Helmet-Mounted Displays: - USAARL - The - U.S. Army

Human Factors Engineering (HFE) Issues 245
population of the Army as well as the large male population.
Defining head anthropometry requires an understanding of the basic
head parameters and how they are measured (Table 9.2). While not fully
defining the head and articulating all measurements that may be required
for head-mounted systems, these are the basic design parameters currently
used. Additional considerations may include: Bizygomatic breadth (the
maximum horizontal breadth of the face (between the zygomatic arches),
menton-sellion length (the distance between the top of the nose and the
bottom of the chin, necessary for oxygen and protective mask nose cups),
eye inset (the distance between the supraorbital notch (eyebrow) and the
cornea of the eye, as well as the distance from the most forward point of the
zygomatic process (cheekbone) to the cornea), the disparity between eye
inset for the two eyes, the disparity between the vertical positions of the
two eyes, and the disparity between the vertical and horizontal positions of
the two ears. In addition, neck circumference could become an issue when
sizing between the large male and small female.
Anthropometric measurement is a difficult skill to develop and
maintain. Accuracy and repeatability of measurements continue to be the
most difficult challenges to the trained anthropometrist. Statistically
reliable measurements require a complex sampling plan, including
measurement methodologies, instrumentation, personnel qualification and
currency, and measurement validation. Recent advances in 3-D
anthropometric imaging/mapping techniques show great promise for future
assessments (Brunsman, Daanen, and Files, 1996; Whitestone, 1994).
However, current limitations include mapping bony landmarks, hair, and
tissue compression as a function of planned fit.
The Army standard for head anthropometry is the 1988 Anthropometric
survey of U.S. Army personnel: Pilot summary statistics (Donelson and
Gordon, 1991). The survey represents the most recent analysis of the
combined U.S. Army and Army aviator populations, both male and female.
However, the 500 attack pilot head anthropometry survey (Sippo, Licina,
and Noehl,1988) revealed a head size disparity within the male attack
helicopter subpopulation. This disparity is that Army attack aviators tend
to have larger head dimensions than the general aviator population.
Requirements for additional (under the helmet) equipment (e.g., protective
masks and hoods) add a delta to the required head sizing considerations.