Document created: 23 September 03
Air University Review,
March-April 1974
Colonel Neville P. Clarke, USAF, VC
The place at which man and a weapon system interact, the man/machine interface, is influenced by four principal variables: the mission to be accomplished; the operating environment, both natural and systems-produced; the characteristics of the machine; and the performance of the human operator in the operational situation. This circle of variables comprises a complex relationship involving plans, environmental quality, hardware technology, and human tolerance. Hardware technology is usually defined at the mission/machine interface; however, consideration must also be given to man’s capability and how he will be required to perform within the proposed mission envelope.
The severity of the natural or induced environment within the system limits man’s ability to perform and creates problems with regard to safe exposure limits for aircrewmen. In addition, the effect of systems operation on the environment is of increasing concern with regard to environmental quality. All these variables meet and interact inextricably at the man/machine interface. Performance of the man/machine complex governs the overall performance of the system and the ability to accomplish the mission for which the system was designed.
Within Air Force Systems Command are two organizations principally responsible for research and development associated with performance at the man/machine interface: Air Force Human Resources Laboratory (AFHRL) and Aerospace Medical Division (AMD). The missions of both organizations are broader than support for system development per se. From different aspects, both organizations consider human problems along a continuum that bears on the performance area at the man/machine interface. It is at this performance interface that the mission areas of the AFHRL and AMD come into juxtaposition and form a mutually supportive and complementary relationship with regard to system development problems. AFHRL’s mission includes developing criteria for selection of the entire Air Force population, not just those individuals concerned with operating systems. The criteria are concerned with developing methodologies, procedures, and hardware for enhancing the training of Air Force personnel in all areas of specialization. They are also concerned with system manpower problems and are ultimately involved in the definition of the overall force structure of the Air Force.
The Aerospace Medical Division mission area is also quite broad. It entails medical selection and care of specialized flying personnel. It deals with human engineering, which includes the development of methods for optimizing man’s performance at the man/machine interface by providing engineering design criteria, man/machine geometry considerations, and methods that make optimum use of man’s native performance capabilities.
We are also concerned with providing safety criteria for Air Force personnel operating in hazardous environments, such as high-altitude flight, crash landing or escape, and exposure to lasers. AMD is also concerned with developing criteria for preserving the quality of the environment in the areas of radiation, chemical hazards, and noise. Early development of appropriate criteria for these environments not only assures the safety of our operational personnel and preservation of the surrounding environment, but it also precludes the imposition of arbitrarily conservative standards on our present operations and on future systems development. This, in turn, reduces the cost of development and operation of current and new systems.
The AMD and AFHRL missions come together in the area of providing criteria for enhancing man’s ability to perform at the man/machine interface. The AMD effort emphasizes applying human engineering and performance design criteria at this interface while AFHRL is involved with assuring that the personnel with appropriate skill levels are available and can be effectively utilized at the man/machine interface. AMD is involved, for example, with target location, weapon aiming, multicrew systems, operation of man as an effective part of high-acceleration weapon systems, and with defining the relationship between man and the machine in the employment of remotely piloted vehicles. AFHRL is concerned, for example, with providing proper skill levels, cost-effective training simulators, and mechanisms for assuring job satisfaction in the operation of complex airborne and land-based Air Force systems.
AMD’s mission in biotechnology, while often directed at specific systems development questions, frequently provides new information and capability that can be generalized to applications supporting entire classes of systems.
Our R&D efforts cover the spectrum from basic research through test and development. I shall describe the kinds of work done in biotechnology to support the development and operation of each of the system classes. The biotechnology effort is divided into five major technical segments, four of which support development and operation of these classes of systems. The fifth, dealing with specialized medical problems of the flyer, is less directly related to the man/machine development issues and is thus presented in more detail elsewhere in this issue.
The four major technical areas of the biotechnology program are operational atmospheres, radiation, mechanical force, and human performance. They are closely related to systems operation and development, since they are involved with such things as altitude temperature, acceleration and vibration, nuclear and laser radiation, control displays, dynamic geometry, etc. All these areas of concern could be of importance for such aerospace systems as fighters, bombers, missiles, airlift, reconnaissance/surveillance, command control and communications. However, individual classes of systems require biotechnology emphasis on selected areas. Let’s take a look, then, at a few specific examples for each class of system and consider some of our work in support of each.
fighters
High-altitude effects continue to be of concern with regard to the Aerospace Defense Command mission and in some air-superiority missions. In the acceleration area, new materials and power plant technology provide an opportunity for operations at sustained high-level acceleration. Providing commensurate capability to utilize the aircrewmen in these environments is a significant effort in the Aerospace Medical Division.
New evaluations of the physiological effects of acceleration have led to a three-pronged attack on the problem by AMD. First, we take a close look at man’s ability to withstand high-acceleration forces, using all available equipment and procedures. Second, this information is passed on to tactical fighter pilots from the Fighter Weapons School through rides in the human centrifuge at the USAF School of Aerospace Medicine. The third prong of the attack is aimed at further increasing man’s ability to withstand acceleration by repositioning him during increased acceleration to change the G-force vector. In this area, we are actively engaged with the Flight Dynamics Laboratory in exploring the utility of a tilt-back seat for future fighter aircraft designs.
As the performance capability of fighter aircraft continues to improve, there remains a concern for providing adequate escape capability over the entire flight envelope. Joint efforts with the Flight Dynamics Laboratory are continuing in the controls and displays area to improve man’s performance. It has recently become more important to achieve better cockpit layout which takes into consideration the capability and limitations of man to perform dynamically during various stressful conditions such as acceleration. This has introduced the idea of developing a dynamic geometry for the fighter crew station.
bombers
In the radiation area, the biotechnology program is defining, on a quantitative level, the ability of aircrews to continue to perform their assigned function following exposure to nuclear radiation. New modeling concepts are being employed so that man and his performance limitations following radiation may be treated as one of the several subsystems in determining overall systems vulnerability to various nuclear threats. In addition to ionizing radiation effects, we are concerned with the problem of flash blindness during night missions.
As a part of the overall effort in developing an improved windscreen segment for the B-1 aircraft, the Aerospace Medical Division is supporting the Materials Laboratory in evaluating a new ferroelectric ceramic material that can become opaque at the onset of a nuclear flash and thereby provide protection to the cockpit.
Turbulence-induced vibration remains another area of concern and is of increasing importance with longer flight time and higher speed during low-level flight. Noise problems are also of concern with new as well as existing bomber systems, particularly as regards increasing emphasis on environmental quality.
The Aerospace Medical Division has been working for some time in programs jointly sponsored by the other services and the Federal Aviation Administration to develop improved methods for assessing the environmental impact of noise produced by aeronautical systems during all phases of their operation. New computerized techniques have been developed to predict the effect of aeronautical operations on surrounding communities as a function of both the physical characteristics of the noise environment and the projected psychological impact. The noise exposure forecast produced by this analysis can be plotted, the contours resenting various levels for acceptable industrial, residential, and community activities.
missiles
There are two general classes of biotechnology problems associated with missiles. First, with regard to the large intercontinental ballistic missiles, the biotechnology effort is directed toward assuring that the potential problems produced by the noise by-products of rocket fuels do not produce hazards either for Air Force operational crews or for the surrounding environment. By realistic assessment of the potential hazards associated with these operations, we are able to provide the Air Force with realistic—as opposed to potentially overly conservative—launch constraints. This maximizes the flexibility in accomplishing the Air Force mission while at the same time assuring that no adverse effects will be produced. The Aerospace Medical Division has a major laboratory facility for the study of environmental quality effects. These are the Thomas Domes, which have the capability for producing controlled concentrations of various chemical substances of potential concern from the standpoint of environmental quality. These facilities are used to produce controlled exposures to chemicals of concern to the Air Force, to determine minimum thresholds beyond which operational exposures should not occur.
The other area of interest for missile development is where the biotechnology program is providing new capability for taking maximum advantage of the pilot’s inherent visual capability for the aiming and guiding of air-to-air and air-to-ground missiles. The visually coupled system being developed for this purpose has the capability to aim automatically either a weapon or a sensor in the direction in which the pilot is looking and to provide him preprocessed sensory imagery that better portrays the target at which he is looking. This latter capability can, for instance, provide low-level-light TV images for targets during nighttime operations.
airlift
Many of the areas of concern that have been related to other aeronautical systems obviously also apply to a development and utilization of aeronautical systems for airlift operations. One of the more important biotechnology efforts supporting such operations is that directed toward determining optimized work/rest cycles for aircrews. Crew utilization ratios in problems related to operational deployment of aircrews in the Military Airlift Command, as well as in the Tactical Air Command and in Pacific Air Forces, are of considerable concern to the operational commands. AMD has recently been involved in studies that led to the development of new computerized rules that can be used for computing crew utilization ratios in the C-5 aircraft as well as other operational systems. These new rules consider a wide diversity of factors that contribute to crew performance, ranging from organization and performance of preflight duties to consideration of the effects of a shift in time zones on crew fatigue and the like.
reconnaissance/surveillance
In manned systems that support this mission area, there is still concern about the effects of high altitude from the standpoint of providing a simple, comfortable capability for emergency pressurization and temperature protection. Ground-based as well as airborne radar-surveillance systems generate electromagnetic energy at frequencies and powers that are of concern from the standpoint of environmental quality. Work currently under way within the Aerospace Medical Division is designed to produce an assessment of the environmental quality problems associated with operation of these devices and to provide appropriate criteria for land use planning. In the area of real-time reconnaissance and surveillance, application of visually coupled systems technology is providing major new improved capability in this area.
command control and communications
New systems such as the airborne warning and control system (AWACS) and the Advanced Airborne Command Post are being evaluated in terms of the possible crew hazards associated with the conglomerate of electronic equipment that will be aboard these new systems. Particular emphasis is being placed on assuring that ground maintenance crews are not exposed to excessive levels of radiation. The Aerospace Medical Division is placing most of its emphasis in this area supporting the Electronic Systems Division’s development of improved ways of presenting and processing complex information for decision-makers. Man/machine interface problems are paramount in both the ground-based and airborne command and control systems. Matching the computational capabilities of modern computer systems with the decision-making capacity of the responsible commander is an increasing challenge in the era of burgeoning electronics capability.
The contribution of the Aerospace Medical Division to the solution of man/machine interface problems is very much dependent upon the continuing active interactions between our R&D activities and those of the other laboratories within Air Force Systems Command. The hardware approach developed by other laboratories to meet the mission goals of the Air Force defines, in large measure, the kinds of information about the crewmen that will be required from the Aerospace Medical Division. We have very active continuing joint efforts with literally every laboratory in the Systems Command. Much of the work done by AMD supports larger activities in the other laboratories. Similarly, much of our effort is directed towards providing short-range-focused answers to the product divisions in Systems Command as they develop major weapon systems. Our activities carry over into the operational arena, where we continue to provide advice and new technology as requested in the broad area of aerospace biotechnology. We believe that the effort currently under way and that planned for the future in aerospace biotechnology are providing new information that is crucial to the entire spectrum of Air Force operations. We believe that the cost of this program is relatively small in comparison to the significant benefits which it provides.
Aerospace Medical Division, AFSC
Colonel Neville P. Clarke (D.V.M., A & M College of Texas; Ph.D., University of Washington) is Director of Research and Development, Aerospace Medical Division, AFSC. Other assignments have been in Aerospace Medical Research Laboratory as Chief, Acceleration, Biophysics, Vibration and Impact branches and in AMD as Special Assistant to the Director of R&D and as Chief, Plans and Operations Division, Directorate of R&D. Colonel Clarke is a member of several professional societies and author or coauthor of many publications.
Disclaimer
The conclusions and opinions expressed in this
document are those of the author cultivated in the freedom of expression,
academic environment of Air University. They do not reflect the official
position of the U.S. Government, Department of Defense, the United States Air
Force or the Air University.
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