Industrial Erg

CHAPTER 3 ANTHROPOMETRY

LEARNING OBJECTIVES

At the end of the chapter, students will have the ability to describe anthropometry, identify the best ergonomic design principle for a given situation, demonstrate how to use anthropometric data tables, and apply anthropometric principles to a workplace design.

INTRODUCTION

In basic terms, anthropometry is the measurement of the physical attributes of humans. Over time, the body dimensions of the human population have changed. In general, people have become taller and heavier than in the past. There is currently an obesity epidemic in the United States (US), and the result is that people are much heavier compared with the population around the 1930s and 1940s. This chapter is not concerned with how people in the US got to this point, rather how the tools people use must be changed to accommodate this heavier population.

In addition to these sorts of changes, the people who work within a population also change. In the early 1980s, a large number of female workers began working in heavy industries. At that time, safety equipment had not yet been adapted yet for smaller females. In one particular instance, a female with size 6 shoe was hired by a chemical company. Because size 6 female chemical boots were not available, the worker had to wear male size 7 chemical boots. This caused a big problem for the worker who had to walk and work in these boots. A female size 6 shoe is 8.9 in. in length. A male size 7 shoe is 9.7 in. in length. This is almost an inch difference, and makes a tremendous difference for the person wearing the shoes. This condition did not change until the mid-1980s. Now work boots of all sizes can be found.

It is obvious that ancient peoples used anthropometry of sorts to adapt tools and clothing to their needs. Even today, consumer goods such as clothing, appliances, cars, and tools are the biggest producers of anthropometric data. Though, in many instances, products adapted to one individual are still produced. Take a tailored article of clothing. In this case, the individual is measured and the product designed and manufactured from these data.

The savant, Alphonse Bertillon (born 1853), gave this name in 1883 to a system of identification depending on the unchanging character of certain measurements of parts of the human frame (Rhodes, 1956). He found by studying patient inquiry that several measures of physical features, along with dimensions of certain bones or bony structures in the body, remain fairly constant throughout adult life.

He concluded that when these measurements were made and recorded systematically every single individual would be found to be perfectly distinguishable from others. The system was soon adapted to police methods when crime fighters found value in being able to fix a person's identity. It prevented false impersonation and brought home, to any one charged with an offense, a person's responsibility for a wrongdoing. After its introduction in France in 1883 “Bertillonage,” as it was called, became widely popular, and was credited with producing highly gratifying results. Many countries followed suit in the adoption of the method, integrating it within their justice systems.

However, it was almost a decade before England followed suit when in 1894 a special committee was sent to Paris for an investigation of the methods used and results obtained with them. It reported back favorably, especially on the use of measurements for primary classification, but also recommended the adoption, in part, of the system of “finger prints” as suggested by Francis Galton, in practice at that time in Bengal, India.

Anthropometry: Greek – Anthro, man; and pometry, measure, literally meaning “measurement of humans.” Physical anthropology refers to the measurement of the human individual for understanding human physical variation.

Today, anthropometry plays an important role in industrial design, clothing design, architecture, and ergonomics. Changes in life styles, nutrition, and ethnic composition of populations lead to changes in the distribution of body dimensions (e.g., food consumption, exercise) and require regular updating of anthropometric data collections.

KEY POINTS

In ergonomics, anthropometry is used as the basis of setting up a workstation. The two primary objectives of the ergonomics process are to enhance performance and reduce fatigue. The ergonomics process is a multistep method to evaluate work, study how the body responds to these work demands, and use this information to design or improve work areas to best meet these two objectives. The design of a work area or equipment can have significant effects on worker fatigue, safety, and performance. In addition, with the expansion of machine technology, new and different equipment is continually introduced to the workplace each year. This expansion of technology in the workplace can both ameliorate workspace problems and create them. For a work area to flow efficiently and productively, both the equipment and the people must be operating smoothly. Any obstacle, difficult reach, congestion or confusion can impair work output and may, at times, compromise worker safety (Bradtmiller, n.d.).

In work design or modification, we need to answer the following questions:

1.

 Does the person fit (body size) in a workplace (see  Figure 3.1 )?

2.

 If one worker fits in a workplace, do all workers fit in a workplace?

3.

 If all workers do not fit in a workplace, are some individuals more likely to experience fatigue, injury, or diminished work performance due to poor fit into a workplace?

4.

 Does the design of the equipment have any adverse effects on the worker's safety and productivity?

Figure 3.1  Daycare worker in a child's chair

It is essential to be aware of the potential effects, both positive and negative, that work design issues can have on both worker performance and fatigue. When designing or modifying equipment or a work area, the following factors need to be considered:

1. Safe clearances or heights – examples, doorways or walkways

2. Safe reach distances – examples, equipment controls

3. Code requirements

4. Safety features – examples, machine guards

5. Workstation design for work flows.

The basis for anthropometry is the careful measurement of human body dimensions of a set population. The dimensions that are measured include the following:

1. Height

2. Weight

3. Reach, both horizontal and overhead

4. Stoop

5. Grip strength

6. Circumferential measurements

7. Limb length.

In addition, gender, age, race, and nationality are variables that should be considered when evaluating standard anthropometric tables or creating specific population tables. Anthropometric data is compiled to make guidelines to make the work areas, equipment, tools, and product fit the size, reach, grip, clearance, and capacity of the working population. Worker populations contain individuals who are male and female, large and small, short and tall, young and old, and strong and weak. The goal of applying the principles of anthropometrics to the workplace as part of work area and system design is to enhance human performance, control fatigue, and prevent accidents.

ANTHROPOMETRIC TABLES

In the science of anthropometrics, measurements of the population's dimensions are obtained based on the population's size and strength capabilities and differences. From these measurements, a set of data is collected that reflects the studied population in terms of size and form.

This population can then be described in terms of a frequency distribution including the mean, median, standard deviation, and percentiles. The frequency distribution for each measurement of the population dimension is expressed in percentiles. The xth percentile indicates that x percent of the population has the same value or less than that value for a given measurement. The median or average value for a particular dimension is the 50th percentile. In addition, 100 − x of the population has a value higher than x.

Example anthropometric data tables are contained in this chapter.  Table 3.1  contains male stature data.  Table 3.2  contains female stature data.  Table 3.3  contains male body mass index.  Table 3.4  contains female body mass index. Others included are male and female weights ( Tables 3.5  and  3.6 ), waist circumferences for males and females ( Tables 3.7  and  3.8 ), and later in the chapter are recumbent length for small children and children's head circumference ( Tables 3.10  and  3.11 ). These data are just a small sampling of the types of anthropometric data collected (CDC, 2012). Each of these data sets has multiple purposes. Stature data are used for designing ingress and egress ways, clearances, clothing, and seating design, for example. Body mass index data are used to assess obesity levels and waist size data are used in designing clothing, seating, and clearances. The question becomes, how long will these data be relevant? Well, that is a hard question to answer. That is why there is almost always an ongoing effort to collect additional data.

Table 3.1  Height in Inches for Males Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race and Ethnicity and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5647	69.3	0.08	64.3	65.4	66.2	67.3	69.3	71.2	72.3	73.0	74.1
20–29 years	895	69.4	0.13	64.4	65.5	66.5	67.4	69.4	71.5	72.6	73.1	74.1
30–39 years	948	69.5	0.14	64.4	65.4	66.3	67.5	69.5	71.6	72.6	73.3	74.2
40–49 years	934	69.6	0.17	64.9	66.0	66.6	67.6	69.6	71.5	72.6	73.5	74.4
50–59 years	938	69.5	0.13	64.5	65.8	66.3	67.7	69.7	71.3	72.3	72.8	74.4
60–69 years	932	68.8	0.10	63.9	64.8	65.7	66.9	69.0	70.7	71.9	72.6	73.6
70–79 years	646	68.2	0.13	63.6	64.6	65.2	66.3	68.2	70.0	70.9	71.9	72.7
80 years and over	354	67.2	0.15	62.5	63.7	64.4	65.3	67.3	69.2	69.9	70.4	71.5
colspan="13">Non-Hispanic white
20 years and over	2738	69.8	0.07	65.3	66.4	67.1	68.0	69.8	71.6	72.6	73.3	74.3
20–39 years	797	70.2	0.14	66.2	66.9	67.5	68.2	70.2	72.1	73.0	73.6	74.4
40–59 years	836	70.2	0.11	66.0	67.0	67.6	68.5	70.2	71.8	72.7	73.6	74.6
60 years and over	1105	68.7	0.09	64.2	64.9	65.7	66.9	68.9	70.6	71.6	72.4	73.4
colspan="13">Non-Hispanic black
20 years and over	1091	69.5	0.10	65.1	65.9	66.5	67.6	69.4	71.2	72.2	73.0	74.0
20–39 years	356	69.7	0.15	65.5	66.2	66.9	67.9	69.4	71.4	72.3	73.3	74.0
40–59 years	373	69.5	0.21	65.0	66.1	66.6	67.7	69.6	71.4	72.3	73.2	74.3
60 years and over	362	68.6	0.17	64.2	64.9	65.7	66.7	68.9	70.3	71.5	72.1	73.1
colspan="13">Hispanicb
20 years and over	1541	67.1	0.13	62.6	63.5	64.1	65.1	67.0	68.9	70.1	70.9	72.4
20–39 years	573	67.4	0.19	62.6	63.6	64.4	65.2	67.3	69.4	70.6	71.6	72.8
40–59 years	577	67.1	0.14	63.0	63.7	64.1	65.1	67.0	68.8	69.8	70.5	71.5
60 years and over	391	65.9	0.18	61.7	62.8	63.2	64.2	66.0	67.4	68.3	68.8	70.0
colspan="13">Mexican American
20 years and over	990	66.9	0.15	62.5	63.3	63.9	65.0	66.7	68.5	69.8	70.8	72.2
20–39 years	386	67.1	0.24	62.5	63.3	64.0	65.0	66.9	69.1	70.3	71.5	72.8
40–59 years	371	66.7	0.14	62.9	63.5	64.1	65.1	66.5	68.2	69.4	70.0	71.2
60 years and over	233	65.8	0.21	61.9	62.6	63.2	64.2	65.9	67.2	68.2	68.5	69.8

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012.Source: CDC (2012).

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.2  Height Inches for Females Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5971	63.8	0.05	59.3	60.3	60.9	61.9	63.8	65.7	66.6	67.3	68.4
20–29 years	980	64.2	0.09	59.9	60.6	61.3	62.2	64.1	66.0	67.0	67.6	68.9
30–39 years	1029	64.3	0.11	59.6	60.9	61.5	62.5	64.3	66.1	67.1	67.9	68.9
40–49 years	1060	64.2	0.09	59.8	60.8	61.4	62.4	64.0	66.0	66.9	67.6	68.7
50–59 years	873	63.9	0.12	59.6	60.4	61.0	62.0	64.0	65.6	66.6	67.0	67.9
60–69 years	952	63.6	0.10	59.3	60.2	61.0	62.0	63.8	65.3	66.2	66.8	38.6
70–79 years	679	62.6	0.13	58.4	59.3	59.8	60.7	62.8	64.3	65.4	66.1	66.9
80 years and over	398	61.4	0.14	56.9	57.9	58.8	59.8	61.5	62.9	63.8	64.3	65.5
colspan="13">Non-Hispanic white
20 years and over	2764	64.2	0.06	59.9	60.8	61.5	62.5	64.2	66.0	66.8	67.5	68.7
20–39 years	824	64.9	0.10	60.6	61.7	65.2	63.2	64.9	66.5	67.6	68.4	69.5
40–59 years	861	64.5	0.11	60.5	61.2	61.9	62.8	64.4	66.1	66.9	67.6	68.7
60 years and over	1079	63.1	0.09	58.7	59.8	60.4	61.5	63.1	64.8	65.8	66.4	67.2
colspan="13">Non-Hispanic black
20 years and over	1154	64.2	0.10	59.9	60.9	61.4	62.3	64.1	66.0	66.8	67.5	68.3
20–39 years	397	64.4	0.13	60.3	61.2	61.8	62.6	64.4	66.2	67.1	67.6	68.4
40–59 years	384	64.4	0.15	60.2	61.1	61.6	62.5	64.2	66.2	67.0	67.6	68.1
60 years and over	373	63.2	0.11	58.9	59.9	60.4	61.4	63.2	64.9	65.8	66.3	67.4
colspan="13">Hispanicb
20 years and over	1763	61.9	0.07	57.6	58.6	59.1	60.1	61.8	63.6	64.5	65.2	66.3
20–39 years	673	62.3	0.09	58.1	58.9	59.6	60.5	62.2	63.9	64.9	65.6	66.7
40–59 years	580	61.9	0.13	57.8	58.6	59.3	60.1	61.7	63.6	64.4	64.9	65.8
60 years and over	510	60.5	0.12	56.6	57.5	58.1	58.8	60.4	62.1	62.9	63.6	64.8
colspan="13">Mexican American
20 years and over	1074	61.7	0.07	57.2	58.4	59.0	59.9	61.6	63.4	64.2	64.9	66.0
20–39 years	427	62.0	0.10	57.4	58.9	59.5	60.3	62.0	63.6	64.5	65.1	66.3
40–59 years	348	61.7	0.16	57.5	58.5	59.0	59.9	61.4	63.4	64.2	64.8	65.7
60 years and over	299	60.4	0.16	56.6	57.4	57.9	58.8	60.3	61.8	62.9	63.5	64.4

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.3  Body Mass Index for Males Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5635	28.6	0.13	20.7	22.2	23.2	24.7	27.8	31.5	33.9	35.8	39.2
20–29 years	894	26.8	0.24	19.4	20.7	21.4	22.9	25.6	29.9	32.3	33.8	36.5
30–39 years	948	29.0	0.22	21.0	22.4	23.3	24.9	28.0	32.0	34.1	36.2	40.5
40–49 years	933	29.0	0.29	21.2	22.9	24.0	25.4	28.2	31.7	34.4	36.1	39.6
50–59 years	934	29.2	0.31	21.5	22.9	23.9	25.5	28.2	32.0	34.5	37.1	39.9
60–69 years	930	29.5	0.25	21.3	22.7	23.8	25.3	28.8	32.5	34.7	37.0	40.0
70–79 years	643	28.8	0.26	21.4	22.9	23.8	25.6	28.3	31.3	33.5	35.4	37.8
80 years and over	353	27.2	0.22	20.7	21.8	22.8	24.4	27.0	29.6	31.3	32.7	34.5
colspan="13">Non-Hispanic white
20 years and over	2728	28.7	0.15	20.8	22.4	23.3	24.8	27.9	31.5	33.9	35.8	39.1
20–39 years	796	27.7	0.25	20.1	21.1	22.3	23.6	26.8	30.9	33.1	34.2	38.2
40–59 years	832	29.2	0.22	21.3	23.1	24.1	25.5	28.3	31.8	34.5	36.8	39.7
60 years and over	1100	29.2	0.18	21.4	23.2	24.2	25.5	28.6	31.9	34.0	35.9	38.8
colspan="13">Non-Hispanic black
20 years and over	1090	29.0	0.23	19.7	21.4	22.4	23.7	28.0	32.7	35.5	38.1	41.9
20–39 years	356	28.7	0.39	19.6	21.1	21.8	23.1	27.3	32.6	35.8	38.1	42.7
40–59 years	372	29.4	0.38	19.7	22.1	22.9	24.8	28.3	33.1	35.8	38.4	41.1
60 years and over	362	28.8	0.32	19.8	21.6	22.6	24.1	28.2	31.6	34.3	36.9	40.8
colspan="13">Hispanicb
20 years and over	1540	28.9	0.25	21.3	23.0	23.9	25.5	28.1	31.6	33.8	35.6	39.0
20–39 years	573	28.5	0.33	20.9	21.9	23.2	24.8	27.5	31.1	33.0	35.5	40.6
40–59 years	577	29.5	0.24	23.1	24.2	25.2	26.5	28.8	32.1	34.4	35.7	37.7
60 years and over	390	29.2	0.32	22.0	23.2	24.3	25.9	28.3	31.9	34.1	35.6	38.5
colspan="13">Mexican American
20 years and over	990	29.0	0.30	21.4	23.2	24.0	25.7	28.1	31.6	33.7	35.6	39.5
20–39 years	386	28.8	0.42	20.9	22.2	23.5	25.1	27.8	31.4	33.0	35.3	41.1
40–59 years	371	29.5	0.28	23.1	24.3	25.3	26.4	28.7	32.0	34.3	35.8	37.8
60 years and over	233	29.2	0.44	22.1	23.2	24.2	25.9	28.3	31.8	33.9	35.3	39.0

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

Note: Body mass index (BMI) is calculated as follows: BMI = weight (kg)/height (m2).

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.4  Body Mass Index Values for Females Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5841	28.7	0.12	19.5	20.7	21.7	23.3	27.3	32.5	36.1	38.2	42.0
20–29 years	906	27.5	0.42	18.8	19.9	20.6	21.7	25.3	31.5	36.0	38.0	43.9
30–39 years	982	28.7	0.33	19.4	20.6	21.6	23.4	27.2	32.8	36.0	38.1	41.6
40–49 years	1056	28.6	0.28	19.3	20.6	21.7	23.3	27.3	32.4	36.2	38.1	43.0
50–59 years	873	29.3	0.27	19.7	21.3	22.1	24.0	28.3	33.5	36.4	39.3	41.8
60–69 years	950	29.6	0.25	20.7	21.6	23.0	24.8	28.8	33.5	36.6	38.5	41.1
70–79 years	677	29.5	0.26	20.1	21.6	22.7	24.7	28.6	33.4	36.3	38.7	42.1
80 years and over	397	26.7	0.26	19.3	20.7	22.0	23.1	26.3	29.7	31.6	32.5	35.2
colspan="13">Non-Hispanic white
20 years and over	2730	28.2	0.20	19.4	20.5	21.4	23.0	26.9	32.0	35.7	37.7	41.5
20–39 years	792	27.5	0.41	19.0	19.9	20.7	22.1	25.6	31.3	35.4	37.5	42.8
40–59 years	861	28.3	0.24	19.4	20.5	21.6	23.2	26.9	32.4	35.8	38.0	41.5
60 years and over	1077	28.7	0.20	20.1	21.4	22.5	24.0	27.8	32.2	35.5	37.6	40.7
colspan="13">Non-Hispanic black
20 years and over	1126	32.0	0.31	20.5	22.1	24.0	25.9	30.8	36.5	40.2	42.8	47.2
20–39 years	372	31.4	0.46	19.8	21.6	22.8	25.0	30.3	35.9	40.0	42.1	47.5
40–59 years	383	33.1	0.49	21.2	23.0	24.5	26.7	31.2	37.7	41.3	44.8	48.0
60 years and over	371	31.1	0.33	20.8	22.9	24.5	26.6	30.3	34.8	38.0	40.0	44.2
colspan="13">Hispanicb
20 years and over	1707	29.5	0.19	20.8	21.9	22.9	24.9	28.5	33.0	36.0	38.0	40.9
20–39 years	619	28.8	0.23	20.3	21.3	22.1	23.6	26.9	32.7	36.1	38.2	40.9
40–59 years	579	30.2	0.34	21.3	23.0	24.2	26.2	29.6	33.2	35.9	37.8	40.7
60 years and over	509	29.9	0.17	21.1	22.8	23.9	25.7	29.4	33.2	36.0	37.7	41.7
colspan="13">Mexican American
20 years and over	1031	29.8	0.17	21.1	22.2	23.3	25.2	29.1	33.6	36.1	38.1	40.9
20–39 years	386	29.2	0.29	20.9	21.8	22.3	24.0	27.6	33.5	36.5	38.3	40.9
40–59 years	347	30.6	0.37	21.6	23.5	25.0	26.7	30.1	33.8	35.9	36.7	40.8
60 years and over	298	30.0	0.21	21.1	23.0	24.1	26.1	29.6	33.1	36.0	37.4	41.7

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.5  Waist Circumference in Inches for Males Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5410	39.7	0.41	30.7	32.2	33.6	35.6	39.1	43.1	45.7	47.6	50.4
20–29 years	862	36.4	0.64	28.9	29.9	30.7	32.0	35.5	39.8	42.4	44.1	46.6
30–39 years	900	39.1	0.52	31.1	32.4	33.5	35.0	38.3	42.1	44.6	47.1	50.1
40–49 years	907	40.1	0.68	31.7	33.7	34.8	36.5	39.2	43.1	45.7	40.4	50.0
50–59 years	906	41.0	0.81	32.2	34.4	35.7	36.9	40.5	44.0	46.5	48.5	51.2
60–69 years	899	41.8	0.64	32.8	35.0	36.2	37.8	41.5	45.3	47.8	49.5	51.3
70–79 years	609	42.0	0.64	33.9	35.9	37.1	38.8	41.8	45.2	47.4	49.3	51.0
80 years and over	327	40.7	06.9	33.1	34.6	35.7	36.6	40.7	43.7	45.3	46.8	48.7
colspan="13">Non-Hispanic white
20 years and over	2624	40.2	0.43	31.2	32.8	34.2	36.2	39.8	43.7	46.4	48.1	50.6
20–39 years	762	37.6	0.65	29.9	31.1	31.9	33.5	37.3	41.2	44.1	45.7	48.9
40–59 years	812	41.0	0.60	32.2	34.5	35.7	36.9	40.4	44.0	46.9	48.4	51.1
60 years and over	1050	40.9	0.41	34.3	35.8	36.9	38.4	41.8	45.3	47.4	49.3	51.0
colspan="13">Non-Hispanic black
20 years and over	1033	38.6	0.62	28.7	30.1	31.1	33.3	37.9	42.7	45.6	47.4	51.9
20–39 years	335	36.9	0.86	28.1	29.1	29.8	31.2	35.7	41.0	44.4	46.7	50.8
40–59 years	351	39.6	0.91	29.9	31.6	32.8	35.2	38.0	43.3	45.7	47.4	52.4
60 years and over	347	40.7	0.90	30.8	32.8	33.9	36.5	40.2	44.2	47.1	49.0	52.7
colspan="13">Hispanicb
20 years and over	1490	39.2	0.68	31.3	32.7	33.9	35.6	38.6	42.0	44.3	46.0	49.3
20–39 years	555	38.1	0.84	29.8	31.8	32.6	34.3	37.4	41.0	42.8	44.7	49.4
40–59 years	567	40.3	0.66	33.6	35.2	36.2	37.3	39.5	42.8	45.2	46.5	48.6
60 years and over	368	41.3	0.57	34.3	35.4	36.4	37.7	41.0	44.0	45.7	47.4	50.4
colspan="13">Mexican American
20 years and over	957	39.3	0.80	31.5	33.1	34.4	36.0	38.8	42.0	44.2	45.8	49.4
20–39 years	371	38.4	41.01	30.2	32.0	33.0	34.8	37.6	41.3	42.9	44.5	49.6
40–59 years	367	40.3	0.82	33.8	35.5	36.4	37.2	39.4	42.8	45.2	46.2	48.5
60 years and over	219	41.2	0.75	34.3	35.6	36.7	37.6	40.9	43.9	45.5	46.7	50.1

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.6  Waist Circumference in Inches for Females Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5552	37.5	0.34	28.3	29.7	30.8	32.8	36.7	41.5	44.3	46.3	49.2
20–29 years	870	35.5	1.04	26.9	28.4	29.3	30.3	33.7	39.1	42.5	45.4	49.3
30–39 years	939	36.9	0.75	28.1	29.2	30.6	32.3	35.7	40.8	43.9	45.9	48.5
40–49 years	1024	37.2	0.62	28.3	29.7	30.8	32.6	36.1	40.9	44.0	46.1	48.9
50–59 years	839	38.4	0.55	28.9	30.5	32.0	33.8	37.6	42.3	44.9	47.1	49.8
60–69 years	903	39.3	0.57	30.6	32.4	33.4	34.8	39.1	43.0	45.4	47.2	50.0
70–79 years	632	39.3	0.62	30.3	32.0	33.6	35.2	38.8	42.9	45.6	47.1	49.6
80 years and over	345	36.4	0.59	29.4	30.7	31.8	33.3	36.5	39.9	42.2	43.5	44.9
colspan="13">Non-Hispanic white
20 years and over	2602	37.3	0.49	28.3	29.5	30.7	32.6	36.4	41.3	44.3	46.2	49.0
20–39 years	762	35.9	1.00	27.7	28.7	29.4	30.8	34.3	39.5	42.6	45.4	48.5
40–59 years	829	37.5	0.58	28.4	29.8	30.9	32.7	36.4	41.5	44.5	46.5	49.2
60 years and over	1011	38.7	0.48	29.8	31.8	32.8	34.5	38.3	42.2	44.9	46.7	49.2
colspan="13">Non-Hispanic black
20 years and over	1046	39.6	0.70	29.0	31.3	32.4	34.5	39.1	43.9	47.0	48.9	51.1
20–39 years	349	38.4	1.17	27.6	29.5	31.1	32.8	37.2	43.0	46.1	48.9	51.0
40–59 years	365	40.6	0.81	30.3	32.1	33.1	35.7	39.8	45.1	48.0	49.5	52.0
60 years and over	332	40.2	0.72	31.3	33.5	34.6	36.6	39.6	43.3	45.9	47.1	50.2
colspan="13">Hispanicb
20 years and over	1642	37.7	0.46	29.4	30.6	31.8	33.6	37.2	41.3	43.3	45.3	47.9
20–39 years	598	36.8	0.60	28.8	29.8	30.7	32.2	35.9	40.7	43.1	45.2	47.8
40–59 years	567	38.3	0.80	30.1	32.0	32.9	34.9	37.9	41.2	43.2	45.2	47.8
60 years and over	477	39.1	0.40	30.6	33.1	34.0	35.8	39.0	42.3	44.1	45.6	48.0
colspan="13">Mexican American
20 years and over	998	38.1	0.47	29.7	31.0	32.1	34.0	37.7	41.8	43.9	45.5	48.3
20–39 years	372	37.4	0.74	29.2	30.1	31.1	32.6	36.2	41.6	43.9	45.6	48.5
40–59 years	342	38.8	0.89	30.5	32.3	33.3	35.4	38.4	41.9	43.3	45.4	47.5
60 years and over	284	39.4	0.50	31.4	33.4	34.4	36.1	39.3	42.4	44.1	45.4	48.3

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

Note: Pregnant women were excluded.

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.7  Weight in Pounds

for Males Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5651	195.5	0.99	135.5	146.6	153.7	165.2	189.8	218.0	236.4	252.2	273.6
20–29 years	894	183.9	1.87	128.7	137.9	143.9	153.2	176.5	206.6	224.0	240.4	257.5
30–39 years	948	199.5	1.66	139.6	149.4	156.0	166.2	191.1	222.9	242.7	259.7	282.2
40–49 years	933	200.6	2.12	142.1	153.2	162.0	173.1	193.7	221.9	239.4	256.1	278.5
50–59 years	934	201.3	2.43	140.6	152.2	160.8	172.3	195.4	226.9	242.1	259.3	279.0
60–69 years	649	190.6	1.95	138.1	147.2	155.1	165.5	186.8	209.8	227.0	241.8	259.9
70–79 years	649	190.6	1.95	138.1	147.2	155.1	165.5	186.8	209.8	227.0	241.1	259.9
80 years and over	360	174.9	1.79	127.1	135.5	141.3	152.2	171.8	194.4	207.9	214.5	230.3
colspan="13">Non-Hispanic white
20 years and over	2738	199.2	0.92	140.4	151.8	159.1	170.3	194.0	221.7	239.6	254.9	273.6
20–39 years	796	194.7	1.71	135.7	145.3	153.0	162.8	188.1	217.2	238.0	250.3	270.6
40–59 years	832	204.9	1.56	146.3	159.0	165.4	177.3	198.5	227.4	246.7	259.5	283.7
60 years and over	1110	196.3	1.21	140.1	152.0	159.1	168.8	191.8	217.1	232.7	248.1	266.7
colspan="13">Non-Hispanic black
20 years and over	1094	199.4	1.63	134.3	143.5	149.7	163.1	191.3	224.5	245.7	264.7	292.0
20–39 years	356	198.1	3.14	135.2	141.6	146.8	158.9	188.7	223.5	246.3	264.5	296.1
40–59 years	372	203.1	2.77	133.4	146.0	156.9	169.5	196.4	227.7	249.8	266.3	291.9
60 years and over	366	193.6	2.54	127.8	140.8	147.8	158.7	188.0	213.0	234.7	256.5	283.9
colspan="13">Hispanicb
20 years and over	1541	186.1	1.95	133.2	143.4	148.5	157.5	180.0	205.4	221.0	236.4	266.7
20–39 years	573	185.1	2.66	129.2	140.4	146.1	154.9	176.1	204.6	221.4	241.2	271.7
40–59 years	577	189.4	1.77	141.6	150.3	155.0	165.2	184.2	207.7	223.3	232.4	258.0
60 years and over	391	180.8	2.50	129.1	138.8	146.5	154.7	177.1	200.5	212.9	223.7	241.2
colspan="13">Mexican American
20 years and over	991	185.4	2.30	133.2	143.3	148.4	157.1	179.6	204.6	218.8	235.6	267.6
20–39 years	386	185.2	3.27	130.9	140.0	146.0	155.0	176.6	204.8	220.6	241.4	276.2
40–59 years	371	187.4	1.98	141.1	150.0	154.6	163.0	182.8	206.6	219.8	229.3	255.3
60 years and over	234	180.6	3.17	130.7	138.9	148.0	155.8	177.2	199.3	208.9	215.2	240.6

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.8  Weight in Pounds for Females Aged 20 and Over and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

Race and Ethnicity	Number of Examined Persons	Mean	Standard Error of the Mean	Percentile
				5th	10th	15th	25th	50th	75th	85th	90th	95th
colspan="13">All racial and ethnic groupsa
20 years and over	5844	166.2	0.78	110.7	118.2	124.8	134.6	157.2	188.6	210.3	255.3	250.9
20–29 years	906	161.9	2.49	107.2	114.8	118.5	126.3	149.4	181.2	208.9	227.3	264.5
30–39 years	982	169.1	2.07	112.2	118.8	126.5	137.2	159.8	194.2	215.1	225.4	253.9
40–49 years	1056	168.0	1.64	111.9	120.8	126.5	134.9	158.4	189.0	212.0	228.7	253.2
50–59 years	873	170.0	1.82	112.7	123.3	128.8	138.5	161.4	193.8	213.3	230.2	255.3
60–69 years	951	170.5	1.44	116.5	126.1	132.2	140.4	165.7	192.5	211.0	226.3	241.4
70–79 years	679	164.9	1.52	109.9	118.0	125.7	136.9	159.4	187.1	201.7	218.4	240.6
80 years and over	397	143.1	1.60	100.2	109.8	114.1	123.1	140.0	158.5	172.9	182.7	192.6
colspan="13">Non-Hispanic white
20 years and over	2730	165.4	1.13	111.6	118.6	125.0	134.9	156.6	187.4	209.3	223.7	246.8
20–39 years	792	164.7	2.55	110.4	117.7	123.0	132.0	154.0	186.6	212.3	225.4	257.5
40–59 years	861	167.7	1.45	112.3	121.3	126.7	136.2	158.5	189.7	212.2	227.0	254.6
colspan="13">Non-Hispanic black
20 years and over	1128	187.9	1.72	118.9	129.5	136.5	151.0	177.5	215.5	237.4	255.1	287.8
20–39 years	372	186.2	2.57	113.8	125.6	134.4	145.1	176.2	216.6	241.8	258.9	294.5
40–59 years	383	194.7	2.68	125.4	133.9	144.2	156.4	183.4	221.5	243.5	257.3	290.3
60 years and over	373	177.8	2.30	116.4	125.9	135.0	149.1	171.4	200.3	221.0	233.9	253.0
colspan="13">Hispanicb
20 years and over	1708	160.6	1.02	109.7	117.0	123.6	133.4	154.7	181.5	198.3	210.7	228.1
20–39 years	619	159.4	1.31	107.6	114.8	119.2	129.6	151.4	183.6	200.8	212.8	231.6
40–59 years	579	164.5	1.84	114.6	125.6	131.0	140.9	158.9	182.3	197.4	210.1	228.6
60 years and over	510	155.8	1.05	105.8	114.2	122.5	133.5	153.0	174.3	188.4	198.8	213.6
colspan="13">Mexican American
20 years and over	1032	161.5	0.89	110.9	118.1	124.6	134.5	156.0	182.9	198.5	208.0	229.3
20–39 years	386	160.3	1.46	110.4	116.4	121.3	132.1	152.1	185.3	202.0	213.0	233.5
40–59 years	347	165.8	2.13	117.5	127.1	133.4	142.8	161.8	182.9	197.0	206.0	226.0
60 years and over	299	155.5	1.23	103.8	113.6	122.4	133.3	153.2	174.8	187.6	197.4	207.5

Source: Adapted from Anthropometric Reference Data for Children and Adults: United States, 2007–2010; DHHS Publication No. (PHS) 2013-1602, 2012. Source: CDC (2012).

Note: Pregnant women were excluded.

a Persons of other races and ethnicities are included.

b Mexican Americans are included in the Hispanic group.

Table 3.9  Critical Anthropometric Dimensions

Segment/Body Dimension	Gender	5th Percentile	50th Percentile	95th Percentile
Stature	M F	64.3 59.3	69.3 63.8	74.1 68.4
Eye height	M F	60.8 57.3	64.70 60.3	68.6 65.3
Hip width (seated)	M F	12.14 12.29	13.95 14.34	16 17.22

Source: Adapted from Helander (2005).

Example Use of Anthropometric Data Tables.

Table 3.10  Recumbent Length in Centimeters for Children from Birth Through Age 36 Months and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

c03f001

Table 3.11  Head Circumference in Centimeters for Infants from Birth Through Age 6 Months and Number of Examined Persons, Mean, Standard Error of the Mean, and Selected Percentiles, by Race, Ethnicity, and Age

c03f001

Figure 3.2  shows a graph of the male stature data and  Figure 3.3  shows a graph of the female stature data.  Figure 3.4  shows the data for both genders. Generally speaking, anthropometric data follows a normal distribution as shown in  Figure 3.5 .

Figure 3.2  Graph of male stature height

Figure 3.3  Graph of female stature data

Figure 3.4  Graph of male and female stature data

Figure 3.5  Distribution of male and female statures

In ergonomic design, we do not design for the average person, or the 50th percentile, we design for the 95th percentile. In other words, 95% of the population can use the work area safely and efficiently, and 5% of the population may need to be accommodated. Conventionally, the 95th percentile has been chosen to determine clearance heights or lengths. That means 95% of the population will be able to pass through a door, while only 5% of the population may need to be accommodated. In addition, the 5th percentile female has been chosen to determine the functional reach distance, that means 95% of the population will be able to perform this reach, and only 5% of the population may need to be accommodated.  Figure 3.6  shows the same graph of the distribution of male and female statures with the critical percentiles.  Table 3.9  contains three (3) of the more commonly used anthropometric body dimensions (Helander, 2005).

Figure 3.6  Statures with percentiles

In some cases, we have to adjust the value for a certain body dimension based on clothing or other considerations.

Adjustments to accommodate clothing include the following:

· 2.5 cm (1.0 in.) for standing height (or seated knee height) to reflect the presence of a shoe heel

· 0.8 cm (0.3 in.) for breadths (due to the bulk of clothing)

· 3.0 cm (1.2 in.) for foot length (to accommodate for shoes being larger than feet).

Adjustments to accommodate for posture include

· 2.0 cm (0.8 in.) for standing height (due to slouching or lack of upright posture).

Table 3.10 contains recumbent lengths of children from 0 to 36 months in age, and Table 3.11 contains head circumference data. If we want to design a new crib, we would select the data we need from these tables, as well as other tables, and produce the design. We would use these data to design the length of the crib mattress and the width of the slates in the sides of the crib. Figure 3.7 is a conceptual design of the crib. Which percentiles of data would we select?

Figure 3.7  Crib design

Well, one option would be the 50th percentile recumbent length for a newborn female (18.8 in.) and 95th percentile head circumference for a 6-month male child (18.1 in. or an estimated 5.74 in. diameter). In reality, a much more accurate head diameter would be needed. However, this would produce a crib that would be too short, and the slates would be spaced such that an infant could get his/her head through the slates and possibly become strangled. In fact, most all female and all but the largest male children could get their heads through the slates. The more reasonable approach would be to use the 5th percentile female head size, with a safety factor subtracted from the width for the slates. The Consumer Product Safety Commission recommends no more than 2.375-in. slate width or, as their website states, “If a soda can will fit through, the slats are too far apart” (CPSC, 2014). The 95th 3-year-old male recumbent length (42.2 in.) should be the starting point for the length of the crib, plus some comfort factor added on.

Average Person

Designing for the “average” person or the 50th percentile is a myth. If you designed a doorway for the “average” person, one-half of the population would not fit through the door. Design considerations for doorways, for example, must be for the 99th percentile male. Reach considerations must be given to the smallest person or the 5th percentile female. There are numerous guidelines and anthropometric tables to assist in designing tasks and equipment, which address all aspects from stature and forward functional reach to eye height for particular tasks.

ANTHROPOMETRY IN DESIGN

All of us have experienced problems with equipment, workspaces, or even our homes not being designed with our body dimensions in mind. The following example illustrates ergonomic issues when a design does not accommodate a wide range of body sizes. In the first example, the task is to remove the ladder from the top of the van (Figure 3.8). The larger individual in the photo can do the task, but the smaller individual cannot. The solution to this issue is to design a device that will lower the ladder to the side of the vehicle so a full range of individuals can remove it at their power zone (Figure 3.9).

Figure 3.8  (a) Poor design with the ladder on top of the van. (b) Unsafe way of getting ladder

Figure 3.9  Better ergonomic design

Poor Ergonomic Design

Ergonomists use the following steps to design equipment based on anthropometric design principles:

1. Define the population – who are we designing for?

2. Determine critical body dimensions – what allows use?

3. Select the percentage of the population to be accommodated (or excluded) – how many do we need to accommodate?

4. Select the anthropometry principle:

Range, extreme, average

5. Locate data tables.

6. Adjust for clothing, posture.

7. Test.*

Next, we need to understand what it means to apply anthropometric data for a certain design principle. There are three ergonomic design principles based on anthropometry: design for a range, design for the extreme, and design for the average. These are explained below.

Design for a Range

1. Principle: Allow for adjustments in position, size, intensity, and duration of the product or system, to accommodate unexpected circumstances and maximize use (preferred option).

2. Design: Common to use from the 5th percentile female to the 95th percentile male; can result in accommodation of 95% of 50/50 mixed population group because of overlap in male and female body dimensions.

3. Examples of use: Car seats, desk height, keyboard support, footrests, purchase in different sizes (chairs, shoes, and tools).

Some ways of using this principle in design are as follows:

· Designing six-way adjustability into car seats

· Providing adjustable height computer workstations

· Providing safe platforms for smaller workers to stand on when working at a higher workstation

· Providing work fixtures to aid workers reaching for equipment.

Design for the Extreme

1. Principle: Accommodate largest percent of the population group where adjustability is costly or not feasible – Maximum Levels: 95th–100th percentile

Clearance, Load Tolerance, Girth (e.g., doorways, size of escape hatches, entry ways, strength of ladders) – Minimum Levels: 1st–5th percentile

Reach, Strength (e.g., distance of control button from operator, force required to operate control lever or button).

Practical Design

1. Use 1st–5th or 95th–100th percentiles of population group as extremes, typically the smallest female and largest male.

2. Examples of uses: Egress ways, control configurations, and safety showers.

Design for the Average

1. Principle: Design for the 50th percentile

1. Acceptable for short-term use

2. Accommodates small population group.

2. Design: 50th percentile only

1. Used as a last resort – may exclude 50% of the population

2. There is no “average” person (e.g., average height may not mean average arm length).

3. Examples of use: Self-serve checkout counter, water fountain.

Rule of Thumb

Design so the tall can fit and the small can reach.

CASE STUDY

Introduction

The following is a description of an aviation accident that occurred on January 8, 2003. The description of the event, analysis, and conclusions come directly from the National Transportation Safety Board (NTSB) report (Beechcraft, 2004). Note that not all of the information is provided, only that relating to the anthropometric aspects of the accident. In general, the text has not been changed from the original report. However, in some cases, the text has been changed for readability. Also, the notes have been provided at the end of the sections.

History of Flight

On January 8, 2003, about 0847:28 eastern standard time, Air Midwest (doing business as US Airways Express) flight 5481, a Raytheon (Beechcraft) 1900D, N233YV, crashed shortly after takeoff from runway 18R at Charlotte-Douglas International Airport (CLT), Charlotte, North Carolina. The 2 flight crewmembers and 19 passengers aboard the airplane were killed, persons on the ground received minor injuries, and the airplane was destroyed by impact forces and a postcrash fire. Flight 5481 was a regularly scheduled passenger flight to Greenville-Spartanburg International Airport (GSP), Greer, South Carolina, and was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 121 on an instrument flight rules flight plan. Visual meteorological conditions prevailed at the time of the accident.

The accident airplane had been flown from the Tri-State/Milton J. Ferguson Field, Huntington, West Virginia (HTS), to CLT on January 7, 2003 (the day before the accident). Air Midwest records indicated that the accident pilots flew the accident airplane on six flight legs that day. The first officer (the nonflying pilot) of the flight from HTS to CLT told the accident first officer, when handing off the airplane, that everything was normal, and it was a good flying airplane. The accident pilots began their trip sequence about 1340 and ended their trip sequence at CLT about 2045. Another flight crew met the accident airplane for a trip that night from CLT to Lynchburg Regional Airport/Preston Glenn Field (LYH), Lynchburg, Virginia. That flight crew flew the accident airplane back to CLT the next morning (January 8th), arriving at 0715. According to postaccident interviews, neither the captain nor the first officer of those two flight legs noticed anything unusual about the airplane.

On January 8, 2003, the accident flight crew was scheduled to fly two flight legs on a 1-day trip sequence, CLT to GSP and GSP to Raleigh–Durham International Airport (RDU), Raleigh–Durham, North Carolina, and then to travel on duty as passengers from RDU to CLT. An Air Midwest pilot saw the captain in the gate area about 0745 and the first officer about 0800. The dispatch release for flight 5481 showed that a maximum of 32 bags were allowed on the flight. One of the two ramp agents working flight 5481 stated, in a postaccident interview, that 23 bags had been checked and that 8 bags were carried on the airplane. The ramp agent stated that two of the checked bags were heavy, with an estimated weight of between 70 and 80 lb. The ramp agent also stated that he told the captain that some of the bags were heavy, although they were not marked as such. According to the ramp agent, the captain indicated that the bags were fine because a child would be on board, which would allow for the extra baggage weight. The ramp agent estimated that the forward cargo compartment was about 98% full by volume. Cockpit voice recorder (CVR) information early in the recording indicated that the flight crew was completing the preflight paperwork regarding the airplane's weight and balance. Air Midwest records indicated that flight 5481 departed the gate on time about 0830.

The captain was the flying pilot, and the first officer was the nonflying pilot. Flight data recorder (FDR) data indicated that, beginning about 0835:16, the flight crew performed a control check of the elevators. The pitch control position parameter, which measures the position of the control column, recorded values from 15° airplane nose up (ANU) to 16.5° airplane nose down (AND). These values corresponded to elevator positions from full ANU to 7° AND. About 0837:20, the CVR recorded the first officer contacting the CLT Air Traffic Control Tower (ATCT) ground controller and informing him that flight 5481 was ready to taxi. The ground controller instructed the flight crew to taxi to runway 18R. About 0846:18, the tower (local) controller cleared flight 5481 for takeoff and instructed the flight crew to turn right to a heading of 230° after takeoff. About 0846:35, the captain asked the first officer to set the takeoff power, and the first officer stated that the power had been set. About 0846:48, the airplane's airspeed was above 102 knots, and the elevator position was 7° AND. About 3 s later, the elevator position was 1° AND, and the pitch attitude of the airplane began to increase. After 0846:53, the pitch trim started moving AND and about 3 s later, the captain called for the landing gear to be retracted. About 0846:57, the elevator position returned to 7° AND, and, about 2 s later, the CVR recorded the sound of the landing gear retracting.

About 0847:02, the

first officer stated, “wuh,” and the captain stated, “oh.” About 0847:03, the captain stated, “help me,” At that point, the airplane was about 90 ft above ground level, and FDR data showed that the airplane's pitch attitude was 20° ANU and airspeed was 139 knots. About 0847:04, the CVR recorded the captain asking, “you got it?” and FDR data indicated that the flight crew was forcefully commanding AND.

During the next 8 s, the CVR recorded multiple statements and sounds from both flight crewmembers associated with their efforts to push the airplane's nose down. Also, about 0847:09, the CVR recorded a change in engine/propeller noise and, about 1 s later, the beginning of a sound similar to the stall warning horn. About 0847:13, the FDR recorded a maximum pitch attitude of 54° ANU. About 0847:16, the captain radioed the ATCT and stated, “we have an emergency for Air [Midwest] fifty four eighty one,” and the CVR recorded the end of the sound similar to the stall warning horn. About 0847:18, the airplane's pitch attitude decreased through 0°, and the elevator position began to move ANU. By 0847:19, the airplane was about 1150 ft above ground level, and the FDR recorded a maximum left roll of 127° and a minimum airspeed of 31 knots. About 1 s later, the FDR recorded a pitch attitude of 42° AND. About 0847:21, the captain stated, “pull the power back,” the elevator position reached full ANU, and the airplane's pitch altitude was 39° AND. At 0847:21.7, the CVR recorded the beginning of a sound similar to the stall warning horn, which continued to the end of the recording. About 0847:22, the airplane's roll altitude stabilized at about 20° left wing down; the pitch attitude began to increase; and the elevator position moved in the AND direction, reaching about 8° ANU. About 1 s later, the elevator position began moving in the ANU direction. About 0847:24, the airplane rolled right through wings level, and the pitch altitude increased to about 5° AND. About 0847:26, the FDR recorded a maximum right roll of 68° and a maximum vertical acceleration of 1.9 Gs. About the same time, the captain stated, “oh my god ahh,” and the first officer stated something similar to, “uh uh god ahh [expletive].” The CVR recording ended at 0847:28.1. The FDR's last recorded pitch altitude was 47° AND; roll altitude was 66° to the right and pitch control position was 19.2° ANU, which corresponded to an elevator position of full ANU. The airplane struck a US Airways maintenance hangar on CLT property and came to rest about 1650 ft east of the runway 18R centerline and about 7600 ft beyond the runway 18R threshold. ATCT controllers heard an emergency locator transmitter signal beginning about 0847:29. The accident occurred at 35°12′25″ north latitude and 80°56′46.85″ west longitude during daylight hours.

Analysis

On the day of the accident, the first officer was seen conducting a walk-around inspection of the airplane. He did not report anything unusual about the airplane, including its elevator control system. The accident flight crew filled out the Air Midwest Beechcraft 1900D Load Manifest form for the flight using the average weight values for passengers and baggage in Air Midwest's weight and balance program at the time of the accident. The load manifest indicated a taxi fuel burn of 220 lb, even though Air Midwest assumes a taxi fuel burn of 110 lb. These figures resulted in a calculated airplane weight of 17,028 lb and a center of gravity (CG) position of 37.8% mean aerodynamic chord (MAC), which were within the Beech 1900D certified weight and CG limits of 17,120 lb and 40% MAC, respectively. The two ramp agents assigned to the accident flight handled the baggage according to company procedures and interacted appropriately with the flight crew. In a postaccident interview, one of the ramp agents reported that he told the captain that 2 of the 31 bags aboard the airplane had an estimated weight of between 70 and 80 lb. However, the bags did not have a heavy bag tag attached to them. (Gate agents use these tags to indicate an overweight bag, that is, a bag that weighs between 70 and 100 lb.) Also, the bags were not identified as overweight on the OF-11E form (the US Airways Express Load Report that is used to account for all passengers, baggage, and cargo loaded on a US Airways Express flight). As a result, the flight crew was not required to account for the extra weight of the reportedly heavy bags on the load manifest form.

Even if the flight crew had (1) accounted for the two reportedly heavy bags or (2) accounted for the two heavy bags, estimated an additional 110 lb of fuel at takeoff, 127 and recorded the 12-year-old passenger's weight as 80 lb rather than 175 lb, 128 the Air Midwest weight and balance program would still have indicated that flight 5481 was within the Beech 1900D certified weight and CG limits. However, for the second scenario, flight 5481's calculated weight would have exceeded the Beech 1900D weight limit if the 12-year-old passenger's weight had remained 175 lb.

Table 3.12 shows calculations for Air Midwest flight 5481 using the weight and balance program in effect at the time of the accident.

Table 3.12  Load Calculations

Load Manifest	Load Manifest Plus Two Bags	Load Manifest Plus Two Bags and 110 lb of Fuel But with 80 lb for the Child Passenger
Weight in Pounds	CG in Percent of Mac	Weight in Pounds	CG in Percent of Mac	Weight in Pounds	CG in Percent of Mac
17,028	37.8	17,078	38.8	17,093	38.8

Source: Adapted from National Transportation Safety Board, Loss of Pitch Control During Takeoff Air Midwest Flight 5481, Raytheon (Beechcraft) 1900D, N233YV, AAR-04-0, 2/26/2004.

Findings

1. The captain and the first officer were properly certified and qualified under Federal regulations. No evidence indicated any preexisting medical or behavioral conditions that might have adversely affected their performance during the accident flight. Flight crew fatigue was not a factor in this accident.

2. The accident airplane was properly certified and equipped in accordance with Federal regulations. Except for the elevator control system, no evidence indicated that the airplane was improperly maintained. The recovered components showed no evidence of any preexisting structural, engine, or systems failures.

3. Weather was not a factor in this accident. The air traffic controllers that handled the accident flight were properly trained and provided appropriate air traffic control services. The emergency response for this accident was timely and effective. The accident was not survivable for the airplane occupants because they were subjected to impact forces that exceeded the limits of human tolerance.

4. The accident airplane entered the detail six maintenance check with an elevator control system that was rigged to achieve full elevator travel in the downward direction.

5. The accident airplane's elevator control system was incorrectly rigged during the detail six maintenance check, and the incorrect rigging restricted the airplane's elevator travel to 7° AND, or about one-half of the downward travel specified by the airplane manufacturer.

6. The changes in the elevator control system resulting from the incorrect rigging were not conspicuous to the flight crew.

7. The Raytheon Aerospace quality assurance inspector did not provide adequate on-the-job training and supervision to the Structural Modifications and Repair Technicians mechanic who examined and incorrectly adjusted the elevator control system on the accident airplane.

8. Because the Raytheon Aerospace quality assurance inspector and the Structural Modifications and Repair Technicians mechanic did not diligently follow the elevator control system rigging procedure as written; they missed a critical step that would have likely detected the misrigging and thus prevented the accident.

9. A complete functional check at the end of maintenance for critical flight systems or their components would help to ensure their safe operation, but no such check is currently required.

10. Flight 5481 had an excessive aft center of gravity, which, combined with the reduced downward elevator travel resulting from the incorrect elevator rigging, rendered the airplane uncontrollable in the pitch axis.

11. Air Midwest's weight and balance program at the time of the accident was not correct and resulted in substantially inaccurate weight and balance calculations for flight 5481.

12. Air Midwest's revised weight and balance program is also unacceptable because it may result in an inaccurate calculation of an airplane's center of gravity position.

13. Air Midwest did not adequately oversee the work performed by Raytheon Aerospace and Structural Modifications and Repair Technicians personnel at its Huntington, West Virginia, maintenance station and did not ensure that the accident airplane was returned to service in an airworthy condition.

14. When an inspector provides on-the-job training for a required inspection item (RII) maintenance task and then inspects that same task, the independent nature of the RII inspection is compromised.

1. Air carriers that use contractors to perform RII maintenance tasks and inspections need to provide substantial and direct oversight during each work shift to ensure that this work is being properly conducted.

2. Air Midwest did not have maintenance training policies and procedures in place to ensure that each of its maintenance stations had an effective on-the-job training program.

3. It is important that air carrier on-the-job training programs are developed in accordance with detailed guidance that emphasizes effective training practices.

4. Air Midwest did not ensure that its maintenance training was conducted and documented in accordance with the company's maintenance training program, which degraded the quality of training and inspection activities at the Huntington, West Virginia, maintenance station.

5. Air Midwest's Continuing Analysis and Surveillance System (CASS) program was not being effectively implemented because it did not adequately identify deficiencies in the air carrier's maintenance program, including some that were found by the Federal Aviation Administration (FAA) before the flight 5481 accident.

6. Accurate and usable work cards developed jointly by air carriers and aircraft manufacturers would improve the performance of maintenance for critical flight systems.

7. The FAA's failure to aggressively pursue the serious deficiencies in Air Midwest's maintenance training program that were previously and consistently identified permitted the practices that prevailed at the Huntington, West Virginia, maintenance station and during the accident airplane's detail six maintenance check.

8. Updated CASS guidance would help FAA aviation safety inspectors ensure that CASS programs are being effectively implemented at 14 CFR Part 121 air carriers.

9. Because proper aircraft maintenance is crucial to safety, air carrier maintenance training programs should be subject to the same standard that exists for other air carrier training programs (i.e., FAA approval).

10. The lessons learned by the FAA through its human factors research program need to be used to develop mandatory programs to prevent human error in aviation maintenance.

11. The use of average weights does not necessarily ensure that an aircraft will be loaded within its weight and center of gravity envelope.

12. The FAA's average weight assumptions in Advisory Circular 120-27C, “Aircraft Weight and Balance Control,” were not correct.

13. Periodic sampling of passenger and baggage weights would determine whether air carrier average weight programs were accurately representing passenger and baggage loads.

14. Current safety margins in air carrier average weight and balance programs do not ensure that aircrafts will be loaded within their manufacturer-certified and FAA-approved weight and center of gravity envelope.

15. Technology may enable air carriers to accurately determine weight and effectively control balance while maintaining operational efficiency.

16. Beech 1900 mechanics would benefit from using Airliner Maintenance Manuals with more specific instructions for critical flight system procedures.

17. Because the CVR can be one of the most valuable tools used for accident investigation, reliable daily test procedures are needed to safeguard CVR data.

Probable Cause

The NTSB determines the probable cause of this accident was the airplane's loss of pitch control during takeoff. The loss of pitch control resulted from the incorrect rigging of the elevator control system compounded by the airplane's aft center of gravity, which was substantially aft of the certified aft limit. Contributing to the cause of the accident were (1) Air Midwest's lack of oversight of the work being performed at the Huntington, West Virginia, maintenance station; (2) Air Midwest's maintenance procedures and documentation; (3) Air Midwest's weight and balance program at the time of the accident; (4) the Raytheon Aerospace quality assurance inspector's failure to detect the incorrect rigging of the elevator control system; (5) the Federal Aviation Administration's (FAA) average weight assumptions in its weight and balance program guidance at the time of the accident; and (6) the FAA's lack of oversight of Air Midwest's maintenance program and its weight and balance program.

OTHER BACKGROUND INFORMATION

Weight and Balance

This section discusses the accident airplane's calculated weight and balance, which was determined using Air Midwest's FAA-approved weight and balance program, and the loading conditions that existed on the day of the accident.

The accident airplane's last weighing on September 8, 2002, determined that the airplane's empty weight was 10,293 lb. The airplane's balance was determined by the location of the CG, which is usually described as a given number of inches aft of the reference datum. At the time of the airplane's weighing, the CG was determined to be located 282.1 in. aft of the reference datum, which corresponds to a CG location of 14.4% MAC.

According to the Air Midwest Beech 1900D (Beechcraft, 2004) load manifest form for flight 5481, the operating empty weight was 10,673 lb, the passenger weight was 3325 lb, the weight in the coat closet was 10 lb, the AFT1 cargo compartment weight was 775 lb, the AFT2 cargo compartment weight was 45 lb, the zero fuel weight was 14,818 lb, the fuel weight at takeoff was 2200 lb, and the gross takeoff weight was 17,018 lb. The flight crew made a 10-lb addition error when summing the weights that comprise the zero fuel weight. As a result, the calculated zero fuel weight was actually 14,828 lb, and the calculated gross takeoff weight was actually 17,028 lb. The Beech 1900D maximum gross takeoff weight is 17,120 lb. The load manifest form also indicated that the calculated CG index for the accident flight was 81 (37.8% MAC). The Air Midwest CG takeoff limits range from indexes of about 23–85 (16.7–39.2% MAC) when a Beech 1900D airplane is at a gross takeoff weight of 17,028 lb. The Beech 1900D aft CG limit is 40% MAC.

Table 3.13 shows information reported on Beech 1900D load manifest forms for flights flown by the accident airplane after the January 6, 2003 D6 maintenance check.

Table 3.13  Weight and Balance for the Last 10 Flights

Date	Gross Takeoff Weight (lb)	CG (Percent of MAC)	Number of Passengers	Cargo (lb)
01-08-03	17,028	37.8	19	820
01-08-03	16,278	25.9	15	470
01-07-03	15,118	19.6	6	195
01-07-03	13,303	17.3	2	70
01-07-03	14,528	19.0	3	120
01-07-03	12,618	12.6	0	45
01-07-03	14,653	20.8	7	345
01-07-03	14,278	23.7	9	320
01-07-03	14,413	24.2	5	455
01-07-03	13,318	13.6	0	45

Source: Adapted from National Transportation Safety Board, Loss of Pitch Control During Takeoff Air Midwest Flight 5481, Raytheon (Beechcraft) 1900D, N233YV, AAR-04-0, 2/26/2004.

The table shows that the accident flight was calculated to be the most aft loaded of all of the postmaintenance flights.

OTHER RELATED ACCIDENTS

Ryan Air Service Flight 103, Homer, Alaska

On November 23, 1987, Ryan Air Service flight 103, a Beech 1900C, 107 N401RA, crashed short of the runway during arrival at the Homer, Alaska airport. Flight 103 was a scheduled 14 CFR Part 135 flight operating from Kodiak, Alaska, to Anchorage, Alaska, with intermediate stops in Homer and Kenai, Alaska. The 2 flight crewmembers and 16 passengers were killed, and 3 passengers were seriously injured. The accident investigation revealed that the airplane was loaded with about 600 lb more cargo than the first officer had requested. The airplane was 400–500 lb over the airplane's maximum takeoff weight and 100–200 lb over its maximum landing weight. In addition, the CG position was 12–16% MAC aft of the allowable aft limit, and the flight crew did not comply with company and FAA procedures in computing the CG position. Even with an extreme aft CG, the airplane was able to take off and establish cruise flight. Evidence indicated that the flight crew lost control of the airplane as its flaps were lowered for landing.

The Safety Board determined that the probable cause of this accident was the failure of the flight crew to properly supervise the loading of the airplane, which resulted in the CG being displaced to such an aft location that airplane control was lost when the flaps were lowered for landing.

Two data points in the figure show the CG range for the flight 103 airplane.

ValuJet Airlines Flight 592, Everglades, Near Miami, Florida

On May 11, 1996, ValuJet Airlines flight 592, a Douglas DC-9-32, N904VJ, crashed into the Everglades, near Miami, Florida, about 10 min after takeoff from Miami International Airport. The 2 pilots, 3 flight attendants, and all 105 passengers were killed. Flight 592 was operating under 14 CFR 121 with a scheduled destination of the William B. Hartsfield International Airport, Atlanta, Georgia. A fire erupted in the airplane's class D cargo compartment. The fire was initiated by the actuation of one or more oxygen generators being improperly carried as cargo. The oxygen generators were prepared and packaged for carriage aboard flight 592 by SabreTech, a 14 CFR Part 145 repair station in Miami that performed heavy maintenance for ValuJet Airlines.

The Safety Board's investigation of the FAA's oversight of ValuJet Airlines revealed that inspectors from the Aircraft Maintenance Division within the Office of Flight Standards had recommended recertification of the airline 3 months before the accident. Specifically, in a February 14, 1996, summary report, the inspectors indicated, consideration should be given to an immediate FAR 121 recertification of this airline because of safety-related issues, such as the absence of adequate policies and procedures for maintenance personnel. The inspectors also indicated that the overall surveillance of ValuJet Airlines should be increased with special attention directed toward “manuals and procedures, structural inspections, the adequacy of the maintenance program, and shops and facilities.”

The Safety Board determined that the probable causes of this accident were (1) the failure of SabreTech to properly prepare, package, and identify unexpended chemical oxygen generators before presenting them to ValuJet for carriage; (2) the failure of ValuJet to oversee its contract maintenance program to ensure compliance with maintenance, maintenance training, and hazardous materials requirements and practices; and (3) the failure of the FAA to require smoke detection and fire suppression systems in class D cargo compartments. Contributing to the accident was the failure of the FAA to adequately monitor ValuJet's heavy maintenance programs and responsibilities, including ValuJet's oversight of its contractors, and SabreTech's repair station certificate; the failure of the FAA to adequately respond to prior chemical oxygen generator fires with programs to address the potential hazards; and ValuJet's failure to ensure that both ValuJet and contract maintenance facility employees were aware of the carrier's “no-carry” hazardous materials policy and had received appropriate hazardous materials training.

During its investigation of the ValuJet Airlines flight 592 accident, the Safety Board determined that the SabreTech mechanics had many shortcomings, including their failure to install safety caps, improper maintenance entries, use of improper tags, and inadequate communications between the maintenance shop floor and stores department. In its final report on the accident, the Board indicated that these shortcomings resulted from human failures that might have been avoided if more attention were given to human factors issues in the maintenance environment. As a result, the Board issued Safety Recommendation A-97-70 on September 9, 1997. Safety Recommendation A-97-70 asked the FAA to include, in its development and approval of air carrier maintenance procedures and programs, explicit consideration of human factors issues, including training, procedures development, redundancy, supervision, and the work environment, to improve the performance of personnel and their adherence to procedures.

On October 2, 2000, the FAA stated that it had reviewed the information contained in its report, “Human Factors in Aviation Maintenance and Inspection, Strategic Program Plan,” and that it was amending AC 120-16C, “Continuous Airworthiness Maintenance Programs,” to include information from the report. The FAA indicated that the revisions to the AC would also expand on CASS programs. On April 24, 2001, the Safety Board stated that it was difficult to determine whether the revisions to AC 120-16C would address the issues in this recommendation. On July 21, 2003, the FAA stated that Chapter 10 of AC 120-16D included human factors as part of initial training. On February 23, 2004, the Safety Board stated that, although AC 120-16D addressed many of the human factors issues related to training, procedures development, redundancy, supervision, and work environment, the AC would be significantly strengthened if the FAA added specific references to its available human factors information related to aviation maintenance operations, such as the Human Factors Guide for Aviation Maintenance and Inspection. The Board also stated that it continued to investigate major accidents in which incorrect maintenance led to a loss of control of the airplane and that human factors in aviation maintenance was an important safety issue. Pending the inclusion in AC 120-16D of references to FAA-published guidance on human factors in aviation maintenance, Safety Recommendation A-97-70 was classified “Open Acceptable Response.”

In its final report on the ValuJet Airlines flight 592 accident, the Safety Board determined that the FAA's surveillance of ValuJet before the accident did not include any significant oversight of the air carrier's heavy maintenance contractors, including SabreTech. The Board further determined that the FAA's limited oversight of ValuJet's maintenance contractors was not sufficient to detect potential problems. The ValuJet PMI was not required to conduct surveillance of the air carrier's contract maintenance facilities. Thus, the Board concluded that the lack of an explicit requirement for a PMI of a 14 CFR Part 121 air carrier to regularly inspect repair stations that are performing heavy maintenance for the carrier is a significant deficiency in the FAA's oversight of the carrier's total maintenance program. As a result, the Board issued Safety Recommendation A-97-74 on September 9, 1997. Safety Recommendation A-97-74 asked the FAA to ensure that Part 121 air carriers' maintenance functions receive the same level of FAA surveillance, regardless of whether those functions are performed in-house or by a contract maintenance facility.

On April 22, 1998, the FAA stated that it issued Flight Standards Handbook Bulletin for Airworthiness 96-05C, “Air Carrier Operations Specifications Authorization to Make Arrangements With Other Organizations to Perform Substantial Maintenance.” On December 15, 1997, the FAA indicated that the bulletin described detailed procedures to ensure that surveillance of each 14 CFR Part 121 air carrier's maintenance function entails the performance of the maintenance, the adequacy of the maintenance organization, the competency of maintenance personnel, and the adequacy of maintenance facilities and equipment, regardless of whether those functions are performed in-house or by a contract maintenance facility.

On July 23, 1999, the Safety Board stated that the FAA's actions met the intent of Safety Recommendation A-97-74 and classified it “Closed Acceptable Action.”

Fine Airlines Flight 101, Miami, Florida

On August 7, 1997, Fine Airlines flight 101, a Douglas DC-8-61, N27UA, crashed after takeoff from Miami International Airport. The 3 flight crewmembers and 1 passenger on board the airplane were killed, 1 person on the ground was killed, and the airplane was destroyed by impact forces and a postcrash fire. The cargo flight, which had a scheduled destination of Santo Domingo, Dominican Republic, was operated under 14 CFR Part 121 as a supplemental air carrier.

The accident airplane was loaded incorrectly, which resulted in an aft CG. Also, an incorrect stabilizer trim setting precipitated an extreme pitch-up at rotation. The Safety Board determined that the probable cause of this accident was the failure of Fine Air to exercise operational control over the cargo loading process and the failure of Aeromar (a cargo shipper) to load the airplane as specified by Fine Air. Contributing to the accident was the failure of the FAA to adequately monitor Fine Air's operational control responsibilities for cargo loading and to ensure that known cargo-related deficiencies were corrected at Fine Air.

In its final report on the Fine Airlines accident, the Safety Board discussed the Sum Total Aft and Nose (STAN) system, which is an electronic system installed on some cargo airplanes that allows flight crews to verify an airplane's weight and balance before departure. According to the report, the STAN system uses pressure transducers to convert main gear and nose gear shock strut air pressure to an electronic signal. The system then provides flight crews with a digital readout in the cockpit (on the flight engineer's instrument panel) of the airplane's gross weight and CG values. The Safety Board's final report on the Fine Airlines accident concluded that, if the flight crew had an independent method in the cockpit for verifying the airplane's actual weight and balance and gross weight, it might have alerted them to loading anomalies and prevented the accident. As a result, on July 10, 1998, the Safety Board issued Safety Recommendation A-98-49 to the FAA. Safety Recommendation A-98-49 asked the FAA to evaluate the benefit of the STAN and similar systems and require, if warranted, the installation of a system that displays airplane weight and balance and gross weight in the cockpit of transport-category cargo airplanes. On December 30, 1998, the FAA stated that it had completed an evaluation of the reliability of onboard weight and balance systems. The FAA found that some operators had reliability and accuracy concerns with such systems because of factors such as wind, ramp slope, oleo stiction, low hydraulic pressure, and asymmetrical gear loads. The FAA stated that the results of its evaluation did not support imposing a requirement to install a system that displays airplane weight and balance and gross weight in the cockpit of transport-category cargo airplanes. On January 11, 2000, the Safety Board stated that, on the basis of the FAA's evaluation and subsequent determination that onboard weight and balance systems do not yet meet the quality standards for a mandatory system, Safety Recommendation A-98-49 was classified “Closed-Acceptable Action.”

Emery Airlines Flight 17, Rancho Cordova, California

On February 16, 2000, Emery Airlines flight 17, a McDonnell Douglas DC-8-71F, N8079U, crashed in an automobile salvage yard shortly after takeoff while attempting to return to Sacramento Mather Airport, Rancho Cordova, California, for an emergency landing. Flight 17 was a scheduled 14 CFR Part 121 cargo flight from Sacramento to James M. Cox Dayton International Airport, Dayton, Ohio. The 2 pilots and the flight engineer were killed, and the airplane was destroyed.

The Safety Board's investigation of this accident determined that the bolt attaching the accident airplane's right elevator control tab crank fitting to the pushrod was improperly secured and inspected during either the airplane's most recent D inspection (heavy maintenance accomplished every 12 years) or subsequent maintenance. Tennessee Technical Services (TTS), an Emery Airlines maintenance contractor, performed the accident airplane's last D inspection between August 27 and November 17, 1999. Eight days after the D inspection was completed, a pilot reported increased control column forces. Emery maintenance personnel found that the left and the right elevator dampers were reversed, and the maintenance logbook indicated that the maintenance personnel moved the dampers to their correct positions. Emery maintenance personnel could have come in contact with the bolt at the control tab crank fitting while troubleshooting the reported problem. The Safety Board determined that the probable cause of the accident was a loss of pitch control resulting from the disconnection of the right elevator control tab. The disconnection was caused by the failure to properly secure and inspect the attachment bolt.

Safety Recommendation A-03-31

In its final report on the Emery Airlines flight 17 accident, the Safety Board discussed the accident airplane's last B-2 maintenance inspection (the second of four segmented inspections generally accomplished at 136-h intervals) on January 21 and 22, 2000. The B-2 inspection includes a visual check of the elevators and tabs for general condition, corrosion, leakage, and security of attachment. The DC-8 elevator assembly design requires the elevator control tab inboard fairing to be removed for maintenance personnel to inspect the inboard hinge fitting and the control tab crank fitting to pushrod attachment.

During postaccident interviews, Emery Airlines maintenance personnel stated that, when performing the accident airplane's last B-2 maintenance, they did not remove the elevator control tab inboard fairing or inspect the crank fitting to pushrod attachment. During public hearing testimony, witnesses from Emery Airlines indicated that its B-2 inspection was intended to be a general visual inspection that was to be accomplished without removing access or inspection panels or fairings. However, witnesses from TTS stated that removal of the control tab fairing was necessary to satisfactorily perform the tasks described on the Emery Airlines B-2 work card, even though that step was not specifically listed on the work card. The Safety Board noted that several air carriers have tried to clarify the intended scope of maintenance tasks by including, on their work cards, an enumeration of the actions that are necessary for the proper accomplishment of the associated work task. The Board stated that the inclusion of this additional detail on work cards, although not required by the FAA, should result in more consistent accomplishment of maintenance tasks. As a result, the Board issued Safety Recommendation A-03-31 on August 18, 2003. Safety Recommendation A-03-31 asked the FAA to Require all 14 CFR Part 121 air carrier operators to revise their task documents and/or work cards to describe explicitly the process to be followed in accomplishing maintenance tasks.

On January 12, 2004, the FAA stated that Safety Recommendation A-03-31 was limited to DC-8 operators only. The FAA also stated that the Boeing Company issued temporary revisions to the DC-8 AMM on May 8, 2002, and that these revisions explicitly described the maintenance task process to be followed. On January 23, 2004, the Safety Board classified Safety Recommendation A-03-31 “Open-Response Received.”

Colgan Air Flight 9446, Yarmouth, Massachusetts

On August 26, 2003, Colgan Air (doing business as US Airways Express) flight 9446, a Beech 1900D, N240CJ, crashed into water near Yarmouth, Massachusetts. The 2 flight crewmembers were killed, and the airplane was substantially damaged. The repositioning flight, which was conducted under 14 CFR Part 91, departed Barnstable Municipal Airport, Hyannis, Massachusetts, for Albany International Airport (ALB), Albany, New York.

Shortly after takeoff, the flight crewmembers declared an emergency and reported a trim problem. The airplane had reached an altitude of about 1100 ft msl. The flight crew requested to land on a specific runway, and the controller cleared the flight to land on any runway. No further transmissions were received from the flight crew. FDR data indicated that the airplane's airspeed continued to increase to about 250 knots and that the airplane's last recorded altitude was about 300 ft msl.

The accident airplane's FDR pitch trim control position parameter had been placed on the minimum equipment list (deferred maintenance) for the flight because the parameter was not calibrated. The Safety Board's airplane performance study for this accident determined that the recorded pitch trim control positions did not reflect the actual pitch trim control positions. The difference between the recorded and actual pitch trim control positions was about 2.1° ANU. According to the airplane performance study, the airplane began the flight with a pitch trim control position of about 0.5° ANU. Shortly after takeoff, the pitch trim control position moved to about 0.8° AND and remained there for about 10 s. The pitch trim control position then moved to about 5° AND and remained there for the rest of the flight. Calculations showed that the airplane would have required about 200 lb of aft (pulling) control force to maintain level flight in the out-of-trim condition.

The accident flight was the first flight after maintenance had been performed on the airplane. The maintenance work included replacement of both elevator trim tab actuators (because of a failed freeplay check) in accordance with Beech 1900D AMM section 27-30-06, “Elevator Trim Tab Actuator, Removal and Installation and the Actuator Cable Replacement.” The procedure required that the elevator be removed before the actuators were replaced. The Safety Board's investigation of this accident determined that the mechanics skipped this procedural step and replaced the actuators with the elevators installed. The mechanics thought that the forward elevator trim tab cable had become jammed or kinked during the replacement of the trim tab actuator. The mechanics then tried to replace the cable according to the procedure in Beech 1900D AMM section 27-30-04, “Elevator Trim Tab Cables, Removal and Installation.” A postaccident examination of a section of the forward elevator trim cable revealed evidence consistent with a misrouted cable. The Beech 1900D AMM and Colgan Air work cards did not include a trim system check at the end of the elevator trim tab cable procedure. Although the mechanics stated that they checked the trim system, evidence was consistent with the trim system operating in a direction opposite from the command of the trim wheel. The Safety Board's investigation of this accident revealed that the illustration of the forward elevator trim tab cable drum appeared backward in section 27-30-04 in the Beech 1900D AMM. On October 22, 2003, Raytheon Aircraft Company revised its Beech 1900D AMM elevator trim tab cable rigging procedure to show the correct illustration for the forward elevator trim tab cable drum (Beechcraft, 2004).

Federal Aviation Administration Airworthiness Directive 2003-20-10

On October 15, 2003, the FAA issued AD 2003-20-10, which applied to all Beech model 1900, 1900C, and 1900D airplanes. The FAA reviewed Raytheon Aircraft's current maintenance procedures for the elevator trim system and determined that the figures in the applicable maintenance manuals depicted the elevator trim cable drum at 180° from the installed position and showed the open, keyed side of the drum instead of the flat side of the drum. The FAA's review of the maintenance procedure also identified the need to add a step to visually confirm that the trim wheel position and the trim tab position were consistent. According to the FAA, such a check would detect and correct any problems with the elevator trim system installation before problems occur during operation. AD 2003-20-10 warned that an incorrectly installed elevator trim system component, if not detected and corrected, could result in difficulties in controlling the airplane or a total loss of pitch control. As a result, the AD required operators of Beech 1900 series airplanes to replace the incorrect figure in the elevator trim system maintenance procedures with the corrected figure, incorporate a temporary revision to the applicable maintenance manual that describes the elevator trim operational check, and perform an elevator trim operational check each time maintenance is accomplished on the elevator trim system.

CommutAir Flight 8718, Albany, New York

On October 16, 2003, CommutAir (doing business as Continental Connection) flight 8718, a Beech 1900D, N850CA, aborted takeoff from ALB because of an elevator control system discrepancy. The pilot stated that, during the takeoff roll, the control column would not move aft when the airspeed reached V1. The intended destination for the positioning flight, which was conducted under 14 CFR Part 91, was Westchester County Airport, White Plains, New York. The 2 flight crewmembers were not injured, and the airplane was not damaged. Maintenance was performed on the airplane 1 day before the incident, and the incident flight was the first postmaintenance flight. Maintenance records showed that a worn detent pin was replaced on the right thrust lever assembly. The mechanic who replaced the detent pin stated that he looked in the Beech 1900D AMM for a procedure to replace the pin or a procedure to access the thrust lever assembly. The mechanic indicated that the Beech 1900D AMM did not contain either procedure, so he looked in a CommutAir manual that contained a list of the manufacturer's field service kits, found a reference to a field service kit for “thrust lever, replaceable detent pin,” and obtained the kit. The field service kit installation instructions included a step to remove the thrust control assembly from the center pedestal, but the instructions did not provide information about how to access the thrust lever assembly so that it could be removed from the pedestal. The instructions also did not provide any reference to technical documents that contained instructions for the removal and installation of the thrust lever assembly. The mechanic stated that he accessed the thrust lever assembly by removing the elevator trim wheel and an access panel from the left side of the cockpit pedestal. No write-up was generated for the trim wheel removal, and no markings or tags were placed on the trim wheel to ensure proper reinstallation. The investigation of this incident determined that, when the elevator trim wheel was reinstalled, the mechanic did not properly align the elevator trim tab position indicator with the elevator trim tab position. As a result, the trim wheel was reinstalled incorrectly. The mechanic did not perform a functional test of the elevator trim control system, as required by AD 2003-20-10. The Safety Board and Raytheon Aircraft Company performed a functional check of the elevator trim control system. The check verified that the elevator trim tab position indicator did not accurately reflect the elevator trim tab position. Specifically, when the elevator trim tab position indicator was set at 3 units of ANU trim, the elevator trim tab was deflected 4.6° AND from its neutral position. (The elevator trim tab's full AND position is 5.5° from neutral.) The functional check determined that the elevator trim tab position indicator pointer was off by about 6 units, which equates to about 8.8° of elevator trim tab, or about 37% of the trim tab's full range of travel. After the cause of the elevator trim control system discrepancy was determined, a CommutAir mechanic properly aligned the elevator trim tab position indicator to the elevator trim tab position. Elevator and elevator trim control system functional tests were accomplished to verify that the systems were operating according to the requirements described in the Beech 1900D AMM. A high-speed taxi test and a flight test were accomplished to verify the functionality of the elevator and elevator trim control systems.

Notes

· Unless otherwise indicated, all times in this report are Eastern Standard Time based on a 24-h clock.

· Raytheon Aircraft Company acquired Beech Aircraft Corporation in February 1980.

· The ramp agents working this flight were employees of Piedmont Airlines, which runs US Airways Express ground operations at CLT.

· In calculating the weight and balance of the airplane, the flight crew used Air Midwest's standard adult weight figure (175 lb) for this child, who was 12 years of age.

· A cargo net separates the forward (AFT1) cargo compartment from the aft (AFT2) cargo compartment. A ramp agent stated that the cargo net was in place before the accident flight.

· An elevator is an aerodynamic control surface hinged to the back of the horizontal stabilizer. An elevator moves up and down to control the airplane's wing angle of attack, pitch, and climb. Normal elevator travel for the Beech 1900D is from 20° to 21° ANU to 14° to 15° AND, and the elevator neutral position is 0°. The elevator control check in the Beech 1900D involves moving the control column from the full forward position to the full aft position.

· In a properly rigged elevator control system, the FDR pitch control position parameter accurately reflects the elevator position. For the accident flight, however, the recorded pitch control positions did not reflect the actual elevator positions. The recorded pitch control positions were about 9° more AND than the actual elevator positions.

· According to Air Midwest's Beech 1900D Performance Manual, the rotation speed during takeoff is 105 knots.

· The three previous flight crews who flew the accident airplane also did not report anything unusual about the elevator control system. In fact, the first officer of the flight from Huntington, West Virginia (HTS), to Charlotte, North Carolina, on January 7, 2003, stated that “everything was normal” and “it was a good flying airplane.”

· The flight crew made a 10-lb addition error when summing the weights that comprise the zero fuel weight. This addition error was not a factor in the accident.

· The Air Midwest Flight Operations Procedures Manual at the time of the accident stated that an average weight of 175 lb could be used for each adult passenger during the winter and that an average of 80 lb could be used for children between the ages of 2 and 12 years.

· The reference datum is an imaginary vertical plane, arbitrarily fixed somewhere along the longitudinal axis of the airplane, from which all horizontal distances are measured for weight and balance purposes.

· According to the FAA's Aircraft Weight and Balance Handbook, the MAC is the chord of an imaginary airfoil that has all of the aerodynamic characteristics of the actual airfoil. The chord is drawn through the geographic center of the plan area of the wing. The location of the CG with respect to the MAC is important because it predicts the handling characteristics of the aircraft.

· The Beech 1900C is generally similar in size and capacity to the 1900D. The airplanes have numerous similar components and share a common FAA type certificate.

· For more information, see NTSB, Ryan Air Service, Inc., Flight 103, Beech 1900C, N401RA, Homer, Alaska, November 23, 1987, Aircraft Accident Report NTSB/AAR-88/11 (Washington, DC: NTSB, 1988).

· For more information, see NTSB, In-flight Fire and Impact With Terrain, ValuJet Airlines Flight 592, DC-9-32, N904VJ, Everglades, Near Miami, Florida, May 11, 1996, Aircraft Accident Report NTSB/AAR-97/06 (Washington, DC: NTSB, 1997).

· For more information, see NTSB, Uncontrolled Impact With Terrain, Fine Airlines Flight 101, Douglas DC-8-61, N27UA, Miami, Florida, August 7, 1997, Aircraft Accident Report NTSB/AAR-98/02 (Washington, DC: NTSB, 1998).

· For more information, see NTSB, Loss of Pitch Control on Takeoff, Emery Worldwide Airlines, Inc., Flight 17, McDonnell Douglas DC-8-71F, N8079U, Rancho Cordova, California, February 16, 2000, Aircraft Accident Report NTSB/AAR-03/02 (Washington, DC: NTSB, 2003).

· Additional information about this accident, NYC03MA183, can be found on the Safety Board's Website.

· The FAA indicated that, although the figures in the manuals were incorrectly depicted, the step-by-step instructions in the procedure, if followed correctly, would result in the proper installation and action of the elevator trim system. If only the figures were used, a reversing of the action of the elevator manual trim system could result.

· Raytheon Aircraft Company addressed these issues in its Safety Communiqué number 234, dated September 2003.

· According to 14 CFR Part 1, “V1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF [the speed at which the critical engine is assumed to fail during takeoff], at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.”

· When the elevator trim tab position indicator is at 0°, the elevator trim tab position should also be at 0°.

· The quality assurance inspector also did not perform a functional test of the elevator trim control system. The inspector stated that he did not know that the mechanic's work involved the trim system.

· Additional information about this incident, NYC04IA010, can be found on the Safety Board's website.

REVIEW QUESTIONS

1. Find your height and weight for your gender and age on the anthropometric data tables and see if the percentiles are the same or different. Do you think most peoples' percentiles would be the same or different?

2. Which anthropometric data table and what percentile would one use to design a safety shower and why?

3. What types of anthropometric data would you collect to aid you in the design of a comfortable airliner seat?

4. Do you feel current airliner seats are comfortable? Why/why not?

5. Why is anthropometric data important?

6. What anthropometric data would you collect for use in the design of a machine guard to prevent someone from having their hand caught in the machinery?

7. Which principle best accommodates the widest range of workers?

8. Which principle is used as the last resort?

REFERENCES

1. Beechcraft, R. (2004). Loss of Pitch Control Takeoff Air Midwest Flight. Charlotte: National Transportation Safety Board.

2. Bradtmiller, B. P. (n.d.). Applied Anthropometry Improves Fit. Retrieved April 2, 2014, from  https://ergoweb.com/complex-anthropometry-made-simple .

3. CDC. (2012). Anthropometric Reference Data for Children and Adults: United States, 2007–2010, Hyattsville, Maryland, October 2012 DHHS Publication No. (PHS) 2013–1602.

4. CPSC. (2014). Safety Standards for Full-Size Baby Cribs and Non-Full-Size Baby Cribs.  http://www.cpsc.gov/en/Regulations-Laws--Standards/Rulemaking/Final-and-Proposed-Rules/Full-Size-Cribs/ .

5. Helander, M. (2005). A Guide to Human Factors and Ergonomics 2nd edn. CRC Press.

6. Rhodes, H., Alphonse Bertillon: Father of Scientific Detection, In H. Rhodes (ed.) New York: Abelard-Schuman, p. 27, 1956.

ADDITIONAL SOURCES

1. http://www.cpsc.gov/en/Newsroom/News-Releases/1995/CPSC-Warns-Consumers-That-Used-Cribs-Can-Be-Deadly/ .

2. National Health Statistics Reports. Anthropometric Reference Data for Children and Adults: United States, 2003–2006. See more at:  http://www.talladaptations.com/2014/04/definining-tall-how-tall-is-tall.html#sthash.gpl1evHW.dpuf .