Human Factors Considerations for the Design and Evaluation of Electronic Flight Bags
Divya C. Chandra, USDOT Volpe Center, Cambridge, Massachusetts
Susan J. Mangold, Battelle Memorial Institute, Columbus, Ohio
Abstract
There is currently great interest in developing
stand-alone electronic devices to support flight deck tasks.
These devices, called "Electronic Flight Bags," (EFBs)
were originally seen as a repository for electronic documents.
Today, some airlines envision EFBs as multi-function devices
supporting an array of applications, while others envision a
simple low-end device used only for viewing documents, or perhaps
for performing flight performance calculations.
The Federal Aviation Administration (FAA) is
charged with approval of EFBs for installation and use in
aircraft. The approval process will be a multi-dimensional effort
requiring an understanding of how the device functions and is
used by crews, how the device interacts with other cockpit
equipment, and training and operating procedures. Volpe Center
has been tasked with writing a document on the human factors
issues related to EFBs.
Our goal is for the document to be of value to
both system evaluators in the FAA and system designers in
industry. Our challenge was to create a document that addresses
the wide range of proposed EFB implementations, suits the needs
of the various readers, and provides useful information for
designers and evaluators. In this paper we review the design of
the document and how it addresses each of these requirements. We
also give an overview of the content of the document and provide
illustrative extracts from the text.
Introduction
In a world where small portable computers are
increasingly common for personal and business use, it is not
surprising to find that aircraft operators would also like to
have small, portable electronic information-management devices to
help pilots conduct flight operations more efficiently and safely.
The original concept for this device was as a repository for
electronic documents. That is, it would be an "Electronic
Flight Bag" storing electronic copies of documents, such as
operating manuals and checklists, that are usually required in
hard copy during a flight.
As the concept of an EFB was explored it became
clear that the device’s potential was much greater
than first envisioned [1, 2]. As evidenced by the development of
the Integrated Crew Information System (ICIS) by Avionitek, Inc.,
an EFB could support a wide array of functions beyond that of an
electronic library. For example, ICIS supports sophisticated
electronic checklists, computation of flight performance
variables, and in the near future, real-time displays of weather.
Even though the operational concept of an EFB
is relatively immature there is significant interest in
developing EFBs from airlines and avionics manufacturers.
Industry groups have asked the Federal Aviation Administration (FAA)
to develop a plan for operational approval of EFBs. This plan
will be distributed in a public document, an Advisory Circular,
to be released for public comment in October 2000 [3].
Because EFBs could strongly affect how the
pilot performs his/her job, their impact must be carefully
evaluated from a human factors perspective. Volpe Center was
tasked with assisting the FAA in developing advisory materials
for the human factors evaluation of EFBs. Our product is a
document in which evaluation topics are identified, and
requirements and recommendations for EFBs are specified. Our goal
is for the document to be of value to both system evaluators in
the FAA and system designers in industry.
In this paper, we begin by exploring the EFB
concept in more detail. Next, we present a more specific
statement of our project challenges. The bulk of this paper
addresses the EFB human factors guidance document in more detail.
We discuss the document scope, content, and format, all in the
context of how the document was crafted to meet its goals. Two
illustrative extracts from the document are also included.
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Background--What is an EFB?
Earlier, we mentioned that the operational concept for an EFB is still immature. While this is true, there are some core characteristics of an EFB that define the basic concept. An EFB is an electronic information management device for use by pilots in performing flight management tasks. It typically consists of a screen and controls in a self-contained unit that is relatively small, weighing only a few pounds at most. EFBs can store and display large amounts of data. Some existing EFBs run proprietary operating systems, but most are compatible with the Microsoft Windows® operating system. For example, the Northstar Technologies CT-1000 (see Figure 1) runs Windows 98®. The Northstar hardware is custom-built for aircraft use, but some manufacturers host EFB software on more standard laptop computers.
Beyond these characteristics, EFB concepts
begin to vary significantly. Some are relatively simple units in
that they support only one or perhaps two functions (e.g.,
electronic documents and flight calculations). Other EFBs support
a wide array of functions that the pilot can select from at any
time. Of course, it may be easy to upgrade EFBs by installing new
software applications, just like any other computer, so a single-purpose
EFB could evolve into a multi-function unit.
Some EFBs may be mounted within the aircraft
cockpit, and even draw power from the aircraft. Other EFBs will
be hand-held, operating on batteries. More sophisticated EFBs
could communicate with cockpit systems and/or each other. For
example, ICIS units communicate with one another via infra-red
signals. (This is useful when, for example, the co-pilot
completes an electronic checklist item; that information is
immediately displayed on the captain’s ICIS unit.) EFBs
could also display real-time weather and/or traffic information
obtained via data link.
While the initial customers for EFBs are
primarily airlines, the EFB is also expected to penetrate the
corporate and general aviation markets. Each market has a
slightly different operational concept for the EFB. Even among
various airlines, there are multiple concepts for use of an EFB.
Some airlines want the low-end devices that support one or two
functions. Others want high-end EFBs that either provide new
information services (e.g., real-time pilot messaging) or support
functions that are traditionally implemented on standard cockpit
avionics (e.g., the Enhanced Ground Proximity Warning System).
Some airlines would also like the EFB to be
integrated into their training programs, so that pilots could
take the devices home and complete part of their training off-site.
For example, pilots could review operating manuals on a stand-alone
portable device at any location.
Finally, it is conceivable that some EFBs could
eventually be certified as the sole source of some types of
flight-critical information. For example, the electronic
checklists on an EFB could replace (not just supplement) paper
checklists.
Figure 1. The Northstar CT-1000 weighs 3.25 lbs. and has a 6.4" diagonal color display. (Photo courtesy of Northstar Technologies.)
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Project Challenges
Volpe Center was tasked with assisting the FAA
in developing advisory materials for the human factors evaluation
of EFBs. We faced three main challenges. First, the guidance has
to address the wide range of proposed EFB functionality,
discussed above. To accomplish this, we needed to be aware of the
many EFB concepts proposed by industry. We also had to be aware
of airline requests for EFB functionality. We met this challenge
through our participation in the Air Transport Association's
Digital Data Working Group (ATA DDWG). The group consists of
airlines and manufacturers, many of whom are pursuing the EFB
concept. This group also provides valuable feedback on our draft
guidance document.
Our second challenge was to package the
guidance in a format that was useful for the audience. Our
audience includes (a) members of the FAA who are involved in the
approval of EFBs, including field inspectors, Aircraft
Certification, and Flight Standards, (b) industry designers of
EFBs and (c) EFB customers. Our readers within the FAA will
approach the document with different interests in mind because
the approval process will be a multi-dimensional effort. The
approval process will require an evaluation of how the device
functions and is used by crews (i.e., "equipment issues"),
how the device interacts with other cockpit equipment (i.e.,
"installation issues"), and training and operating
procedures. FAA field inspectors will be interested in very
practical, operational issues. Manufacturers of different EFBs
will also approach the document from their own points of view;
they will want to see the guidance related to only the functions
performed by their EFB. Therefore it was important to organize
the document by both EFB function and approval aspect.
Our final, and on-going, challenge is to
provide information that is useful to both system designers and
system evaluators. Each piece of guidance in the document must be
relevant, specific, and to the point. If the guidance is well
written, the jobs of both the system designers and evaluators
will proceed more smoothly. In the next section, we go into more
detail about how the guidance document is organized and written
to meet this challenge.
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Document Overview
In this section, we discuss the scope of the
EFB human factors document, its content, and structure. At the
end of the section, two extracts from the document are presented.
The extracts illustrate the structure and type of guidance
provided in the full document.
Scope
Creating guidance for all possible EFB
functions is a long-term effort. We chose to split up the task
into yearly efforts. Our first year’s effort will be
distributed as "Version 1" of the document. This allows
us to distribute guidance on an initial, basic level of EFB
functionality as soon as possible. The document is modular, so
adding information on newer or more complex EFB functions will be
straightforward.
Version 1 of the EFB human factors document
contains both general human factors considerations and specific
considerations for an initial set of functions that includes
electronic documentation, electronic checklists, and flight
performance calculations. These functions were chosen because
they are the most mature applications to date. Several airlines
are in the process of converting manuals into electronic form,
the first step towards placing the documents on a portable flight
deck device. Electronic checklists are already available on some
newer aircraft models. The algorithms for computing flight
performance are well understood, and have been implemented for
use on standard personal computers. These functions have even
been implemented in industry prototypes of multi-function EFBs.
Version 2 of the EFB human factors document, to
be completed in 2001, will address more complex functions, such
as electronic charts, and functions that involve display of real-time
data, such as weather or traffic information.
Content
We cover four key types of human factors issues
in the guidance document:
- Usability of hardware
- Usability of software user interface
- Integration of hardware and software with existing cockpit systems
- Design of training/procedures for EFBs
Note that there is no single "best design"
solution for these issues. We are not telling manufacturers what
design choices to make. We are providing them with information on
the human factors issues that arise given different EFB design
choices.
Structure
The structure of the document has evolved to
meet the needs of the various readers. The final structure is a
combination of techniques and suggestions that we culled from
other guidance documents [4–6] and feedback from our FAA and
industry reviewers.
There are four main content sections in the
document. The first section covers general topics, under the
title of System Considerations. Each of the other sections
pertains to a particular EFB function: electronic documentation,
electronic checklists, or flight performance calculations.
Within each main content section, guidance is
organized into one-page "considerations." (An example
of a complete one-page consideration is given in the next section.)
The title of the consideration states the function or general
issue that is being addressed; if a particular EFB does not
support that function or that issue is not relevant, then that
guidance statement does not apply. So, the title of the
consideration helps the reader determine whether that information
applies to a given product.
Each consideration contains one or more summary
guidance statements at the top of the page, followed by detail
information in three subsections:
- Problem Statement
- Example(s)
- Evaluation Questions
In the Problem Statement, we clearly identify
why the topic is important, and what risks are taken if the
problem is not addressed. Below that, we give examples of the
problem and possible solutions. In the Evaluation Questions, we
give guidance on what a field inspector should look for during
the evaluation. These questions are open-ended. They prompt the
evaluator for areas to examine instead of giving him/her a formal
set of criteria that must be met by the EFB to pass some minimum
approval standard. The open-ended questions allow inspectors to
use their own judgment in each specific situation.
Each formal guidance statement is labeled. The
label reflects the FAA approval aspect and the level of guidance.
Labeling guidance statements helps different readers, especially
those from the FAA, find topics of interest quickly.
There are three types of FAA approval aspects.
- Equipment
- Installation
- Training/Procedures
These approval aspects were discussed earlier,
in the section on Project Challenges. The first aspect, Equipment,
is concerned with how the EFB is used in and of itself. These are
issues that can be tested in a laboratory setting. Most software
design issues will be Equipment issues. The second approval
aspect, Installation, concerns EFB evaluations that must
be performed in the context of a cockpit. For example, when the
EFB is mounted in a structural cradle, it should not obstruct
access to other critical flight controls and displays. Some
considerations contain more than one guidance statement that
address multiple approval aspects. For example, in the sample
consideration on stowage requirements (see Figure 2) there
are two guidance statements, one related to installation and the
other related to training/procedures.
Our guidance statements are classified as
Requirements, Recommendations, Good Practices, or Issues. These
categories reflect the fact that we do not always know in advance
what the "right" design is. The guidance statements
should identify unacceptable design solutions without requiring
that manufacturers implement the "best" designs. For
installation and equipment issues, the different levels of
guidance leave room for innovation in the design of EFBs. For
training/procedures issues, the different levels of guidance
allow room for different operators to develop training/procedures
that are consistent within their company.
The guidance statements are written to (a)
allow flexibility (rather than requiring design solutions) (b) be
specific to EFB functions, which the EFB may or may not support,
and (c) be specific to operational environments such as the type
of operations (e.g., general aviation versus airline) and phase
of flight.
Sample Considerations
Two extracts from the EFB human factors
document are presented below in Figures 2 and 3. Figure 2
shows an excerpt on the stowage area for portable units. Each guidance statement is
labeled by the FAA approval aspect and the level of guidance.
Also, notice how the installation requirement is written to apply
to a specific situation. Exceptions are noted. The exception
regarding EFBs that are not used for flight critical information
is designed to allow less expensive implementations for general
aviation users who may want less capable units. The problem
statement below is short and to the point, as are the examples.
Notice also how the Evaluation Questions are open-ended, leaving
some room for adjustment to individual situations.
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Stowage Area for Portable Units
Installation Requirement(s)
A stowage area with a securing mechanism for the EFB is required for storage of portable units when they are not in use.
Note: If the EFB is designed to be held in a structural cradle, the cradle may satisfy the requirement for a stowage area.
Note: For EFBs that are not used as the only means of performing any flight critical tasks, this requirement may be downgraded to a strong recommendation.
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