Electrical propulsion has been identified as a key enabler of greener, quieter, more efficient aircraft. However, electrical propulsion aircraft will need to demonstrate a level of safety and reliability at least equal to current aircraft to be a viable alternative. Therefore, a robust and reliable fault management system is needed to prevent electrical faults causing loss of propulsion and critical flight functions. To date, fault management of the electrical propulsion system has not been considered in detail for future electrical propulsion aircraft, nor has it been effectively integrated into the electrical architecture design. This poses a risk that the proposed electrical architectures will be infeasible from a fault management perspective, and key fault management technologies may not be sufficiently developed. Therefore, a methodology to incorporate fault management into the early stages of design of electrical architectures is required to determine viable fault management solutions for a given electrical propulsion aircraft concept. This paper describes a novel, systems-level electrical architecture design framework for electrical propulsion aircraft which incorporates fault management from the outset. This methodology captures the significant assumptions in the design and acknowledges the novel interfaces which exist between the electrical, conceptual and fault management design of electrical propulsion aircraft.

Abstract-The TeDP concept has been presented as a possible solution to reduce aircraft emissions despite the continuing trend for increased air traffic. However, much of the benefit of this concept hinges on the reliable transfer of electrical power from the generators to the electrical motor driven propulsors. Protection and fault management of the electrical transmission and distribution network is crucial to ensure flight safety and to maintain the integrity of the electrical components on board. Therefore a robust fault management strategy is required. With consideration of the aerospace-specific application, the fault management strategy must be efficient, of minimal weight and be capable of a quick response to off-nominal conditions. This paper investigates how the TeDP architecture designs are likely to be driven by the development of appropriate fault management strategies.

Electrical propulsion has been identified as a key enabler of greener, quieter, more efficient aircraft. However, electrical propulsion aircraft (EPA) will need to demonstrate a level of safety and fault management at least equal to current aircraft. This will rely heavily on the capability and design of the electrical fault management (FM) system. Given the functional limitations and current lack of availability of FM technologies suitable for a future EPA application, strategic development of FM devices is required. Whilst there are a variety of roadmaps for EPA concepts and some of the key electrical components, the necessary strategic development of FM solutions targeted towards EPA has yet to be established. This paper proposes FM strategy maps which go beyond projections of expected development in various FM technologies to scope the feasibility of key FM solutions. This method can then be used to present FM technology projections, electrical oversizing and wider system redundancy alongside the various aircraft concepts in development. This results in strategy maps which capture the impact of any FM technology barrier on the viability of a given aircraft concept, enabling critical FM solutions to be integrated into the wider electrical system development. Index TermsFault management strategy map, electrical propulsion aircraft, electrical power systems, protection technology development. I. INTRODUCTIONElectrical propulsion has been identified as a key enabler of greener, quieter, more efficient aircraft. Novel electrical propulsion aircraft (EPA) will depend on the development of a range of electrical technologies, many of which are currently at low TRL (Technology Readiness Level). Given the risk that an EPA concept may rely on key technologies which may not be sufficiently developed as desired at the aircraft's point of entry into service, it is important to develop understanding of the particular challenges which must be addressed in bringing technologies to maturity. One of the most challenging set of technologies for EPA are the fault management (FM) devices,

Electrically driven distributed propulsion has been presented as a possible solution to reduce aircraft noise and emissions, despite increasing global levels of air travel. In order to realise electrical propulsion, novel aircraft electrical systems are required. Since the electrical system must maintain security of power supply to the motors during flight, the protection devices employed on an electrical propulsion aircraft will form a crucial part of system design. However, electrical protection for complex aircraft electrical systems poses a number of challenges, particularly with regard to the weight, volume and efficiency constraints specific to aerospace applications. Furthermore, electrical systems will need to operate at higher power levels and incorporate new technologies, many of which are unproven at altitude and in the harsh aircraft environment. Therefore, today's commercially available aerospace protection technologies are likely to require significant development before they can be considered as part of a fault management strategy for a next generation aircraft. By mapping the protection device trade space based on published literature to date, the discrepancy between the current status of protection devices and the target specifications can be identified for a given time frame. This paper will describe a process of electrical network design that is driven by the protection system requirements, incorporates key technology constraints and analyses the protection device trade space to derive feasible fault management strategies.

Background The evaluation of treatment response in patients with gliomas is performed using the Response Assessment in Neuro-Oncology (RANO) criteria. These criteria are based on cerebral magnetic resonance imaging (MRI), steroid use and neurological function. However, a standardized tool for evaluating neurological function was lacking. We compared changes in the National Institute of Health Stroke Scale (NIHSS) to changes in the RANO categories to determine the relationship between clinical and neuroradiological findings. Methods We reviewed data on all adult patients with supratentorial gliomas WHO grade II-IV who were treated at the Cantonal hospital St. Gallen from 2008 – 2015. The NIHSS was performed prospectively at baseline and at 3-months intervals simultaneously to MRI. Associations between changes in the NIHSS and RANO categories were assessed using the Stuart-Maxwell test. Results Our cohort consisted of 61 patients from which 471 observations were analyzed. The most common histological diagnosis was glioblastoma (49.2%). In total, 74% of RANO categories and 81% of the NIHSS scores remained stable on follow-up. Statistically, contemporaneous changes in the RANO category did not correlate with changes in the NIHSS (p < 0.0001). Conclusion The application of the NIHSS is easy and feasible in the heterogeneous population of glioma patients. In our cohort, the RANO categories did not reflect contemporaneous changes in the NIHSS. A validated clinical outcome measure with a well-defined minimal clinically important difference is warranted in neuro-oncological research and clinical practice.