Comparison of univariate and multivariate anthropometric design requirements methods for flight deck design application.

Designing aircraft cockpits to accommodate the wide range of body sizes and shapes existing in the world population has always been a difficult problem for crew station engineers. There is no consensus on the best method for obtaining measurements for body forms that statistically represent the variation within a population. The aim of this research is to compare the two most commonly used anthropometric approaches for dimension specification and flight deck design: the boundary cases multivariate and the percentile univariate. The multivariate approach captured more subjects than the percentile approach (p < .05) for all accommodation assessments using Brazilian Air Force pilots' anthropometry, but was not as effective as had been suggested in the literature. This study showed that the Boundary Cases Multivariate Method was better at evaluating design criteria for cockpit accommodation than the Percentile Univariate Method for accommodation of the central 90% envelope for the Brazilian Air Force crew application. Practitioner summary: The findings show that the Multivariate Boundary Cases approach can better provide anthropometric limits for the desired accommodation level when multiple body dimensions need to be simultaneously considered in a design. It will help researchers, designers, and engineers to solve complex design situations, make improved judgement and take right decisions. Abbreviations: FAR: federal aviation regulation; CS: certification specification; FAA: federal aviation administration; EASA: European union aviation safety agency; EMB: embraer; FAB: Brazilian Air Force; CAD: computer-aided design; MAM: multivariate anthropometric method; USAF: United States Air Force; PCA: principal component analysis; PC: principal component; JSF: joint strike fighter; NATO: North atlantic treaty organization; ISO: International Organization for Standardization; BPAD: Brazilian pilots anthropometric database; RD: radial distance; Error = A-E: error = achieved - expected; SPSS: statistical package for the social sciences; IBM Corp.: International business machines corporation; Acr. Ht, st: acromion height, sitting; But-kn lgt: buttock-knee length; Eye Ht, sit: eye height, sitting; Knee Ht, sit: knee height, sitting; Sitting Ht: sitting height; Thumbtip rch: thumbtip reach; Accom %: accommodated percentage; Af, Am, …, Zf, Zm: cases A-D and W-Z ("f" for female subjects and "m" for male subjects); T: trainer; A: atack; KC: anker and cargo; F: fighter; NG-BR: new generation - Brasil; PPE: personal protective equipment.

A three-dimensional parametric adult head model with representation of scalp shape variability under hair.

Modeling the shape of the scalp and face is essential for the design of protective helmets and other head-borne equipment. However, head anthropometry studies using optical scanning rarely capture scalp shape because of hair interference. Data on scalp shape is available from bald men, but female data are generally not available. To address this issue, scalp shape was digitized in an ethnically diverse sample of 100 adult women, age 18-59, under a protocol that included whole head surface scanning and scalp measurement using a three-dimensional (3D) coordinate digitizer. A combined male and female sample was created by adding 3D surface scans of a similarly diverse sample of 80 bald men. A statistical head shape model was created by standardizing the head scan data. A total of 58 anatomical head landmarks and 12 head dimensions were obtained from each scan and processed along with the scans. A parametric model accounting for the variability of the head shape under the hair as a function of selected head dimensions was developed. The full-variable model has a mean shape error of 3.8 mm; the 95th percentile error was 7.4 mm, which were measured at the vertices. The model will be particularly useful for generating a series of representing a target population as well as for generating subject-specific head shapes along with predicted landmarks and dimensions. The model is publicly available online at http://humanshape.org/head/.