Search Results

This paper briefly describes the background to the design, the process used in designing, and the “missionized” crew station designs of the F-15 Dual Role Fighter (DRF). The McDonnell Aircraft Company (McAir) had begun an Advanced Fighter Capability Demonstrator program to develop and demonstrate an enhanced air-to-ground capability in the F-15 years before the USAF identified the need for a DRF. This experience, plus a closely coordinated effort between McAir and USAF personnel, and extensive use of a high-fidelity simulator have resulted in F-15 DRF crew station designs that afford both tremendous flexibility and capability.

The advances in avionics technology have dictated new approaches in cockpit design to enhance the single-seat fighter pilot's ability to perform complex mission tasks. One such cockpit under development and test is in the F-16C/D aircraft scheduled for production delivery to the Tactical Air Forces in late 1984. This paper discusses the requirements for new cockpit designs, the F-16C/D cockpit, and the impacts of the pilot-aircraft interface on mission performance.

An advanced trajectory control system is defined for operation in the 1990's. Basic functions of trajectory control are the selection and control of the aircraft trajectory. For the 1990's, the system needs to operate on all available knowledge of the mission and environment. It needs to use this knowledge and the full maneuvering capabilities of the aircraft for responding to unexpected events during the mission, including control resource reconfiguration in the presence of failures. Decision, estimation, and control technologies must be integrated to provide these advanced capabilities. Identified as key to this integration are Artificial Intelligence and predictive path control technologies. These technologies and their potential application in trajectory control systems are discussed. Flight safety and system robustness are established as issues that need to be addressed early in the trajectory control system development.

This paper discusses a series of studies in which the objective is to develop advanced methods of information transfer for the pilots of high performance fighter aircraft. Traditional cockpit designs have resulted in aircraft where there are more controls and displays in the crew compartment than a human operator can effectively deal with. Development of more efficient means of communication between aircraft and aircrew is an absolute necessity for survival in future high threat environments. This paper addresses some new displays that have been evaluated for that purpose.

Hydraulic power is used on an aircraft to control the various services that require a relatively high instantaneous power with a sufficiently high degree of safety compatible with minimum weight requirements.

The future of the Air Force tactical and strategic forces will depend upon the ability of the future fighter-bomber to be able to effectively penetrate enemy defenses, kill the targets and survive while at the same time being easily supportable in the field. That future technology is now being matured in the exploratory development program of the Aeronautical Systems Division, Flight Dynamics Laboratory, Flight Control Division and is aimed at providing options for the solutions to the requirements of the Air Force such as avoiding detection, increasing the probability of finding and destroying targets with multiple kills per pass, having enhanced crew capability and improved force availability. These technologies will give the future fighter-bomber the capability for night all-weather autonomous operation thus enabling the pilot of the future to quickly kill targets with increased survivability, while at the same time being easily supportable at high sortie rates in the field.

The B-1 is a long-range strategic bomber designed to perform safely in a hostile environment with a high probability of mission success. The flight control system achieves these objectives with redundant hybrid combinations of fly-by-wire and conventional design techniques. The primary mode of control in each axis is fail-operational, fail-safe, fly-by-wire with simultaneously operating mechanical control. The flight control system is described, and selected flight and ground test experiences and resultant development activity are discussed. Developments include reduction of force fight in surfaces with multiple actuators, reduction of horizontal stabilizer control hysteresis, elimination of pitch control/structural mode coupling, reduction in lower rudder load oscillations, increase in the operational reliability of the flap/slat system, elimination of the susceptibility of the augmentation system to electrical power transients, and other items.

The development of the F-16 flight control system (FCS) had definite impacts on the design of the primary control surface actuation devices. The YF-16 employed one of the first aircraft fly-by-wire (FBW) control systems. One of the challenges of the YF-16 FCS design was to use existing state-of-the-art components with little or no development required yet provide the necessary redundancy and reliability levels needed for a fly-by-wire system. The FSD and production F-16 programs allowed for the development of an integrated servoactuator (ISA) for use on the primary control surfaces. This ISA design combined the command servo and power actuator functions and allowed all types of actuator inputs to be summed electrically. The AFTI/F-16 airplane presented some unique requirements due to the implementation of a digital FBW system. Twin vertical canards meant additional actuation requirements.

The vehicle specification for all modern fighter aircraft requires some level of flight control system redundancy. The MCAIR approach to meeting the F/A-18 flight control system actuator redundancy requirements is presented. The actuator configurations, servoloops, and redundancy management concepts are described. Early interface compatibility and redundancy management testing of breadboard hardware were used to identify potential problem areas before iron bird testing of flight worthy hardware. The development history and the flight test experience are discussed.

A decentralized, multivariable controls methodology is being developed for the functional integration of a fighter's aerodynamic controls with those of its propulsion system (inlet, engine, and thrust vectoring/reversing nozzle). Integrated controls account for, and take advantage of the significant cross-coupling between these system elements. A high-fidelity, six-degrees-of-freedom (6 DOF) aircraft simulation has been developed, incorporating advanced tactical fighter features such as variable cycle engines, variable geometry inlets, 2D-CD TV/TR nozzles, canards and a propulsive lift concept. A comprehensive evaluation test plan, including a piloted simulation, has been developed to validate this integrated-controls design methodology. Preliminary results show significant benefits of integrated control in terms of enhanced aircraft maneuverability, precise flight path control, reduced pilot workload, and fault tolerant system design.

COMBINED ENVIRONMENT RELIABILITY TESTING (CERT) has been completed for a military and commercial jet engine mounted digital electronic fuel control application. CERT testing has revealed several failure modes not normally identified by traditional development, qualification and burn-in testing. This paper discusses the manifestation and corrective action of these failure modes and identifies several secondary anomalies that were discovered during repair actions or deliberate inspections. These anomalies, although not directly responsible for a control malfunction, could eventually have caused a control removal. CERT tests on two different engine controls have highlighted meaningful comparative results that tend to verify initial reliability predictions. Analysis of test data has also indicated potential improvements in future CERT testing to yield more cost effective results.

Garrett full-authority electronic fuel control systems have been in service on executive type jet aircraft since 1972 and have accumulated over five million flight hours. This paper presents the merits, design features and evolution of analog through digital full-authority electronic control systems coupled with their flexibility in adding new functions.

The authors present a frame work - the scientific approach - within which they suggest the currently in use techniques and processes associated with advanced crew system design, should be used. They advocate considering the cockpit and crew as components of a “Crew System”, an entity which must be responsive to requirements and needs the same way the more traditional systems must be responsive to requirements and needs. They strongly urge improved communications with the user and suggest increased activity be expended on the definition of the problem - what is the mission, and how does the User anticipate performing it? The use of various test facilities, ranging in sophistication from simple mockups to flight test aircraft, is discussed, with specific recommendations made as to how these test facilities should be used.

The man-machine interface is commonly thought of as the controls and displays in the cockpit or crew stations of an aircraft. The authors contend that the real interface will lie deep within the computers of tomorrow's aircraft, both in the control algorithms and in the software driving the displays. This paper describes the authors' approach to designing a flight management system and shows how such a system could be used, in a mission context.

Advances in technology have continuously provided new flight capabilities. Along with these new capabilities have come new demands on the flight crew. Pilots are now seeing a greater percentage of flight tasks being performed by automatic systems; however, data handling and integration tasks have reached new heights that now require more pilot attention. The pilot's changing role creates a greater burden on the system design and evaluation process, which is used to ensure the man-machine interface operates at satisfactory levels. Discussed in this paper are various methods for evaluating this interface at the different levels of system design.

With each new generation of tactical jet aircraft, the number of alerts is increasing. Since cockpit space is at a premium, a system of displaying alerts to the aircrew must be designed and integrated into the airframe. A cost effective method of accomplishing this task includes appointing a panel of pilots to advise the manufacturers about the cockpit from a user's point of view. In order to reduce distractions to the aircrew during critical combat phases of flight, a scheme of inhibiting alerts should be adopted. The decision concerning which alerts should be inhibited during which phases of flight should be made by the panel of pilots convened by the manufacturer. The final product will be an airplane that will inform the pilot only of the most severe system failures during combat which will allow the mission to be accomplished without unnecessary distractions, thus reducing the crew's workload.

The rapid growth of technology has allowed development of systems which are limited not by the processing capabilities of the sensors but by the quality of the information presented to the operator for control and analysis. Such systems are either enhanced or degraded based on the design of the human interface. Additionally, the speed of growth in the technologies has resulted in a need for a faster weapons system development cycle or improved response to the rapidly changing threat environment. This is achieved by capitalizing on the flexibility inherent in newer, software driven systems. The operator interface for such systems must also demonstrate a similiar flexibility. These problems have been attacked by the Navy's Long Range Maritime Patrol community through the use of Integrated Control Panels (ICP's) as replacements for existing and proposed standard knob-and-dial control panels. The ICP's consist of a small plasma panel with a touch sensitive overlay.

New developments in cockpit displays and integrated weapons system avionics have changed military aviation significantly. The role of the pilot has been altered from that of a skilled manual operator to an executive manager of a computer-driven integrated weapons system. We are approaching a critical threshold of pilot workload with manual and visual information-transfer overload.

Many passenger cars exhibit various driveability malfunctions during cold start operation. These engine malfunctions, such as stalling, hesitation, stumble, and backfire, can usually be lessened or eliminated with increased ambient temperatures and increased gasoline volatility. Based upon laboratory performance testing of 99 cars, we have developed a Driveability Number (DNT), which is a gasoline quality parameter that can be used to predict the driveability performance of a fleet of cars. DNT is calculated from a model which is a function of ambient temperature and gasoline volatility. The gasoline volatility parameters used in this model are the 10%, 50%, and 90% evaporation points. The model was developed using late-model (1976-1982) cars, which were tested under controlled environmental conditions on a chassis dynamometer.

The Coordinating European Council for the Development of Performance Tests for Lubricants and Engine Fuels (CEC) was founded 20 years ago with primary objective of developing simple and cheap standardized performance tests in European equipment in order to avoid the proliferation of in-house test procedures. This paper describes the changing emphasis on CEC terms of reference over the years and quotes examples of specific European tests which have become well established and are being used by oil and additive companies, vehicle manufacturers and users. The European engine lubricant environment is described and the interaction between the industries and standardizing bodies involved is highlighted. The CEC is endeavouring to meet the challenge of providing appropriate performance tests to the industries, requiring flexibility and close cooperation, particularly at a time when the evolution of engine designs and usage is relatively rapid.