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Medical Services in New Zealand and The Pacific

IV: Medical Investigation Unit

IV: Medical Investigation Unit

The Evolution of Aircrew Selection Methods in the RNZAF

Until the early part of 1941 all aircrew applicants were interviewed by a travelling selection board. If considered suitable they were given an aircrew medical examination and entered the Initial Training Wing from civilian life. On entering ITW they were given a mental alertness test made up of sixty short questions. The test was administered by ITW ground instructors and the marks were referred to the medical section for noting on the man's medical documents. Little notice was taken of these results and no other steps were taken to assess the entrant's suitability for aircrew duties.

In August 1941 the SMA3 machine was introduced as a method of testing motor co-ordination. This test was administered by the medical section in conjunction with the routine physical examination for fitness for aircrew. At first only the mechanical side was noted on the trainee's medical documents, but it soon became obvious that emotional behaviour during the test was also of great value and notes were made accordingly. At this stage a few of the trainees who did particularly badly were recalled for interview by the medical officer and occasionally were rejected, but, again, little use was made of the test in the final selection of candidates. Generally, provided a trainee came up to the physical requirements and reached the necessary standard in his ground subject examinations, he was passed on to the flying training, navigation and gunnery schools.

Early in 1942 it was considered that the wastage rate at Elementary Flying Training Schools was too great and means were sought to reduce this by some method of pre-selection during the pre-flying stage. To assist in this end the Medical Investigation Unit was brought into being. The aim of the unit was to attempt to put selection methods on a scientific footing both in regard to the trial of suitable tests and the validations of these tests by statistical follow-ups and surveys. The methods used were largely based on the tests carried out by the Royal Canadian Air Force, which were again based on current American methods of aircrew pre-selection. Since at this stage of the conflict both the RCAF and American Air Force schemes were largely in the experimental stages and little information was obtainable regarding their validity, it will be seen that the unit had, as it were, to start from scratch and attempt to validate its findings as it went along.

The problem was to select, from a pool of men of varied age groups, occupations and civilian backgrounds, those who by reason of physical fitness, moral fibre, motivation, education and ability to acquire new skills were considered to have a reasonable chance page 212 of ‘making the grade’ in the exacting duties of aircrew, and further, to decide which of these would be most suitable for the various categories of aircrew such as pilot, navigator, and air gunner.

Other duties carried out by the unit were the indoctrination of aircrew in the effects of high altitude and lack of oxygen, the testing of oxygen equipment, advising generally on the medical problems of flight and survival following crashes on sea or land, and, if facilities and time were available, carrying out appropriate research work on problems of aviation medicine.

With these ends in view the unit was established with a staff of three medical officers, one psychologist and a number of medical orderlies trained in psychological testing and statistics. Squadron Leader Gunn1 had had some experience with a Clinical Investigation Unit in Canada in 1941.

Once the unit was established the administration of the mental alertness test was taken over, and at the same time a night vision test (Livingston's Rotating Hexagon) was introduced.

In June 1942 a decompression chamber was obtained from Canada and the unit commenced the training of all aircrew in the effects of altitude.

In September 1942 the medical officers of the unit commenced interviewing all candidates. The aim of the interview was to assess temperament, motivation, and general suitability for aircrew, and to gather biographical data. The interview was carried out at the same time as the general medical examination for aircrew.

Towards the end of 1942 the testing programme developed quickly. The mental alertness test was revised and modified and called the RNZAF classification test. Then two further written group tests, the arithmetical reasoning and the space perception tests, were added to the battery. The results of these tests, as well as those of the SMA3 test and the medical officer's interview, were assessed on a five-point scale. These results were then handed on to a selection committee consisting of the CO of ITW, the chief ground instructor, navigators and mathematics instructors, and the senior medical officer of MIU. All candidates came before this committee and were selected for a particular aircrew category or rejected.

The progress of successful candidates was followed through flying training and full results kept so that the value of each test could be correlated with their ultimate success or failure. This was possible only in regard to pilots who carried out the initial part of their flying training in New Zealand. Other aircrew categories were sent page 213 direct to Canada and, in spite of the unit's efforts, no adequate follow-up was possible. For this reason most of the unit's follow-up surveys refer only to pilots in the initial stages of training and no correlation was possible in regard to air gunners', navigators' and pilots' success in operations.

As the results of statistical follow-ups became available and the experience of unit personnel increased, various modifications were made to the testing programme but the broad outlines remained unchanged. During this time the wastage rate at EFTSs was reduced from 25 per cent to 12 per cent. Although there is no method by which it can be proved, it is certain that some recruits were rejected who could have learned to fly – such a problem, however, is inherent in any method of pre-selection.

With the change in policy in aircrew training in November 1944 the unit was dissolved and formed the nucleus of the Aviation Medicine Unit, which was established at Ardmore in December 1944. This unit was responsible for the indoctrination of all fighter aircrew personnel in the physiological problems of flight, fitting and testing of oxygen masks, instruction in the medical aspects of tropical survival and the development of improved personal and safety aircrew equipment.

From December 1944 onwards all trainees passed through a grading school and were given twelve hours' dual instruction in flying and selected prior to the commencement of the ITW course.

Survey of Results and Conclusions

It was unfortunate that the urgency of the need for aircrew selection methods did not permit the unit to carry out any extensive research on test methods and validate them on a large number of candidates before they were actually applied in selection. Nevertheless, it was possible to correlate the scores in ground subjects with the group tests and also to correlate the SMA3 and the unit's final overall assessment of the individual's capabilities with pilot success up to EFTS in the groups sent out as pilots from ITW. There was also, of course, no way of knowing what percentage of those rejected at ITW on the basis of psychological tests and interview would have succeeded or failed in their flying training. The following conclusions were come to in regard to the various methods used:

Medical Officer's Interview

It is extremely difficult to assess the value of this method of selection. When the results of the MIU assessments, based largely on the results of the interview, were acted upon by the ITW selection page 214 committee the failure rate at EFTS was definitely lowered from 25 per cent to as low as 12 per cent. It seems probable, however, that the total wastage rate at ITW plus EFTS may have been increased, because possibly as many as 50 per cent of those rejected would have made the grade had they been permitted to continue. Most of those were rejected as ‘Temperamentally unsuitable’, but it was only necessary to consider pilots who proved themselves on operations to agree that amongst them it was possible to find all types of personalities, and some would have been quite unsuitable according to the standards used at MIU.

Motivation was much easier to decide upon. This assessment really justified the time spent on the interview. A number of candidates admitted when given the opportunity that they did not wish to continue with flying training. Thus much time and expense was saved.

The interview also afforded a convenient and very suitable opportunity to gather biographical data, the value of which will be emphasised later.

To sum up, the medical officer's interview proved an unsatisfactory method of selection but was useful in gathering information upon which more satisfactory methods were based.

The Group Tests

Of the three group tests employed, the classification test and the arithmetical reasoning test were used purely as a measure of intelligence. On the results of these two tests alone it was possible to predict with some degree of certainty whether a candidate would pass or fail in the ground subjects. In one group of 110 trainees who scored below average in both tests only 7 pilots and 13 gunners were selected, the remainder rejected. The relationship between success in these tests, the pre-entry examination marks and navigation marks at ITW was well demonstrated.

The space perception test is a test of practical ability as well as of intelligence and was found to be of some value in predicting success in actual flying training, although the correlation was not high.

These tests would appear to be of definite value in the selection of aircrew material from a pool of low educational standard. They would be best applied and acted upon prior to commencement of ground training.

The SMA3

This test was of definite value in the selection of pilots out of the group. Other factors being equal, it was clearly proved that the man with a good SMA3 test was less likely to fail as a pilot than page 215 one with a poor test. It did not follow, however, that because the result of the SMA3 test was bad the candidate would fail. The machine provided a simple method of measuring co-ordination but is not as accurate as the Visual Link Trainer or flight test in predicting pilot success.

Black and white photograph of pacific and islands


Biographical Data

The value of biographical data was confirmed. This appears to be the choice of all methods used by the MIU.

Of these data the amount of schooling, success in sporting activities and family background were found to be not so important as age and civilian occupation, both of which, as exemplified in the following report, were found to be of great significance.

Occupation and its Bearing on Pilot Success

Whether or not occupation has any bearing on pilot success was one of the first problems the Medical Investigation Unit dealt with. A classification of occupational categories into five groups was drawn up, but investigation showed that the classes were not detailed enough.

After detailed analysis of some 1000 occupational questionnaires, a new scheme of classification was introduced, four main groups being subdivided in thirteen categories as below:

Category Remarks
I. Professional: Administrative To be judged by professional qualification, degrees, diplomas, etc.
II. Clerical (repetitive) Where not professionally qualified or only partly so.
III. Salesmen Shop assistants, insurance agents, etc.
IV. Consists of Categories II and III above where the trainee has had more than two jobs of these types.
V. Skilled Tradesmen Apprenticed and apprenticeship completed
VI. Semi-skilled tradesmen Manual work (repetitive)
VII. Unskilled
VIII. Consists of Categories VI and VII above, where the trainee has had more than three jobs of these types.
IX. Farm owner or manager
X. Farming cadet Category IX under training
XI. Farm labourer (permanent)
XII. Agricultural contractors
page 216
XIII. Schoolboys and those who have recently left school and have been filling in time prior to entry into the services.

This new scale had its advantages; it gave a truer picture of the trainees' occupations; it abolished the anomalies of skilled and unskilled workers of the same class being classified together; and made allowance for two factors resulting from prevailing wartime conditions – separate categories for those trainees who had never settled to a definite job, and for those who had come straight from school into the forces.

On the assumption that an interview yields a truer analysis than does any questionnaire, it was decided that the medical officer, conversant with the new classification scale, should classify the trainees' occupations during their routine interview, the category numbers to be annotated ‘A’ where the trainee was under 21 years of age.

To find what relation this new classification scale bore to success in pilot training at Elementary Flying Training School, three courses 49, 50, 51 (600 cases approximately) were studied and the following results obtained:

Category Total Number Cases Number of Cases Failed Percentage Failure
I 44 8 18.2
II 167 38 22.7
III 64 23 35.9
IV 4
—— —— ——
Total Group 1 279 69 24.7
V 74 10 13.5
VI 77 20 26.0
VII 16 4 25.0
VIII 16 3 18.7
—— —— ——
Total Group 2 183 37 20.0
IX 27 5 18.5
X 60 6 10.0
XI 25 4 16.0
XII 1 1 100.0
—— —— ——
Total Group 3 113 16 14.1
XIII 26 1 3.8

Discounting categories where there were not enough cases to be significant (i.e. Categories IV and XII) it may be seen that schoolboys had the greatest success, with farming cadets next, and then skilled labourers. Least success page 217 was had by salesmen, semi-skilled and unskilled workers. It is significant that those having a greater chance of success as pilots were in the younger age groups – that is those just leaving school and young farmers.

Figures for the four main groups were combined and show that trainees in professional, clerical and commercial occupations had the least success: tradesmen, skilled and unskilled, had a slightly better success: then the agricultural workers, with the schoolboys still having the most success.

Not enough figures were available to determine the chances of success of the 'rolling stone', though indications were that, if a man had had several jobs of the skilled or semi-skilled trades, he had a slightly better chance in pilot training than a man who had had one job of an unskilled nature.

With the older men, their previous occupation was of much higher significance in pilot training than it was with the lower ages. This one would judge as due to a more highly-developed occupational set. There is less adaptability in the adjustment to the acquiring of a new and complicated skill. This statement is given objective justification in the figures worked out covering success and non-success of particular trade groups. For instance, clerical and professional workers find adaptation much harder than the skilled manual labourer.

This dichotomy of hand and brain is not so significant in the younger age groups – a young clerk has not acquired a sufficient degree of occupational mould to prejudice his adjustment to such an extent as an older man.

There are, of course, other factors which must be taken into account. Though unassessable on a purely statistical basis, such variables as added responsibility, family ties, etc., which tend to make for cautiousness and restraint in action in the older groups, are of obvious importance in this connection. Where these may act disadvantageously with the pilot trainee, it is possible that they may contribute to successful training as a navigator. This would be consonant with the different skills involved in piloting and navigating ability. It is significant that research reports from overseas show that the better navigators are, on the average, in the higher age groups.

1 Wg Cdr A. M. Gunn; Gisborne; born Carterton, 26 Jun 1912; medical practitioner; ADMS (Air) Sep 1943–Jul 1944; SMO No. 1 (Islands) Gp, Jul 1944–Aug 1945.