Abstract: Aircraft are provided with a pair of auxiliary power units (APUs) adjacently mounted in parallel relative to one another within the tail cone section of the aircraft's fuselage. In some embodiments, the APUs are mounted generally vertically adjacent to one another. Alternatively, the APUs may be mounted generally horizontally adjacent to one another. The aircraft fuselage may include a pair of downwardly and outwardly oriented strakes adjacent the tail cone having lower edges which establish a maximum take-off pitch angle of the fuselage and define a spatial zone therebetween. The APUs are positioned within such a spatial zone defined between the strakes so that the maximum take-off pitch angle is not required to be changed when modifying an existing single APU aircraft with dual APUs.

Abstract: The Climb-Optimized Takeoff System is an aircraft functionality aimed at improving the takeoff performance. The improvement is obtained by allowing the airplane to rotate to an optimized pitch attitude at and after VR, while ensuring that the minimum required takeoff climb gradients and the geometric limitations of the airplane are being respected. The optimum takeoff performance is obtained by granting that the airplane pitch attitude, instead of being limited by a single takeoff constraint (such as a given pitch to avoid tail strike) is being tracked to its instantaneous, most constraining limit during the air transition phase (d2).

Abstract: A flight control system moves elevators according to a pilot command summed with an automatic command. The flight control system monitors a set of flight parameters to determine if the flight vehicle is operating inside a permitted envelope. The flight controls system incorporates automatic protections thru the automatic elevator command if the flight vehicle is close to its envelope limits. The exemplary illustrative non-limiting implementation herein provides automatic protections in order to protect the flight vehicle from low speeds, high attitude, stalls and buffetings.

Abstract: Methods and systems are provided to comply with structural load requirements applicable to aircraft additional fuel tank systems. A plurality of aircraft fuel tanks may be positioned adjacent to one another, preferably within the fuselage (e.g., a cargo compartment) of the aircraft so as to be disposed generally along a longitudinal axis of the aircraft. The tank body defining an interior space for holding aircraft fuel, an intercommunication conduit assembly between the fuel tank modules configured to refuel and transfer fuel from the tank modules by a cascade mode and an intentional air-filled ullage space are operatively associated with the tank body to prevent an overpressure condition within the interior space of the fuel tank body. The intentional air-filled ullage is obtained through the predetermined positioning of the terminal open end of the intercommunication tube inside the respective fuel tank module.

Abstract: Rudder assist mechanisms and methods are capable of being operably connected to an aircraft's rudder control system. The rudder assist mechanisms most preferably have over-the-center spring biasing functions so as to cause either substantially no spring force (i.e., when the linkage is over the spring-bias center) or substantially all spring force (i.e., when the linkage is left or right of the spring-bias center) to be exerted on the rudder control system. The rudder assist mechanism may include a control spring assembly, and a linkage assembly which operably connects the control spring assembly to the rudder control assembly. The linkage assembly is moveable operably between a null position wherein substantially no spring force of the control spring assembly is transferred to the rudder control system by the linkage assembly, and right and left spring-biased positions wherein right and left spring forces of the control spring assembly are transferred to the rudder control system, respectively.

Abstract: Aircraft air scoop icing protection systems and methods include an air duct having air inlet and outlet openings and a fairing which covers the air duct and defines an interior fairing space in which at least a forward portion of the air duct is positioned. The fairing has a forward end which surrounds the air inlet of the air duct. At least one tube is provided having an inlet end in communication with a heated air chamber associated with an airframe structure of the aircraft, and an outlet end in communication with the interior fairing space. Heated air in the heated chamber is directed through the tube to the interior fairing space so as to provide icing protection to the air duct. The air scoop icing protection systems may advantageously be employed so as to provide icing protection to air scoops associated with an aircraft engine nacelle using the residual heat from the nacelle's inlet lip primary bleed air system.

Abstract: A method for detecting and predicting total hydraulic fluid level for aircraft hydraulic systems includes determining an estimated value for a parameter indicative of total fluid level or mass. Each new value is combined with an historical indication (e.g., from previous flights) to provide a prediction for the future value of total quantity indication. With the same combination, one can provide an estimated value for total system leakage or level loss. An alert can be generated if hydraulic fluid level or mass is predicted to fall below a predetermined level.

Abstract: The present invention provides an alternative to the auto-throttle integrated in an aircraft autopilot by restricting the conditions in which the system operates. The proposed system removes the auto-throttle function from the autopilot system and gives it directly to the Full Authority Digital Engine Control (FADEC). A cruise control mode is available to the pilot only under stable flight conditions.

Abstract: Galley units are provided having a moveable galley structure in the interior aircraft cabin. During passenger ingress/egress and during certain phases of the aircraft's flight (e.g., take-off and landing), the galley structure may be moved so as to be laterally adjacent the main cabin door and thereby provide access to the door. During other phases of the aircraft's flight (e.g., during cruise flight at altitude), the galley structure may be moved laterally so as to cover the main cabin door and thereby provide enhanced acoustic and/or thermal insulation in the main cabin door area. The space vacated by the moveable galley structure may thus expose other galley structures and/or equipment. An aircraft which includes such an aircraft galley unit and methods to achieve acoustic and/or thermal insulation for an aircraft cabin door using such an aircraft galley unit are also provided.

Abstract: Friction stir welding equipment control force spindle for mounting in an orbital head housing uses a coaxial sensor to measure downforce. Simultaneously, an axial electrical actuator is controlled to dynamically correct the axial tool position during the welding, by a direct axial force system control, in order to maintain controlled downforce according to parameters previously set, based on numerical control. The equipment also sets up, monitors and controls spindle rotation speed, welding speed, acceleration speed and downforce using for example closed loop control functions. A laser system may scan the backing surface before welding and correct original tool path, in order to get an offset tool path. A precision alarm system may provide safe welding while preventing the tool from colliding with the backing surface.

Abstract: A flight control system moves elevators according to a pilot command summed with an automatic command. The flight control system monitors a set of flight parameters to determine if the flight vehicle is operating inside a permitted envelope. The flight controls system incorporates automatic protections thru the automatic elevator command if the flight vehicle is close to its envelope limits. The exemplary illustrative non-limiting implementation herein provides automatic protections in order to protect the flight vehicle from low speeds, high attitude, stalls and buffetings.

Abstract: Friction stir welding (FSW) processes, systems and the resulting friction stir welded components are disclosed whereby first and second workpieces are welded to one another using a first workpiece having mutually orthogonal structural components and a junction region therebetween which defines a bearing surface of predetermined geometry. A shoulder of a FSW tool may be brought into bearing contact with the bearing surface so that a pin extending from the shoulder of the FSW tool may be advanced into and through the one structural component of the first workpiece at an angle relative thereto so as to thereby form a friction stir weld region between the first and second workpieces. Some preferred embodiments will provide a bearing surface which defines an arcuately concave geometry, in which case the shoulder of the FSW tool defines an arcuately convex geometry conformably mateable with the bearing surface.

Abstract: Methods and resulting laminate structures are provided wherein the lay-up of composite materials is accomplished more symmetrically and more continuously as compared to prior techniques to form a composite structure from two composite parts in which their principal laminate directions form a non-singular angle.

Abstract: In one exemplary illustrative non-limiting aircraft radio communications system, a “POCI” (“Presence Of Communication Interlock”) is comprised of a double balanced low pass LC filter covering the voice range. The voice signals coming from the two VHF's are filtered and processed by an amplifier at an adequate level to be peak detected. The resulting signal is applied to an amplifier with a defined hysteresis and time constant and finally drives the relay interlock circuit that inhibits an ACARS VHF radio from transmitting whenever other on-board comm. VHF transceivers are receiving voice signals. Visual indicators provide information on system operation and system power failure.

Abstract: A bleed leakage detection system includes an arrangement of thermostats that are capable of detecting the place where the bleed air leakage is occurring (e.g., the failed junction in bleed air duct work). The exemplary illustrative non-limiting implementation provides a bleed leakage detection system with continuous monitoring of thermostat sensor wiring during flight and thermostat self-test function (“Initiated Built In Test”—“IBIT”). The IBIT self-testing can be initiated before the aircraft takes off or optionally, during periodic self testing that may be run during predetermined periods such as overnight when the aircraft is not being flown. By the continuous monitoring the pilot is alerted when a bleed leakage has occurred or when the bleed leakage detection system has failed.

Abstract: A method and system for monitoring and predicting the health of electro-mechanical systems and components includes collecting data for a fixed pattern of actuation of such system or component. This data is used to build statistical models that correspond to a normal state of the system or component. New measurements are compared to this model in order to monitor the health of the system or component. The comparison can be made using a distance calculation. The combination of new measurements with historical data provides the prediction for future health states of the system or component.

Abstract: An aircraft flight control system advantageously is provided with a control rod which is spline-connected to a bearing assembly so as to permit simultaneous independent longitudinal and rotational movements of the control rod while isolating such movements from one another (e.g., so as to allow operative interconnection to an aircraft's aileron and elevator control surfaces). Thus, the control rod is moveable in longitudinal and rotational directions relative to a longitudinal axis of the control rod in response to pitch and roll command inputs, respectively. The control rod is splined operatively to the bearing assembly so as to allow for independent simultaneous longitudinal and rotational movements of the control rod relative to the longitudinal axis thereof to thereby allow the command inputs to be transferred to the aircraft's respective flight control surfaces.