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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