Abstract: The CARE 3 reliability model for aircraft avionics and control systems is described by utilizing a number of examples which frequently use state-of-the-art mathematical modeling techniques as a basis for their exposition. Behavioral decomposition followed by aggregration were used in an attempt to deal with reliability models with a large number of states. A comprehensive set of models of the fault-handling processes in a typical fault-tolerant system was used. These models were semi-Markov in nature, thus removing the usual restrictions of exponential holding times within the coverage model. The aggregate model is a non-homogeneous Markov chain, thus allowing the times to failure to posses Weibull-like distributions. Because of the departures from traditional models, the solution method employed is that of Kolmogorov integral equations, which are evaluated numerically.

Abstract: The meeting gave PTTI managers, systems engineers, and program planners a transparent view of the state-of-the-art, an opportunity to express needs, a view of important future trends, and a review of relevant past accomplishments. The PTTI users were provided with new and useful applications, procedures, and techniques. Emphasis is placed on military applications and avionics.

Abstract: : This report describes a series of parametric equations for use in estimating the depot maintenance cost of new Air Force aircraft, particularly for the five major maintenance categories: airframe rework, engine overhaul, airframe component repair, engine component and accessory repair, and avionics component repair. The equations are intended to provide cost estimates for Defense Systems Acquisitions Review Council Milestone II, at which point some design details of major aircraft subsystems (airframes, engine avionics) are available. The report presents a single set of equations that are the most representative and applicable to the widest range of estimating situations, but presents alternative equations and supporting data and analyses.

Abstract: The generally safe and dependable commercial aviation industry has never had properly designed Caution and Warning Systems (CAWS) to alert the aircrew to operational or system malfunctions or emergency situations. When flight systems were simpler, relatively crude CAWS were manageable. Today, however, the complexity and size of modern avionics systems makes it crucial to have optimal systems to alert the crew to problems, and to assist them in handling them.

Abstract: The hardware configuration, software organization, and applications software for the NASA IKONAS color graphics display system are described. The systems were created at the Langley Research Center Display Device Laboratory to develop, evaluate, and demonstrate advanced generic concepts, technology, and systems integration techniques for electronic crew station systems of future civil aircraft. A minicomputer with 64K core memory acts as a host for a raster scan graphics display generator. The architectures of the hardware system and the graphics display system are provided. The applications software features a FORTRAN-based model of an aircraft, a display system, and the utility program for real-time communications. The model accepts inputs from a two-dimensional joystick and outputs a set of aircraft states. Ongoing and planned work for image segmentation/generation, specialized graphics procedures, and higher level language user interface are discussed.

Abstract: An automatic tuning system for controlling the avionics in an aircraft includes an operator actuated keyboard for entering any available frequency for the many avionic receiver/transmitters and/or transponders employed in the aircraft. Signals from the keyboard are applied to a microprocessor programmed to detect first a valid frequency selection for one of the instruments aboard the aircraft and provide control output signals which are converted to a data format for tuning the device to which the selected frequency applies to the frequency selected. Such a system eliminates the need for the pilot or other operator to individually tune a particular device since it is necessary only to enter a desired frequency with a control signal being automatically applied to tune the electronic unit to which the selected frequency corresponds.

Abstract: Electronic displays are being increasingly used in aircraft for the presentation of information to aircrew. This trend is due to two principal reasons, the steady improvements in the technology of electronic displays which are finding growing use in a wide range of markets, and the radical changes to the methods of distributing and processing data on board both military and civil aircraft. However, the peculiar environmental and other factors which constrain the design of airborne displays have caused the aircraft world to lag behind other markets in the use of new types of electronic display. It is the aim of the paper to review both the available and potentially promising display technologies, the human factors and environmental constraints, and the integration of the display devices into the total avionic systems, in order to present a balanced view of both the advantages and the problems associated with the use of airborne electronic displays. The design of the aircraft cockpit and the wide range of ambient light levels impose particular problems, and these are considered in relation to the characteristics of the human eye to provide some overall guidelines for display design. The types of information which are typically presented and the design of symbology are reviewed. Electronic display devices described include monochrome and colour CRTs, which are coming into use in the new generation of civil aircraft after many years of use in military aircraft, digitally-addressed CRTs, and a range of solid-state matrix and alphanumeric displays, both emissive and reflective. Image intensifiers for use in night operation are discussed. Some types of display, particularly for military aircraft, incorporate optical elements for magnification, collimation and image combination, and the use of both refractive and diffractive optial techniques is reviewed. The design of complete display systems to provide multifunction capability and protection against component failure is seen as one of the greatest potential advantages of integrating electronic displays with digital data highways.

Abstract: Investigations have been conducted regarding the techniques required for Loran-C navigation with application to the general-aviation pilot. The goal has been to produce prototype equipment for flight evaluation which will provide enroute navigation in both latitude-longitude and rho-theta coordinates and to evaluate the nonprecision approach capabilities of such equipment. In connection with the considered project, a prototype Loran-C receiver has been flight-tested using a variety of flight paths, with and without simultaneous ground radar position data collection. Attention is given to a receiver overview, an antenna preamplifier/coupler, the Loran-C receiver RF processor, the tracking loop hardware, tracking loop programming, video output, the laboratory and flight evaluation, and work currently in progress.

Abstract: The air carrier avionics arena is witnessing some interesting evolutionary developments in flight guidance. Among these are the strapdown attitude and heading reference system, the ring laser gyro inertial navigator and the Omega/VLF navigator. Passive navigation systems are now available which emulate VOR/DME. However, there is another development on the horizon which could be revolutionary. It is the Global Positioning System, which has the potential to overtake many of the developments now becoming available. This paper addresses the design and capability of an integrated GPS/strapdown AHRS as a replacement for the pure inertial navigator and other sensors now widely used by the air carriers. This integrated system simultaneously exhibits the excellent verticality of a dynamically erected AHRS and the outstanding position and velocity accuracy of the satellite navigator. The splendid velocity accuracy of GPS, even with the C/A code and controlled position accuracy, provides the key link to the potential of the integrated system. The system does not require external air speed or heading but can use encoded barometric altitude. As an output the system can provide a comprehensive slate of vehicle data for the flight management, flight control and flight instrument systems. This single system will outperform the pure inertial navigator at substantially less acquisition and maintenance cost. The potential for global and continuous position is not available at any price. The system can also be fitted with the same kind of VOR/DME emulation now appearing in other passive navigators. Unprecedented capability and economy in air carrier operations are in the offing in this new generation of flight guidance avionics.

Abstract: : This report documents a study which applied an analytic method known as the Controls and Display Evaluation Model, or CODEM, to the flight deck avionics improvements identified in the Flight Control Division's (AFWAL/FIGR) Tanker Avionics and Aircrew Complement Evaluation (TAACE) program. TAACE, in support of the USAF KC-135 Avionics Modernization Program, sought to establish design criteria for the controls and displays of improved avionics, in the event the crew of the KC-135 is reduced by eliminating the navigator. The objective of this study was to apply CODEM to a previously evaluated design, so that the resulting data could be used to evaluate the validity of CODEM by comparing the two sets of data. CODEM, which is still in the developmental stage, embodies a 'limit design' approach to the problem of controls and displays engineering and integration. Absolute design limits and progressive tests are used to test the emerging design in terms of task complexity. CODEM output consists of plots of task complexity vs. time and a printout of associated equipment-related tasks which allows the designer to diagnose the source of any undersirable crew loading. CODEM's application to the TAACE flight deck design concluded that the air-refueling mission could be performed without excessive workload on the crew.

Abstract: : The communications systems on all Army aircraft flying today are based on design concepts that are over 50-years old. We have designed a totally modern, state-of-the-art communications system for Army aircraft, and have published two new specifications which contain many of the modern test procedures required to accurately test and evaluate the various components of the communication system. As a first step in the development of new test procedures, we evaluated both ASA and ANSI standards and found them lacking. The components of the new state-of-the-art communications system will include, as a minimum: high impedance DC powered noise canceling microphones (using piezoelectric ceramic, electret, or PVF2 diaphragms); earphone elements designed and tested to have flat frequency response when inside the circumaural earcup of the hearing protective device; and intercoms which replace positive peak-clipping with fast-acting AGC circuits and expander/compander circuits for maximum output signal without distortion, even under conditions of extremes stress. In the future, audio signals in the microphone will be converted into the digital mode or directly into the optical spectrum for high efficiency, and secure communications inside the aircraft. The savings in weight and security improvements will be considerable.

Abstract: : A total systems approach methodology and computer-aided design tool for integrated flight control design and evaluation has been formulated. This methodology is a composition of classical system design steps and system performance, reliability/survivability, packaging, and cost evaluation techniques assembled for interactive computer-based execution. The interactive sensor integration program developed under this methodology addresses the sensor requirements of the flight control, guidance and navigation, and weapon delivery functions as directed interactively by the designer and the mission, the system configuration, cost, power, weight, volume constraints, and total system performance. The demonstration program contains performance reliability, size, power, weight, cost data for gyros, accelerometers, radars, seekers, and air data systems in addition to analysis tools for evaluating navigation system accuracy, probability of target acquisition, and probability of kill for selected targets and weapons.

Abstract: : This report describes research directed toward developing parametric estimating relationships for the production costs of avionics suites and systems. The research sample comprised 17 combat aircraft and their avionics equipment. Potential explanatory variables were selected based on interviews with manufacturers about factors affecting avionics costs and the appropriateness of the variables for use in planning studies early in system acquisition. Multivariate regression analysis techniques were used to determine the statistical properties of candidate estimating relationships for whole suites and individual systems. The estimating equations derived for suites were generally satisfactory but not always as statistically efficient as desirable. Attempts to derive estimating relationships for avionics systems were much less satisfactory but offer improvements over the simple cost per pound metrics often used. The authors conclude that objective means for expressing technology change and its importance for avionics cost estimation remain a concern for future research.

Abstract: In the predictive mode, the system synthesizes a horizontal path from an initial aircraft position and heading to a desired final position and heading and then synthesizes a fuel-efficient speed-altitude profile along the path. In the track mode, the synthesized trajectory is reconstructed and tracked automatically. An analytical basis for the design of the system is presented and a description of the airborne computer implementation is given. A detailed discussion of the software, which should be helpful to those who use the actual software developed for these tests, is also provided.

Abstract: : This study assessed the availability and applicability of error budget data for avionics certification requirements. The investigation includes a review of data for both station oriented (VOR/DME-RNAV) navigation systems and wide area (Loran-C, Omega and GPS) navigation systems. The primary thrust of the analysis was to determine the operational capabilities of the various navigation systems currently being certified. A secondary objective was to examine the viability of current certification procedures, techniques and accuracy criteria to any advanced navigation system. To accomplish these objectives, a detailed assessment of error budget data, error combination techniques and functional performance standards was performed.

Abstract: Since the advent of the modern combat system and use of sophisticated avionics test equipment, there has evolved an ever increasing problem in interfacing these loads to the normal Type I/Type II shipboard power system. This paper addresses past initiatives which led to a proliferation of motor-generators in the fleet; the current major interface problems which have led to degraded performance of the ship service power system as well as the systems serviced, and makes recommendations to reverse the incompatibility. In order to ensure that the interface problem is understood, several specific current system problems are described and impending future potential problems assessed. The by-product of this dialogue should be a better understanding of the interface problems which can occur in electrical and electronic systems and subsystems when early attention is not given to overall ship system design of both the power generation system and mission-oriented payload systems and subsystems.

Abstract: Electronic displays are being increasingly used in aircraft for the presentation of information to aircrew. This trend is due to two principal reasons, the steady improvements in the technology of electronic displays which are finding growing use in a wide range of markets, and the radical changes to the methods of distributing and processing data on board both military and civil aircraft. However, the peculiar environmental and other factors which constrain the design of airborne displays have caused the aircraft world to lag behind other markets in the use of new types of electronic display. It is the aim of the paper to review both the available and potentially promising display technologies, the human factors and environmental constraints, and the integration of the display devices into the total avionic systems, in order to present a balanced view of both the advantages and the problems associated with the use of airborne electronic displays. The design of the aircraft cockpit and the wide range of ambient light levels impose particular problems, and these are considered in relation to the characteristics of the human eye to provide some overall guidelines for display design. The types of information which are typically presented and the design of symbology are reviewed. Electronic display devices described include monochrome and colour CRTs, which are coming into use in the new generation of civil aircraft after many years of use in military aircraft, digitally-addressed CRTs, and a range of solid-state matrix and alphanumeric displays, both emissive and reflective. Image intensifiers for use in night operation are discussed. Some types of display, particularly for military aircraft, incorporate optical elements for magnification, collimation and image combination, and the use of both refractive and diffractive optical techniques is reviewed. The design of complete display systems to provide multifunction capability and protection against component failure is seen as one of the greatest potential advantages of integrating electronic displays with digital data highways.