Technical Report 1210 

Foundations of Military Pilot Selection Systems: 

World War I 

Diane L. Damos

Damos Aviation Services, Inc. 

 

September 2007 

 

 

 United States Army Research Institute 

 for the Behavioral and Social Sciences 

 

Approved for public release; distribution is unlimited. 
U.S. Army Research Institute 

for the Behavioral and Social Sciences 

A Directorate of the Department of the Army 

Deputy Chief of Staff, G1 

Authorized and approved for distribution: 

 PAUL A. GADE, Ph.D. MICHELLE SAMS, Ph.D. 

 Acting Technical Director Director 

Research accomplished under contract 

for the Department of the Army 

Damos Aviation Services, Inc. 

Technical review by 

John E. Stewart, U.S. Army Research Institute 

Michael L. Wesolek, U.S. Army Research Institute 

NOTICES 

DISTRIBUTION: Primary distribution of this Technical Report has been made by ARI. 

Please address correspondence concerning distribution of reports to: U.S. Army 

Research Institute for the Behavioral and Social Sciences, Attn: DAPE-ARI-MS, 

2511 Jefferson Davis Highway, Arlington, Virginia 22202-3926. 

 

FINAL DISPOSITION: This Technical Report may be destroyed when it is no longer 

needed. Please do not return it to the U.S. Army Research Institute for the Behavioral 

and Social Sciences. 

NOTE: The findings in this Technical Report are not to be construed as an official 

Department of the Army position, unless so designated by other authorized documents.
REPORT DOCUMENTATION PAGE 

1. REPORT DATE (dd-mm-yy)

September 2007 

2. REPORT TYPE

Final 

3. DATES COVERED (from. . . to) 

May 2005-May 2006 

4. TITLE AND SUBTITLE 

Foundations of Military Pilot Selection Systems: World War I 

5a. CONTRACT OR GRANT NUMBER 

DASW01-03-D-0016 

5b. PROGRAM ELEMENT NUMBER 

622785 

6. AUTHOR(S) 

Diane L. Damos (Damos Aviation Services, Inc.) 

5c. PROJECT NUMBER 

A790 

5d. TASK NUMBER 

351 

5e. WORK UNIT NUMBER 

 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

Damos Aviation Services, Inc. 

5250 Grand Ave, Suite 12, PMB 124 

Gurnee, IL 600314 

8. PERFORMING ORGANIZATION REPORT NUMBER 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 

U.S. Army Research Institute for the Behavioral Sciences 

ATTN: DAPE-ARI-IR 

10. MONITOR ACRONYM 

ARI-RWARU 

2511 Jefferson Davis Highway 

Arlington, VA 22202-3926 

11. MONITOR REPORT NUMBER 

Technical Report 1210 

12. DISTRIBUTION/AVAILABILITY STATEMENT 

Approved for public release; distribution is unlimited. 

13. SUPPLEMENTARY NOTES: 

 Contracting Officer's Representative and subject matter POC: Dr. William Howse 

14. ABSTRACT (Maximum 200 words): 

This report describes the development of the U.S. Army pilot selection system beginning in World War I. It 

starts with a review of aviation in the United States up to 1917. The phases of flight training then are described with 

the associated failure and fatality rates. Some cost estimates for each phase also are provided. Finally, the pilot 

selection system itself is described. Because the selection system was revised over time, the early system 

(administered from May, 1917 to February, 1918) is described first, followed by the revised system (administered from 

March, 1918 to November, 1918). Additions to the initial battery are described, as are the tests that were under 

development at the time of the Armistice. 

15. SUBJECT TERMS 

pilot; Army aviator; selection; ab initio; World War I

 SECURITY CLASSIFICATION OF 19. LIMITATION OF 

ABSTRACT

20. NUMBER 

OF PAGES

21. RESPONSIBLE PERSON

16. REPORT 17. ABSTRACT 

Unclassified 

18. THIS PAGE 

Unclassified 

 

Unlimited 

 

19 

Ellen Kinzer 

Technical Publication Specialist 

(703) 602-8047

Unclassified 

i 
ii 
Technical Report 1210 

Foundations of Military Pilot Selection Systems: 

World War I 

Diane L. Damos 

Damos Aviation Services, Inc. 

Rotary-Wing Aviation Research Unit 

William R. Howse, Chief 

U.S. Army Research Institute for the Behavioral and Social Sciences 

2511 Jefferson Davis Highway, Arlington, Virginia 22202-3926 

September 2007 

Army Project Number Personnel, Performance 

633007A792 and Training 

Approved for public release; distribution is unlimited. 

iii 
iv 
FOUNDATIONS OF MILITARY PILOT SELECTION SYSTEMS: WORLD WAR I 

EXECUTIVE SUMMARY 

Research Requirement: 

Pilot selection has a long history in the United States military beginning with World War 

I. Reports dealing with this early period have become increasingly difficult to obtain, and recent 

literature reviews have not addressed this period in any depth. As a result, some individuals 

involved in pilot selection question the usefulness of instruments and procedures that have been 

effective for over 90 years. 

Procedure: 

This report describes the development of the U.S. Army pilot selection system beginning 

in World War I. It starts with a review of aviation in the United States up to 1917. The phases 

of flight training then are described with the associated failure and fatality rates. Some cost 

estimates for each phase also are provided. Finally, the pilot selection system itself is described. 

Because the selection system was revised over time, the early system (administered from May, 

1917 to February, 1918) is described first, followed by the revised system (administered from 

March, 1918 to November, 1918). 

Findings: 

The development of the pilot selection system from early 1917 to late 1918 was driven by 

the need to reduce training costs. The early system did not adequately identify individuals who 

could not pass flight training or required inordinate amounts of time to do so. An intelligence test 

and an expanded survey of the applicant’s athletic interests were introduced in order to reduce 

training costs. Tests of tolerance to hypoxia and auditory reaction time were also approved but 

not implemented before the Armistice. By mid-1918 investigators recognized that daily flight 

grades were influenced by factors other than flying skills, often lacked sufficient variance to be 

used as criteria, and suffered from poor interrater reliability. 

Utilization and Dissemination of Findings: 

The primary impetus for improving pilot selection systems was, and still is, a reduction in 

training costs. Intelligence tests and measures of athletic interest have proven their worth over 

90 years and need to be retained in pilot selection batteries. The development of good criterion 

measures remains as much a priority today as it was, almost a century ago.

v 
vi 
FOUNDATIONS OF MILITARY PILOT SELECTION SYSTEMS: WORLD WAR I 

CONTENTS 

INTRODUCTION .......................................................................................................................... 1

Limitations of the Current Report............................................................................................... 1 

Background................................................................................................................................. 2

STAGES OF TRAINING............................................................................................................... 3

Ground school............................................................................................................................. 3 

Preliminary Training................................................................................................................... 3 

Advanced Flight Training........................................................................................................... 4 

Mission-Specific Training .......................................................................................................... 4

FAILURE AND FATALITY RATES............................................................................................ 5

Ground School ............................................................................................................................ 5 

Preliminary Training................................................................................................................... 5 

Advanced Training...................................................................................................................... 6 

Mission-Specific Training .......................................................................................................... 6

COSTS OF FLIGHT TRAINING .................................................................................................. 7

SELECTION................................................................................................................................... 8

Selection to 1917......................................................................................................................... 8 

May, 1917-February, 1918 ......................................................................................................... 8 

February, 1918 ............................................................................................................................ 9 

March, 1918-November, 1918.................................................................................................. 10

SUMMARY.................................................................................................................................. 11

REFERENCES ............................................................................................................................. 13 

vii 
viii 
FOUNDATIONS OF MILITARY PILOT SELECTION SYSTEMS: WORLD WAR I 

Introduction 

Many reviews of pilot selection (Hunter & Burke, 1995; Koonce, 1984; North & Griffin, 

1977; Turnball, 1992 begin with a short overview of the World War I efforts. The authors agree 

that the scientific basis for pilot selection began during this period. Because documents from 

World War I are often difficult to obtain, these reviews may leave the impression that the WW I 

efforts were unsystematic, narrowly focused, and superficial. 

This report attempts to lay a foundation for understanding pilot selection in the U. S. 

Army during World War I. It describes the stages of pilot training and presents data pertaining 

to training costs. It describes in as much detail as possible the pilot selection tests that were used 

during World War I. The primary goal of this is to show that far more research and development 

occurred during World War I than has been previously recognized. 

Limitations of the Current Report 

Articles published between 1917 and approximately 1920 often were impossible to 

obtain. Consequently, several potentially important articles could not be included in this review. 

Because this paper in concerned only with pilot selection in the United States, it ignores all of the 

research and development conducted in other countries. Interested readers may consult Hoff and 

Fulton (1942) for an extensive bibliography on early pilot selection and assessment including 

articles published in Russian, Polish, German, Chinese, Italian, Spanish, Portuguese, and 

Japanese. 

The available World War I training data are often confusing and apparently 

contradictory. As will be described below, all stages of flight training were conducted in both 

the United States and Europe throughout America’s participation in World War I. Some of the 

European training was conducted by the Allies and some by the Americans. No documents were 

found indicating that the curricula were standardized among the Allies, and different training 

aircraft were used at different bases. Thus, failure rates and other measures of training 

performance may be affected by the type of aircraft the students flew, the curriculum at the 

schools contributing data, and the English fluency of the instructors. To make matters more 

confusing, some training data are based on the period from the entry of the United States into the 

war on April 6, 1917 to the Armistice. Other data are accumulated from April, 1917 to the 

withdrawal of the Army from Europe in mid-May, 1919 (Gorrell, 1940). In some cases, it is 

impossible to determine the time period for the aggregation of the data. 

The literature also demonstrates confusion between physiological and psychological 

phenomena. For example, sensitivity to tilt and to rotation sometimes were seen as 

psychological rather than strictly physiological phenomena. Selection tests involving 

physiological and medical factors were separated as much as possible from cognitive and 

personality tests in this review and are not discussed in the present report. The sole exception is 

the hypoxia tolerance test, which was seen partially as a reflection of psychological factors rather 

1
than strictly physiological factors. Modern psychological terminology is used whenever possible 

in this report, to describe topics concerning cognition, intelligence, and personality. 

Background 

It is necessary to understand the state of aviation in the United States prior to its entry 

into World War I, in order to understand pilot selection during this period. The United States 

had no airlines, no civil airports, and no civil pilots prior to 1917, and was ranked 14th

internationally in terms of aviation. Between 1908 and the American entry into World War I, the 

Army received a total of 224 aircraft, none of which was a combat aircraft (Gorrell, 1940). By 

1917, the Army had trained a total of 139 pilots, of which 26 were actually qualified aviators 

(Gorrell, 1940). The Army at that time had only two flying schools. Aircraft production 

facilities were extremely limited; the first American-made aircraft did not see service in Europe 

until August, 1918. Thus, America had little in terms of aircraft, production facilities, flying 

training schools, or pilots at the beginning of the war. 

No documents were found describing flight training prior to 1917. In early 1917, the 

U.S. Army decided to adopt a modified version of the Canadian and British flying training 

programs. The U.S. version divided flight training into three consecutive stages: ground school, 

preliminary flying training, and advanced flying training. Mission-specific training (pursuit, day 

bomber, night bomber, observer) was added to the curriculum by December, 1917 and occurred 

after the cadet had successfully completed advanced training. 

The Army was very successful at establishing ground schools and flying training schools 

quickly. The first six ground schools in the U.S. were opened on May 21, 1917, approximately 

six weeks after the declaration of war (Gorrell, 1940). The last two were opened in July, 1917. 

By May 1918, the United States had established 25 flying schools in the United States and 16 in 

Europe. 

At the beginning of the war, the Army entered into agreements with the Allies for flying 

training because of its lack of training facilities, experienced instructors, and aircraft. 

Consequently, American cadets were taught to fly using Allied instructors, aircraft, and training 

curricula. These arrangements continued throughout the war but apparently were of increasingly 

less use to the Army. Because the Army established American ground schools very quickly, 

only one agreement was reached for ground school training in Europe. This agreement was with 

the British and resulted in fewer than 500 Americans attending the school. 

Gorrell (1940) notes that only 1791 cadets were sent directly to Europe for preliminary 

training versus 15,627 who were sent to bases in the continental U.S. Indeed, the proportion of 

cadets sent to Europe for preliminary fliflying training appears to have decreased over time 

although the absolute number remained relatively constant. 

Because the Army initially had no combat aircraft, all advanced training had to be 

conducted in Europe. Initially, the instructors were Allies. Gradually, as the Americans gained 

combat experience, the Allied instructors were replaced with Americans. Some documents 

2
indicate that the training was self paced and that the curriculum varied from school to school. 

Mission-specific training varied among the specialties. 

The Armistice was declared on Nov. 11, 1918. Flight training in Europe continued until 

March 5, 1919. Although the United States was only in the war approximately 19 months, the 

innovations were truly amazing. By November, 1918, the United States could produce 23,000 

aircraft per year. The horsepower of the aircraft engines increased from 150 to 300 with a 500 

horsepower engine under development at the end of the war. The 41 flying schools that had been 

established cost over $100 million in 1918 dollars to build, maintain, and operate (Gorrell, 1940). 

Stages of Training 

Pilot selection systems typically are evaluated in terms of performance on operational 

criteria, failure rates during training, and training costs. For the U.S. Army World War I pilot 

selection system, no documentation was found linking selection variables to operational criteria, 

such as number of aircraft shot down in air-to-air combat or number of reconnaissance missions 

flown. Consequently, all evaluations of the selection system must use criteria from each of the 

training phases. Although the data are not complete, it is possible to obtain some estimates of 

failure rates at each training stage. Limited data on training system costs and failure costs also 

are available and will be discussed in subsequent sections. 

According to Gorrell (1940), both the Allies and the initial American experience 

indicated that it took about 90 hr of flying time and about 6 months to produce a pilot ready to 

fly at the front. These figures include preliminary, advanced, and mission-specific training. 

Gorrell does not indicate if the 6 months included ground school training. 

Ground school 

Students in modern military flight training often begin flying during the ground school 

phase of their program. In contrast, during World War I ground school training did not include 

any flight time. The U.S. Army ground schools were all established at colleges and universities 

and were taught by university faculty (Morin, 1997). The curriculum was taken from the Royal 

Flying Corps (Morin, 1997) and initially required 8 weeks. Sometime later, the ground school 

was expanded to 12 weeks. The extent to which the grading at these ground schools was 

standardized is not known. Morin (1997) notes that the Army decided to keep the failure rate 

high in ground school, the least expensive stage of training, to eliminate as many cadets as 

possible who would prove to be unsuccessful. This statement implies that the ground school was 

believed to have predictive validity to success in flight training. No evidence to support this 

belief was found. It also implies that the Army was concerned with the cost involved with pilot 

training and was seeking ways to contain the costs. 

Preliminary Training 

If the cadet passed ground school, he was sent to a flying training school and began 

preliminary flight training. Preliminary flight training in the United States lasted 6 to 8 weeks. 

Typically, cadets received 30 to 50 hr of flight instruction. This training stage apparently was at 

3
least partially proficiency based. Consequently, cadets took varying amounts of time to 

complete the program and received different amounts of flying time (Morin, 1997). Cadet 

classes had varying mean total flight times, which may be related to individual differences in 

aptitude or to the training aircraft used at specific flying training schools. Based on 1600 cadets 

trained in the United States, Henmon (1919) states that the mean flight hours to complete 

preliminary training was “well below 50.” This average apparently applies to data collected 

through June, 1918. Students were expected to solo after 3 to 4 hr of training; 6 hours without a 

solo flight was considered grounds for elimination in some schools (Morin, 1997). 

Little information is available on the preliminary flying training conducted in Europe by 

the Allies or by the U.S. Army. Morin (1997) indicates that the British had developed a dualcontrol aircraft, which led to faster learning. Students soloed after 3 to 4 hr of flight time. The 

average total time to complete primary training in a British school was 8 hr. However, unlike the 

American system, a cadet was not considered to be an aviator until he had passed advanced 

training (Morin, 1997). By July 1, 1918 the American forces in Europe ended preliminary 

training and only conducted advanced and mission-specific training (Toulmin, 1927). 

Advanced Flight Training 

After graduation from preliminary flight training, most cadets were sent to advanced 

training in Europe, which began in late September, 1917. Advanced training familiarized the 

pilot with combat aircraft in contrast to training aircraft and taught more advanced aerobatic 

maneuvers. No documents were located describing the curriculum or the length of training. 

Gorrell (1940) provides one table indicating that some advanced training was conducted in the 

United States in 1918 but not in 1919. 

Mission-Specific Training 

At the end of advanced training, the pilot was assigned to a specific type of aircraft and 

mission (pursuit, day bomber, night bomber, observation). Several accounts hint that students 

were assigned to missions based on their performance in advanced training, but no policy papers 

could be located confirming this assignment strategy. Mission-specific training was designed to 

train specialized flying skills as well as skills that were unique to each type of training, such as 

gunnery for pursuit pilots and targeting for bomber pilots. By the summer of 1918, some 

mission-specific training had begun in the United States, but the war was over by the time the 

first U.S. trained pilot arrived in Europe (Morin, 1997). 

Pursuit, day bombardment, and night bombardment training began on November 1, 1917 

in Europe (Toulmin, 1927). Observation training did not begin until July 1, 1918. No documents 

were located describing the curricula or the length of training for any of the specialties. 

Morin (1997) indicated that pursuit pilots were taught aerobatic maneuvers used in 

combat and formation flying. They also were taught dogfighting. Toulmin (1927) indicates that 

after flying training, pursuit pilots were sent to a special base to be trained in gunnery. This 

training lasted 10 to 14 days according to Toulmin and 4 weeks according to Mourrin. Toulmin 

shows the first class in gunnery beginning on December 28, 1917. This date implies that pursuit 

4
training required about 7 weeks. Toulmin also indicates that pursuit pilots had to train in at least 

six different types of aircraft before completing the pursuit course. The need to fly so many 

aircraft was caused by a shortage of appropriate training aircraft. Toulmin complains that 

coordinating pursuit training was difficult and that the entire training process occasionally came 

to a complete halt, apparently because of aircraft problems. 

Some of the information on bombing training provided by Toulmin is contradictory. He 

gives two different dates for the beginning of night bombing training: November 1, 1917 and 

September, 1918. Both of these dates refer to training conducted in England. Toulmin indicates 

that the training was delayed because of the lack of appropriate aircraft. He also indicates that 

day bombardment training was conducted in the United States, but that few pilots graduated 

from these schools and that all of these pilots had to be re-trained in Europe. 

Failure and Fatality Rates 

Ground School 

The available literature produced two different estimates of the failure rate in ground 

school. According to Henmon (1919), 15% of cadets failed ground school and were eliminated 

from flight training. Henmon’s estimate appears to be based only on training records from 1917. 

Gorrell (1940) indicates that the ground schools in the U.S. accepted 22,689 students from May 

21, 1917 until the Armistice, of which 17,540 (77.3%) graduated. The 22.7% who did not 

complete ground school consisted of cadets who transferred to other assignments, failed training, 

or were discharged because of the Armistice. Gorrell provides no other data that allow the 

training failure rate to be separated from the transfer and discharge rates. Thus, 15% is the best 

estimate for the actual failure rate in ground school.

Preliminary Training

Henmon (1919) is the only source dealing strictly with failure rates in preliminary 

training for U.S.-trained cadets. Henmon estimates that at least 6% failed flying training for lack 

of aptitude but does not mention the time period used to make this estimate. However, Henmon 

provides data from Kelly Field, a training school in the United States, showing a failure rate of 

6.7% (55 failures for lack of aptitude out of 824 cadets). These data appear to reflect all cadets 

trained at Kelly Field to June 1, 1918. Henmon (p. 104) notes that at least half of the “physical 

disability or incapacity” discharges were actually for lack of aptitude. Addition of 50% of the 

physical disability discharges (11 cadets) to the lack-of-aptitude failures results in a failure rate 

of 7.3%. A report published by the Director of Military Aeronautics and cited by Henmon 

appears to have data through June 30, 1918 and shows that approximately 7.4% of the cadets 

were eliminated from training for lack of aptitude. This reference does not indicate if the data 

were obtained just from U.S. flying schools or included data from European flying schools. 

Morin (1997) is the only source dealing with preliminary training in Europe. He gives 

data for a school built by the Italian government specifically to train American pilots. The 

instructors were Italians, but the administration was under control of the U.S. Army. Again, like 

5
U.S. training schools, solo was expected after 3 to 4 hr of flight training in a dual-control aircraft. 

This school graduated 406 out of 450 cadets, for a failure rate of 9.8%. 

Gorrell (1940) provides data on the average flight time per fatality during preliminary 

training for Allied pilots. He shows an average time of 2887 hours of flight time per fatality for 

American pilots trained in France versus 2680 hr for French pilots. For Americans trained in the 

United States, the comparable figures are 2973 hr in 1918 and 1309 hr in 1919. The reason for 

the sharp increase in the fatality rate in 1919 is not known. 

Advanced Training 

No data were found for failures in advanced training although students did fail this phase 

of training. However, unlike preliminary training, advanced training had a significant fatality 

rate. For example, Gorrell (1940) records that 34 out of 542 (6.3%) Americans were killed in 

flight training in British schools. This figure represents all advanced training until March 5, 

1919 and apparently does not include those who survived a crash but were hospitalized. Figures 

for Issodun (a large U.S. training base in France) can be used to give an approximation to the 

fatality rate for advanced training in U.S. schools. Gorrell shows a total of 1839 graduates of the 

advanced course to November 11, 1918. He also shows 25 fatalities in the advanced course to 

March 5, 1919, which gives approximately a 1% fatality rate. Toulmin (1927) indicates that 

many of the fatalities were the result of air-to-air collisions near the airfields. 

Gorrell also provides time between fatalities for comparison purposes. Unfortunately, he 

shows the average flight time per fatality for Americans trained in Europe as 1487 hr in one chart 

(pg 17) and as 936 hr in the body of report (pg 22). It is impossible to determine which of these 

numbers is correct. For comparison purposes, the comparable flight times for the British and 

Italian pilots were 573 and 747 hr, respectively. Thus, the American fatality rate compares 

favorably to that of the Allies. 

Mission-Specific Training 

Only Toulmin (1927) provides any data on mission-specific training. His data are limited 

to August, September, and October, 1918 and include only pilots trained by the U.S. Army in 

Europe. Several new mission-specific training schools had been started during the summer of 

1918 and the capacity of the existing schools had been expanded. Thus, his data represent the 

largest number of cases per month for the war. Toulmin, however, only presents the number of 

pilots who began training and the number who successfully completed training. Thus, true 

failures, fatalities, and sickness/hospitalizations are included in the number who failed to 

complete training. Toulmin does not discuss transfers to other specialties at any point, and the 

data do not include early terminations because of the Armistice. The non-completion rates were 

47.3%, 33.6%, and 6.1% for pursuit, observer, and bomber (day and night), respectively. 

No data for overall fatality rates were found. Nevertheless, fatality data were located for 

Issodun for its pursuit training curriculum. Gorrell shows 829 graduates of the pursuit course at 

Issodun to November 11, 1918 with 46 fatalities to March 5, 1919. These numbers give 

approximately a 5.3% fatality rate for the pursuit course. The comparable figure for observation 

6
training was 443 graduates with 6 fatalities (1.3% fatality rate). Gorrell gives flight time per 

fatality for each type of mission-specific training. He shows 833, 605, 1096, and 359 hr for 

pursuit, observation, day bomber, and night bomber, respectively. Thus, although the pursuit 

specialty was the equivalent of the modern fighter pilot, the night bomber trainee had the highest 

fatality rate, which may be attributed to poor aircraft instrumentation. The lack of appreciation 

for visual illusions may also have contributed to the high fatality rate. These numbers include 

training conducted by the Allies as well as training conducted by the U.S. Army in Europe. 

Costs of Flight Training 

The major goal of any selection system is to identify the best applicants for the job. As 

noted earlier, the only criteria mentioned for the U.S. Army pilot selection system are training 

criteria because, like its modern counterparts, the Army was trying to minimize the cost of pilot 

training. Henmon (1919, p. 104) provides data on training failures and costs and then states “the 

need for improvement in methods for selecting flyers was and is very great.” The most 

appropriate analysis of the World War I selection data would divide the 20 months of U.S. 

involvement in World War I into periods defined by the introduction of new selection tests. The 

training failure rates, fatality rates, and cost data then would be presented for each period. 

Currently, no records permit the data to be divided in this manner; and some information, such as 

fatality costs, is not available. Therefore, this document will discuss some of the unusual aspects 

of World War I flight training that made this training expensive. 

Perhaps the most unusual feature of World War I training was the accident rate. The cost 

of destroyed and damaged training aircraft and the resulting fatalities was unusually high. 

Although modern military flight training schools experience a few accidents, in World War I, 

training accidents were common. Accidents during initial solo flights seemed unremarkable and 

both Rippon and Manuel (1918) and Henmon (1919) comment on aircraft losses and fatalities. 

The need for replacement aircraft, repair costs, and fatality-related costs clearly added to flight 

training costs. 

The second unusual feature concerns extra training. Because of manpower demands 

during a war, military training organizations often will provide extra training to marginal 

students to increase the probability that they pass. This extra training increases the overall 

training costs and does not ensure that the student passes the course or eventually becomes a 

combat pilot; the extra training may simply delay the failure. In modern U.S. military training 

schools, the need for extra training is carefully scrutinized and limited. During World War I, 

however, the Army provided excessive extra training to marginal students. Henmon (1919) 

observes that at Kelly Field one cadet was given 106 flight hr to complete the course, whereas 

another received 94 hr. Another cadet got 55 hr of flight time and wrecked 5 aircraft before he 

was failed out of the program. These numbers should be compared to average completion times 

ranging from 30 to 50 hr (Henmon, 1919). 

Flight failures add to the overall training costs. Henmon (1919) reports that a total of 74 

cadets out of 824 at Kelly Field failed to complete training. Henmon estimates these 74 cadets 

wasted 1400 hr of flying time and destroyed 30 aircraft. He states that preliminary flight training 

cost $120 per hr but was unsure if this figure included the cost of damaged and destroyed 

7
aircraft. Assuming that the estimate includes aircraft replacement and repair, the total cost of 

these 74 failures was a minimum of $168,000 in 1919 dollars. 

Gorrell (1940) indicates that the average cost of advanced and specialized training at a 

U.S. school in Europe (Issodun) was $8693 per student in 1918 dollars. Again, this value 

appears to be an average, but Gorrell gives no information on how it was calculated. For 

comparable courses taught by the British in the U.K., the U.S. paid $5000 per student. 

Selection 

Selection to 1917 

 The earliest pilot selection efforts were concerned with medical issues associated with 

flying. The first paper on aviation-related medical issues appeared in 1907 (Anderson, 1919), 

only 4 years after the Wright brothers’ first flight. In 1910, the Germans developed special 

medical qualifications for pilots (Armstrong, 1943), followed by the Americans in 1912. 

According to Armstrong (1943) these standards were ignored during the early years of World 

War I with disastrous consequences. The Germans subsequently revised their standards and 

implemented the new version in 1915. By October, 1916, the Royal Flying Corps had 

established its medical selection board; France followed in 1917 (Anderson, 1919; Armstrong, 

1943). 

During this period, the aviation medical community realized that psychiatric factors 

affected flying performance. In 1914, Ovington, an American, published a letter in a medical 

journal entitled “The psychic factor in aviation.”1

 By 1916, the Royal Air Corps had 

documented nervous breakdowns of cadets (Anderson, 1919). However, no systematic attempt 

was made to screen cadets for possible psychiatric problems until May, 1917. 

May, 1917-February, 1918 

The U.S. Army Air Services revised its medical examination and implemented the 

revised version, “Form 609,” in May, 1917. The medical examination was comprehensive and 

not altered until after World War I (Anon., 1919). The U.S. Army clearly understood that 

careful medical selection of applicants decreased training costs (Anon., 1919). Consequently, 

the standards were rigorous: Armstrong (1943) indicates that 30.3% of the pilot applicants failed 

one or more parts of the medical examination. 

Form 609 was the primary pilot selection instrument of World War I. From its inception, 

Form 609 contained many non-medical elements, which were administered and scored by 

Aviation Examining Boards. The few descriptions of the earliest version of Form 609 are 

particularly vague and brief (Henmon, 1919; Stratton, McComas, Coover, & Bagby, 1920). 

Stratton et al. refer to a “professional and mental examination” that was based upon “the 

candidate’s written answers to a series of questions covering his parentage, education, business 

experience, athletic attainments, responsibilities placed upon him by others, military training....” 

Pilot candidates had to provide the Board with at least three letters of recommendation attesting 

 

1

 No reference is given for this document by Anderson (1919). 

8
to their moral character and credentials documenting their education. They also had to appear 

before an Aviation Examining Board for an oral examination. 

No documents were located describing the professional, mental, and oral examinations in detail. 

The “mental examination” is particularly puzzling. Stratton et al. (1920) indicate that the mental 

examination was distinct from the psychiatric examination included in Form 609. The mental 

examination probably was not the Army Alpha test, which was not completed until July, 1917 

(Gould, 1981). Although records indicate that the Alpha Test was administered at Army camps 

(Gould, 1981), no records show that it was administered by Aviation Examining Boards. Like 

the three examinations, no source for the biodata questions was found with the exception of the 

questions pertaining to athletic activities and interests, which were developed by E. L. 

Thorndike. 

Henmon (1919) estimates that between 50 and 60% of the pilot applicants failed Form 

609. Given that approximately 30% failed the medical portion, the non-medical portion 

accounted for significant attrition. Again, these estimates appear to cover all of 1917 and may 

include early 1918. 

February, 1918 

The Army stopped all pilot applicant examinations on February 9, 1918 because the 

number of successful pilot applicants waiting to begin training greatly exceeded the capacity of 

the training facilities. Applicant testing was never resumed because the Armistice was signed 

before the backlog of pilot applicants had been sufficiently reduced. The pilot selection 

literature dealing with the period from February to November, 1918 is vague but seems to imply 

that at least two selection tests that had been under development, the Mental Alertness Test and 

an expanded survey of athletic interests, were administered after February 9, 1918. However, 

there is no evidence that cadets who had passed an earlier version of Form 609 were eliminated 

because of their scores on either instrument. Because derivatives of both of these instruments are 

still in use today, their validation process should be examined as carefully as the record permits. 

The information pertaining to the athletic survey is brief but relatively clear. Henmon 

(1919) implies that sometime prior to March, 1918, Thorndike found a positive correlation 

between success in flying training and athletic ability. Thorndike subsequently expanded the 

biodata section dealing with athletic activities and developed a new scoring key. Henmon 

indicates that the expanded version was adopted but gives no date for the adoption. 

According to Henmon (1919), Thorndike also developed the Mental Alertness Test, 

which was an intelligence test. It was composed of 13 subtests assessing different aspects of 

intelligence, but no description of the subtests was found. Stratton et al. (1920) show that the test 

was strictly an addition to Form 609; it did not replace the mental, professional, oral, or 

psychiatric examination. 

In a presentation given in December, 1918 and subsequently published, Thorndike (1919) 

reported that scores on the Mental Alertness Test correlated 0.50 with success in ground school. 

He contrasted this number with the 0.25 correlation between years of schooling and success in 

9
ground school. Scores on the Mental Alertness Test also correlated 0.3 with flying performance 

and with ratings of general officer quality. Thorndike (1919) indicated that he had insufficient 

data to determine how well the Mental Alertness Test predicted operational performance. 

Henmon (1919) seems to imply that the Mental Alertness Test had been validated and 

accepted for use prior to March, 1918. In contrast, Yerkes (1919) states that Thorndike began 

work on the Mental Alertness Test in August, 1918. This date seems unlikely unless the test was 

developed in a few weeks and administered immediately to cadets at the beginning of ground 

school. To produce the correlation with flying performance given above by December, the test 

also must have been administered immediately to cadets at the beginning of preliminary flight 

training. In such a case, only those cadets who successfully completed ground school took the 

test, and range restriction would have caused an underestimation of the correlation between test 

score and flying performance. 

Further investigation will have to determine when the Mental Alertness Test was 

developed. Investigators recognized the need for better selection instruments during the summer 

of 1917 (Henmon, 1919). Why they felt the need for a complex intelligence test and how the 

subtests were selected needs to be established. 

March, 1918-November, 1918 

Several articles (e.g. Henmon, 1919; Stratton et al, 1920) imply that investigators 

assumed that pilot selection would resume as soon as the training facilities had cleared the 

backlog of cadets. Consequently, the Army continued research on pilot selection until the 

Armistice in November, 1918. Tests under consideration were administered either using a 

predictive validity or a concurrent validity approach. Investigators using the predictive validity 

approach administered the tests prior to the beginning of preliminary flight training or very early 

in flight training (Henmon, 1919) and then collected data on instructor ratings and success in 

flight training. None of the papers reviewed showed any appreciation of problems associated 

with range restriction; all of those tested had passed both Form 609 and ground school prior to 

testing. Investigators using the concurrent validity approach gave the tests to two groups of 

cadets. The first group was rated as performing very well in preliminary flight training. The 

second group was rated as performing very poorly or had failed flight training. Investigators 

then attempted to determine how well the test discriminated between the two groups. 

Using both validity methods, Henmon (1919) identified five new tests that were approved 

in mid-1918 for inclusion in the pilot selection battery. Three of these tests—swaying, 

equilibrium reaction, and perception of tilt—now would probably be classified as medical tests 

of the inner ear. The fourth was a measure of the startle response and, again, probably would be 

seen today as a medical test. The fifth was a simple reaction time test using auditory stimuli. 

Because no new pilot applicants were being accepted, these five new selection tests were to be 

administered at ground schools. Henmon is vague about exactly when the cadets were to be 

tested. Logically, they should have been administered just before the cadet began ground school. 

However, by the time the testing facilities had been set up, the Armistice was declared, and the 

ground schools were disbanded. 

10
By 1918, aircraft with service ceilings over 23,000 ft were in use. Because military 

aircraft had no supplementary oxygen, the Army wanted to identify individuals who could 

function at higher altitudes. Before pilot selection was suspended in February, 1918, the U.S. 

Army had intended to include a test of hypoxia tolerance in Form 609 but had not yet 

implemented the test. After March, 1918, the hypoxia test was changed to a classification test 

rather than a selection test. 

Unlike the modern understanding of the effects of hypoxia on performance, investigators 

in World War I attributed some of the observed individual differences to psychiatric problems as 

well as to physiological differences. Armstrong (1943) indicates that the test was administered 

to all pilots stationed near branch laboratories (see Dunlap, 1918 for testing details). The exact 

point in training at which this test was administered and its effect on pilot assignments are 

unclear. 

Summary 

The development of the U.S. military aviation infrastructure during World War I was 

impressive. In approximately 20 months, the Army went from two flying schools to 25 and from 

26 fully qualified pilots to over 16,000. The development of aircraft production facilities was 

equally impressive. The classic U.S. pilot training scheme of ground school, preliminary, and 

advanced training followed by mission-specific training was adopted at this time. 

Before the beginning of the war, the only pilot selection tests were medical. Within six 

weeks after the declaration of war, the pilot selection battery had expanded to include biodata, 

including a survey of athletic interests, and a mental assessment. The relationship between 

athletic achievement and success in flying training was noted early and a detailed survey was 

developed to provide more information on a candidate’s athletic interests. This relationship has 

continued to the present. The need for more in-depth assessment of the candidate’s intelligence 

was also noted and an extensive intelligence test was added to the battery in 1918. 

Tests involving reaction time were approved for inclusion in 1918. Again, reaction time 

tests have continued to be used in U.S. pilot selection except for a brief period from 

approximately 1960 to 1985, when the reliability of the testing apparatus was questioned. The 

need for assessment of vestibular function was also recognized during this period. 

Changes to the selection system during World War I were clearly motivated by a desire 

to contain training costs, which included aircraft repair and replacement. The need for a 

standardized curriculum with a maximum number of flight hours per module does not appear to 

have been appreciated, which increased costs by allowing marginal students to continue too far 

into training. Cost containment at the advanced and mission-specific phases of training was 

clearly hampered by the early need to rely on the Allies for instructors and facilities and later, for 

training aircraft. Toulmin (1927) commented on the poor quality of the training aircraft, the 

large amount of repairs needed to maintain the aircraft, and the need to use different types of 

aircraft to maintain a flying schedule. 

11
Perhaps more importantly, by the end of World War I, investigators made three 

observations that are still valid today, almost 90 years later. First, no one test can be used to 

predict success in flight training (Henmon; 1919; Stratton et al, 1920; Thorndike, 1919); many 

factors need to be assessed. Second, flying grades are frequently poor criteria because of the 

lack of variability in the scores (Johnson, 1920), poor interrater reliability, and because other 

factors, such as bearing as a military officer affect grades (Stratton et al, 1920). Third, late stage 

failures are disproportionately more expensive than early failures (Henmon, 1919).

12
References 

Anderson, H. G. (1919). The Medical and Surgical Aspects of Aviation. London: Henry Frowde 

Hodder & Stoughton. 

Anon. (1919). Air Service Medical. Washington, D.C.: War Department: Air Service. Division of 

Military Aeronautics Government Printing Office. 

Armstrong, H. G. (1943). Principles and Practice of Aviation Medicine (Second ed.). Baltimore, 

MD: The Williams & Wilkins Company. 

Dunlap, K. (1918). Psychologic observations and methods. Journal of the American Medical 

Association, 71, 1392-1393. 

Gorrell, E. S. (1940). The Measure of America's World War Aeronautical Effort. Northfield, 

Vermont: Norwich University. 

Gould, S. J. (1981). The Mismeasure of Man. New York: W.W. Norton & Company. 

Henmon, V. A. C. (1919). Air Service tests of aptitude for flying. Journal of Applied 

Psychology, 3(2), 103-109. 

Hoff, E. C., & Fulton, J. F. (1942). A bibliography of Aviation Medicine. Springfield, IL: Charles 

C. Thomas. 

Hunter, D. R., & Burke, E. F. (1995). Handbook of Pilot Selection. Aldershot, UK: Avebury 

Aviation. 

Johnson, H. M. (1920). Resume of research in the psychology of aviation during the year 1919. 

Science, LI(1323), 449-452. 

Koonce, J. M. (1984). A brief history of aviation psychology. Human Factors, 26(5), 499-508. 

Morin, D. P. (1997). Training Air Service Pursuit Pilots in World War I. Air Command and Staff 

College, Maxwell AFB, AL. 

North, R. A., & Griffin, G. R. (1977). Aviator Selection 1919-1977 (Technical Report). 

Pensacola, FL: Naval Aerospace Medical Research Laboratory. 

Rippon, T. S., & Manuel, E. G. (1918). Report on the essential characteristics of successful and 

unsuccessful aviators. Lancet (September 28), 411-415. 

Stratton, G. M., McComas, H. C., Coover, J. E., & Bagby, E. (1920). Psychological tests for 

selecting aviators. Journal of Experimental Psychology, 3(6), 405-423. 

Thorndike, E. L. (1919). Scientific Personnel Work in the Army. Science, XLIX(1255), 53-61. 

13
Toulmin, J. A., Jr. (1927). Air Service American Expeditionary Force 1918. Nashville: Battery 

Press. 

Turnball, G. J. (1992). A review of military pilot selection. Aviation, Space and Environmental 

Medicine, 63(9), 825-830. 

Yerkes, R. M. (1919). Report of the Psychology Committee of the National Research Council. 

Psychological Review, 26, 83-149. 

14