pilot selection anthropometry a comparison with measures taken by a single avmo- smith

RAAF Institute of Aviation Medicine

Pilot selection anthropometry

Dr Adrian Smith16 AVN BDE / AVMED

MAJ (Dr) Sue SteeleArmy Aviation Training Centre


Sitting height limit: Kiowa 92-95 cm

Sources of differences

• Growth • Diurnal variation

• Repeatability– Inter-observer – Intra-observer

• Technique*– Measurement technique– Posture– Equipment– Training

Differences up to 2 cmnormal.

• Mistake/error– unintended, random

• Bias– systematic distortion



The present study

• Army Aviation Centre, Oakey• Single experienced AVMO• 56 student pilots

• Anthropometry measurement (“Measured”)– Stature, sitting height, BKL, BHL

• Recruit medical examination (“Recorded”)

• De-identified.• Analysed at AVMED


Stature

165

170

175

180

185

190

195

165 170 175 180 185 190 195

Stature (cm), Measured

Stat

ure

(cm

), R

ecor

ded

Aircrew Data Linear (Perfect Match) Linear (+/-2 cm) Linear (+/-5 cm)

Correlation 0.881


Sitting Height

80

85

90

95

100

105

80 85 90 95 100 105

Sitting Height (cm), Measured

Sitt

ing

Hei

ght (

cm),

Rec

orde

d


Correlation 0.705


Buttock-Knee Length

50

55

60

65

70

75

50 55 60 65 70 75

Buttock-Knee Length (cm), Measured

But

tock

-Kne

e Le

ngth

(cm

), R

ecor

ded


Correlation 0.768


Buttock-Heel Length

95

100

105

110

115

120

125

95 100 105 110 115 120 125

Buttock-Heel Length (cm), Measured

But

tock

-Hee

l Len

gth

(cm

), R

ecor

ded


Correlation 0.588


Difference Stature Sitting Height Buttock-Heel Buttock-Knee

<2 cm 91% 53% 53% 68%

2-5 cm 9% 27% 31% 25%

>5 cm 0 20% 16% 7%


Measure Mean difference (cm)

Range (cm)

Over-recording(cm)

Under-recording(cm)

Stature 0.68±1.5 -2 to 5 1.75±0.83 -1.12±0.3

Sitting Height -2.50±3.0 -8 to 3 1.47±0.71 -3.90±2.5

Buttock-Heel Length

-1.50±3.5 -12 to 7 1.77±1.47 -4.07±2.4

Buttock-Knee Length

-0.29±2.8 -8 to 6 2.39±1.57 -2.87±1.9


0

5

10

15

20

25

30

35

40

45

50

1 2 3 4 5 6

Recruiting Location

Per

cent

of s

ittin

g he

ight

s m

easu

reds

Difference 2-5 cmDifference >5 cm


0

5

10

15

20

25

30

35

40

45

50

1 2 3 4 5 6

Recruiting Location

Per

cent

of s

ittin

g he

ight

s m

easu

reds

Difference 2-5 cmDifference >5 cm

Military Health Facilities DFRCs


Correlation of measurements

Parameter Mil Centres DFRCs

Stature 0.926 0.943

Sitting Height 0.588 0.845

Buttock-heel length 0.730 0.812

Buttock-knee length 0.428 0.725


Parameter Location Under-recorded(cm)

p

Stature DFR Centre -0.07±1.3 <0.05

Military Centre -1.33±1.5

Sitting Height DFR Centre -2.71±2.5 <0.05


Buttock-Heel Length DFR Centre -1.54±4.4 0.87


Buttock-Knee Length DFR Centre -0.04±3.3 0.15


Is the difference consistent?

What happens when you get close to an anthropometric limit?



Under-recorded (cm)

Relative Difference (cm)

p

Sitting Height ≤98 cm

Military Centre -3.3±3.2 -2.0 0.03

DFRC -1.4±2.6

Sitting Height >98 cm

Military Centre -5.6±1.9 -4.9 0.01

DFRC -0.7±2.1

Under-recorded (cm)

Relative Difference (cm)

p

Military Centre

Sitting Height ≤98cm -3.3±3.2 -2.3 0.03

Sitting Height >98cm -5.6±1.9

DFR Centre

Sitting Height ≤98cm -1.4±2.6 -0.6 0.31

Sitting Height >98cm -0.7±2.1

• “But they may have grown.”



Sitting height, 12 months

2008-2009 n Under-recorded(cm)

p Range

Military Centre 20 -5.28±2.1 <0.001 -8 to 0

DFR Centre 14 -1.43±0.79 -3 to 0

“Growth”: it doesn’t add up

Stature ≈ sitting height + buttock-heel length1

Group-mean differences• Sitting Height 2.5 cm (grown)• Buttock-heel length 1.5 cm (grown)

but• Stature 0.7 cm (slightly smaller)


1 Not quite, but close enough.


Summary

• Differences in anthropometric measures– Frequent– Large (>5 cm)– Aeromedically significant

• Sitting height most affected– Critical dimension for current aircraft

Summary

• Current system of anthropometry– Not reliable– Inaccurate– May not inform the pilot-selection process.

• DFRCs more accurate than some ADF facilities.

• Some centres better than others.


Summary• Pattern of differences

– SH, BHL >> ST – Under-recording error > over-recording– Magnitude greater close to anthro limit– Military > DFRC

• Unlikely due to:– Diurnal variation– Growth– Random Error



Possible explanations

• Staff– Untrained– Inexperienced– Competency, proficiency

• Primitive equipment• Non-standard facilities / room layout

• Candidate advocacy?


What can be done?

• Formal training in anthropometry– For those engaged in measuring pilots

• QA, maintenance of competency, proficiency

• Standardised anthropometry– Equipment– Layout

• ? Centralised anthropometry

Centralisation

• Advantages– Equipment– Training– Experience

• ? Location– Demographics– Geographics– Logistics– Training

• ‘Hubbing’?

• DFRC-only anthro?



Which tool?


Take-home message

• Anthropometry – Is important.– Can directly affect flight safety.– Needs to be done accurately.

• It is easy to measure pilots, • but hard to measure them well.

– Trained, experienced staff– Proper equipment


Thank you.

Questions / Discussion

Dr Adrian [email protected]

Ph: 08 7383 3169

pilot selection anthropometry a comparison with measures taken by a single avmo- smith

Education

sitting height

raaf institute

perfect match

heel length

knee length

recording

anthropometry

recorded