Document created: 4 September 03
Air University Review, September-October 1975

An Introduction to Individualized Instruction

Master Sergeant Frederick K. Snyder

Failure to provide for individual differences among students is perhaps the greatest single source of inefficiency in education.”1 With the advent of new communication technology in the 1960s, the long-desired goal of individualized instruction, which provides for the differences among students, is capable of being reached.2 A 1972 study by the Air Force Human Resources Laboratory of 38 existing individualized instruction programs found not only a 25 to 44 percent reduction in training time but also a significant improvement in graduate performance. 3 These are motivations to change to individualized instruction.

As with most changes, one of the first things that needs to be changed is attitude. The most important attitude is that of the instructors who will do the work involved and then present the new training methods to the students. The attitude of the instructors’ supervisors also matters because each instructor responds to what he feels his supervisor really wants.

A major permanent change in Air Force training procedures requires an attitude change at the very top of the Air Force. At this level the Air Force has responded to the leadership of its managers. Presidents Kennedy and Johnson asked and received from Congress support for educational technology research. In 1965, Secretary of Defense McNamara asked the services to recommend ways to improve military training. For the Air Force, Air Training Command (ATC) experimented with and evaluated individualized instruction.4 In 1970 the Air Force Chief of Staff established this policy for all commands: new training will be organized according to the Instructional System Development (ISD) method and existing training will he selectively converted to the ISD concept.5 AFM 50-2, Instructional System Development, implements this policy. ATC conducts several courses on ISD. The intent of this article is to explore the major facets of individualized instruction. To explore individualized instruction, it helps to have before us a picture of current conventional training procedures. With knowledge of today’s training behavior, we can interpose new learning theory, and training quality can be improved.

A typical class is a group of students, individually different in their abilities and interests, who sit listening to an instructor lecture about a subject. The students take whatever notes they desire. If the instructor uses the chalkboard or other teaching aids, he uses them rather sparingly. When he directs attention to a displayed item, his hand stays there only a short time. The students are relying mostly on their sense of hearing to take in new information. When a student realizes he missed a key point, he asks for a repeat explanation. The whole class stops its progress while one student gets his needed facts. This routine is interrupted only infrequently with a test to measure student progress formally. Little effort is made to reteach identified weak areas; there is no time for that in a conventional class. The result is that only a few students get high grades, most students have gaps in their understanding of the subject with less than desirable retention, and some students fail.

My analysis of this picture puts importance on these factors: (1) differences in student abilities, (2) sparse use of training aids, (3) great reliance on one sense—hearing, (4) a student’s need for repeat explanations, (5) a student’s needs holding the class back, (6) infrequent testing, (7) little reteaching, (8) less than desirable results.

redefining student aptitude

Aptitude tests are often considered to be measurements of prior achievements. Aptitude test scores are used to predict which students should succeed or fail in training. Students with low aptitude scores are usually denied certain training, and the Air Force loses when needed jobs go unfulfilled for lack of qualified people. A student’s aptitude score for a particular subject predicts the level to which he could learn the subject in a given period of time.

The fixed part of the definition of student aptitude is in a given period of time; the variable part is the level of learning. The definition can be restated to read: student aptitude is the time required to learn a subject to a given level.7 Fixing the level of achievement and letting time vary implies that practically every student can succeed when given enough time.

The time needed, which is predicted by the student’s learning rate (aptitude), is determined by: (1) the quality of his instruction, (2) the quality of his instructional materials, and (3) his ability to understand the instructions and materials.8

When time is allowed to vary and the quality of instruction is improved, then a majority of students, up to 95 percent, can achieve the required level of performance. 9 Three key actions make up individualized instruction: (1) clearly state what each student is expected to learn and to what level, (2) help each student when and where he has learning difficulties, (3) give each student sufficient time to learn. 10

Proficiency in applying modern instructional technology to implement these actions requires increased instructor training equivalent to at least a college course of three semester hours.11 Therefore this article is limited to an overview of individualized instruction.

Glaser’s instructional model with feedback system12
Figure 1. Glaser's instructional model with feedback system

an individualized instructional model

The cycle of individualized instruction may be illustrated by the accompanying instructional model. In block I the objectives are clearly stated. In block II each student’s entering behavior (current ability) is determined by diagnostic testing. If he has met any of the objectives stated in block I, the training for these objectives is eliminated from his schedule. Objectives minus entering behavior equal the training requirements for the individual student. Training for this reduced set of objectives is prescribed in block III, where the student interacts with the instructional system in ways that help him reach his objectives. In block IV the student is involved in frequent performance testing, the results of which feed back to block I objectives, showing what objectives have been mastered and what objectives remain for further learning. Individualized instruction is a continuous cycle of diagnosis, prescription, and evaluation until the student has mastered all stated objectives.

instructional system development

Before this instructional model can be employed, much preliminary work must he done. Clearly stated objectives must be written; diagnostic tests must be formulated; instructional procedures that help the individual student must be developed; and performance evaluations must be prepared. The work involved is more than one instructor should be expected to handle. It may take as much as 250 hours to produce a 15-minute lesson. 13 This expenditure of effort has produced a more proficient group of graduates in less time compared to conventional training systems. There are eight steps for developing an instructional system: 14

(1) Write a set of Task Analyses

(2) Write a set of Objectives based on the Task Analyses

(3) Write tests that fully measure each Objective

(4) Decide what available instructional media will best help the students reach the objectives

(5) Use the Task Analyses to develop the information it contains into the format required by the chosen media

(6) Edit for obvious shortcomings

(7) Validate this developed instructional system by trying it on a small group of students; make necessary improvements

(8) Implement this individualized instructional program for all students and continue to improve as necessary. 15

These steps require diligent and skillful preparation by the instructor staff. The traditional role of the teacher has been to find ways to explain subjects to his students. With individualized instruction, the instructor will find this role an even greater challenge.

task analysis

The instructional system development process indicates that a training system must he more precisely organized. This precision starts with the task analysis. The task analysis, a detailed outline of behavior that comprises a task,16 is prepared in a two-column format for easy visual reference (refer to Appendix A). The task analysis states the behaviors, skills, and knowledges in a logical sequence that makes up the task. Each left column entry becomes a teaching step with a teaching step appraisal, which is student activity that constitutes the feedback mechanism. Right column entries are the skills and knowledges that must be learned in order to perform the student activity. The student masters each teaching step by learning the accompanying skills and knowledges and by performing the teaching step appraisal. With mastery of the teaching steps, the student is prepared for the overall objective of the task. This task objective is called a criterion objective with its associated criterion test.

When each task is broken down into such detail, appropriate objectives (criterion and teaching step appraisals) can be written without any objective being overlooked. Tests to measure objective achievement can be written with the same confidence that nothing important is left out. Finally, the detailed task analysis serves as the outline for those instructors who select and prepare appropriate instructional media, again insuring that nothing is omitted.

behavioral objectives

Behavioral objectives clearly state what each student is expected to learn and to what level. Schools have long had objectives, but they have been too general and vague to provide the direction thought necessary. 17 Objectives must he stated specifically and in such a way that a student’s attainment of each objective is measurable.

A measurable objective consists of a statement of performance, condition, and standards.18 Let’s examine a simple objective: The student will be able to read. This objective states a performance, but it is too general and vague. If the student is 16 and can read the word “cat,” he has met the stated objective. Clearly we must add some standard of acceptable performance. A better objective is: the student will read 250 words per minute with 80 percent comprehension. This objective fails when more than one instructor is responsible for different students’ achieving the objective. Compare three students: one is tested for achievement using a college chemistry text, a second is measured with a chapter of John Steinbeck’s The Grapes of Wrath, while the third student is given a copy of a third grade reader. The degree of difference has been expanded to show that some condition must be stated.

In any instructional system where there are many students and instructors, there will be honest misinterpretations of what goals must he reached and how to train to reach the goals. Explicitly stated objectives will minimize these honest errors that cause either student failures or a waste of time.

If we decide that the student must learn to read at a common adult level, we could so state our objective: the student will read a chapter of Steinbeck’s The Grapes of Wrath at 250 words per minute with 80 percent comprehension. This is a behavioral objective because it states a specific performance with certain conditions to a measurable standard. An individualized instructional system rests on a set of clearly defined objectives.

Should the student be made aware of his objectives before he begins his training? Definitely, yes. Concrete objectives not only control the thrust of the instructional system but also direct each student’s activity. When a student has clear objectives before him, he can more easily focus his energy on achieving these goals. Learning should be the business of acquiring skills and knowledges that are necessary for later use. This is especially true when the training has a direct job relation and when costs are involved.

performance testing

To help students when and where they have learning difficulties, we must have some way to identify their needs. We can identify each student’s needs by examining his performance with a test. This diagnostic test differs from the usual connotation of tests (formal grading) because the purpose is solely to identify the student’s needs. 19 Once these needs are known, both the student and the instructor realize what the student must learn to achieve the objectives. When the student can succeed on the diagnostic test, there is no need for training in that subject. The test, of course, must be written in such a way as to measure completely the established explicit objective.

A criterion objective and its performance test state and measure the student’s acceptable achievement of a task. The task analysis breaks down each criterion objective into smaller units called teaching steps. Tests are developed for each teaching step. These teaching step appraisals and criterion tests are perhaps the single most important component in individualized instruction. 20 From the instructor’s point of view, the tests measure student progress and identify student problems. From the student’s view, these tests are activity through which he is able to increase and internalize his learning by doing something with the training just received. 21 Opportunities to use new skills and knowledge immediately tend to increase retention. Performance testing confirms student progress or points to the need for correction.

For example, both Mel and Jim must reach the same criterion objective which has three teaching steps. Jim masters steps one and two but has difficulty with step three. He needs some kind of assistance to overcome his difficulty. Mel, who had problems on steps one and two, receives the help he needs and finds step three within his ability because he mastered the first steps. Mel may be ready for the criterion test in thirty minutes while it takes Jim an hour. The important point is that both Mel and Jim have mastered the criterion objective by overcoming their individual learning difficulties. The teaching step appraisals have been used to find these problems and allow for individual correction. Neither Jim nor Mel has slowed the other down while overcoming his particular problems.

The most effective way discovered so far to find each individual’s strengths and weaknesses is through the use of performance tests. 22 Instructional systems that use behavioral objectives and performance tests to diagnose progress and allow for immediate correction of problems are said to be efficient and effective. The instructional system is effective because each student can actually perform to explicit objectives, and it is efficient because each student has received only that training necessary for him to achieve the objectives. Each student is neither undertrained nor overtrained. Undertraining is avoided because each student must reach all objectives. Overtraining is avoided because training in an area stops once the criterion objective is met.

instructional media

Explicit behavioral objectives focus the entire training effort. Frequent diagnostic testing shows when and where students are experiencing learning difficulties. But how does one instructor have time to help each student and give each student sufficient time to learn? The answer is through the use of instructional multimedia.

Media are the means of communication. In conventional training, the instructor and the textbook are the predominant media. In individualized instruction, the information to be learned is presented by a much wider variety of media. While slides and tape recordings appear most often, “media” actually refers to anything that presents information to the student (see Appendix B). The use of multimedia affords the instructor time to help each student whenever that student experiences a problem.

To make intelligent decisions concerning the use of media, instructors must have sufficient knowledge of existing media and the principles of media utilization. Instructional media are expensive; the cost must be measured against media effectiveness in teaching. Cost-effective media should be chosen objectively rather than on the basis of personal preference. Supervisors of training systems should have their instructors complete one or more courses in media and audiovisual instruction.23 Without such training, most instructors have only personal bias on which to recommend the purchase of expensive hardware. Without such training, instructors who develop the software will do so without sufficient knowledge of the techniques for effective production.

During the past ten years, media technology and techniques have been expanded so rapidly that few instructors are aware of the impact on their efforts to train their students. Having the media and accepting their value is one thing; knowing how to use them effectively is something that requires additional instructor training.

Some of the advantages of using instructional media for the teacher include the following:

(a) Using instructional media to present the teaching segment of the teaching-learning activity (TLA) frees the instructor from lecturing on the same subject class after class. Instructors can suffer from boredom, too, and it is understandable that there are days when the instructor just does not put forth his best effort. Once the media have been developed into top-quality tools’ the instructor can be confident that all the material is well presented every time.

(b) With the various teaching media, the teacher is no longer the sole source of information in the class. 24 The teacher has time for communicating with each student in ways that establish rapport and a spirit of cooperation. There is little time to do this in conventional training because the teacher is occupied presenting the lesson. Increased cooperation and communication between the teacher and the individual student can create a learning environment in which the student feels he is important and has a stake in the system. When the student sees himself as really belonging, his ability to learn is improved. 25

(c) Besides motivating the student, the instructor works with each individual, searching for student understanding. Students who can explain what they are learning actually learn that subject better. In conventional training, not every student has the chance to explain what he is getting out of his learning. If the student can explain his new knowledge, he has confidence in it; if the student finds he is confused, he realizes he needs to recycle his learning effort to get a better grasp of the subject.

(d) The instructor should determine the student’s reaction to instructional media. There will he media presentations that, from the student’s point of view, are difficult to understand. Perhaps the student can suggest what he feels is a better way to present the material. If the instructor remains aloof from the student, his chances of finding out what to improve will be reduced.

For the student, use of instructional media has certain advantages, also:

(a) The student acquires instruction through the multiple sensory approach. In conventional systems, the student depends greatly on his sense of hearing to absorb lecture materials. How many of us feel we learn our best through the use of one sense only—hearing? With instructional media, the student is receiving information through several of his senses at the same time or at closely timed intervals. The training is more intense, and the student is more involved. Better and faster learning occurs when a combination of senses is employed. The greater the number of senses taking data in, the higher the learning retention is likely to be.26

(b) While the instructional media intensify student involvement, the need for repeat explanations still remains. The student simply resets the media to the appropriate place, and he has the explanation as many times as he needs without slowing the progress of the rest of the class. A good instructional system will have alternate presentations available for students who develop a mental block with certain media.

Within one decade the role of the media has changed from that of a supplement to a primary source of instruction.27 The major burden for presenting the material in class is delegated to a system of instructional media. The student interacts with this selected variety of media with the personal guidance and help from the instructor that he could not get in conventional classes.

expected results

Individualized instruction, based on the principles described in this article, has been used worldwide at all levels of education and in a variety of subjects. There are some problems in interpreting the results of the past seven years of experience; however, it seems reasonable to state the following:

(a) Two to three times as many students using individualized instruction have achieved A and B grades as compared to students studying the same subjects in conventional ways. The number of failures with individualized instruction also has been reduced. 28

(b) Although time is a flexible factor, the total time in training has been reduced. Reductions of 25 to 44 percent have been reported in military, industrial, and academic training programs. 29 This time savings translates into a financial savings that compensates for the initial investment in expensive media and increased instructor training.

(c) Students really enjoy individualized instruction because they no longer are passive participants. Their active involvement in doing things with newly acquired skills and knowledge during the learning process has caused them to express greater interest and more positive attitudes toward their training. Success and enjoyment of learning instill confidence in their ability to learn, which can carry over to other endeavors.30 If these student benefits are important to the reader, he has a good portion of the attitude necessary to be a part of an individualized instructional system.

Individualized instruction is student-centered and not teacher-centered as in conventional systems. It is student-centered because it focuses all activity on the needs of each student in his efforts to achieve predetermined specific objectives. It responds to individual student abilities in three ways: (1) multiple sensory approach to teaching; (2) increased student activity, which helps him internalize his training; and (3) sufficient time to overcome his weaknesses.

Although the emphasis is on the student, the teacher’s role has not become outmoded. Rather, the teacher finds his role even more demanding. Individual learning activity must be prescribed for each student according to his recent progress and remaining goals. The teacher becomes more professional and assumes the role of learning guide and consultant. The teaching staff is responsible for the creative development and effective use of the instructional media. The individual teacher manages the learning process of diagnosis, prescription, and evaluation.

The individual student’s training is intensified by the multisensory approach, and his activity is intensified by responding to frequent teaching step appraisals and criterion tests. The student is doing more than he did in conventional systems. Experience is the best teacher, and student activity is the experience by which he learns.

Individualized instruction is attained through the Instructional System Development process. Using Webster’s New Word Dictionary, we describe the process: “To cause to become better” (develop) “the orderly way” (system) of “giving the facts of the matter” (instruction). More simply stated, “It is a better way to teach.”

Citrus Heights, California


1. B. F. Skinner, The Technology of Teaching (Appleton-Century-Crofts, 1968), p. 242.

2. James H. Block, Mastery Learning, Theory and Practice (San Francisco: Holt, Rinehart and Winston, 1971), p. 4. The Winnetka Plan (1922) by Carleton Washburne and another approach by Henry C. Morrison (1926) at the University of Chicago’s Laboratory School fell into disuse primarily because of lack of technology to sustain a successful strategy.

3. Hq MAC/DOTO, Introduction to Individualized Training, USAF ISDQ-4-003 (1974), an audiovisual production.

4. Air University Review (September-October 1968) featured the “Air Training Command: Providing for the Future.” In that issue, Lt. Col. Vernon J. Elslager’s “Toward Individualized Instruction” (p. 10) and John P. Murphy’s “Behaviorally Oriented Instruction in ATC” (p 21) describe ATC’s pioneering work in ISD. Now, seven years later, the major principles of ISD are intact web only a few changes in terminology. i.e., Instructional System Development has replaced the term Systems Approach to Training (SAT). Since 1970, ISD has been spreading throughout the major air commands.

5. L. F. Miller, Major General, Hq USAF letter, subject: USAF Policy on the Systems Approach to Training (SAT), dated 13 November 1970.

6. John B. Carroll, “Problem of Measurement Related to the Concept of learning for Mastery,” Educational Horizons, 48, No. 3 (1970), pp. 71-80.

7. John B. Carroll, “A Model of School Learning,” Teachers College Record, 64 (May 1963), pp. 723-33.

8. James H. Block, “Teachers, Teaching, and Mastery Learning,” Today’s Education, (November-December 1913), pp. 30-36 (hereafter cited as “Teachers”).

9. Ibid.

10. Ibid.

11. One Air Force course equal to at least three semester hours is ATC Course 3AZR75100, Instructional System Materials Development. Two college texts are Brown, Lewis, and Harcleroad, AV Instruction, Technology, Media and Methods (San Francisco: McGraw-Hill, 1973) and Wittich and Schuller, Instructional Technology, Its Nature and Use (San Francisco: Harper and Row. 1973).

12. Richard Hersh and Stuart Cohen, “Beyond Behavioral Objectives: Individualizing Learning,” Elementary School Journal, November 1972, p. 102.

13. Hq MAC/DOTO, USAF ISD-Q-4-003.

14. USAF ATC Course 3AZR75100, Instructional System Materials Development (1973), p. 402.

15. AFM 50-2, Instructional System Development, (December 1970), pp. 5-21.

16. USAF ATC Course 3AZR75100.

17.S herman Frey, “Behavioral Objectives: Attitudes of Teachers,” The Clearing House, 48 (April 1974).

18. Robert F. Mager, Preparing Instructional Objectives, (Palo Alto, CA: Fearon, 1962).

19. AFM 50-2, p. 1-1.

20. Block, “Teachers,” pp. 31-33.

21. USAF ATC Course 3AZR75100, p. 202.

22. Wittich and Schuller, p. xiv.

23. AFM 50-2, p. 63. See also note 11.

24. Ibid., 6-3.

25. Block, “Teachers,” p. 36.

26. Rita and Kenneth Dunn, Practical Approaches to Individualizing Instruction (West Nyack. N.Y.: Parker, 1972), p. 99.

27. Ibid., p. 62.

28. Block, “Teachers.” p. 34.

29. Hq MAC/DOTO, USAF-ISD-Q-4-003.

30. Block, “Teachers,” p. 34.

A Sample Task Analysis


Obtain, validate and plot a time difference reading from the EC-121 LORAN C System


AN/ARN-92(v)-2, Local Area Navigation Charts and Log, pencil, dividers, and Weems plotter


 The plot must be within 3NM of actual EC-121 position.

Teaching Steps

Skills and Knowledges

1. Identify the purpose, theory of operation and location of components and controls of the LORAN C.


 1. PCS statement controls the Criterion Objective and Test.
2. Each Teaching Step will have a Teaching Step Appraisal.
3. A Teaching Step is measurable student activity
4. Right column entries are skills, knowledges and supporting teaching points for each Teaching Step.
5. Students do not see or use the Task Analysis. The instructor who selects the media and writes the subject explanation uses the Task Analysis as his outline.






2. Obtain, validate and plot a time difference reading for the LORAN C.


la Purpose of the LORAN C

1) Micro-miniature receiver indicator
2) Converts an analog system to a digital system.
3) Inserts time difference into a memory mode, holds it there, and continues to update it with more current time difference data.

1b. Theory of Operation

1) Operates on the principle of Group Repetition Rate (GRR), or a burst of eight pulses.

2) Five basic rates are used.

a) The distance of the Master and Slaves determines the rate.

b) The rates are:

1 SS  


2 SL


3 SH



4 S


5 L


 2a Obtain a time difference reading

1)Presetting is accomplished IAW 552 GPMan 55-1, Vol. II. To expedite search phase, preset a value of 1,000 to 2,000ms below actual aircraft position.
2) Warm-up is 15 minutes after power switch is placed in STBY.

Source: Format from USAF ATC Course 3AZR75100 (July 1973), p. 159. Data: USAF ADC Course ADC12100T, Navigator.

Instructional Media

Individualized instruction was not possible until technological advances made possible a wide variety of media. Too often when we think of media, only two or three examples come to mind, and we tend to think that that is all there is to media. We also forget the many experiences and learning options that should be considered when individualizing instruction.

The lists in this appendix may convince the reader of the magnitude of choices and combinations confronting the teaching staff as they select and develop their instructional system. The quality of training can suffer, and certainly time, money, and effort can be wasted when media are overlooked, or the wrong media are purchased, or the instructors lack knowledge in how to blend the media into the student’s learning activity.

I recommend that instructors pursue their personal training in the field of audiovisual Instruction. Training supervisors should consider taking steps to have their instructors attend audiovisual courses at organizational expense. This financial investment will pay off in the development of an efficient and effective training program.

Experiences leading to learning
Discussing, conferring, speaking, reporting
Reading (words, pictures, symbols)
Writing, editing
Graphing, charting, mapping
Demonstrating, showing
Experimenting, researching
Problem solving
Observing, watching
Outlining, taking notes
Constructing, creating
Drawing, painting, lettering
Displaying, exhibiting
Singing, dancing
Imagining, visualizing
Organizing, summarizing
Judging, evaluating

Individualized learning options
Read textbooks
Read nonfiction books
Read pamphlets
View transparencies
Listen to records
View filmstrips
Study periodicals
Watch instructional television programs
Work on self-instructional kits
Give oral reports
Study charts
Study maps
Take self-administered tests
Interview resource personnel

Participate in small group discussions
Use the amplified telephone
Study reference books
Refer to fiction books
Listen to tape recordings
Study pictures
Study programmed instructional materials
Study models or objectives
View 35mm slides
View microscopic slides
Write reports
Produce learning materials
View graphs
View films
Participate in student teaching conferences
Conduct experiments
Play educational games

Facilities for learning
Lecture halls
Independent study areas
Discussion rooms
Resource centers
Electronic learning centers
Playing fields
Community resources
Home study centers

Equipment for learning

Record players, tape recorders, radios
Slide and filmstrip projectors and viewers
Overhead projectors
Motion picture projectors and viewers

Television receivers
Videotape recorders, players, viewers
Teaching machines
Computer terminals and print image producers
Electronic laboratories: Audio/ video/access and interaction devices
Telephones with or without other media accessories
Microimage systems—microfilm, microcard, microfiche
Copying equipment and duplicators
Cameras, still and motion

Media for learning
Supplementary hooks
Reference books, encyclopedias
Magazines, newspapers
Documents, clippings
Duplicated materials
Programmed materials
Motion picture films
Television programs
Radio programs
Recordings (tape and disc)
Flat pictures
Drawings and paintings
Slides and transparencies
Microfilms, microcards
Maps, globes
Graphs, charts, diagrams
Models, mockups
Collections, specimens
Flannel-board materials
Magnetic-board materials
Chalkboard materials
Construction materials
Drawing materials
Display materials
Multimedia materials

Source: AV Instructional Technology Media and Methods, Chapter I.


Master Sergeant Frederick K. Snyder is an Instructor Radar Supervisor, 552d Airborne Early Warning and Control Group (ADC), McClellan AFB, California, where he applies Instructional System Development (ISD) principles to training EC-121 radar operators. He has more than 3800 hours in the EC-121, including 130 combat missions in Southeast Asia, and tours at ground radar sites in Iceland and the Philippines. Sergeant Snyder is a distinguished graduate of ADC’s NCO Academy.


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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