Air Combat Maneuvering Research Articles

Military aircrew head support system

This article describes research work undertaken to determine a suitable method of supporting the military pilot's head during high g maneuvers, enabling him to maintain his head in an upright position, thereby enhancing his ability to monitor head-up displays, and increasing his awareness of the external environment. In addition, the operation of the system also serves to reduce the incidence of incapacitating and nonincapacitating neck and nerve injuries experienced by pilots during air combat maneuvering. The article also describes how the military aircrew head support system (MAHSS) can serve as an effective head restraint system during an ejection from the aircraft, and how its operation differs between normal high g flight and ejection. A description is given of the work carried out to date including biomechanical modeling of the human body under high g loads and trials on the human centrifuge at Royal Aerospace Establishment (RAE) Farnborough, designed to validate the automatic control system. Plans for future trials are also outlined.

Sonic Boom Environment Under a Supersonic Military Operating Area

A measurement program was conducted to record the sonic boom environment under a busy supersonic air combat maneuver training (ACM) arena. Simultaneous with sonic boom measurements, a complete record was made of supersonic activity. The measurements provided validation of the predicted elliptical pattern of C-weighted day-night average sound level (Lcdn) contours and demonstration of the nature of ACM sonic boom, which often includes non-W-wave signatures. Correlation of measured booms with flight activity data provided a quantitative model for prediction of LCdn contours for other similar airspaces. I. Introduction E NVIRONMENTAL assessment of sonic booms generated by supersonic air combat maneuver (ACM) training requires prediction of the C-weighted day-night average sound level (Lcdn). Initial efforts to compute LCdn contours1 were based on analysis of tracking data from an air combat maneuver instrumentation (ACMI) system, combined with simplified calculations2 of carpet booms (i.e., booms from steady level flight) for average supersonic conditions. The resultant model showed that supersonic activity occurs in an elliptical maneuver area centered between setup points used by pilots before engagement, and that LCdn contours are elliptical and aligned with the maneuver ellipse. Field validation of predictions for a new supersonic military operating area (MOA) confirmed the elliptical pattern, but measured LCdn values were at least 10 dB below predictions.3 The difference was thought to be due to the difference between carpet sonic boom footprints and the more complex footprints (described in Sec. III.B, below) which actually result from the supersonic phases of air combat maneuvers. The data collected and reported in Ref. 3 were, however, too sparse to draw general conclusions. Accordingly, a project was undertaken to measure sonic booms in a busy supersonic airspace. A 6 month sonic boom measurement program was conducted in the Lava/Mesa airspace at the White Sands Missile Range, New Mexico. This airspace is used for ACM training, primarily by F-15 aircraft from Holloman AFB. Thirty five sonic boom monitors were deployed. During the measurement period, all flight activity data for the airspace was reviewed and correlated with measured booms. A sample of ACMI tracking data was obtained for detailed analysis of particular events and to develop an understanding of how and when supersonic events occurred. Section II contains a description of the measurement program. Following completion of the measurements, statistical analyses were made of sonic booms identified with ACM activity.

Maneuver prediction in air combat via artificial neural networks

The goal of this paper is to consider, formulate, and solve prediction problems encountered in tactical air combat. The problem involves prediction and identification of continuous-trajectory air combat maneuvers where only partial/incomplete information is given. This problem is solved using a qualitative representation of the maneuvers and their implementation as a neural network. We have broken our central dynamical problem down into several smaller subproblems (“eigencurves”), which describe the states of a continuous-trajectory dynamic system. We find that the resulting sequences of vectors uniquely express the time evolution of interacting dynamic objects. This method has been used to describe the forms of relationships between accelerations and velocities (not the values themselves.) All possible modes of a system can be identified while offering a complete parametrization of all possible tactical maneuvers. Additional information can be used to establish which of the several alternative behaviors will actually take place. These sequences serve as the symbolic input to the artificial neural network we have provided. We found that due to high correlation of input data, a single hidden layer could not satisfactorily distinguish (with at least 55–85% accuracy) simple one-on-one maneuvers, such as the Turn-In, from more complex two-on-one maneuvers; for this reason, two hidden layers were incorporated. For each layer, many different architectures and learning rules were tested; the network described here gives the best results (55–95% accuracy for partial information). Thus, we found that the neural network implementation provided a high-speed, fault-tolerant, and robust computational cell for the identification of tactical maneuvers and suggestions for a best countermaneuver. We note that, for the sake of completeness, we include considerable background material about neural networks also.

Sonic boom effects on unconventional structures in air combat training areas

Sonic booms generated by supersonic flight portions, of air combat maneuver (ACM) training for military aircraft are a source of environmental concern to the U.S. Air Force. One of the concerns relates to potential effects on unconventional structures such as historic buildings, early American structures, and avalanche-prone areas. An upgraded statistical model is outlined for the sonic boom environment based on recent measurements and prior studies. The model is applied to the prediction of the probability of damage to unconventional structures using simple shock-response concepts and the relationship between structural velocity and stress [F. V. Hunt, “Stress and strain limits on the attainable velocity in mechanical vibration,” J. Acoust. Soc. Am. 32, 1123–1128 (1960)]. Measured residual shock spectra of a range of ACM sonic booms of widely different wave shapes are shown to be closely predicted by an ideal N-wave spectra. Structural responses to sonic booms measured on two historic buildings in the White Sands Missile Range are shown to be in good agreement with theory. [This work was supported in part by the Dept. of the Air Force, Noise and Sonic Boom Impact Technology Program, code OC-AC HAD/YA-NSBIT, Wright-Patterson AFB, OH 45443-6573.]

Comparing Oculometer and Head-Fixed Reticle with Voice or Switch for Tactical Display Interaction

An experiment with 15 U.S. Army enlisted military subjects was conducted to compare the performance of an oculometer, head-fixed reticle, and touch panel for data entry on a generic tactical air combat display. The subjects used voice or switch to designate data items on the display that were selected with the oculometer or fixed reticle. The touch panel was included as a standard data entry device. Statistical analysis showed a significant difference in performance for the five configurations at the .0001 level. The reticle/switch, oculometer/switch, and touch panel are significantly faster than the reticle/voice, which in turn is significantly faster than the oculometer/voice. The reticle methods are faster than the oculometer methods. The switch action is faster than voice entry. The touch panel is twice as accurate as the other methods, all of which have about the same spatial accuracy whether oculometer or reticle, voice or switch. However, the oculometer/voice has nearly twice as many selection errors as the other methods.

F-5E departure warning system algorithm development and validation

Most fighter aircraft exhibit a departure mode that is predictable, repeatable and, therefore, avoidable through the use of warning systems and/or flight control limiters. On the other hand, some aircraft, such as the F-5E, have unique departure/spin-entry mechanisms that are impossible to produce at will, apparently random in occurrence, and extremely difficult to sense by the pilot. Providing a timely and reliable warning of impending departure is a very difficult problem in these latter kinds of aircraft. This paper summarizes the work done to analyze the F-5E departure characteristics, isolate the critical parameters, derive a departure warning algorithm, and flight-validate the system with live air combat maneuvering missions. Results confirmed the combat feasibility of sensing the aircraft's rotational rates, computing the roll-yaw coupled pitch acceleration, which is the essential ingredient of the F-5E departure, and providing the pilot a warning of the presence of a critical magnitude of this intertial pitch acceleration. The algorithm, in an F-5E departure warning system, promises to prevent future inadvertent spin entries, and with appropriate parameter thresholds could be adapted to other aircraft with similar departure mechanisms.

Performance Measurement during Simulated Air-to-Air Combat

Measurement and assessment of operator performance of complex tasks with decisional and psychomotor components of which only ultimate outcome measures are well defined provide difficult methodological challenges. One such task is the practice of air-to-air combat skills in simulated combat environments such as the Air Force Air Combat Maneuvering Instrumentation (ACMI) or ground-based visual flight simulators. Measurement and assessment of pilot performance in these environments are especially challenging because of the special cognitive and psychomotor skills involved in the freeplay and gamesmanship of two or more competing pilots. A review of the existing approaches to automated aircrew performance measurement was performed. Although the most common measurement models, using positional advantage or disadvantage, provide an adequate performance metric, other measures, such as control manipulation and the management of kinetic and potential energy, must be added to provide a refined performance measurement algorithm.

Cockpit Cursor Control: Effects of Task Loading and Controller Location

Current trends in tactical aircraft missions and avionics require two-dimensional control of a display cursor by the pilot. This study varied cursor controller location (left hand: throttle; right hand: stick grip) and task loading (concurrent flight control) in a 2 × 2 within-subjects design. Nine test pilots, seated in a laboratory cockpit mockup, used an isometric rate controller to acquire targets on a head-up display with a cursor. This task was performed either alone or concurrently with compensatory pitch/roll tracking. There were no main effects for hand used (controller location) on any performance measures, nor did this factor interact with any other. As such, there is no evidence of design constraints on cursor controller location. Task loading increased time to initiate cursor control trials by 0.5 sec (p<0.01) and target acquisition time by 2.2 sec (p< 0.01). Diagonally located targets took 0.92 sec longer to acquire than targets on the vertical or horizontal axes (p<0.05), and were more susceptible to task loading interference (p<0.05). The “diagonal problem” and task loading decrements appear to be central effects and may not be amenable to equipment design solutions. These perceptual-motor limitations will constrain the allocation of mission functions to the display cursor, which are time-critical and must be performed during air combat maneuvers.

Human Factors Implications of Project Forecast II: Aircrew Combat Mission Enhancement (ACME) Technology

Aircrew combat mission enhancement (ACME) technology consists of the hardware, software, and associated interfaces and integration that will enable aircrews to reach the acme of tactical air combat performance. In time of peace, ACME technology provides the realistically complex scenarios necessary for effective combat mission training. In time of war, it provides the real-time, updated, combat-arena visual scenes of a combat mission rehearsal enhancer, especially when it is coupled to the capabilities envisioned with the virtual cockpit technology and its use in future tactical aircraft systems.

Video Game as a Covariate for Carrier Landing Research

In behavioral research, individual differences account for the bulk of the variance in the data and thereby limit the power of an experiment to demonstrate the presence of actual differences. Covariates offer a convenient and inexpensive means of increasing power. Air Combat Maneuvering, a game from the Atari home video series, was studied for its relationship to glideslope tracking scores in a carrier-landing flight simulator. After correction for attenuation due to unreliability of the measures, scores on video-games accounted for 48 to 86% of the variance. Air Combat Manuevering appears to be potentially useful as a covariate in carrier-landing training research.

VIDEO GAME AS A COVARIATE FOR CARRIER LANDING RESEARCH

In behavioral research, individual differences account for the bulk of the variance in the data and thereby limit the power of an experiment to demonstrate the presence of actual differences. Covariates offer a convenient and inexpensive means of increasing power. Air Combat Maneuvering, a game from the Atari home video series, was studied for its relationship to glideslope tracking scores in a carrier-landing flight simulator. After correction for attenuation due to unreliability of the measures, scores on video-games accounted for 48 to 86% of the variance. Air Combat Manuevering appears to be potentially useful as a covariate in carrier-landing training research.

Dynamics of air combat

New short- and medium-range air-to-air weapons have been analyzed by means of computerized and manned air combat simulation. As a result of their peculiar capabilities, air combat maneuver characteristics are expected to change significantly. The all-aspect capability of new short-range weapons leads to a dominance of head-on engagements and thus to an increase of importance of instantaneous maneuver capability over the classical sustained performance. Typical flight conditions are analyzed in terms of turn rates, rates of climb and rates of longitudinal acceleration and in terms of the resulting power and energy management. The guidance and performance capabilities of new medium-range weapons lead to a maneuvering-type combat in the supersonic speed regime. Typical flight conditions and power/energy management characteristics of medium range air combat engagements are analyzed similar to short-range combat and mutually compared. Finally, the impact on fighter design requirements is discussed. Nomenclature D = level flight drag E - total energy g = gravity h = altitude MR = medium range SR = short range t = time T = propulsive thrust V = speed of flight Vs = sink/climb speed W - aircraft weight AD = drag increment due to turning SEP = specific excess power

Video-game and conventional tracking.

The performance evaluarion tests for environmental research (PETER) program is a series of studies involving extended practice on a variety of task. One of these tasks is a compensatory tracking task which requlres the subject to keep a moving circle centered in a horizontal track by making approptlate left-right manipulations of a control stick ( 1 ) . Eighteen subjeas practiced this task every working day for three consecutive weeks, 10 1-min. trials a day. Approximately 1 yr. later 10 of the same 18 subjects practiced a commercially available video game, Atari's Air Combat Maneuvering. The video task requires the subject to align a black approximately triangular attack jet with a same-sized white target or drone jet so that a fired missile will intercept ( 2 ) . These requirements traditionally define a pursuit tracking task. This task was also practiced 10 trials (games) a day every working day for three consecutive weeks; each game lasted 2 1/3 min. Differential stability refers to that point in practice after which individual learning curves are parallel and at most slowly increasing, except for random error; after this point all intertrial (interday) correlations are the same except for sampling variations ( 2 ) . Such constancy indicates that neither the subjects' strategies nor the nature of what is being measured are changing with practice, that is, the task has stabilized. Analysis is confined to stabilized trials (days) only. For the game the average correlation among stabilized trials was .93. The. average correlation between stabilized trials on the game and compensatory tracking was .78. The average correlation among stabilized trials in compensatory tracking was also .78. Hence, the correlation between game scores and compensatory tracking was as large as the reliability of the latter would allow. The implication is that the video game, a pursuit tracking task, measures the same thing at stabilized levels as compensatory tracking does, only more reliabiy. It appears, therefore, that this particular video game may have a future as a portable, low-cost substitute for traditional computer-driven laboratory tracking tasks. This future, moreover, may include predictive testing and training as well as evaluation of performance.

A Video Game for Performance Testing

Twenty-two subjects practiced a video game, an Atari Air Combat Maneuvering task, 10 trials a day for 15 days. The dependent variable was number of hits per trial (game). The group mean followed an increasing, negatively accelerated course. The group standard deviation increased slowly for the first six days and then followed a level course thereafter. The interday correlations showed clear superdiagonal form, with complete differential stabilization after day 6. The results are discussed in the context of a performance test battery for environmental research. It is concluded that the Air Combat Maneuvering task is an excellent prospect for such a battery.

Utilization of Energy Maneuverability Data in Improving In-Flight Performance and Performance in Air Combat Maneuvering

Energy maneuverability (EM) has been defined as the ability to perform a change, or a combination of changes, in direction, altitude and airspeed expresssed in terms of energy and energy rate. This paper describes two situations in which EM data have been presented to pilots in an effort to improve their ability to maximize the performance capability of their aircraft. In the first situation, EM information (in terms of “g” and calibrated airspeed, CAS) was presented in analog format on a helmet-mounted display (HMD). In preliminary testing, one USAF pilot was trained with the HMD, while another served as a control. Both pilots flew the T-38 through 12 EM related maneuvers. On a comparison flight (during which the display was not utilized) the HMD trained pilot outperformed his non-HMD trained counterpart. Additionally, after a one week interval both pilots reflew the flight test profile and the HMD trained pilot again out-performed the non-HMD trained pilot. Because of the surprising ease with which pilots could use the display, a comparison was also made between two pilots (who were trained with the display and had less than 100 flight hours in the T-38) and an instructor pilot with approximately 1000 hours in T-38s. On their second flight with the HMD, the subject pilots flew the required maneuvers as well as the more experienced pilot. On the basis of the above, it was concluded that the display could be used to present EM information to pilots in a usable fashion; however, more complete data are needed regarding utilizing the display with student pilots. In the second situation, energy maneuverability data were again presented in an analog format (turn rate vs. CAS) as a debriefing aid for use on the Air Combat Maneuvering Range (ACMR). The ACMR gathers in-flight data from aircraft while they are engaged in air combat maneuvering. Upon returning from the ACMR aircrew are presented with 1) a pictorial display of the engagement, and 2) a digital printout of selected encounter parameters (e.g. velocity, “g”, altitude of each aircraft, range between aircraft). The display integrates these relevant energy maneuverability data into an analog format, thus providing an immediate comparison of the performance of each aircraft with respect to the maneuvering envelope of that aircraft and that of the opponent. The display also allows the aircrew to recognize very rapidly whether they are gaining or losing energy and the rate of gain or loss. It is expected that this new format 1) will provide a better means for pilots to determine how well they have maximized the performance of their aircraft, and 2) may serve as an aid in tactics development.

Air Combat Maneuvering Performance Measurement

Due to the complex, dynamic and fast-moving nature of the air combat task, performance assessment during air-to-air combat provides many unique measurement problems. A combined analytical and empirical technical approach was used to develop a candidate measurement structure and algorithm for the measurement of pilot performance during one-versus-one air combat maneuvering. Nearly all of 28 candidate measures were found to discriminate between high and low skilled pilots during free engagements on the Simulator for Air-to-Air Combat. Discriminant analyses provided a measurement algorithm consisting of 13 measures which accounted for 51% of the variance in the performance data and which predicted membership in high or low skill groups with 92% accuracy.

Air Combat Maneuvering Range (ACMR): Has Operational Performance Measurement Entered a Golden Age?

Three years of aircrew performance measurement related to air combat effectiveness using the Navy's Air Combat Maneuvering Range (ACMR) are described. Performance assessment methods were based on air combat engagement outcomes (i. e. wins, losses, draws), weapon delivery accuracy measures, and metrics derived from antecedent events. When used in an operational setting, the aircrew assessment methods have been used to identify squadron performance differences, evaluate competitive exercises, and provide diagnostic training feedback to operational users. The use of continuously recorded quantitative measures from systems such as ACMR represents a ‘Golden Age’ in the performance measurement field. The availability of objective performance criteria promises to be of substantial benefit to both the operational user and the research community in such areas as pilot selection and training, fleet combat readiness and pilot workload and stress.

The Air Combat Maneuvering Range (ACMR), a New Approach to Aircrew Training

The Air Combat Maneuvering Range (ACMR), a New Approach to Aircrew Training

Development of Automated Performance Measures for Introductory Air Combat Maneuvers

An exploratory study was conducted to develop automated performance measurement (APM) techniques for introductory air combat maneuvers. The method and results of the study can be summarized as follows: (1) The study used Northrop's LAS/WAVS air combat simulator, mechanized to simulate the F4J. (2) Seven F4J student pilots and six F4J instructor pilots each flew 16 barrel roll attacks against an autopilot-controlled bogey, for a total of 208 simulator runs. (3) A total of 552 objective performance measures and an average of 35 subjective performance measures were obtained on each run. (4) Using the simulator's replay capability, 64 of the original 208 runs were evaluated independently by three different instructors to obtain estimates of inter-observer reliability. Sixteen of these 64 runs were evaluated a second time by these same three instructors to obtain estimates of intra-observer reliability. (5) A master APM measures tape was constructed, which contains all of the subjective and objective measures obtained for each run in a format that permits statistical analyses to be conveniently performed on any desired subset of subjects, evaluators, or performance variables. (6) Several different univariate and multivariate statistical analyses were performed on selected subsets of the data, using the BMDP programs developed by UCLA. The objectives of this task were: a) to identify a preliminary set of automated measures which could be used to augment instructor evaluation of performance in introductory air-to-air tactics; and b) to assess the relative effectiveness of alternative statistical techniques for the measure identification process.

An Air Combat Effectiveness Study (ACES) Program

History has demonstrated that there is a pressing need for improved selection, training, and management procedures for fighter pilots. In World War II, only one in twenty pilots became an ace. The U.S. Air Force kill ratio in Southeast Asia was approximately 2.5 to 1. In contrast, the Israelis claim to have a kill ratio of 60 to 1. This feasibility study focuses upon enhancing our record of air-to-air combat kills through more stringent and comprehensive selection procedures. Specifically, empirical evidence is presented which demonstrates that a program can be developed to select pilots who will be effective in air-to-air combat. From reviews of U.S. and foreign selection research dating from World War II to the present and an assessment of pilot opinion from hundreds of aces, 45 factors were identified as potential predictors of combat effectiveness. Of these 45 factors, only 10 are adequately evaluated within current military selection programs upon entrance into pilot training. Assessment of the remaining 35 untapped factors is within our technological reach. In fact, many of these factors can be assessed by tests which are presently available. An Air Combat Effectiveness Study (ACES) program is recommended which would provide selection test measures for virtually all of the factors identified as underlying combat effectiveness. As part of the ACES program, selection test measures would be correlated with performance in air combat maneuvering ranges, thereby providing a method for selecting fighter pilots during peacetime. Armed with these selection test scores and an effectively executed validation program, researchers will, for the first time in history, be able to specify a definitive profile of the ace fighter pilot.