Abstract: A finished floor assembly covers a floor area of an aircraft and includes a subfloor, a padding assembly, and a finish flooring layer. Noise radiates from the subfloor due to vibrations transmitted by an aircraft structure. The padding assembly attenuates the noise and includes a first pad layer, a second pad layer, and a plurality of discontinuous couplings. The first pad layer abuts the subfloor. The second pad layer is adjacent to the first pad layer. The plurality of discontinuous couplings are laterally separated from each other along the floor area by void portions. The discontinuous couplings secure the first pad layer to the second pad layer and the first pad layer and the second pad layer are in contact at the void portions. The finish flooring layer disposed overtop the padding assembly.

Abstract: An apparatus for monitoring health of one or more cells in a battery includes a health monitoring system configured to measure voltage on one or more cells when a waveform is injected into the one or more cells. The waveform is measured at an end of a pulse for each current.

Abstract: Provided herein are circuits and methods for processing samples of a received in-phase and quadrature (I/Q) domain signal that includes a desired signal and an interference signal that spectrally overlaps the desired signal. In the I/Q domain, a first contribution to the interference signal is removed from the samples using a first algorithm to generate first processed signal samples. Amplitudes and phases of the first processed signal samples are obtained. In an amplitude domain, a second contribution to the interference signal is removed from the amplitudes of the first processed signal samples using a second algorithm to generate second processed signal samples. A signal quality metric of the second processed signal samples is obtained. Based on the signal quality metric of the second processed signal samples, one or more parameters of the first or second algorithm are adjusted to improve the signal quality metric of the second processed signal samples.

Abstract: Outflow valve assemblies for an aircraft, aircraft including an outflow valve assembly, and methods for installing an outflow valve assembly on an aircraft, are provided. In one example, an outflow valve assembly includes a louver that is movably disposed to at least partially cover an opening formed through a fuselage on an aircraft. A motor is coupled to the louver and is configured to move the louver between a closed position to obstruct fluid communication through the opening and an open position to allow fluid communication through the opening between inside and outside of the aircraft. A sound absorptive panel is disposed adjacent to the opening to attenuate noise that is generated when the louver is in the open position.

Abstract: Fractional Fourier Transform (FrFT)-based spectrum analyzers and spectrum analysis techniques are disclosed. Rather than using the standard Fast Fourier Transform (FFT), the FrFT may be used to view the signal content contained in a particular bandwidth. Usage of the FrFT in place of the frequency or time domain allows viewing of the signal in different dimensions, where “spectral” features of interest, or signal content, may appear where they were not visible in these domains before. This may allow signals to be identified and viewed in any domain within the continuous time-frequency plane, and may significantly enhance the ability to detect and extract signals that were previously hidden under interference and/or noise, provide or enhance the ability to extract signals from a congested environment, and enable operation in a signal-dense environment.

Abstract: An inlet arrangement for a propulsion system includes an actuator, a linkage and an inlet assembly. The inlet assembly includes (1) a lip, (2) a cowl extending downstream from the lip, the cowl defining an external surface of the inlet assembly, (3) an inlet duct extending downstream from the lip, the inlet duct disposed radially inward of the cowl, and (4) a movable component associated with the lip, the cowl, or the inlet duct. An outer surface of the inlet duct and an inner surface of the cowl define a gap therebetween. The linkage is disposed in the gap and coupled with the moveable component. The linkage is configured to move within the gap and to move the moveable component when the linkage moves. The actuator is coupled with the linkage and moves the linkage when the actuator is actuated. The actuator is mounted remotely from the inlet assembly.

Abstract: High-throughput software-defined convolutional interleavers and de-interleavers are provided herein. In some examples, a method for generating convolutionally interleaved samples on a general purpose processor with cache is provided. Memory is represented as a three dimensional array, indexed by block number, row, and column. Input samples may be written to the cache according to an indexing scheme. Output samples may be generated every MN samples by reading out the samples from the cache in a transposed and vectorized order.

Abstract: Vertical resolution and/or vertical accuracy of terrain elevation data near an aircraft runway is adjusted by obtaining local terrain data, yielding a first elevation value for a query location. A processor receptive of the first elevation value computes plane equations based on a predetermined standard model adapted to geometrically conform to the aircraft runway, yielding a second elevation value for the query location. The processor selectively uses the first and second elevation values to generate an adjusted elevation value that is supplied to a terrain avoidance and warning system.

Abstract: A thrust reverser for an aircraft includes a jetpipe and a thrust reverser door. The thrust reverser door has an aft end, a forward end, and an interior surface facing radially inward. The interior surface defines a continuous profile with a downstream nozzle portion directly adjacent to the aft end, a concave portion directly adjacent to the downstream nozzle portion, and a convex portion directly adjacent to the forward end and adjacent to the concave portion.

Abstract: Methods for monitoring engine health of an aircraft having a first engine and a second engine are provided. In one example, the method includes obtaining a first turbine gas temperature of the first engine and a second engine turbine gas temperature of the second engine from a first flight. The first turbine gas temperature and the second turbine gas temperature are related to each other to define a first value. The first value is compared to a data set for monitoring the engine health.

Abstract: A flight guidance panel for an aircraft includes a subpanel display, a joystick, rotary encoders, a deflection sensor, and a processor. The subpanel display indicates autopilot modes and flight value goals and has a top-level state and a subpanel control state. The joystick is for user interaction with the subpanel display. The rotary encoder is coupled with the joystick to receive rotation inputs from a user of the joystick. The deflection sensor is coupled with the joystick to detect a deflection input from the user of the joystick. The processor is programmed to: change a state of the subpanel display to the subpanel control state corresponding to a selected subpanel in response to receiving the deflection input while the subpanel display is in the top-level state; and change the flight value goals in response to receiving the rotation inputs while the subpanel display is in the subpanel control state.

Abstract: The aircraft threat envelope protection system employs a threat envelope data structure in a computer-readable medium that stores at least one trigger condition for each of a plurality of different types of threats associated with the aircraft, and modeled using a common schema. A processor computes plural different projected trajectories representing different possible aircraft paths through spacetime. The processor associates at least some of the plurality of the threats to specific trigger points in spacetime along each of the projected trajectories. The processor will deprecate ones of the projected trajectories when they are deemed not viable to recover from a threat. The processor initiates an aircraft protective response when all projected trajectories but one have been deprecated and the aircraft is within a predetermined proximity to the closest trigger point in spacetime along the non-deprecated trajectory.

Abstract: An engine inlet cover and a method for covering an engine inlet are provided. A method for covering an engine inlet includes providing a collapsible cover comprising a connection pin defining an axis; a frame including interconnected arms; and a web. Further, the method includes storing the collapsible cover in a stowed configuration in which the arms are aligned. Also, the method includes rotating the arms from the stowed configuration to an operating configuration in which the arms are radially spaced about the axis, enclosing the frame in the operating configuration with the web to define an interior volume, and placing the cover over the engine inlet.

Abstract: A multi-purpose in-situ contamination sampler includes an inner frame surrounded by a plurality of removable or attachable pieces, each of which include of a single witness surface configured to collect both particulate and molecular contamination within an environment on a payload or a spacecraft.

Abstract: Cell-based systems may interlock in a reconfigurable configuration to support a mission. Space systems, for example, of a relatively large size may be assembled using an ensemble of individual “cells”, which are individual space vehicles. The cells may be held together via magnets, electromagnets, mechanical interlocks, etc. The topology or shape of the joined cells may be altered by cells hopping, rotating, or “rolling” along the joint ensemble. The cells may be multifunctional, mass producible units. Rotation of cell faces, or of components within cells, may change the functionality of the cell. The cell maybe collapsible for stowage or during launch.

Abstract: Cyberattacks are rampant and can play a major role in modern warfare, particularly on a widely adopted platforms such as the MIL-STD-1553 standard. To protect a 1553 communication bus system from attacks, a trained statistical or machine learning model can be used to monitor commands from a bus controller of the 1553 communication bus system. The statistical and/or machine learning model can be trained to recognize communication anomalies based at least on the probability distribution of patterns of one or more commands. The statistical model can be stochastic model such as a Markov chain that describes a sequence of possible commands in which the probability of each command depends on the occurrence of a group of one or more commands.

Abstract: An indicator for monitoring temperature and wear of one or more aircraft brakes. One or more sensors are provided for sensing a parameter of usage, and an estimate of usage of the part can be determined based upon the signal indicating the sensed value of the parameter of usage of the aircraft part. A plurality of sensors can be provided for sensing usage of a plurality of parts of the aircraft, and the estimate of usage of the part can be stored for access of the estimate by ground personnel. In addition, the sensed usage data are critical inputs for the brake controller to regulate which brakes are applied.

Abstract: An expandable fuel line section for an aircraft, a fuel line for an aircraft, and a method for fabricating an expandable fuel line section for an aircraft are provided. In one non-limiting example, the expandable fuel line section includes a first inner tube section subassembly. A second inner tube section subassembly is in fluid communication with the first inner tube section subassembly. An outer tube subassembly has an outer tube wall surrounding an outer tube channel. The first and second inner tube section subassemblies are slidingly disposed in the outer tube channel to move between retracted positions and extended positions.

Abstract: A steering system for a skid steered vehicle has a variable-speed steering motor, and an asymmetrical steering differential operatively connected to the steering motor and rotatably mounted on a first side of the chassis separately from the propulsion system. The steering differential has a first differential shaft and a second differential shaft, where the asymmetrical differential imparts a greater speed change on the second differential shaft than the first differential shaft. The first differential shaft is connected to a first steering output shaft operatively connected to at least one ground-engaging element on the first side of the vehicle. A speed reducer mounted fixedly on the chassis connects the second differential shaft to a second steering output shaft operatively connected to at least one ground-engaging element on the second side of the vehicle so that the second steering output shaft experiences the same speed change but in an opposite rotational direction as the first steering output shaft.

Abstract: Systems and methods are provided for operating to an initial optimized baseline solution to a multi-objective problem. As the initial optimized baseline solution is determined, some regions, such as local or global maxima, minima, and/or saddle points in the objective space may be mapped. The mapping may be performed by storing mesh chromosomes corresponding to some of the features (e.g., extrema, saddle points, etc.) in the objective space along with the location of those chromosomes within the objective space (e.g., objective values corresponding to each of the objectives). The mesh chromosome may be used in subsequent re-optimization problems, such as with reformulation. Although in a re-optimization the objectives, decision variables, and or objective/constraint models may change, the mesh chromosomes may still provide information and direction for more quickly and/or with reduced resources converge on a re-optimized solution.