Prognostic Health Management of Aircraft Power Generators

In this paper, prognostic tools are developed to detect the onset of electrical failures in an aircraft power generator, and to predict the generator's remaining useful life (RUL). Focus is on the rotor circuit since failure mode, effects, and criticality analysis (FMECA) studies indicate that it is a high priority candidate for condition monitoring. A signature feature is developed and tested by seeded fault experiments to verify that the initial stages of rotor faults are observable under diverse generator load conditions. A tracking filter is used to assess the damage state and predict generator RUL. This information helps to avoid unexpected failures while reducing the overall life-cycle cost of the system.     

ATS-6 Synchronousi Orbit Trapped Radiation Studies with an Electron-Proton Spectrometer

The University of Minnesota Electron-Proton Spectrometer Experiment consists of two nearly identical detector assemblies. One of these assemblies was mounted in a position fixed on the satellite in the Environmental Measurements Experiments (EME) east direction and the other was rotated so that the spectrometer scanned a range of spatial directions covering 1800 from EME north to EME south through west. Each of the detector assemblies is a magnetic spectrometer containing four gold-silicon surface barrier detectors. This instrument provides a very clean separation between protons and electrons by the combination of pulse height analysis and magnetic deflection. Each detector assembly measures protons in three nominal energy ranges (30-50 keV), (50-160 keV), and (120-514 keV). Electrons also are measured in three energy intervals (30-50 keV), (150-214 keV), and (more than 500 keV). Data are transmitted from the experiment at rates as high as 8 measurements/s. Decreases in the flux of the energetic electrons and protons followed by very rapid increases are frequently observed on the nightside during periods of geomagnetic activity. Separation of temporal and spatial effects is possible using proton gradient information obtained when the detector systems are oppositely directed. Using this technique, the decreases have been interpreted as motion of the trapping region equatorward and Earthward of the satellite. The boundary motion associated with the particle recovery shows a marked local time dependence. Particle increases observed in the evening sector have been interpreted as motion from Earthward and equatorward of Applications Technology Satellite-6 (ATS-6).     

Avionics for Aeronautical Systems

Advancements in technology have led to increased demand for avionics in airborne applications. Although aeronautical system suppliers have implemented improved procedures and design approaches which are generally effective, challenges continue to exist. This paper explores several areas where overall aeronautical system design might be improved by proper emphasis on avionic subsystem design. The topics selected include standardization, weight impact, environmental control, maintainability, and avionic equipment growth. Comparisons are made in terms of ultimate cost to the aeronautical system user.