An Anthropometric Analysis of Korean Male Helicopter Pilots for

An Anthropometric Analysis of Korean Male Helicopter Pilots for Helicopter
Cockpit Design
Wonsup Lee, Kihyo Jung, Jeongrim Jeong, Jangwoon Park, Jayoung Cho, Heeeun Kim,
Seikwon Park, and Heecheon You*
* Corresponding author
Wonsup Lee; Pohang University of Science and Technology; San 31 Hyoja-dong, Nam-gu,
Pohang, Kyungbuk, 790-784, Republic of Korea; Tel. +82-54-279-8247, Fax: +82-54-2792870, [email protected]
Kihyo Jung; University of Ulsan; 93 Daehak-ro, Nam-gu, Ulsan, 680-749, Republic of Korea;
Tel. +82-52-259-2709, Fax: +82-52-259-1683, [email protected]
Jeongrim Jeong, Loughborough University, Address: James France bldg, Loughborough Design
School, Loughborough University, Leicestershire, LE11 3TU, UK; Tel.: +44 7716
491231, [email protected]
Jangwoon Park; Pohang University of Science and Technology; San 31 Hyoja-dong, Nam-gu,
Pohang, Kyungbuk, 790-784, Republic of Korea; Tel. +82-54-279-8247, Fax: +82-54-2792870, [email protected]
Jayoung Cho; Korea Research Institute for Fashion Industry; 1561-4 Bongmu-dong, Dong-gu,
Daegu, 701-170, Republic of Korea; Tel: +82-53-721-7465, Fax: +82-53-986-
6344, [email protected]
Heeeun Kim; Kyungpook National University; 1370 Sankyunk-dong, Buk-gu, Daegu, 702-701,
Republic of Korea; Tel. +82-53-950-6224, Fax: +82-53-950-6219, [email protected]
Seikwon Park; Korea Air Force Academy; PO Box 335-2, Cheongwon, Choongbuk, 363-849,
Republic of Korea; Tel. +82-43-290-6494, Fax: +82-54-279-2870, [email protected]
Heecheon You; Pohang University of Science and Technology; San 31 Hyoja-dong, Nam-gu,
Pohang, Kyungbuk, 790-784, Republic of Korea; Tel. +82-54-279-2210, Fax: +82-54-2792870, [email protected]
An Anthropometric Analysis of Korean Male Helicopter Pilots for Helicopter
Cockpit Design
Anthropometric Analysis of Pilots
Abstract
The present study measured 21 anthropometric dimensions (ADs) of 94 Korean male
helicopter pilots in their 20s to 40s and compared them with corresponding
measurements of Korean male civilians and the US Army male personnel. The ADs and
the sample size of the anthropometric survey were determined by a four-step process:
(1) selection of ADs related to helicopter cockpit design, (2) evaluation of the
importance of each AD, (3) calculation of required sample sizes for selected precision
levels, and (4) determination of an appropriate sample size by considering both the AD
importance evaluation results and the sample size requirements. The anthropometric
comparison reveals that the Korean helicopter pilots are larger (ratio of means = 1.01 ~
1.08) and less dispersed (ratio of SDs = 0.71 ~ 0.93) than the civilians and that they are
shorter in stature (0.99), upper limbs (0.89 ~ 0.96), and lower limbs (0.93 ~ 0.97), but
taller in sitting height, sitting eye height, and acromial height (1.01 ~ 1.03), and less
dispersed (0.68 to 0.97) than the US Army personnel.
Keywords: anthropometric measurement, Korean male helicopter pilots, helicopter
cockpit design, sample size determination
Practitioner Summary
The anthropometric characteristics of Korean male helicopter pilots were compared
with those of Korean male civilians and US Army male personnel. The sample size
determination process and the anthropometric comparison results presented in this study
are useful to design an anthropometric survey and a helicopter cockpit layout,
respectively.
1. Introduction
Anthropometric data of pilots have been utilized for the design of an aircraft cockpit for
comfort of pilots and effectiveness of mission fulfillment. Roebuck et al. (1975) and
Roskam (2002) provided a method to design a cockpit layout using anthropometric data
and recommended values on selected design dimensions such as the locations of the
design eye point and the cyclic control in a helicopter cockpit. Military standards such
as MIL-STD-1333B (Department of Defense, 1987) also specified ergonomics design
requirements of a helicopter cockpit for the aircrew personnel of the US Army to help
pilots accomplish operations with efficiency, safety, and comfort.
A customized survey and an in-depth analysis of anthropometric data are
needed to develop an ergonomics helicopter cockpit design which properly
accommodates a designated user population. The South Korean government launched
the Korean helicopter program (KHP) in 2006 to develop a utility helicopter that would
be operationalized in the Korean Army by 2013 (Defense Acquisition Program
Administrator, 2010). Although an anthropometric database of Korean civilians (n =
21,295) compiled at the nation-wide Size Korea 2004 project (Korean Agency for
Technology and Standards, 2004) is available, its applicability to helicopter cockpit
design for the Korean Army may be limited because the anthropometric characteristics
of the Korean civilian population can be significantly different from those of the Korean
helicopter pilot population due to occupational factors (Roebuck, 1995, Sanders and
McCormick, 1998). Moreover, there is a need to understand the differences in
anthropometric features between the Korean helicopter pilots and the US Army
personnel (Gordon et al., 1988) for the design of a helicopter cockpit for the KHP (Jung
et al., 2008). Although the Korean utility helicopter is being developed primarily for
Korean helicopter pilots, the KHP includes a plan to export helicopters to overseas
markets. The anthropometric data of the US Army personnel was utilized in the present
study for its data accessibility and ethnic diversity of the US population.
The present study is intended to examine the anthropometric characteristics of
Korean helicopter pilots to develop an ergonomics design of a utility helicopter cockpit.
Anthropometric measurements were collected from 94 Korean male helicopter pilots
and compared with those of Korean male civilians and the US Army male personnel.
2. Anthropometric Survey Method
2.1. Anthropometric Dimension Selection and Importance Evaluation
Twenty-one anthropometric dimensions (ADs; see Table 1 and Figure 1) were selected
as those related to the design of a cockpit layout. A panel of five experts (two
ergonomists, two mechanical engineers, and one fighter pilot) reviewed literature and
evaluated the importance of each AD in designing a cockpit layout. The literature
review included studies of ergonomics workstation layout designs such as Bittner
(2000), Kim and Whang (1997), Lee and Song (2002), You et al. (1997), and Zehner et
al. (1999). For example, sitting height (AD3) and sitting eye height (AD4) were
selected because they are related to head clearance and design eye point position,
respectively, in a cockpit layout design. Next, the importance of an individual AD in
designing a cockpit layout was assessed using a 3-categorical scale (high, medium, and
low). For example, the importance of buttock-to-popliteal length (AD16) was rated as
high because it strongly affects the seat length in a cockpit, while that of chest depth
(AD8) was determined as low because it weakly affects the design of a cockpit layout.
The AD importance evaluation results were applied in the present study to situations
where a trade-off between precision and practical constraints needed to be compromised
in sample size determination.
[Table 1 about here]
[Figure 1 about here]
2.2. Sample Size Determination
The sample size of the anthropometric survey was determined in two steps: (1)
statistical sample size requirement analysis and (2) sample size selection by considering
the AD importance evaluation results and practical constraints. First, the sample sizes of
the ADs required for the confidence level (1-α) of 95% and four precision levels (k =
2%, 3%, 4%, and 5%) were calculated as displayed in Figure 2 by Equation 1 of sample
size formula (ISO, 2006):
[Figure 2 about here]
n = (1.96 ×
CV 2
) × 1.5342
k
(Equation 1)
where: CV = coefficient of variation,
k = precision level
The precision level (k) refers to the ratio of a sampling error to the corresponding
sample mean. For example, 2% of precision level when the sample mean of stature =
170 cm means 3.4 cm (= 170 × 0.02) of sampling error in estimating the corresponding
population mean with a selected confidence level. Coefficient of variance (CV) is
calculated by dividing SD with mean. The mean and SD of each AD of the Korean male
helicopter pilot population in their 20s to 40s were estimated using Equations 2 and 3
(derived in the present study) and corresponding descriptive statistics reported for each
age group (20 ~ 24, 25 ~ 29, 30 ~ 34, 35 ~ 39, 40 ~ 44, and 45 ~ 49) in the 2004 Size
Korea survey results:
j
X=
∑X
i =1
× ni
i
(Equation 2)
j
∑n
i
i =1
where:
X = sample mean of a composite population,
X i = sample mean of population i,
ni
= sample size of population i
j = the number of populations
∑ [n × X
j
s=
i =1
i
2
i
]
j
+ (ni − 1) × si2 − ∑ ni × X 2
i =1
j
∑ n −1
i =1
i
(Equation 3)
≅
∑ [p × ( X
j
i
i =1
where:
2
i
]
+ si2 ) − X 2
s = sample SD of a composite population,
X
= sample mean of a composite population,
Xi
= sample mean of population i,
si
= sample standard deviation of population i,
ni
= sample size of population i
pi
= proportion of population i
j = the number of populations
For example, the mean and SD of shoulder-to-elbow length (AD13) of the Korean
helicopter pilot population were estimated as 33.8 cm and 1.5 cm, respectively, using
the corresponding means and sample SDs of the Korean male civilian data in their 20s
to 40s. As shown in Figure 2, a sample size requirement geometrically increases as the
level of precision becomes high; for example, the sample size requirements of thumb-tip
reach (AD14) are 9 for k = 5%, 14 for k = 4%, 24 for k = 3%, and 54 for k = 2%.
The present study determined 94 as the sample size for the Korean helicopter
pilot anthropometric survey by accommodating the AD importance evaluation results,
sample size requirement analysis results, and practical considerations. Out of the sample
size requirement analysis results, the AD importance analysis results were further
considered. Then, the sampling errors of the ADs having high importance for the three
precision levels were calculated and k = 2% (maximum sampling error = 1.9 cm in
popliteal height) was found acceptable in the cockpit design process. Finally, of the
sample size requirement results for k = 2% (high importance) and k = 5% (medium and
low importance), the largest value was used to determine the sample size of the
helicopter pilot anthropometric survey.
Lastly, the present study reports the anthropometric data of Korean male
helicopter pilots due to a very small number of Korean female helicopter pilots (n < 10)
commissioned in the Army (Jung et al., 2008). We measured six female pilots, but their
measurements are not reported in this paper due to their small sample size.
2.3. Measurement Protocol
Anthropometric measurements of the selected ADs were collected by following
corresponding standard measurement protocols. Measurement locations and landmarks
for the ADs were identified as illustrated in Figure 1 by referring to Gordon et al. (1988)
and Korean Standard Association (2005). A Martin-type anthropometer (Takei Co.,
Japan) and aids such as a chair, a foot-rest, and a grid board were utilized during
measurement. Two measurements were collected for each AD, but additional
measurements were made until the difference between two measurements < 2 mm (Jung
et al., 2008). Then, the average of each pair of measurements was entered into a
computer program coded in the present study; the computer program checks the validity
of an input value (x) by classifying it into one of three categories based on
corresponding mean and SD from the Size Korea 2004 data: normal, |x – mean| ≤ 3 ×
SD; cautionary, 3 × SD < |x- mean| ≤ 5 × SD; abnormal, |x- mean| > 5 × SD (Jung et al.,
2008). Proper actions such as checking the validity of data and correcting typos were
taken if a validity level of measurement was cautionary or abnormal.
2.4. Statistical Testing
The population of Korean male helicopter pilots was compared with those of Korean
male civilians and US Army male personnel by a two-sample t test for comparison of
means and an F test for comparison of variances using MINITAB v. 12. The Size Korea
data of Korean male civilians (Korean Agency for Technology and Standards, 2004) and
the 1988 anthropometric survey of US Army personnel (Gordon et al., 1988) were
utilized in the present study for comparison purposes.
3. Results
Anthropometric measurements were collected from 94 Korean male helicopter pilots
and their descriptive statistics (mean, SD, min, max, and percentiles) on the
anthropometric measurements summarized in Table 2. For example, the average of eye
height (AD4; unit: cm) of the Korean male helicopter pilots is 81.3 (SD = 3.0), ranging
from 74.0 to 89.0 with p .01 = 74.2, p .05 = 76.8, p .95 = 86.7, and p .99 = 88.1.
The sample size (n = 94) measured for the Korean helicopter pilot was found to
be sufficient. Post-hoc analysis on the sample size revealed that the required sample
sizes of ADs at the designated level of confidence (95%) and precision (2% for high
importance ADs; 5% for medium and low importance ADs) were 66 or less.
[Table 2 about here]
A comparison in mean and SD between the Korean male helicopter pilots and
Korean male civilians (Table 3) revealed that the helicopter pilots were larger (ratio of
means = 1.01 ~ 1.08) and less dispersed (ratio of SDs = 0.71 ~ 0.93) overall. Out of the
21 ADs, 19 ADs were available in the Size Korea data for comparison. The helicopter
pilots were found statistically larger at α = .05 in all of the ADs and a relatively large
mean difference (ratio of means > 1.07) was observed in hip breadth and thigh clearance.
Next, the helicopter pilots were found less dispersed in all of the ADs but a statistically
significant difference in SD at α = .05 (ratio of SDs < 0.84) was observed in 14 ADs
(stature, weight, sitting height, biacromial breadth, chest circumference, waist
circumference, elbow-to-fingertip length, forearm-to-forearm breadth, shoulder-toelbow length, buttock-to-popliteal length, foot length, knee height, popliteal height,
thigh circumference, and thigh clearance).
[Table 3 about here]
Lastly, a comparison in mean and SD between the Korean male helicopter
pilots and the US Army male personnel (Table 3) showed that the Korean helicopter
pilots were shorter in stature (ratio of means = 0.99), upper limbs (0.89 ~ 0.96), and
lower limbs (0.93 ~ 0.97), but longer in head and trunk (1.01 ~ 1.03), leaner (0.93 ~
0.98 in weight and circumference dimensions), and less dispersed in all of the ADs
(ratio of SDs = 0.68 ~ 0.97). Out of the 21 ADs, 20 ADs were available in the US Army
data for comparison. Table 3 shows that the Korean helicopter pilots had shorter body
sizes (ratio of means = 0.93 ~ 0.99) than the US Army personnel except for the head and
trunk related ADs (sitting height, sitting eye height, and sitting acromial height) and the
dispersions of the body sizes of the Korean helicopter pilots were considerably smaller
(ratio of SDs = 0.68 ~ 0.97) than those of the US Army personnel overall.
4. Discussion
The present study collected anthropometric data of Korean helicopter pilots to design a
helicopter cockpit layout. A comprehensive literature review was conducted to select
ADs in four body categories (whole body, head & trunk, upper limbs, and lower limbs)
which are applicable to the design of a helicopter cockpit layout. The anthropometric
data of helicopter pilots compiled in the study was effectively used together with the US
Army data in the design and evaluation phases of helicopter cockpit development for
Korean helicopter pilots, which were conducted as a follow-up study by the authors as
illustrated in Figure 3.
[Figure 3 about here]
Human errors which may occur in reading or recording measurements could be
systematically prevented by checking the difference between repeated measurements
and comparing a key entry with corresponding statistical data obtained from a national
anthropometric survey. Repeated measurements were collected until their difference
reached less than 2 mm to avoid an error in measurement due to misreading and/or
application of an inconsistent measurement protocol. Then, the validity of each key
entry was checked using its standardized score—a recheck of an input value was made
if the standardized score > 3.
The sample size of the anthropometric survey for Korean helicopter pilots was
determined as 94 in the present study by incorporating statistical and practical
considerations. First, a statistical analysis was conducted to identify a sample size
requirement for each of the ADs for a designated level of confidence and various levels
of precision using the corresponding sample mean and sample SD. The sample SD
formula for a composite population was derived in the present study to estimate a
pooled sample SD using SDs of subpopulations. Next, out of the sample size
requirement analysis results, ADs identified as high importance were considered for
effective utilization of limited resources in the study. Then, the acceptable level of
precision in helicopter cockpit layout design was identified by evaluating sampling
errors at different precision levels. Finally, the sample size of the helicopter pilot
anthropometric survey was determined for the selected precision level (k = 0.02 for high
importance ADs, k = 0.05 for medium and low importance ADs) among the sample size
requirements of the ADs. The aforementioned sample size determination process is
applicable to identify a proper sample size by considering statistical and practical
requirements.
The Korean male helicopter pilots showed a higher level of homogeneity in
all the ADs than Korean male civilians and the US Army male personnel. Demographic
factors such as occupation, age, and race significantly affect the variability of an AD
(Roebuck, 1995). The difference in SD (ratio of SDs = 0.71 ~ 0.93) between the Korean
pilots and Korean civilians can be mainly explained by occupational diversity, while
that (ratio of SDs = 0.68 ~ 0.97) between the Korean pilots and the US Army personnel
by racial diversity. It is also noticeable that Korean civilians are more homogenous than
the US Army overall. The higher the homogeneity indicates the lower the adjustability
required for a cockpit layout design, the smaller the space required for a cockpit, the
lighter the weight of the helicopter, and the higher the air combat performance of the
helicopter.
The Korean helicopter pilots were found larger than Korean civilians in all the
ADs. The body sizes of a particular population can be influenced by occupational
factors such as selection and training (Wickens et al., 1998). It is likely that Korean
pilots are larger than Korean civilians due to physical requirements (height, weight, and
physical fitness) for pilots, military training, and self-management of pilots for physical
fitness.
The Korean helicopter pilots were found shorter in stature, upper-limbs, and
lower-limbs and smaller in weight, body circumference, and thickness than the US
Army personnel, but longer in upper-body heights such as sitting height, sitting eye
height, and acromial height. The former ADs affect the clearance and reach of a cockpit
layout design, while the latter affect the visibility of the layout design. These distinctive
features of the Korean helicopter pilots compared with the US Army personnel support
the necessity of an anthropometric survey on a target user population to develop an
optimal, customized design.
Lastly, the present study has limitations in terms of availability of female pilot
data and application of secular trend analysis. Due to a small number of Korean female
helicopter pilots (n < 10) when the present anthropometric survey was conducted, their
anthropometric characteristics were not formally reported. An anthropometric survey
can be planned in the future as the number of Korean female pilots becomes sufficiently
large. Next, the anthropometric characteristics of the US Army personnel are likely to
have changed over last 25 years (Tomkinson et al., 2010). Adjustments should have
been made to the US Army anthropometric data based on a secular trend analysis for
better comparison with those of Korean helicopter pilots collected relatively recently.
Acknowledgments
This research was jointly supported by Korea Helicopter Program (KHP) grant funded
by Korea Aerospace Industries (KAI) and Korea Science and Engineering Foundation
(KOSEF) grant funded by the Korea government (MOST) (R01-2007-000-20754-0).
The authors appreciate the assistance of Jeeeun Park in anthropometric measurement.
References
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List of Tables
Table 1. Anthropometric dimensions (ADs) and their importance in helicopter cockpit
layout design
Table 2. Descriptive statistics of Korean male helicopter pilot anthropometric data
Table 3. Comparison of Korean male helicopter pilots, Korean male civilians, and US
Army male personnel
List of Figures
Figure 1. Anthropometric dimensions (ADs) measured for helicopter cockpit layout
design
Figure 2. Sample size requirements by precision
Figure 3. Ergonomics evaluation of a helicopter cockpit for Korean helicopter pilots
Table 1. Anthropometric dimensions (ADs) and their importance in helicopter cockpit layout
design
Body part
Code
Anthropometric dimension
Whole
body
AD1
AD2
AD3
AD4
AD5
AD6
AD7
AD8
AD9
AD10
AD11
AD12
AD13
AD14
AD15
AD16
AD17
AD18
AD19
AD20
AD21
Stature
Weight
Sitting height
Sitting eye height
Sitting acromial height
Biacromial breadth
Chest circumference
Chest depth
Hip breadth
Waist circumference
Elbow-to-fingertip length
Forearm-to-forearm breadth
Shoulder-to-elbow length
Thumb-tip reach
Buttock-to-knee length
Buttock-to-popliteal length
Foot length
Knee height
Popliteal height
Thigh circumference
Thigh clearance
Head &
trunk
Upper
limbs
Lower
limbs
Importance
(H: high; M:
medium; L: low)
M
L
H
H
H
M
L
L
H
L
H
M
H
H
H
H
L
H
H
L
L
Table 2. Descriptive statistics of Korean male helicopter pilot anthropometric data (unit: cm,
kg)
Percentile
Body part
Anthropometric dimension (AD)
Mean
SD
Min
Max
st
1
th
5
95th
99th
AD1
Stature
173.0
5.2
163.4
186.0
163.8
164.7
182.0
185.2
AD2
Weight
73.3
8.6
AD3
Sitting height
93.1
2.9
54.5
94.5
55.9
61.4
88.9
92.4
86.6
100.0
87.3
88.4
98.3
99.3
AD4
Sitting eye height
81.3
3.0
74.0
89.0
74.2
76.8
86.7
88.1
AD5
Sitting acromial height
60.9
2.7
55.6
67.7
55.9
56.3
65.8
67.3
AD6
Biacromial breadth
40.1
1.7
34.2
43.8
36.1
37.4
42.5
43.6
AD7
Chest circumference
100.1
5.0
90.4
113.4
91.1
91.9
108.9
112.8
AD8
Chest depth
19.3
1.6
16.1
23.4
16.5
16.9
22.2
23.2
AD9
Hip breadth
37.6
1.8
31.9
41.6
33.4
35.1
40.7
41.4
AD10
Waist circumference
84.2
6.6
57.7
96.2
70.0
74.0
93.9
95.8
AD11
Elbow-to-fingertip length
46.1
1.7
42.2
49.5
42.6
43.6
48.6
49.4
AD12
Forearm-to-forearm breadth
48.9
3.9
35.3
60.0
40.0
43.3
55.6
57.3
AD13
Shoulder-to-elbow length
34.9
1.4
31.9
39.0
32.5
32.8
37.2
38.3
AD14
Thumb-tip reach
76.6
3.0
70.1
83.8
71.5
72.1
81.1
83.1
Whole body
Head & trunk
Upper limbs
Lower limbs
AD15
Buttock-to-knee length
57.6
2.4
49.4
62.5
52.1
53.5
60.8
62.3
AD16
Buttock-to-popliteal length
47.6
2.1
41.8
52.2
43.1
43.9
50.4
51.8
AD17
Foot length
25.2
1.0
23.1
28.1
23.2
23.7
26.8
27.3
AD18
Knee height
51.9
2.2
47.2
57.6
47.7
48.4
55.2
56.1
AD19
Popliteal height
41.4
1.7
37.7
45.8
38.0
38.5
43.9
45.1
AD20
Thigh circumference
57.2
3.6
48.4
66.0
49.9
51.8
63.4
65.8
AD21
Thigh clearance
16.3
1.2
13.8
19.2
14.5
14.6
18.4
18.7
Table 3. Comparison of Korean male helicopter pilots, Korean male civilians, and US Army male personnel (unit: cm, kg)
Body part
Anthropometric dimension (AD)
Korean helicopter pilots
(KP; n = 94)
MKP
Whole body
Head & trunk
Upper limbs
Lower limbs
SDKP
Korean civilians
(KC; n = 1800)
MKC
US Army
(UA; n = 1774)
KP vs. KC
SDKC
MKP - KC
MKP/MKC
SDKP / SDKC
MUA
KP vs. UA
SDUA
MKP -UA
MKP/MUA
SDKP / SDUA
AD1
Stature
173.0
5.2
170.0
7.0
3.0 **
1.02
0.74 **
175.6
6.7
-2.6 **
0.99
0.77 **
AD2
Weight
73.3
8.6
69.3
10.5
4.0 **
1.06
0.81 *
78.5
11.1
-5.1 **
0.93
0.77 **
AD3
Sitting height
93.1
2.9
91.9
3.6
1.2 **
1.01
0.80 *
91.4
3.6
1.7 **
1.02
0.81 **
AD4
Sitting eye height
81.3
3.0
80.4
3.5
0.9 **
1.01
0.87
79.2
3.4
2.1 **
1.03
0.88
AD5
Sitting acromial height
60.9
2.7
59.4
2.9
1.4 **
1.02
0.93
59.8
3.0
1.1 **
1.02
0.90
AD6
Biacromial breadth
40.1
1.7
39.5
2.4
0.6 **
1.02
0.72 **
39.7
1.8
0.4 *
1.01
0.97
AD7
Chest circumference
100.1
5.0
95.6
6.9
4.5 **
1.05
0.72 **
102.3
6.5
-2.2 **
0.98
0.76 **
AD8
Chest depth
19.3
1.6
20.9
2.0
N/C
N/C
24.3
2.1
N/C
N/C
N/C
AD9
N/C
Hip breadth
37.6
1.8
34.9
2.1
2.7 **
1.08
0.89
36.7
2.5
1.0 **
1.03
0.73 **
AD10 Waist circumference
84.2
6.6
81.2
8.5
3.0 **
1.04
0.78 **
86.2
8.6
-2.1 **
0.98
0.76 **
AD11 Elbow-to-fingertip length
46.1
1.7
44.6
2.3
1.5 **
1.03
0.75 **
48.4
2.3
-2.3 **
0.95
0.73 **
AD12 Forearm-to-forearm breadth
48.9
3.9
47.3
4.8
1.6 **
1.03
0.82 *
54.6
4.4
-5.7 **
0.89
0.90
AD13 Shoulder-to-elbow length
34.9
1.4
33.5
1.8
1.4 **
1.04
0.81 *
36.9
1.8
-2.0 **
0.94
0.80 **
AD14 Thumb-tip reach
76.6
3.0
N/A
N/A
N/A
N/A
80.1
3.9
-3.5 **
0.96
0.76 **
AD15 Buttock-to-knee length
57.6
2.4
56.8
2.7
0.8 **
1.01
0.86
61.6
3.0
-4.0 **
0.93
0.79 **
AD16 Buttock-to-popliteal length
47.6
2.1
46.5
2.7
1.0 **
1.02
0.77 **
50.0
2.7
-2.5 **
0.95
0.79 **
AD17 Foot length
25.2
1.0
24.9
1.3
0.3 **
1.01
0.74 **
27.0
1.3
-1.8 **
0.93
0.73 **
AD18 Knee height
51.9
2.2
50.7
2.6
1.1 **
1.02
0.84 *
55.9
2.8
-4.0 **
0.93
0.78 **
AD19 Popliteal height
41.4
1.7
39.7
2.3
1.7 **
1.04
0.73 **
43.4
2.5
-2.0 **
0.95
0.68 **
AD20 Thigh circumference
57.2
3.6
55.9
4.5
1.3 **
1.02
0.80 **
59.7
4.9
-2.4 **
0.96
0.72 **
AD21 Thigh clearance
16.3
1.2
15.2
1.6
1.1 **
1.07
0.71
16.8
1.3
-0.5 **
0.97
0.92
* P < .05; ** P < .01; N/C: not comparable due to use of different landmarks; N/A: not available
N/A
A
A
AD6
AD7
AD14
AD10
AD1
AD20
A
AD3
AD8
AD13
AD4
AD5
B
AD11
AD12
C
AD21
AD9
AD16
AD19
AD15
AD18
AD17
(Notes) 1. Landmarks: A: acromion, B: rear olecranon, C: superior patella
2. Refer to Table 1 for the names of AD codes.
Figure 1. Anthropometric dimensions (ADs) measured for helicopter cockpit layout design
500
Sample
size
kk==0.02
.02
kk==0.03
.03
400
kk==0.04
.04
.05
kk==0.05
300
200
100
0
2
Level of
importance
High
Medium
Low
(Notes) 1. Refer to Table 1 for the names of AD codes.
2. The sample size requirement of AD14 (thumb-tip reach) was estimated using the US Army data due
to its unavailability in the Korean civilian data.
Figure 2. Sample size requirements by precision
(a) Visibility evaluation with a virtual mockup
(b) Head clearance evaluation with a physical mockup
(c) Usability evaluation with a physical mockup
Figure 3. Ergonomic evaluation of a helicopter cockpit for Korean helicopter pilots