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Guidelines for Aircraft Boarding Chairs






Guidelines for Aircraft Boarding Chairs

A Technical Paper on the Design of Chairs Used Primarily for Enplaning
and Deplaning Physically Handicapped Passengers

Prepared for: ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD
1331 F Street, N.W.; Suite 1000; Washington, D.C.  20004-1111 (202) 272-
5434 (voice or TDD) 

Prepared by: AMERICAN INSTITUTES FOR RESEARCH 45 North Road Bedford, MA
01730 (617) 275-0800   


PREFACE

      Aircraft boarding chairs, wheelchair-like devices used to transport
disabled passengers onto airplanes, have been cited for safety and other
problems. The Architectural and Transportation Barriers Compliance Board
(ATBCB), in an effort to gain more information, distributed a survey on
boarding chairs through the Federal Register (49 Fed Reg 36210, September
14, 1984). Passengers using aircraft boarding chairs responded by
reporting complaints regarding safety, comfort, independent mobility, and
personal dignity. In response to these problems and complaints, the ATBCB
sponsored research to examine aircraft boarding chairs. The objective of
the research was to develop non binding guidelines aimed at improving
aircraft boarding chair design and use.

The ATBCB retained the services of a human factors engineering consulting
firm to perform the research and develop performance specifications. A
human factors team, which included human factors engineers and a
physician and physical therapist specializing in wheelchair design and
prescription, analyzed existing aircraft boarding chairs in both their
static state and during use. This approach permitted a comprehensive 
evaluation of the physical features of aircraft boarding chairs and the
"human-machine" interactions.  A draft advisory standard was  reviewed
by the ATBCB, industry experts, boarding chair  designers, airline
personnel, airport operators and aircraft  boarding chair users prior to
publication for public comment. 

On May 15, 1986, the ATBCB published a proposed  advisory standard in the
Federal Register (51 Fed Reg 17762), for the purpose of eliciting public
comment. Shortly after  publication in the Federal Register, a copy of
the proposal was  sent to each of a group of reviewers (rehabilitation
engineers, designers, air carriers, physical therapists, consumers, and 
governmental agencies) previously identified by the contractor and to
members of the National Transportation Facilitation  Committee (NTFC)
subgroup on Air Travel Accessibility. Together these groups include a
broad cross-section of air  carriers, wheelchair designers and
manufacturers, rehabilitation  engineers, government officials, and
disabled consumers. In  addition, copies were sent to the committee
developing  wheelchair standards convened by the American National 
Standards Institute (ANSI) from the Rehabilitation Engineering  Society
of North America (RESNA), past participants in the  Access to the Skies
conferences, Air Transport Association  (which represents major
carriers), Regional Airline Association  (which represents most of the
small regional carriers), Airline  Pilots Association of Flight
Attendants, National Air Carrier  Association, Society for Advancement
of Travel for the  Handicapped, Paralyzed Veterans of America, national
Council of  Independent Living Centers, Transport Canada, and 
Rehabilitation International USA among others.

The ATBCB received a total of five substantive comments addressed to
Docket Trans-1-86.  An analysis of the public comments and associated
changes to the May 15, 1986, published draft are provided in the sections
which follow.

On March 9, 1987, the Board's Standards Committee reviewed the final
report submitted by the contractor, including the incorporation of
comments submitted by those who responded to the Federal Register
publication.  The Committee  recommended that the product of this
research be published as  a technical paper.  The contents should be
viewed as the product of the contractor, distributed by the Board in the 
furtherance of its technical assistance mandate, not to be interpreted
as a determination by the Board as to the suitability of specific
provisions.

ANALYSIS OF PUBLIC COMMENTS

      In the May 15, 1986, Federal Register publication of the  proposed
advisory standard, the ATBCB included an invitation  for general comments
on the technical provisions and specific comments on the following four
issues: 
      1. Use of the 99th percentile male weight, as opposed to the  95th
      percentile male weight, in guidance associated with load  bearing; 

      2. The cost impact of the proposed advisory standard in terms  of
      new designs, existing boarding chair modifications and  boarding
      chair replacement; 

      3. Whether the final advisory standard, when published and  provided
      for public information, should also be included in the  Code of
      Federal Regulations even though it will be a non-binding standard; 
        
      4. The size of the area on which the downward force is  applied to
      the seat [see guideline 4.1(d)]. 

The limited number of comments was interpreted as a sign  of concurrence
with the proposed technical provisions given that  a large number of
comments typically signals disagreement and controversy over the
published material.  In fact, the majority of  comments received
supported the development of the document  and concurred on technical
details.  The Eastern Paralyzed Veterans Association (EPVA) stated, "In
general terms as this  standard relates to the nature of our membership,
we believe  that it is an excellent document" EPVA cited eleven (11)
specific  items it considered strong points.  One respondent who also is 
a physically handicapped traveler stated, "I was impressed with  the
comprehensive, competent effort evident in the draft."

It is worth noting that, although copies of the proposal were sent to
major airlines, aircraft manufacturers, and especially aircraft boarding
chair and wheelchair manufacturers, no comments were received from any
of these organizations.

Specific comments (paraphrased) and associated analyses by the human
factors engineering consultant are presented  below.  Comments received
which affirmed the contents of the guidelines have not been addressed.


PUBLIC COMMENTS AND ATBCB RESPONSES

      One respondent suggested that, instead of transferring the disabled
person laterally, a transfer from a ninety degree angle would be less
taxing and safer for aircraft personnel.  This suggestion relates to
transfer procedures versus boarding chair design.  The suggested transfer
method would require an area wider than the boarding chair in front of
the passenger's seat and involves standards for seating access, an
aircraft cabin design topic not addressed in the guidelines.  No change
was  made to the technical provisions.

Another respondent recommended use of the 95th (as opposed to the 99th)
percentile male weight in guidelines  associated with load-bearing
capacity.  Since only one respondent among all reviewers recommended use
of the 95th  versus the 99th percentile value, the 99th percentile male
weight value was retained in the load-bearing capacity guidelines.

A representative of the Minnesota State Council for the Handicapped
recommended inclusion of the advisory standard in the Code of Federal
Regulations even though it would be a non-binding standard.  The ATBCB
has determined that publication in the Federal Register and codification
in the Code of Federal Regulations could be misinterpreted as giving the
guidelines more weight than they are intended to have and has instead
decided to publish a technical paper as a source of information only.  

Another respondent suggested modifying Appendix draft test procedure
(ISO/173 SCI/WIC-220) to include a note stating that domestic standards
should be in effect within the year and will supersede the draft
standards at that time.  In concurrence, reference to the RESNA/ANSI
wheelchair standards was added to Appendix A.

One respondent pointed out that several federal government 
organizations. e.g., IRS and Social Security, use the word  "disabled"
exclusively to mean unable to earn an income by reason of impairment. 
The respondent suggested that it may  increase consistency in federal
terminology to substitute the  word "handicapped" instead.  The term
"disabled" had originally  been selected because many individuals find
the term  "handicapped" demeaning.  However, the reason cited for using 
the term "handicapped" was deemed justified and the change  was made.  

Another respondent felt that the topic of boarding chair comfort should
be given additional emphasis in the design  guidelines.  While
improvement in comfort is intrinsic to many of the guidelines, such as
recommendations on seat padding and use of armrests, the purpose of the
guidelines is to improve safety and accessibility.  Therefore, no
additional comfort performance guidelines were considered warranted or 
appropriate.

One respondent felt that folding backrests should be recommended.  The
document identifies the need for easy transfers and suggests folding
features where needed to meet the performance criteria [see 4.3(i)].  The
technical provisions have not been made more specific since they are
limited to performance guidelines.

Concerning Section 4.7(b), another respondent felt that the wording
indicated that four separate restraints should be used and believed that
four separate restraints would not be cosmetically acceptable to many
passengers.  The respondent suggested stating that do not necessarily
have to be four separate belts.  No change was made to the technical 
provisions since they specify restraint performance by virtue of support
functions, not a belt design.  It is preferred to allow  designers to
develop their own design solution which meets the four stated restraint
functions.  

One respondent believed that USDOT regulations have been in effect since
1979 which prohibit the carrying of disabled passengers up and down
stairs for access to the aircraft. It was found that, while the
regulation cited requires airport operators to provide certain boarding
equipment, it does not prohibit carrying passengers up stairs. 
Therefore, no changes were made to guidelines which reference aircraft
boarding via stairs.  

Regarding the four specific issues identified by the ATBCB for comment,
issues 1 & 3 were addressed above.  A single comment which concurred with
the document's contents regarding issue 4 was the only response to that
question.  No respondents addressed the cost impact issue; no boarding
chair manufacturers commented on any portion of the proposal.
    
Technical assistance with respect to this and related subjects is
available by writing to Office of Technical and Information Services,
ATBCB, 1331 F Street N.W.; Washington, D.C. 20004-1111 or by calling
(202) 272-5434.


CONTENTS -- INTRODUCTION
I. THE PURPOSE OF THE TECHNICAL PAPER
      1.  Why Boarding Chair Design Guidelines were Created
      2.  Application of the Guidelines
      3.  Scope of the Guidelines
      4.  How the Technical Paper is Organized
II. PROJECT BACKGROUND
      1.  The Need for Boarding Chair Guidelines
      2.  The Role of the ATBCB
      3.  How this Technical Paper was Developed
      4.  The Needs of Passengers and Airline Personnel
      5.  Goals for Boarding Chair Designers and Airlines
TECHNICAL PROVISIONS
PART 1 DEFINITION OF TERMS
PART 2 HUMAN AND ENVIRONMENTAL FACTORS
      2.1  Physical Characteristics of Users
      2.1  The Aircraft Boarding Environment
PART 3 GUIDELINES FOR BOARDING CHAIR OPERATION
      3.1  Mobility
      3.2  Safety
      3.3  Maintenance
      3.4  Storage
PART 4 GUIDELINES FOR DESIGN FEATURES
      4.1  General Physical Characteristics
      4.2  Seating
      4.3  Backrests
      4.4  Headrests
      4.5  Armrests
      4.6  Gripping Surfaces
      4.7  Restraints
      4.8  Footrests
APPENDIX A:  ADOPTED ISO PROCEDURES
APPENDIX B:  GUIDELINES FOR TRAINING  

INTRODUCTION
I. THE PURPOSE OF THE TECHNICAL PAPER

      This technical paper is intended to promote improvements in the
accessibility of facilities and services to disabled people. As described
in Section II, this particular document is part of a  larger effort by
the ATBCB to provide technical assistance on  eliminating architectural
and transportation barriers encountered  by disabled people.  The ATBCB's
mechanism for accomplishing  this goal with respect to aircraft boarding
chairs is the  publication of guidelines on their design and use.      

1. WHY BOARDING CHAIR DESIGN GUIDELINES WERE CREATED

      The guidelines presented in this paper do not constitute a  legally
enforceable regulation. Neither are they necessarily  exhaustive or
definitive.  Rather, since the ATBCB does not have legal jurisdiction
over such devices, this technical paper was  deemed the most effective
and appropriate means to promote  and facilitate improvements in aircraft
boarding chair design and  use.  The need for some form of guidance
arises from safety  problems and complaints regarding these chairs.  The
technical  provisions provide a range of guidance that is intended to
help  eliminate the most common problems encountered by disabled 
passengers and airline attendants.

The development of the guidelines is the result of several years work in
the aircraft boarding chair area.  Over several years, representatives
of the government, airlines, airport operators, aircraft boarding chair
manufacturers and wheelchair users have organized and worked together in
an effort to identify problem areas and improve boarding chair design and
use.

Many of the reported problems appear to be due to design while others
appear to be due to improper use of the devices. The latter may be due
to improper or inadequate training. Therefore, the technical paper
addresses both of these areas.

2. APPLICATION OF THE GUIDELINES

      Aircraft boarding chair designers and specifiers should find  the
comprehensive design guidance useful.  It can be utilized as the basis
for detailed design criteria or specifications to develop new designs,
or enhance an existing one, or to develop product specifications and
evaluation checklists.  Aircraft boarding chair design is an optimization
problem that requires tradeoff analysis so the guidance is
performance-oriented rather than prescriptive to allow for creative,
trade-off solutions.  Data on desirable  design features are based on
user testing and preferences to which the designer or specifier may not
otherwise have access.  

The technical provisions identify performance requirements for boarding
chairs that the purchaser should look for in devices on the market and
identifies how a specific feature should operate or be designed to
satisfy passenger and attendant needs. It can also be used to improve
boarding chair maintenance and airline attendant training. The technical 
provisions may also help to evaluate boarding chairs currently in use and
help determine whether they should be replaced with improved products. 
The guidelines may also be useful when designing training courses. 

In addition, aircraft designers may find the technical provisions useful
in designing seating layouts and interior  configurations which
facilitate boarding chair use.

3. SCOPE OF THE GUIDELINES

      The technical provisions apply to aircraft boarding chairs. They are
not intended to be applied directly to devices used for functions other
than aircraft boarding, such as on-board chairs used for in-flight
mobility or wheelchairs used for mobility within the airport terminal. 
However, some features desirable for boarding chairs may also be
desirable for on-board chairs and, where an on-board chair is used for
boarding and deplaning, the technical provisions are applicable.

The scope of the guidance provided in this technical paper is broad
enough to accommodate the many types of aircraft boarding chairs
currently in use.  The broad scope also supports the objectives of
sustaining or increasing the number of boarding chair manufacturers.  The
technical provisions are not intended to restrict design freedom.  The
performance-based guidelines are designed to eliminate safety hazards
while  permitting different and creative solutions to the engineering 
problems.

Not all of the guidance provided will or can be applied to a single type
or design of aircraft boarding chair.  This is due to the fact that such
chairs have competing design requirements such as maximum adjustability
and mechanical simplicity.  It is the responsibility of the user to
interpret the guidelines and determine where specific provisions apply. 
Technical assistance to supplement the technical paper and provide
guidance for interpretation and implementation will be available through
the ATBCB.

4.  HOW THE TECHNICAL PAPER IS ORGANIZED

      This document is divided into six parts.  Sections I and II provide
background information regarding the function of the guidelines and the
topic of architectural barriers and aircraft boarding chairs.  The
technical provisions themselves are in four parts.  Part 1 provides a
list of key terms; Part 2 defines the  physical characteristics of the
users, both the passenger and attendant, and the environment in which the
boarding chair is used.  The remainder of the provisions, Parts 3 and 4,
consist of detailed guidelines for boarding chair design.  Appendix A 
provides the version of the International Standard Organization (ISO)
test procedures which were used to define whether a specific performance
criterion was met. Appendix B contains guidelines on personnel training
and defines who should be trained, how often training should be
conducted, and the extent of training needed.

II  PROJECT BACKGROUND
1.  THE NEED FOR BOARDING CHAIR GUIDELINES

      There is a continuing need to provide disabled people with equal
access to places and services.  With improved recognition of rights of
disabled people, many public works and services have been modified to
provide access.  However, modifications have not included provisions for
complete unhindered access to aircraft.  While many airport terminals now
provide accessible restrooms, electric doors and ramps, few aircraft
manufacturers have designed accessible restrooms and airlines have not 
specified seating configurations with wide aisles to allow standard
wheelchair access. 

Because a standard wheelchair will not fit down the airplane aisle (17"
wide), it is necessary that some other device be used for boarding and
deplaning disabled passengers. It would seem that wheelchair
manufacturers solved the problem already by designing aircraft boarding
chairs (examples of existing boarding chairs are shown in figure 11-1).
However, aircraft boarding chairs do not fulfill all of the needs of the
passengers and  attendants.  Reports of accidents and near accidents
involving existing aircraft boarding chairs have indicated that 
improvements in aircraft boarding chair design are needed.  Guidelines
that provide for the basic needs of aircraft boarding chair users are
essential in eradicating existing architectural barriers for disabled
persons in air transportation.

2.  THE ROLE OF THE ATBCB

      Under section 502 of the Rehabilitation Act of 1973, as amended, the
Architectural and Transportation Barriers Compliance Board (ATBCB) is
vested with various functions relating to transportation barriers
confronting persons with disabilities (29 U.S.C. 792). First, the Board
is directed to investigate and examine alternative approaches to
eliminating  transportation barriers, particularly with respect to public 
transportation (including air, water, and surface transportation whether
interstate, foreign, intrastate, or local), and to determine what
measures are being taken by Federal, State, and local governments and
public and private agencies to eliminate such barriers (id. at 792 (b)(2)
and (3)). 

The Board is also required to "prepare plans and proposals for...actions
as may be necessary to the goals of adequate transportation...for
handicapped individuals, including proposals for bringing together in
cooperative effort, agencies, organizations, and groups working toward
such goals or whose cooperation is essential to effective and
comprehensive action" (id. at 792(c) (3)). The Rehabilitation,
Comprehensive Services, and Developmental Disabilities amendment of 1978
(P.L. 95-502) amended section 502 to provide the ATBCB with new functions
regarding transportation barriers.  Under the Amendments, the Board is
required to "Insure [sic] that public conveyances, including rolling
stock, are readily accessible to, and usable by physically handicapped
persons" (29 U.S.C. at 792(b)(8)).

The amendments also require that the ATBCB, in consultation with other
concerned agencies, to "develop standards and provide appropriate
technical assistance to any public or private activity, person or entity
affected by regulations prescribed pursuant to this title [Title V of the
Rehabilitation Act] with respect to overcoming...transportation...
barriers" (id. at  792(d)(3)). 

Since the ATBCB had received a number of reports of accidents or near
accidents involving the use of aircraft boarding chairs, the board was
concerned with the lack of standards that would ensure adequate safety
features, equipment and procedures necessary to secure the safe enplaning
and deplaning of physically disabled passengers by airport operators and
airline carriers.  This concern led to further research and the
initiative to develop this technical paper.

3. HOW THIS TECHNICAL PAPER WAS DEVELOPED

      The development of this document was based on human factors
engineering research and analysis.  The human factors engineering
research conducted to develop the technical provisions included full
consideration of the product users (disabled passengers and airline
attendants).  Research methods included a complete literature search,
static evaluations of the current product designs, dynamic observations
of the products in use in their intended environment (the airport
skybridge and aircraft), an assessment of the user's physiological needs,
and extensive interviews with wheelchair users, airline attendants and 
boarding chair designers. 

A set of problems, complaints, and concerns regarding boarding chairs was
derived from each of the techniques.  For each of the problems,
complaints, and concerns identified, as well as for potential problems
not actually observed or reported, a performance guideline was written
to help alleviate the problem. The guidelines were then classified by
topic (aircraft boarding chair feature, documentation issue, or training
concern) for inclusion in this technical paper.

Standards or standardized test procedures developed by industry consensus
groups such as the International Organization for Standardization (ISO)
or the American National Standards Institute (ANSI) have been
incorporated where available and appropriate.  Preliminary drafts were
circulated for review and comment to the National Transportation
Facilitation Committee (NTFC) subgroup on Air Travel Accessibility, 
members of the ATBCB, and over 60 reviewers selected for their expertise
in the subject area.

4. THE NEEDS OF THE PASSENGERS AND AIRLINE PERSONNEL

The guidelines address the needs of both disabled passengers and airline
attendants.  For the passenger, the boarding chair must provide adequate
body support and restraint.  Typically, a passenger is seated in the
boarding chair for approximately 5 minutes or less.  However, under 
circumstances when flight changes must be made, delays occur, or a
standard wheelchair is unavailable, the time spent seated in the boarding
chair can extend to an hour or longer.  In such cases, support, ease of
body repositioning and passenger independent mobility are vital. 
Regardless of the length of time spent seated in the boarding chair,
proper support can only be achieved if the boarding chair accommodates
the size of the passenger.

The airlines are concerned not only with the safety and comfort of the
passenger, but also with the safety and comfort of the airline attendant
and the ease of use of the aircraft boarding chair.  The attendant is
susceptible to injury if the transfer is performed incorrectly.  Often,
the size of the attendant in relation to the size of the boarding chair
and passenger makes a proper transfer difficult.  If the airline
attendant must assume an awkward position while boarding or deplaning a 
passenger, there is potential risk of injury for both the attendant and
passenger.

5. GOALS FOR BOARDING CHAIR DESIGNERS AND AIRLINES

It should be the goal of boarding chair designers and  manufacturers to
develop boarding chairs that minimize the  potential for injury and
increase overall comfort without  sacrificing ease-of-use and low cost. 
The airline should select  and purchase boarding chairs that best suit
the needs of the  passengers and attendants and provide adequate training
for  personnel.  This technical paper provides guidelines to help fulfill 
these goals.
TECHNICAL PROVISIONS
Part 1.  Definition of Key Terms

      Air Carrier Airport:  Airport that serve airlines utilizing aircraft
that seat fifty or more passengers or receive federal funds for  terminal
facilities. (REF:  49CFR Part 27, Section 27.5)

      Aircraft Boarding Chair:  Narrow, wheelchair-like device used to 
transport non-ambulatory passengers between the airport terminal gate,
via skybridge or aircraft steps, and the aircraft  seat. 

      Anthropometric:  Measurement of various human physical traits  such
as size, mobility (range-of-motion) and strength.

      Attendant:  Any individual who participates in the task of 
transporting transferring a passenger; can be an airline employee, a
service contractor, or a passenger's private assistant.

      Boarding:  The process of moving a passenger from the terminal, via
a skybridge or aircraft steps, to the aircraft seat. The boarding task
incorporates both transporting and transferring tasks.

      Boarding Chair:  Same as aircraft boarding chair.

      Channeling:  A groove used to direct or guide an attached 
mechanical part such as a strap in a specified direction.

      Clarity of Function:  Degree to which it is obvious how a boarding
chair feature should be used.

      Deplaning:  The process of moving a passenger from the aircraft 
seat, via a skybridge or aircraft steps, to the airport terminal.  The
deplaning task incorporates both transporting and transferring.  

      Extended Periods (period of time): A duration of 15 minutes or 
longer.

      5th Percentile Female: An adult woman who is smaller than 95% of the
female population for a given parameter. 

      Independent Mobility: The capability of moving without the help  of
another person while using a manual device.

      ISO (Test) Dummy:  A test apparatus, developed by the international
organization for Standardization (ISO), used as an equivalent human load
for wheelchair testing. The dummy is equivalent to a male weighing 220
lbs with a standing height of 78 inches and is constructed according to
Draft International Standard ISO-DIS 7176/11.

      Lifting Device:  Device used to elevate disabled passengers to the
aircraft cabin entrance level, eliminating the need to use a stairway
(REF:  49 CFR Part 27, Subpart D, Section 27.71 (a)(2)(v)) 95 Percentile 

      Male:  An adult man who is larger than 95% of the male population
for a given parameter.

      Quadriplegia:  Paralysis involving the trunk and all limbs.  

      Repositioning:  Shifting body position to redistribute weight. 


      Restrain:  To restrict body movement or keep the body under 
control.

      Skin Ulceration:  Breakdown of skin tissue caused by prolonged 
external pressure on the skin.

      Skybridge:  Ramp that connects the airplane cabin door to the 
airport terminal gate entrance.

      Standard Loading Mass:  A regulation soccer ball (European 
Football) filled with lead shot of approximately 3.0 mm to 4.0 in 
diameter to a specified weight (ISO definition).

      Standard Loading Pad:  A rigid circular object 100 mm in diameter
whose face has a convex spherical curvature of 300 mm radius with a 12
mm front edge radius. Pad should be faced with a layer of hard polyether
foam 2mm thick (ISO definition).

      Storage Location:  A place within the terminal (not on the 
aircraft) where boarding chairs are kept when not in use.

      3.0 Safety Factor:  A 200% increase in load capacity to ensure
safety. To calculate load capacity with a 3.0 safety factor, multiply the
baseline load by 3.0. This safety factor is generally accepted by
wheelchair manufacturers and the ISO.

      Transfer:  The process of lifting up and moving a passenger  from
one seated position to another.

      Transfer Board:  Accessory used to bridge the gap between the 
aircraft boarding chair and aircraft seat.  Passenger slides over  the
board thus reducing the time the passenger is held by the  attendants. 

      Transport:  The process of moving a passenger in a boarding  chair
whether it be by pushing, pulling or lifting.

Part 2.  Human and Environmental Factors
2.1 Physical Characteristics of Users 

      Designing aircraft boarding chairs requires close attention to the
physical dimensions and biomechanical capabilities (together termed
anthropometric) of the people who will use the devices: the disabled
passenger and the airline attendant.  The aircraft boarding chair, the
disabled passenger, and the airline attendant together form a system
which has several physical interrelationships or interfaces.  Designing
the interfaces which meet the anthropometric requirements of the users
will help  assure that the "Boarding Chair" system is easy and safe to 
operate.  

Body Dimensions

      The boarding chair user population includes both adult males and
females.  Therefore, the physical characteristics of the aircraft
boarding chair must accommodate a large range of human dimensions and
physical capabilities which varies from small females to large males. 
It is normal in engineering and  design to develop a product to meet the
anthropometric  requirements of 95% of the user population; meeting a
larger range which approaches 100% is usually infeasible or unwarranted. 
The range of anthropometric data is normally defined in terms of
percentiles.  To match the  anthropometric of approximately 95% of the
aircraft boarding chair user population, one needs to find minimum and
maximum  anthropometric values (for a given parameter) for the 5th 
percentile female and 95 percentile male, respectively. 

A percentile is determined as follows:

      For a 5th percentile female dimension, 5 out of 100 females would
      be smaller in that dimension.

The result of calculating parameter values for the 5th percentile female
and 95th percentile male is a practical range of physical 
characteristics that can be used as a basis for design. This approach
optimizes a design but may not meet as effectively the needs of 5% of the
(small) females and 5% of the (large) males in the user population. It
is not the intent to exclude any portion of the population.  In practice
a "5th - 95th" design usually accommodates more than 95% of the user
population.

Anthropometric data is presented in Figures 2-1 and 2-2 for use in
designing aircraft boarding chairs.  Figure 2-1 provides overall
dimensions for the 5th percentile female and the 95th percentile male. 
Figure 2-2 provides hand, arm, foot and head dimensions for the same
anthropometric range.  This data is referenced from the "Human Factors
Design handbook."  Additional data that relates specifically to the
aircraft boarding chair design problem is presented below.  The data
includes  body weight and strength.  Other anthropometric data can be 
found in NASA Reference Publication 1024, "Anthropometric Source Book,
Volume I:  Anthropometry for Designers." 

Body Weight

Maximum body weight determines the maximum load or stress on the
components and frame of the aircraft boarding chair:  A 99th percentile
male weighs 241 lbs.  A weight of 241 lbs. should be used as a design
basis with appropriate consideration  given to the safety factors in
design, since there are still many  people who weigh more than 241 lbs. 
Clearly, an aircraft  boarding chair can not be designed to accommodate
the  heaviest person imaginable.  Nonetheless, the designer is  advised
to maximize weight bearing capacity in aircraft boarding  chair design. 
The 99th percentile weight has been used, as  opposed to the 95th
percentile (which is 224 pounds), since the  potential for damage or
collapse of the aircraft boarding chair is  a significantly more serious
safety hazard than the failure of  other design features that affect
comfort more than safety.

Physical Strength and Endurance

Figure 2-3 illustrates the lifting strength and pushing force capacity
of the 5th percentile female.  A 5th percentile female in a standing
position is capable of lifting 74 pounds from a starting point 15 inches
off the ground.  The same individual can apply a horizontal force of 24
pounds to a handle device which is 33 inches off the ground.  Strength
declines continuously after initial application to the point that
strength is reduced to 25% of the original maximum capacity after four
minutes of force  application.  This data suggests that many disabled
passenger transfers will require two or more attendants or that only 
relatively strong attendants will be capable of performing all aspects
of the boarding task which culminates with a transfer (involving a lift). 
For this reason, strength and endurance requirements of the transporting
task should be minimized in  any given design.  Attendant training should
incorporate  procedures for transporting heavy passengers.

Physical Disability 

Aircraft boarding chairs should be designed for passengers with maximum
disability.  Therefore, a person with quadriplegia involving total loss
of arm and leg control and weakened head control should be considered as
the design basis.  Designs should also consider the potential needs of
individuals with missing limbs or deformities and/or involuntary
movements.

2.2  The Aircraft Boarding Environment

Aircraft are not optimized for wheelchair access. Aircraft cabin 
interiors and aisles, in particular, are designed to be narrow so that
the cabin can accommodate the maximum number of people.  The narrow aisle
is one of the major complicating factors in disabled passenger access. 
The other major factor is the continuing lack of skybridge connections
to airplanes at many smaller airports and with many commuter airlines, 
requiring the use of a stairway to board an airplane.  Stairways are
still used at some airports to board even large, wide-body airplanes;
especially during rush periods of the day when there  are not always
enough gates with skybridges available.  The  U.S. Department of
Transportation requires that operators at federally assisted airports
assure that adequate assistance is provided for enplaning and deplaning
handicapped persons.  Boarding by jetways and by passenger lounges are
the preferred methods for movement of handicapped persons between
terminal and aircraft at air carrier airports; however, where this is not
practicable, operators at air carrier airport terminals shall assure that
there are lifts, ramps, or other suitable devices not normally used for
movement of freight that are available for enplaning and deplaning
wheelchair users [49  C.F.R. 27.71 (a) (2) (v)].  A lift eliminates the
need to carry the passenger up a stairway.  However, lifts are not
consistently available and stairways are often used.

Since stairways will continue to ba common means of aircraft access for
the indefinite future, aircraft boarding chairs must be designed so that
they are safe to use on stairways. 

Stairway operation is the most critical mode of aircraft boarding chair
use.  In stairway operations, the dropping or tipping hazard is greatest
for the passenger, while the physical exertion requirement for attendants
is also at its peak.  Such operations also cause the disabled passenger
the greatest discomfort and  anxiety.  Boarding chair design and boarding
methods must be implemented which minimize the risk of injury.

Skybridges are the preferred boarding approach.  There are two basic
types of skybridges: stationary and movable.  Stationary skybridges have
a fixed floor inclination.  Movable skybridges have vertical and
horizontal adjustability and can result in a steeper overall floor
incline of up to 7.5 degrees (13%).  This slope angle of the connecting
ramps between skybridge sections may be as high as 13 degrees (25%).  The
movable skybridge is also narrower to enhance its movability but
satisfies the width requirement for wheelchair access.

Passengers who use wheelchairs normally travel down the skybridge in
standard-sized wheelchairs.  At the base of the skybridge they are
transferred into an aircraft boarding chair and brought onto the
airplane.  When a skybridge is used for access, the only potential
architectural barriers outside the aircraft are the inclination of the
skybridge floor and the gap at the threshold between the aircraft cabin
door and the skybridge.   A steep skybridge floor inclination requires
extra strength to  control the wheelchair or boarding chair (in the case
that the boarding chair is used from the terminal gate point).  Brakes
are required in case there is a need to stop and hold the boarding  chair
on the incline.  The threshold gap may require backward tilting of the
aircraft boarding chair to overcome it and has implications in wheel and
caster design.

The aircraft, depending on make and cabin configuration, may present an
access problem.  This is particularly true for small commuter aircraft. 
Although the cabin doorway and entranceway are wide enough to permit easy
entry into the aircraft with a boarding chair, the aisles between seats
are  narrow.  The narrow aisle width increases the danger of a 
passenger's limbs getting wedged between the boarding chair  and an
aircraft seat.  The narrowness of the aisle also presents a problem when
the passenger must be moved from the  boarding chair to the aircraft
seat.  The attendants are required to reach around the seated passenger
to lift him or her into the aircraft seat.  Space for the attendants'
arms in the area between the aircraft seats and the boarding chair is
tight.  Therefore, in cases where the aircraft seat armrest does not
pivot out of the way, transferring is further complicated.  A fixed
armrest necessitates that one attendant reach over the back of the 
aircraft seat and lift the passenger up over the armrest.  This presents
risk to the passenger and attendant.  Reaching around the back of the
seat does not permit the attendant to obtain secure grip of the passenger
and the approach is generally less gentle and comfortable for the
passenger.  The attendant also risks back injury due to poor posture
during lifting. 

Part 3.  Guidelines for Boarding Chair Use
3.1  Mobility  
      (a)  Number of Attendants.  When boarding, a minimum of two airline
      attendants should be  present to transport a passenger. If the
      passenger is particularly heavy or the attendant(s) is not
      physically strong, the transport task may require more than two
      attendants.  

      (b)  Time.  Once the boarding chair is at the aircraft entrance, the
      time to  prepare the boarding chair for passenger seating should be
      less  than two minutes.  

      (c)  Attendant Posture.  Transfers should not require the attendant
      to bend in awkward  positions.  Figure 3-1 illustrates the proper
      body posture that the boarding chair should permit.

      (d)  Passenger Posture.  The boarding chair design should ensure
      proper passenger posture.  Figure 3-1 illustrates a proper body
      posture for passengers seated in a boarding chair.

      (e)  Boarding Chair Orientation.  The boarding chair should not
      require tilting for movement  unless negotiating curbs, stairs, or
      similar barriers. 

      (f)  Turning.  The occupied boarding chair should be able to turn
      within the confines of the boarding environment and the aircraft
      cabin layout shown in figure 3-2.  Turning should not require
      tilting or rocking the boarding chair.

      (g)  Ease of Movement.  The force required to push and turn (on a
      level surface) a  boarding chair occupied by a 241 pound passenger
      (the 99th  percentile male) should not exceed 24 pounds (the maximum 
      force which can be exerted by a 5th percentile female).

      (h)  Ease of Transfer.  The boarding chair should be designed to
      facilitate the use of a transfer board.

      (i)  Vibration.  The boarding chair should be free of noticeable
      vibration when moving on a smooth surface such as a carpeted
      aircraft aisle.

      (j)  Alignment.  When the boarding chair is pushed in a straight
      line it should continue to track accurately along that path.

      (k)  Independent Mobility.  Boarding chairs designed to be used in
      the airport terminal should provide manual independent mobility for
      passengers who have manual independent mobility in their own
      wheelchairs.

      (l)  Locking Mechanisms.  Wheel locks should be accessible to the
      passenger. To the extent possible, the force required to
      engage/disengage locks should not exceed that which a passenger with
      limited hand and/or upper extremity function can exert.  Wheel locks
      should  hold the boarding chair (occupied by the 100 kg ISO dummy) 
      motionless when placed at a 13 degree angle (maximum skybridge ramp
      angle) and faced either uphill or downhill. Wheel locks should not
      cause tire damage or excessive wear.

3.2  Safety  

      (a)  Posture. The boarding chair should be designed so that the
      passenger and attendant maintain proper posture during the passenger 
      transport and transfer. (see figure 3-1).

      (b)  Support.  The boarding chair should provide adequate passenger
      body support for the full range of users, including quadriplegics
      and amputees.  The passenger should not require supplementary 
      seating or restraints outside those that are part of the boarding 
      chair.

      (c)  Restraints.  The restraining system should prevent the
      passenger from falling out of the boarding chair under all
      circumstances.

      (d)  Hinges and Locking Mechanisms. Hinges and locking mechanisms
      on movable and removable components should be located where they
      cannot pinch or damage the attendant's or passenger's skin or
      clothing.

      (e)  Releases.  Releases (for components such as locks and
      footrests) should  be located where they cannot be accidentally
      activated (released). Where accidental activation is possible and
      a safety  concern, a guarded release or two-step release procedure 
      should be used.
      (f)  Rounded Edges.  The boarding chair design should incorporate
      rounded edges on all components to avoid injury to passenger,
      attendant, or passerby and to protect the physical environment
      (stairway,  skybridge, airplane).

3.3  Maintenance

      (a)  Preventive Maintenance.  Preventive maintenance tasks, task
      frequency, and specific procedures should be specified by the
      manufacturer.   Maintenance task descriptions should include
      inspecting, cleaning, and performing minor repairs.  All parts
      requiring maintenance should be easily accessible.

      (b)  Cleaning.  Surfaces which come in contact with the passenger
      and  attendant should be cleaned easily and cleaned as frequently
      as  deemed appropriate by the airline.  Boarding chair hardware 
      components should be cleaned on a regular basis as deemed 
      appropriate by the manufacturer.  All surfaces and mechanisms 
      requiring cleaning, as specified by the manufacturer, should be 
      cleaned by airline personnel or the responsible contractor.

      (d)  Inspection.  Parts which are subject to wear should be easily
      accessed and inspected on a regular basis.  Inspection procedures
      should not require special knowledge, skills, tools, or equipment
      and should  be performed by airline personnel or the responsible
      contractor.

      (e)  Replacement of Parts.  Damaged or missing parts which are not
      part of the chair frame (main structure) should be available for
      purchase and replaceable according to paragraph 3.3(g).

      (f)  Tools.  Only common tools should be required to perform
      maintenance tasks.  Specialized or one-of-a-kind tools should not
      be required for maintenance tasks performed by airline personnel. 
      
      (g)  Spare Parts.  Components of the boarding chair which are easily
      replaced (such as fasteners and bearings) and not part of the chair
      frame (main structure) should be made readily available as spare
      parts stocked by the manufacturer and at least one other source.  
      Available spare parts should be easily replaced.

3.4  Storage 

      (a)  Damage Resistance.  Boarding chairs should be of durable
      construction to avoid damage during storage.  Fabric on the chairs
      should be  resistant to tears, stains, or fading which may occur
      during  storage.

      (b)  Compactness.  When possible, boarding chair design should
      utilize adjustable  features which maximize compactness during
      storage.

      (c)  Collapsibility. Collapsible boarding chairs should lock in the
      collapsed position. Collapsible chairs should be easy to move when
      in the collapsed position. Reconfiguring the chair for use should
      be achieved easily and quickly.

      (d)  Removable Items.  To avoid loss or theft, removable components
      should be attached to the chair during storage, though not
      necessarily in their operational configuration. Configuring
      components for storage should be performed easily and quickly. 
      Small parts such as nuts and bolts) should remain fastened to the
      chair  during storage.

      (e)  Loose Items.  Loose items (such as restraints) should have a
      clear method for storage so they do not get lost or damaged.

      (f)  Time Requirements.  Time required to prepare the boarding chair
      for storage should not exceed two minutes.

Part 4.  Guidelines for Design Features

4.1  General Physical Characteristics

      (a)  Overall Dimensions.  The boarding chair should, to the extent
      possible, be sized to  comfortably accommodate 95% of the passenger
      population (see  section 2.1), but should not exceed the dimensional
      limitations  of the aircraft on which it is to be used.  The
      narrowest part of  the aisle (17") is generally at the aircraft seat
      armrest height but  wide ___________________.

      (b)  Overall Weight.  Overall weight should be minimized.

      (c)  Load Capacity.  The boarding chair should support 723 lbs (the
      99th percentile male body weight with a 3.0 safety factor).

      (d)  Static Stability.  The boarding chair should not structurally
      deflect (bend), rock or tip from the placement of a 241 lb vertical,
      downward force at any point on the seat.  The object should be a
      rigid circular object 4 inches in diameter (see ISO Definition for
      Standard Loading Pad).  The boarding chair should also meet the 
      requirements for static stability as defined in Draft International 
      Standard ISO/Dis7176/1 (See Appendix A).

      (e)  Static and Impact Strength.  For boarding chairs, the following
      sections of Draft International Standard ISO TC173/SCI N3,"Static
      and Impact Strength Test", should be applied:
           (1)  1-5.7 (Background Test Information)
           (2)  6.1.1 Armrest Downward Static Load Test
           (3)  6.1.2 Push handle(s) Downward Static Load Test
           (4)  6.1.3 Footrest Downward Static Load Test
           (5)  6.1.4 Tipping Levers Downward Static Load Test
           (6)  6.1.5 Hand Grip Static Load Test
           (7)  6.1.6 Armrest Upward Static Load Test
           (8)  6.1.7 Footrest Supports Upward Static Load Test
           (9)  6.1.8 Push Handle(s) Upward Static Load Test
           (10) 7.0  Conditions for Acceptance After Static Strength
           Tests
           (11) 8.1.1 Seat Impact Strength
           (12) 8.1.2 Backrest Impact Strength
           (13) 8.2.1 Drop Test Impact Strength
           (14) 8.2.2 Rolling Test Wheels and/or Castors Impact Strength

For all above tests, the 220 lb ISO dummy should be used (See  Appendix
A for test procedures).

      (f)  Adjustable.  Where practical, adjustable features should be
      used to increase safety, support and comfort.  The features should
      be easy to  adjust and should not sacrifice chair and passenger
      stability.

      (g)  Removable Parts.  To avoid loss, the number of removable parts
      should be minimized, or if possible, eliminated.

      (h) Construction Materials.  Construction materials should be
      durable, damage resistant, fire retardant and low and high
      temperature resistant.  

      (i)  Protective Features.  The boarding chair should have protective
      features (such as rounded edges and bumpers) to avoid damage to the
      aircraft boarding environment.

4.2  Seating

      (a)  Function.  Seating should accommodate 95% of the passenger
      population and should be designed to facilitate transfers by
      providing  unobstructed access for lifting.

      (b)  Dimensions.  Seating should be sized according to the
      dimensions given in figure 4-1.
      
      (c)  Strength.  Seats should support a weight of at least 723 pounds
      (the  weight of the 99th percentile male with a 3.0 safety factor)
      and should meet the requirements in guideline 4.1 (e).
      
      (d)  Location.  Seat surface height (compressed) should be 17-19
      inches to match the height of aircraft seats and should incline 5
      degrees to increase body restraint (See figures 4-2 and 4-3).
      
      (e)  Shape.  Seat shape should provide passenger body support and 
      restraint and distribute body weight evenly to avoid the risk of 
      skin ulceration.  Seat shape should not hinder passenger transfers.

      (f)  Material.  Seat material should be water repellent, stain
      resistant, fire  retardant, non-abrasive, durable, cleanable, and
      aesthetic. Based on ISO research, the cushion should be constructed
      of a  good quality foam at least 2 inches thick with a indentation
      load  deflection (ILD) of 70 as measured by ASTM Designation D 
      1564-71, "Standard Methods of Testing Slab Flexible Urethane  Foam." 
      The cushion cover should be a color which is low in heat absorption
      so that the cover does not overheat (if left in the sun) and cause
      thermal trauma to passengers.

      (g)  Texture.  Seat material texture should not be so rough (high
      friction) that it hinders passenger body positioning.

      (h)  Cushioning.  Cushioned seating should be provided to distribute
      body weight  evenly and to protect against skin ulceration.  Seat
      cushions  should not strike the back of the passenger's knee,
      thereby  avoiding blood flow restriction and cause nerve damage (See 
      Figure 4-4).

      (i) Construction.  Seats should keep their shape, even after
      extended use.



4.3  Backrests

      (a)  Function  Backrest should support the passenger and aid in
      restraining the passenger's torso and be comfortable.

      (b)  Dimensions.  Backrests should be sized according to dimensions
      given in  figure 4-1.  Note:  Where boarding chairs must be carried
      up  stairways (i.e., at locations which are not air carrier
      airports) the  backrest height should be a minimum of 38 inches. 
      Refer to  Section 4.4, Headrest.

      (c)  Orientation.  The angle between the base of the backrest and
      the seat should  be 90 degrees. For comfort purposes, the middle to
      upper  portion of the backrest may be gradually reclined as shown
      in  Figure 4-1.

      (d)  Strength.  Backrest should meet the requirements in guideline
      4.1 (e).

      (e)  Shape.  Backrests should be constructed to provide support, aid
      in  restraining a passenger, and avoid interference with passenger 
      transfers.
      
      (f)  Material. Backrest material should be water repellent, stain
      resistant, fire retardant, non-abrasive, durable, cleanable, and
      attractive. For aesthetic purposes, cover material used on the
      backrest should  be coordinated with the material used on the seat. 

      (g)  Texture.  Backrest cover material should not be so rough (high
      friction) that it hinders passenger body positioning.

      (h)  Cushion.  The backrest cushion should provide a firm surface. 
      However,  cushion firmness should not compromise skin protection. 
      
      (i)  Folding.  Folding backrests should collapse in a manner which
      does not  hinder transfers. Hinging mechanisms should automatically
      lock  in place when the backrest is fully extended and folded.

      (j)  Adjustment Mechanisms.  The method of operation of backrest
      adjustment mechanisms  should be readily apparent and easy to
      perform.  

4.4  Headrests

      (a)  Function.  Headrests should be provided to support the head,
      preventing the head from falling back or to the sides.

      (b)  Dimensions.  Headrests should be dimensioned to accommodate 95%
      of the user population.  (see figure 2-2)

      (c)  Location  Headrests should support the passenger's head at ear
      level.

      (d)  Strength.  Headrests should support a force of 30 lbs (the
      average weight of a male's head with a 3.0 safety factor) applied
      in the aft and  both lateral directions and should meet the
      requirements in  guideline 4.1(e).

      (e)  Material.  Headrest material should be water repellent, stain
      resistant, fire  retardant, non-abrasive, durable and cleanable.  

      (f)  Ease of Transfer.  The position of the headrest should be one
      which does not require an attendant to assume an awkward body
      position (with  poor leverage) during a transfer.  (e.g., the
      headrest could fold  or retract out of the way).

4.5  Armrests

      (a)  Function.  Armrests should be provided to support the
      passenger's arms.  Armrests should provide a firm gripping or
      resistance surface for  passengers to push against when
      repositioning themselves and  to assist in protecting the passenger
      from injury.

      (b)  Dimensions.  Armrests should be sized to accommodate 95% of the 
      passenger population for the dimension of arm length. (see  figure
      2-2).

      (c)  Location.  Armrests should be located at the seated elbow
      resting height optimized for 95% of the passenger population.  The
      armrests  should be adjustable over the range of 7.0-12.0 above the
      seat  surface.

      (d)  Strength.  Each armrest should support 241 lbs (the weight of
      the 99th  percentile male) and meet the requirements in guideline
      4.1(e).

      (e)  Material.  Armrest material should be durable, non-slip, water
      repellent,  stain resistant, fire retardant and cleanable.

      (f)  Orientation.  Armrest should be oriented to provide vertical
      and lateral arm  support.

      (h)  Adjustability/Removability.  Armrests should be removable or
      fold away. Adjustable, folding, and/or removable armrests should
      have locking and quick release mechanisms that are accessible to the
      passenger.

4.6  Gripping Surfaces

      (a)  Function.  Clearly identified gripping surfaces should be
      provided for  attendants to hold onto during the transport of a
      passenger.   

      (b)  Number.  Gripping surfaces should be provided where needed for 
      pushing, pulling, and lifting, as determined by defined operating 
      procedures.  As many gripping surfaces as possible should be 
      provided to adapt to a variety of boarding chair-to-attendant 
      orientations.  As a minimum, the number of gripping surfaces  should
      fulfill the requirements of paragraph 4.6(d).

      (c)  Dimensions.  Gripping surface size should accommodate the 95th
      percentile  male hand for width and length and the 5th percentile
      female  hand for diameter (see Figure 2-2).  Physical clearance
      between  the gripping surface and surrounding boarding chair parts 
      should be provided for the 95th percentile male hand.

      (d)  Location  As a minimum, gripping surfaces should be provided
      on the  boarding chair frame near the shoulders and feet of the
      seated  passenger.  The pushing surface should be located at the 
      attendants' standing elbow height, 40-42 inches optimized for  the
      50th percentile of the total user population.  (see Figure 2-1)

      (e)  Material.  Gripping surface material should be textured, water
      repellent, stain resistant, temperature resistant, fire retardant
      and durable.   Gripping surface materials should be firmly attached
      to avoid  turning, slipping, or accidental removal.

      (f)  Strength.  Each gripping surface should be capable of
      supporting (for all  possible load applications) the total weight
      of the boarding chair  plus 723 lbs (the 99th percentile male weight
      with a 3.0 safety  factor).  Each gripping surface should meet the
      requirements in  guideline 4.1(e).

      (g)  Body Posture  The attendants should not be required to assume
      awkward  positions (such as twisted back or bent wrists) while
      pushing or  lifting the chair.

      (h)  Skin Protection.  The attendant's hands should be protected
      from contact with  surrounding surfaces such as aircraft walls,
      seats, doors, or  stairways while holding onto the gripping
      surfaces.  

      (i)  Clarity of function.  Gripping surfaces should be readily
      apparent to the attendant.
      
      (j)  Chair Stability.  When the boarding chair, occupied by the 5th
      percentile female  or 99th percentile male, is pushed, pulled or
      lifted in the  direction of travel by the gripping surfaces, the
      boarding chair  should not tip or fall to either side.

4.7  Restraints

      (a)  Function.  Restraints, such as safety belts, should be used to
      secure a passenger in the boarding chair and ensure the safety of
      the  passenger during transportation.

      (b)  Placement.  Restraint should be designed to securely support: 
           (1)  Torso
           (2)  Pelvis
           (3)  Knees
           (4)  Feet.
Restraint placement should ensure that the passenger's body is 
centralized and stabilized in the boarding chair.  Restraints  should be
attached rigidly to the boarding chair frame and held  in their intended
position of use by their method of attachment,  channeling or some other
means.  Pelvic straps should be  attached at a 30-45 degree angle from
the seat connected at the  seat and back joint to hold the pelvis against
the back of the  boarding chair (see Figure 4-5)

      (c)  Material.  Material should be stain resistant, non-abrasive,
      fire retardant,  water resistant, durable, cleanable and attractive. 
      

      (d)  Texture.  Material used should not cause skin irritation or
      promote skin  ulceration at contact points.

      (e)  Fastening Mechanisms.  Restraint connect and release mechanisms
      should require as  few steps as possible to be secured effectively
      (1-2 steps is  optimum).  Fastening mechanisms should connect and
      release  quickly and be within the passenger's reach. Fastening
      mechanisms should be able to be released by individuals with
      impaired strength and reduced hand and arm dexterity.

      (f)  Adjustability.  Restraining devices should be easily adjustable
      in size to  accommodate the body dimensions of passengers ranging
      from  the 5th percentile female to the 95th percentile male (see
      Figure  2-1)  Once a restraining device has been adjusted to fit a 
      passenger, any excess portion of a strap should not interfere  with
      boarding chair operation and create a potential hazard for  tripping
      or catching.

      (g)  Clarity of Function.  Restraining device method of use and
      connection should be obvious. Incorrect use should be impossible.
      The need for instructions on use should be minimized. Coding
      techniques,  such as color or shape should be used to simplify the
      identification of interacting parts (see Figure 4-6).

      (h)  Strength.  Restraining devices should withstand a force of 723
      pounds (the  weight of the 99th percentile male with a 3.0 safety
      factor) as  shown in Figure 4-7.

      (i)  Storage.  When not in use, restraining devices should not
      interfere with  chair movement.  Restraining devices not in use for
      a particular  passenger should not interfere with operation or cause 
      discomfort to the passenger.  The method of restraint storage should
      be obvious and efficient.

4.8  Footrests.

      (a)  Function.  Footrests should be provided to support and
      stabilize the  passenger's feet and legs during transport.  The
      footrest should  prevent the passenger's foot from slipping off the
      footrest when  tilted back and should prevent the passenger's feet
      from sliding  sideways or forward under all circumstances.

      (b)  Dimensions.  Footrests should be a minimum of 4.3 inches in
      width for each  foot.  The depth of the footrest should maintain a
      secure and  comfortable foot posture for extended periods.  (See
      Figure 2-2).

      (c)  Location  The contact point between the foot and footrest
      should be  located at an adjustable distance over the range of 16.0
      to 29.0  inches from the front of the seat as shown in figure 4-8. 
      
      (d)  Orientation  Footrests should allow the passenger's foot and
      lower leg to rest  in the position typical to that person (this may
      not be directly  side by side).

      (e)  Adjustability.  Footrests should be easy to adjust.

      (f)  Strength  During operation, a collision between the footrest
      and a  surrounding object should not cause passenger injury,
      alteration  of passenger leg position, or damage to the boarding
      chair.   Footrests should meet the requirements in guideline 4.1(e).
      
      (g)  Support.  Footrests should provide complete support to the
      passenger's  feet and lower legs.  Foot supports should prevent the 
      passenger's feet from slipping beneath the boarding chair under  all
      operating conditions.

      (h)  Material  Footrest material should be durable, resistant to
      cracking  chipping, or splintering, temperature resistant and
      cleanable.

      (i)  Padding  Footrests should not promote skin ulceration even
      after  prolonged contact.  Padding should be used, as necessary, to 
      provide a comfortable contact surface; particularly in the area of 
      the lower leg.

      (j)  Ease of transfer.  Transfer of passengers should not be impeded
      by footrest size  or location.  If necessary, footrests should be
      retractable or  swing away to ensure attendant and passenger safety. 
      

Appendix A:  Adopted ISO Test Procedures

      Note:  Test procedures have been paraphrased and adapted for 
applicability to aircraft boarding chairs.  Although several testing 
protocols were considered practicable, the ISO protocol has  been
designated to provide testing consistency and to facilitate  product
performance comparisons.  For comparison with  comprehensive wheelchair
testing procedures, see the complete  Draft ISO Test Procedure Document,
ISO/173 SCI/WC1-220 and  similar domestic version pending publications
by RESNA/ANSI.

      A1  Scope  This part of ISO 7176 specifies a method for determining
      the  static, impact and fatigue strength of manual wheelchairs.

      A2  References  ISO 6440 Wheelchairs - Nomenclature, Terms and
      Definitions  ISO/DIS 7176/11 "Wheelchairs - Part II:  Test Dummies" 
      
      A3  Definitions  For the purpose of the part of ISO, 7176, the
      definitions of ISO  6440 apply.

      A4  Test Principles  The Static Tests are intended to assess the
      static strength of the  wheelchair and its component parts under the
      high levels of loading that occur only occasionally.  The evaluation
      of boarding chairs does not require destructive  tests. 

      A5  General Conditions  The following conditions shall be
      established and recorded  during the testing of boarding chairs in
      accordance with this  evaluation protocol.  
A5.1  The boarding chair shall be fully equipped for normal use.   

A5.2  If the wheelchair has pneumatic tires, the air pressure in  them
shall be adjusted in accordance with the directions set  forth by the
manufacturer/supplier.  If a pressure range is  specified, the highest
recommended pressure shall be selected. 

A5.3  The seat unit, if adjustable, shall be set to correspond to a 
natural sitting posture.  The leg support/footrest, if adjustable, 
should be positioned 50 mm above the ground.  Horizontally  adjustable
seat units shall be set at their mid position.  If  adjustable, the slope
of the seat relative to the horizontal shall  be as close as possible to
4 degrees, and the slope of the  backrest relative to the vertical shall
be as close as possible to  10 degrees.  The angle between the seat and
leg support shall  be as close as possible to 10 degrees.  The angle
between the  seat and leg support shall be as close as possible to 90 
degrees.  Wheelchairs with fore/aft adjustment on the rear  wheels shall
be adjusted at their middle position.

A5.4  The wheelchair shall be inspected to insure that:
      (1)  All supporting wheels are contacting the ground
      (2)  All wheels meet the specified alignment tolerance limits  
      (3)  The folding mechanism (if it exists) fully and readily deploys 
      (a wheelchair with a folding x-frame should fold under the 
      influence of gravity when laid horizontally)
      (4)  All detachable components detach and reassemble readily   
      (5)  The tires are firmly seated in their rims
      (6)  There are no loose spokes (if existing)

A5.5  The dimensions shall be recorded before the  commencement of the
tests and again after all tests have been  completed.  Before any
measurements are taken, any free play  in the structure of the boarding
chair which might affect the  measurements should be taken up by loading
the wheelchair  with appropriate ISO dummy (Refer to ISO/DIs 7176/11). 
Measurements should be made from well-defined points on the  structure
to give maximum indication of any deformation that  might occur as result
of the tests.

A5.6  Immediately before commencing each test procedure the components
for which the test was conducted shall be thoroughly inspected.  Any
visible defects shall be noted, and  any defects considered sufficiently
significant as to affect further testing shall, if possible, be
rectified.

A5.7  References to an appropriate standard test dummy shall  mean a test
dummy of 220 lbs constructed according to the  details in ISO/DIS 7176/11
of this standard.

A6.1.1  Armrests Downward Static Load Test 
      A downward force of 147ON, at 45 degrees, shall be applied to the
upper surface of both armrests simultaneously with a load fixture at the
front of the horizontal surface of both armrests. For tests on chairs
with removable armrests, check that armrests remove and reinstall
correctly.

A6.1.2  Push handle(s) Downward Static Load Test 
      A vertical downward force of 197ON shall be applied to the  push bar
or both push handles simultaneously. If the wheelchair is equipped with
a push bar, the force is applied to  the center of the push bar. If there
are separate push handles  the force is applied simultaneously by placing
a bar over the  push handles and applying the force, using the standard
loading  pad, midway between the handles. 

A6.1.3  Footrest Downward Static Load Test 
      A downward force of 132ON shall be applied once vertically downward,
to the center of each footrest plate.  If the footrest is of one-piece
construction, the specified force shall be applied to its center, using
the standard loading pad.  If the wheelchair has adjustable knee angle
leg rests they shall be adjusted as close as possible to 90 degrees
between the seat and leg rest.   Adjustable height footrests shall be
extended to their lowest position of 50 mm above the ground, whichever
is higher. If the footplate is adjustable, adjust to 90 degrees to the
leg reference plane. During this test, slippage of adjustment shall not
exceed  25 mm. The movable caster shall be placed in its normal trailing
position.

A6.1.4  Tripping Levers Downward Static Load Test 
      A vertical downward force of 147ON shall be applied to each tipping
lever in turn.  The force shall be applied over a length of 50 mm at the
end of each tipping lever.  This applies to any  rearward projection that
might be used as a foot tipping lever. 

A6.1.5  Hand Grip Static Load Test  
      A force of 160ON shall be applied once to each handgrip using a
loading fixture.  The force should be applied for 10 seconds without the
handgrip pulling off. 

A6.1.6  Armrests Upward Static Load Test  
      An upward force of 160ON shall be applied at 10 degrees to the 
vertical, outward to the side.  Force shall be applied to the underside
of each armrest simultaneously, in the middle of the  armrest, using 50
mm webbing or strap material.  For test on  chairs with removable
armrests check that armrests remove and  reinstall correctly.  Note: 
Vertically pivoting or non-locking  armrests should pivot or remove
easily and will therefore pass  the test with regard to safety
considerations.  

A6.1.7  Footrest Supports Upward Static Load Test  
      A vertical force of 43ON shall be applied to both footrest support
structures simultaneously (or most forward projecting part), using  50
mm webbing or strapping material. If the footrest is constructed in one
piece, the specified force shall be applied to  its center.  Note: 
Adjustable knee angle leg rests shall not be  tested. 

A6.1.8  Push Handle(s) Upward Static Load Test  
      A vertical upward force of 850N shall be applied to the push 
handle(s) simultaneously using 50 mm webbing or strapping  material.  If
a push bar is used, the load is applied to the center. 

A7  Conditions for Acceptance after Static Strength Tests  
      The boarding chair shall be visually inspected after static 
strength tests are completed noting the following:
           (1)  Any fracture of any member, joint or component;
           (2)  Any fracture, cracking or discontinuity of the surface
           finish  of the structure;
           (3)  Free play or loosening in the frame structure, folding 
           mechanism, armrests, footrests, brakes, wheels or wheel
           bearings and any other component of the wheelchair, greater
           than that noted in the initial inspection;
           (4)  Any deformation or maladjustment of any part of the 
           wheelchair, or of its attachments, that will adversely affect
           its  function;
           (5)  Wheel alignment shall be remeasured and recorded noting 
           the tolerances given; 
           (6)  The boarding chair dimensions shall be remeasured and 
           recorded.  These dimensions should be within 3 mm of the
           pretest dimensions recorded;
A pass/fail disclosure shall be made based on the visual  inspection and
the alignment and dimensions noting the tolerances given.  

A8.1.1  Seat Impact Strength
      The seat shall be tested for impact with the Standard Loading  Mass
filled with a weight of 25 kg.  During these tests the wheelchair shall
be secured to the floor to prevent folding for  movement. With the
wheelchair in the normal open position, the weighted mass shall be
dropped onto different areas of the seat  from a height of 200 mm.  The
specified impact tests are as  follows:
      (1)  Drop mass onto center of the seat.
      (2)  Drop mass onto each front corner of seat as near to the  corner
      as possible.  If the wheelchair has removable armrests  they shall
      be removed.

A8.1.2  Backrest Impact Strength
      The backrest shall be tested for impact with the Standard  Loading
Mass with a weight of 25 kg.  The specified impact tests for the backrest
are as follows:
      (1)  Suspend the standard loading mass as a pendulum such that it
      impacts the center top edge of the backrest from the front  at a 45
      degree angle.  The standard loading mass shall be  dropped from a
      height of 500 mm.
      (2)  Suspend the standard loading mass as a pendulum such that it
      impacts each back frame member at the top, from the front at a 45
      degree angle.  The standard loading mass shall be dropped from a
      height of 500 mm.  During this test the boarding chair shall be
      secured to the floor to prevent folding or movement. 

A8.2.1  Drop Test Impact Strength  
      (1)  With all folding mechanisms (if existing) deployed to the 
ready-to-use condition (open), lift the wheelchair loaded with the  220lb
standard test dummy above a hard, flat surface at a height of 100 mm. 
Using a quick release device drop the chair allowing it to fall freely
under the influence of gravity to impact the flat surface.  The
wheelchair should be suspended from a single point so that it is tilted
10 degrees laterally (side-to-side) with an inclination 10 degrees aft
so that a rear wheel will contact the floor first.  The height of the
chair should be measured from the floor to the lower surface of the wheel
being tested.

      (2)  For folding chairs, repeat with an inclination fore 10 degrees 
so that a front wheel strikes the floor first. 

A8.2.2 Rolling Test Wheels and/or Castors Impact Strength
      With the chair unfolded and loaded with the 220 lb standard test
dummy, the chair is rolled on a straight line path at the velocity of 1.1
m/sec towards a standardized obstacle, which is securely fastened to the
floor. The velocity should be measured by sue of a standardized
procedure. The test dummy shall be securely fastened into the boarding
chair. If there are removable/adjustable footrests or other projections
they should  be adjusted to the most upward position in order to clear 
obstacles. If the distance between the floor and non-removable structures
or footrests is less than the height of the standardized obstacle, the
maximum possible height object should be used and recorded. Each front
wheel or castor should contact the standardized obstacle independently. 
The impact angle should be 45 degrees to the long dimension of the
standardized obstacles.

A9.  Conditions for Acceptance after Impact Strength Tests
      The boarding chair shall be visually inspected after impact strength
tests are completed.  A pass/fail disclosure shall be made based on the
criteria to be determined by the ISO. 

Appendix B:  Guidelines for Training 

B1  Training Course Responsibility: Airlines or responsible contract
personnel shall conduct training  courses. The airline will ensure that
contract personnel conduct adequate training and will be ultimately
responsible for training  content, frequency, and adequacy.

B2  Frequency of Training: The airline or responsible contract personnel
shall train all personnel who will perform disabled passenger transports
with  aircraft boarding chairs before they are allowed to perform the 
boarding task on the job. Refresher courses shall be taught  when
different equipment is acquired, new staff are hired, and  routinely,
according to an established schedule.

B3  Level of Training.  All attendants shall successfully perform a
passenger transport and transfer using both a skybridge and stairway to
gain access to the airplane.

B4  Training Course Content  Training courses shall include the material
covered in guidelines on passenger services, transfers and stairways. 

Effectiveness of Passenger Services.  Training courses shall include the
following topics to reduce the likelihood of passenger injury:
      (a)  Maintain proper attitude toward the passenger to avoid 
      mistreatment.
      (b)  consult with the passenger to identify the best method for 
      transferring.
      (c)  be aware of the risk of injury.
      (d)  Obtain the owner's chair during layovers if at all possible.
      (e)  Minimize the numbers of transfers per passenger.
      (f)  Restrain the passenger firmly, but not so tight as to cause 
      injury
      (g)  Take caution against legs and feet becoming dislodged  from the
      support and getting caught on corners, seat braces or  seats.
      (h)  Avoid pressure sores; allow the passengers to stay in their 
      own wheelchairs (that is specifically padded for them) for as  long
      as possible.
      (i)  Know where the movable armrests are located on the  aircraft.
      (j)  Know where the boarding chair can be parked (greatest percent
      incline without danger of brakes not holding).

Passenger Transfers.  Training courses shall include the following
information to  reduce the likelihood of passenger or attendant injury: 
      (a)  Consult with the passenger on the best way to accomplish 
      transport procedure. 
      (b)  If possible, use a seat with a movable armrest. 
      (c)  Do not lift a person who is too heavy for your strength.
      (d)  Stand with feet 12 - 18 inches apart, lift from the knees and 
      not the back by keeping the back as straight as possible and  stand
      as close to the passenger as possible.
      (e)  Engage brakes/locks on wheelchair and boarding chair  whenever
      making a transfer.
      (f)  Allow the passenger to assist with the lift whenever possible. 
      
Use of Stairways for Boarding: Training courses shall include the
following information to reduce the likelihood of injury:
      (a) Whenever possible, avoid carrying a passenger up stairs.
      (b) At air carrier airports, locate and know how to utilize the 
      airport provided lifting device.
      (c) Before starting, make certain that all restraints are securely 
      fastened, especially about the lower extremities that could splay 
      and injure the attendant or upset the balance of the boarding 
      chair.
      (d) Place the less experienced attendant at the foot of the 
      passenger and the more experienced attendant at the shoulders. 
      (e) Take a practice run if not fully familiar or comfortable with 
      the layout.  Practice with a heavy staff member.
      (f)  Keep the passenger informed at all times as to the progress. 
      (g)  Make sure hands and gripping surfaces are not wet or slippery. 
      (h)  Rest at each step to preserve stamina.
      (i)  do not wear baggy clothing which could get caught.  Wear
      non-slip footwear, such as rubber-soled shoes.
      (j)  Keep the boarding chair tilted back slightly but as 
      horizontally straight as possible.  Even the slightest sideways 
      tilting can jeopardize control.
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