propulsion system and avionics, and performing tests to verify the adequate operation of all systems before flight. Also encouraged is detailed record- keeping of any repairs, modifications, overhauls or replacements, with a view to establishing a long-term and reliable maintenance schedule. While helpful, these guides do not identify any failure modes or signs indicating the need for preventative or corrective measures. Also, UASs larger than 55 lb are not required to comply with Part 107, leaving insufficient safeguards against major software or hardware issues during flight. This lack of regulatory requirements for standard maintenance instructions has the potential to cause a major slowdown or ‘reset’ of the unmanned systems industry in the near future. Even without regulations that push for more consistent maintenance practices, however, liability requirements will ‘pull’ the industry towards better standards-keeping. Poor guidelines sold with small, hobby- type consumer drones, lacking wiring diagrams or fault isolation manuals, will lead to accidents caused by system failures. If that leads to litigation then the courts must determine whether the user had been irresponsible or whether the manufacturer of the airframe or faulty subsystem failed to provide sufficient documentation to ensure the safety of the user, their equipment and third parties. It is crucial therefore that OEMs remain aware of the best practices, tools and services for keeping unmanned aircraft and components airworthy, and instruct their customers accordingly. The proliferation of UASs has coincided with improvements in maintenance systems and the emergence of a global maintenance infrastructure, with networks of MRO (maintenance, repairs and overhauls) depots and servicers working closely between operators and OEMs. It is increasingly common for such servicers to perform major as well as minor checks, repairing what they can and returning more complex components (particularly payload sensors and avionics) to their manufacturer, for any major repairs and replacements on loan – mirroring trends in manned aviation. Data logging It is unfortunate that standards have lagged, because UAVs are largely better positioned than manned aircraft for highly productive maintenance practices, by the many sensors commonly integrated throughout a system’s architecture. Advances in microprocessors from companies such as ARM and Intel have spurred the development of MEMS sensors and data storage systems to record the operating time and usage levels of both the UAV and its constituent systems, enabling operators to anticipate with unprecedented accuracy when an item needs a periodic check or to be replaced – the latter typically occurring after a given number of hundred or thousand hours. This proliferation of MEMS and solid-state devices is further aided by their increasing miniaturisation, cost- effectiveness, robustness and tolerance of environmental extremes. MEMS sensors convert mechanical inputs into electrical signals, allowing for digital inputs with precise records and automated data analysis from ECUs, to produce accurate logs of each mission. That in turn allows routine inspections and overhauls to be scheduled in line with OEM directives, and helps determine non-routine maintenance tasks when indications of poor system health or malfunctions are identified in the flight parameters from the engine and airframe. Judicious use of data storage drives and filtering techniques should also be encouraged among maintenance teams and OEMs to enhance the effectiveness of regular data logging. Fuel engines In the case of UAV engines, data should be collected for regular holistic examinations. Targeted inspections Maintenance | Focus Unmanned Systems Technology | April/May 2017 The proliferation of MEMS sensors allows maintenance engineers to log, track, filter and analyse system behaviour from UAVs and their component systems (Courtesy of Canadian UAVs)