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62



ADJUST ENGINE OIL SYSTEM
PRESSURE

1, Disconnect pressure sensing
line (3) from bearing
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Figure 15

125



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Foreword

Maintenance procedures to support world-wide air transport are being given considerable
attention today. The growth of air transportation since the 1978 deregulation of the industry has
caused demand for new carrier aircraft to exceed production. Under these conditions, older
aircraft must remain in the operating fleet for many years, often beyond the anticipated retirement
date established when these aircraft were designed. To ensure continuing highest levels of safety,

maintenance of this aging carrier fleet must be rigorous. Indeed, aircraft inspection and
maintenance must be effectively error-free operations.

The Federal Aviation Administration (FAA), aircraft manufacturers, and airline operators all
are commited to achieving the highest standards in aircraft maintenance. However, the quality of
maintenance ultimately depends directly on the performance of maintenance personnel. The FAA
recognizes the need to establish a proper working environment for maintenance personnel and to
understand those features of this environment which either enhance or degrade the performance of
maintenance technicians.

The FAA is conducting a series of meetings to address Human Factors Issues in Aircraft
Maintenance and Inspection. At the first meeting, in December 1988, "communications" was
identified as an important issue underlying effectiveness and proficiency at all levels of
maintenance. The meeting convened here, the second in the FAA series, addresses "information
exchange and communications." All segments of the aviation maintenance community are
represented through those speaking and those in attendance. The contribution of each of you toa
program of continuing improvement in aviation maintenance is gteatly appreciated.

William T. Shepherd, Ph.D.
Federal Aviation Administration


The use of words rather than numbers for call-outs is shown in Figure 13, with considerably
less clutter presented than in Figure 12. The greater clarity of Figure 13 will reduce scanning
time. However, scanning time can be further reduced and accuracy increased if call-outs are
shown as numbers rather than words, as seen in Figure 14. Words must be read; one cannot scan
them very effectively. Numbers, in some sequence, can be scanned more rapidly. The specific
sequence is not important. It also is not important whether the sequence proceeds clockwise or
counterclockwise -- left to right or right to left. What does matter is that the sequence is quickly
recognizable and that one can locate "6" quickly after passing "5."

Figure 15 presents an example of a basic format recommended for use. This combines text
and graphics with numbered call-outs. It does not matter whether the text is below, above, to

the left, or to the right of the graphics. The important point is that the graphic is keyed to the
text. .

Presentation principles (Figure 16) for descriptive materials are not as clearly defined as those
for procedural information but are nonetheless useful.

Presentation Pri

ples for Descriptions

* Whole-to-part-to-whole
(Graphics)

* Functional context
(Graphics)

* Text-graphic integration

Figure 16

Descriptive information provides a description of equipment operation or systems operations.
Descriptive information taps the long-term memory capability of the reader. A technician has to
retain the information and apply it to the job usually months after he first reads it. In providing
this information, the preferred hierarchy is whole-to-part-to-whole. The whole provides the
context and is presented first; the particular activity or detail is described next; and the activity
then is related again to the context. Information presented in the context of some known whole
will have a better chance of being acquired and retained, Acquisition also will be improved if a
graphic is used to provide the context, with associated text speaking to the graphic.

Another principle for descriptive materials is that of “functional context." According to this
principle, derived from learning research, acquisition and retention of information will be
enhanced if new information is presented in the sequence in which people do the work, even

though one is describing equipment, or the sequence in which the process takes place in the
equipment.

Another principle concerns density. How much information should be presented per unit of
Presentation? In print form, we treat the paragraph as the basic unit of presentation. According
to the principle, the presentation should be restricted to no more than three to four related
system actions per paragraph, e.g., sends a signal, processes the signal, transmits a signal, etc.
When you exceed the limit, the reader tends to move on without understanding the content.

121



Data Base Support for Maintenance Requirements
of the Nuclear Power Industry

Thomas G. Ryan, Ph.D.
_ US. Nuclear Regulatory Commission

My experience with the Departments of Transportation and Defense, the aerospace industry,
land now the U.S. Nuclear Regulatory Commission has shown me that these agencies and
activities, while they deal with ‘Fifferent systems, have more commonalities than differences. All
are involved with complex, high-reliability systems where a maintenance failure or an operator
error can be catastrophic, not only for the operator but for those around him. This basis for
commonality means that each activity can learn from the others.

To provide a context for this presentation, | would like to describe briefly the operation of the
U.S. Nuclear Regulatory Commission. The Commission was formed at the breakup of the old
Atomic Energy Commission and has responsibility for regulating civilian applications of nuclear
power. At present, the USNRC is responsible for some 119 nuclear power plants located within
the 48 contiguous states and some 65 nuclear research reactors located primarily at universities.
We also are responsible for spent fuel handling until it leaves the operating site. Finally, we are
beginning to be involved in the regulation of nuclear materials as used in the medical profession.
Within the USNRC, human factors research is directed toward the development of data
gathering instruments, data management systems, performance analysis tools, performance
criteria, and provision of technical data to support various licensing and regulatory decisions
made by the USNRC dealing with both operations and maintenance.

This presentation has three objectives. The first is to acquaint participants with five human
performance data management systems and analysis tools developed by the USNRC and the
U.S. commercial nuclear industry to support the design, development, and evaluation of
maintenance, test, and surveillance programs. Two of these are data management systems; two
are computer simulations; and the last involves development of criteria to allow us to equate
tasks in our industry with ones in your industry so that data may be exchanged to support
technical analyses in each industry.

The second objective is to indicate procedures whereby participants might gain access to any
or all data management systems and analytic tools described here. Documentation is free of
charge; the technologies themselves are available on an information-exchange basis.

The final objective today is to request participant assistance on a USNRC project. This project
will be noted later in the presentation.

The USNRC became interested in maintenance tests and surveillance as a direct result of
the familiar Three Mile Island accident (or event) in March 1979. Until that time, the USNRC
was strictly a nuclear engineering organization. However, a review of the Three Mile Island event
indicated that people were very much involved. That initiated an era of human factors in our
industry and at the Commission.

For the next three or four years, the Commission focused on human factors in operations. A
particular interest was in the behavior of operators once an abnormal event was initiated.

Two things changed the focus on operators. One is our experience in analyzing abnormal
events that have occurred since then. We have found that much of the cause of these events
often has to do with latent factors in maintenance, test, and surveillance that preceded the
actual event. Another factor causing a change in focus was a requirement placed on industry to

71



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81



Frequently the FAA determines that more detailed information must be provided to support
a Federal Aviation Regulation and, in turn, communicated to industry. The resulting publication
is called an Advisory Circular and generally is used to illustrate one means of compliance with
the rule. A considerable amount of work and, frequently, a number of public meetings go into
the development of an Advisory Circular, To ensure the broadest audience for advisory circulars,
they often are published in the Federal Register.

Advisory circulars are directed primarily at industry. However, we also have a need to
communicate this type of information to our own employees within the FAA. We need to
inform them concerning the policy or provide guidance for implementing an Advisory Circular,
for example, from an FAA inspector's standpoint. This information is provided in the form of FAA
Orders or Handbooks which are distributed in an effort to have all individuals work from a
common information base and to implement the FAA rules in a standardized manner across the
country.

The FAA also uses other communication documents called action notices, or just notices, to
communicate with its employees when handbooks or more formal orders are not appropriate.
In some instances, a simple telephone call is sufficient to ensure that FAA policy is being
implemented on a uniform basis.

Another communications problem faced by the FAA is that of communicating to the
operating and maintenance communities the technical status of an airplane as it may change
during its period of service. In order to support such communications, we collect considerable
information from manufacturers and also from users through the Service Difficulty Reporting
System. From the information we receive, we can do trend analyses to pinpoint a possible
adverse trend with an aircraft or one of its components.

As one means of disseminating trends or describing possible problems to FAA personnel, we
frequently use another communication tool called Alerts, which is put out in Advisory Circular
form, AC4316. Alerts are distributed through a mailing list maintained at Oklahoma City and are
directed to aircraft inspectors, repair stations, and others interested in overseeing and
accomplishing aircraft maintenance. Alerts represent a compilation of all of the trends that we
see, It is our belief that maintenance actions will be improved if maintenance personne!
understand these trends.

Also in an attempt to deal with the changing status of an airplane, manufacturers often put
out Service Bulletins. Such bulletins address a problem that requires attention or correction and
identify a recommended means for dealing with the problem.

Closely allied with the direct interest of the FAA in communications are programs to identify
the knowledge, skills, and abilities required by different personnel to perform their jobs. At this
time, a significant program is development of job task analyses for the various positions of FAA
Aviation Safety Inspector. Results of this effort will provide a better understanding of the
requirements of these jobs and the materials needed to support the positions. We also hope to
use this technique to identify requirements for training for Journeyman through Senior Expert
Inspectors. All of this will allow us to do a better job of developing policy and guidance materials
for FAA inspection functions. In essence, the communication link between the FAA and the
Aviation Safety Inspector will be improved.

To this point, we have been concerned mostly with communications in the form of written
materials, whether they be directives or manuals, which support maintenance operations.
Verbal communications also are quite important. Some of us have had the luxury of attending
communications courses which attempt to improve communications skills and can be quite
valuable. Such courses teach one how to actively listen. How does one actively talk and share

16



factors group simply gives a "go" or a "no go" to the design. The people who understand human
factors and the people who design equipment need to work together from the beginning.

So what can be done? The jury is still out on that, but the Human Factors Research Program
of which this conference is a part is attempting to bridge those gaps in understanding. The one
common denominator to meeting the challenges of the future will be the need for cooperation
and communication at all levels. No one group can operate independently. Designers of
equipment will have to talk with the maintenance community to identify requirements and also
the human factors community to address human factors issues.

The FAA has taken this approach in putting together a diverse team of researchers for its
Aging Aircraft Human Factors Research Program.

The point being that just because some of our efforts to utilize advances in technology have .

been awkward and frustrating, that does not have to be the rule for the future.

Job Performance Aids

So now let me talk a little about some of the existing systems we have identified. One of the
systems talked about today, IMIS, is an excellent example of a job performance aid. Currently we
are looking at this system and others that have been implemented in aviation or a related field.
The value of this effort can be viewed from the perspective of a typical maintenance
department. If you are responsible for carrying out the duties of maintenance on a day-to-day
basis, you do not have time to keep up with all of the technology that exists or evaluate all of the
technologies that are brought to your attention. Currently, only the larger and more profitable
airlines can afford the investment of time and money to investigate utilization of performance
aids. Our effort is designed to make this information accessible to everyone who is interested.
Our effort will also provide background on what it takes in terms of labor and overall cost to
implement a job performance aid, and an awareness of the down side issues as well. Managers
can then make informed decisions on the application of new technology.

| have selected a few representative examples from our initial research to give you a flavor of
what is possible today. Most of the systems are designed to provide the mechanic with a better
source of information. This is not a surprise since mechanics point out that they spend up to 70
percent of their time just looking for the correct information.

We were surprised at the number of systems, approaching 60 at varying levels of
development and complexity. One of the common denominators is the use of expert system
technolo y. | will talk about expert systems in more detail in a few minutes. As | mentioned,
most of the technology has been developed and tested by the military. | have pulled six systems
out to describe. IMIS (Integrated Maintenance Information System) is one of the best examples
of a job performance aid, But you have already heard about it today so | will not go into it any
jurther.

A large portion of the systems we uncovered revolve around maintaining the engines. After
engines, avionics were the most common systems. The maintenance aids that we are looking at
fall into a several basic categories. There are systems that (1) support diagnosis, (2) information
delivery, and (3) training.

TEMS: Turbine Engine Monitoring System. TEMS is representative of one of the earliest
applications of technology to the maintenance process. As the name implies, its focus is to
monitor engine performance parameters seeking to predict when and what maintenance is
required on the engine, thus achieving on-condition maintenance. There are a number of
systems that vary in how engine performance data is collected and the number of engine

130

aeu eso


CD-ROM and Hypermedia for Maintenance Information

Robert J. Glushko, Ph.D.
Search Technology, Inc.

Introduction

Problems with Maintenance Information

Modern aircraft are complex systems that require tens or hundreds of thousands of pages of
technical information to operate and maintain them. This information is organized as hundreds
of manuals created by dozens of contractors and subcontractors. To make it easier to keep
information accurate and up-to-date, this information is logically organized (perhaps according
to ATA or other standards), which helps minimize redundancy. However, this means that many
tasks require information from different parts of a manual or from more than one manual. In
principle, following cross references to find needed information is a simple task: we all can
visualize using a bookmark or a thumb to hold our place in a book while we turn elsewhere. But
in practice, it is always time-consuming and error-prone for the maintenance mechanic to track
down needed information that is spread throughout manuals, since thousands of pages of
manuals occupy dozens or even hundreds of "shelf-feet.". The mechanic might have with him
the three or four most useful manuals, since that is all he can carry, and important information
always seems to be back at the hangar or maintenance depot in yet another manual. This means
that maintenance must often be carried out without all the information that could conceivably

e needed.

The Solution: An “Intelligent Electronic Manual”

Recently, many people have been proposing various realizations of an “intelligent manual"
to solve these problems with locating and using information in large document collections. The
common theme is to use a portable computer with enough storage capacity to contain all of the
information from the printed manuals. Typical features oF this intelligent electronic manual are:

* vast amounts of storage for text, graphics, illustrations, and other kinds of information

* support for familiar ways of finding information, using tables of contents and indexes

* other entry points that are impossible on paper but made possible by the presence of the
computer, such as (1) full-text search through the information database for sections that contain
key words or phrases or (2) interactive troubleshooting using intelligent assistance

* display functions for viewing information page by page or for browsing by jumping many
pages at a time

* progressive display of detail, so that a reader can start with an outline view of the
information (like a table of contents) and then "zooming in" to get details where they are
needed

* computer-supported cross references or links between related information that can be
quickly followed to display the cited information as if it were directly connected

* embedded training and job aids, often using media like audio or video to optimize the
instructional transfer.

77



NEAR “PERFECT AIRLINE COMMUNICATIONS”

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VENDOR GOVERNMENT

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COMMUTER
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33



4. Orders - These are issued by FAA Headquarters to regions in order to convey specific
engineering information.

5. Technical Standard Orders - TSOs are certifying documents either for a manufacturing
process or for a procedure for testing discrete aircraft components.

6. Alerts - A method for general communication to the industry.

7. Notice of Proposed Rule Making - NPRMs are a means of alerting the industry to changes
under consideration by the FAA.

Aircraft Manufacturer

1. Performance Certification - Results of negotiations between the manufacturer and the
FAA allowing the manufacturer to request a Certificate of Airworthiness or a Type
Certificate for an aircraft to allow it to go into passenger service.

2. NDI Manual - The manufacturer's means of communicating inspection procedures to air
carriers.

3. Notices - An adjunct to a larger publication such as the NDI Manual.

4. Service Bulletins - Messages to aircraft operators which provide recommendations
concerning correction of some problem. :

5. Supplementary Structural Inspection Document - A message to operators to update

recommendations concerning structural inspections.

Air Carriers

1. Certificate of Airworthiness - A certificate required to be physically in each operating
aircraft.

2. Inspection Procedures Manual - This manual is prepared for Repair Stations and directs
the repair station concerning FAA-approved procedures.

3. Process Specification - This document is developed as a result of a carrier's interpretation
of the manufacturer's NDI Manual and makes the process specific to his aircraft. It is
approved by the FAA.

The communication process supporting non-destructive inspection will be affected by the

Aging Aircraft NDI Program initiated by the Federal Aviation Administration. This program is
diagrammed in Figure 10. This R&D program has a significant survey activity under its technology
transfer effort. An assessment is being made of all NDI technology to find that most relevant for
aviation requirements. Considerable work done by the Department of Defense, the Electric
Power Research Institute, and others will be incorporated into aviation NDI procedures. At the
bottom of Figure 10 is ISU, which is lowa State University, an institution with a large Non-
Destructive Inspection Center.

Another activity of interest within the Aging Aircraft NDI Program is the audit of heavy

maintenance checks accomplished by an FAA Audit Team. One part of this audit covers human
factors issues including communications.

105


Examples of communication processes oriented to efficiency concerns are shown in this next
listing:

Team conferences

Maintenance audits

Abbreviated component maintenance manual

Customer support directory

Periodicals for customers (Douglas Service)

Participation in industry associations (Aerospace Industries Association, Air Transport
Association)

eoeeee

Team conferences can be very useful. Douglas Aircraft has just published a report of the
Team Conference for the MD-11 and the DC-10 aircraft held at Douglas recently. These
documents cover many topics. The basic theme is to introduce a concern communicated by an
Operator to the manufacturer, ask for operator comments, and then present manufacturer
comments. The meeting serves the needs of the customer in providing an opportunity for many
different operators to talk about their concerns with certain products. The conferences have
been successful because operators have a chance to talk to just about anyone they meet when
they visit the manufacturer's plant. They also talk with other operators who might be having
similar or related problems with their equipment.

During maintenance audits, teams of specialists from the manufacturer visit the facility of an
operator. The operator benefits by understanding the extent to which he is meeting required
maintenance and by obtaining a scale or an index of operator efficiency. Maintenance audits
offer a useful exchange between the operator and the manufacturer.

Abbreviated Component Maintenance Manuals (CMMs) are another example of
communication. The background of these manuals rests with the experience of one airline
which found that, due to rising costs of parts, they would rather repair parts of certain
components - bushings, bearings, sleeves, or wrought ends - than replace entire components. A
suggestion was made that Douglas Aircraft produce abbreviated Component Maintenance
Manuals. In less than a year, draft abbreviated CMMs were produced by Douglas which met the
operators' need. | believe that Revision 27 of ADA-100 provides specifications for the
publication of abbreviated CMMs. This is an example of communication taking place with the
services of a voluntary association which worked quite successfully. Two examples of abbreviated
CMMs at Douglas are for the inboard slat drive anti-torque wrought end assembly and for the air-
driven generator retainer assembly. These manuals are only five or six pages in length but they
enable an operator to repair a part and therefore not discard an entire component and have to
buy a new one.

Customer support directories are another form of communication oriented to efficiency. It is
efficient for an operator to have individual points of contact for different types of questions. At
Douglas, there is a Customer Support Directory for the MD-11, the DC-10, the MD-80, and the
DC-9. These directories list the area of specialization for scores of people. They show not only
business but home telephone numbers. By developing these directories, the manufacturer
illustrates that he is providing needed customer service support and satisfaction. He also shows
that customer service is available 24-hours a day, seven days a week, throughout the year.
Business can be conducted efficiently and as needed.

Periodicals are the final example of communication processes oriented to efficiency. The
Boeing Aircraft Company produces a number of very fine periodicals. Douglas Aircraft, | am
pleased to say, has reinstituted Douglas Service, a publication prepared for 42 years, followed by

40



For NDT work the initiate task also includes obtaining and calibrating the equipment. From
observation of the NDT equipment currently in use, calibration is not as straightforward as it
would appear from equipment manufacturers! brochures. The controls, and particularly the
displays, are not usually well designed for rapid, unequivocal information transfer with inspectors.
They give the impression that they were designed as pieces of scientific equipment with none of
the human factors engineering input which has been available for decades (VanCott and
Kinkaid, 1972).

Feedback from the initiate task is obvious is many cases because it comes from Task 2 --
Access. Thus, if the part to be inspected is left inner flap track, this needs to be physically located
on the aircraft in Task 2. The potential problems are best dealt with under that task.

Task 2: Access. In order to access an area of an aircraft, the area must first be opened and
cleaned, neither of which are under the control of the inspector. Thus, scheduling information
required for access is the assurance that the area is ready to inspect. Work scheduling systems
typically assure this, but wrong information does get to the inspector at times, giving time loss
and frustration. It is at Access that confusions in location from Task 1 become apparent--
hopefully. The next time the wrong location has been inspected will not be the first time. . .nor
the last. improved information systems for locating an area on an aircraft unequivocally are
needed. Physical access for both the inspector and equipment represent a human factors
difficulty in much inspection, but are not the concern of this paper.

It should be noted that feedback on accessing the correct area can be given by the work-
card system by incorporating unique landmarks into the diagram on the work card so the
inspector can be assured that the correct area has been reached.

Task 3:_Search. It is in the tasks of Search and Decision Making that information has the
largest potential impact. In visual search the inspector must closely examine each area for a list of
potential faults. Which areas are searched is a matter of prior information -- from training,
experience, or the workcard. The relative effort expended in each area is similarly a matter of
both directive and feedforward information. if the area of main effort is reduced, the inspector
will be able to give more thorough coverage in the time available. The workcard can, if accurate
and up to date, provide an information source which can overcome the prior biases of training
and experience, if indeed these biases need to be overridden. Similarly, the fault list the
inspector uses to define the targets of search comes from the same three sources. This fault list
must be realistic and consistent.

in many industrial inspection tasks, developing a consistent list and definition of fault names
to be used by all involved is a major contribution to improving inspection performance (Drury
and Sinclair, 1983). Faults often go by different names to inspection personnel, manufacturers,
and writers of workcards, causing misdirected search and subsequent errors in decision and
responding. Probabilities of the different targets or defects are rarely presented.

Feedback of search success only comes from Task 4 -- Decision Making, and then only if an
indication was found. If the indication was missed, then feedback awaits the next inspection or
audit of that area. Hopefully, the subsequent inspection occurs before the fault affects safe
operation. Note that if an indication-is found, feedback is immediate, but if missed, feedback is
much delayed. Delayed feedback is often no better than no feedback.

Task 4; Decision Making. The information required to make a correct decision on an
indication is in the form of a standard against which to compare the indication. Such standards at
the working point can be extremely effective. For example, McKennel (1958) found that the
reduced the average error of a trained inspector to 64 percent of its magnitude without suc

67



located the woman who was on vacation and had her authorize another person in the office to
punch the necessary holes. After a DHL delivery and a delay of three days, we were ready legally
to get the airplane in the air.

The above example illustrates the kinds of problems faced by commuter airlines using aircraft
made by foreign manufacturers. The issue is not insignificant. At this time, there are about 130
commuters flying aircraft made by at least nine foreign companies. And the commuters flyin
these aircraft may not have Technical Publications Departments ready to deal with suc!
problems. Continental Express, TWA Express, and United Express are not necessarily
representative of the entire commuter airline industry. Commercial airlines live with difficult and
cumbersome communications. Communications and the exchange of information throughout
the air transport industry are not perfect, as we have heard today. When a foreign government
and a foreign manufacturer are introduced into the communications network, matters do not
improve. Therefore, | request that as we work toward improvements in the exchange of
information in the airline industry, we keep in mind that these changes must recognize the
existence and the role of foreign governments and manufacturers. These foreign regulators and
vendors represent important parts of our industry.

36



Smith, TJ., & Smith, K.V. (1987). Feedback control mechanisms of human behavior. In G.
Hi Salvendy (Ed.), Handbook of Human Factors, Wiley, N.Y., 251-293.

Wickens, C.D. (1984), Engineering Psychology & Human Performance. Scott, Foresman &
Co., Glenview, IL.
Wiener, E.L. (1975). Individual and Broup differences in inspection. in

C.G. Drury, Human {
Reliability in li ol, Taylor & Francis, London, 19-30.

70



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Figure 10. Aging aircraft NDI program.

The Aging Aircraft NDI Program also is teviewing various NDI handbooks available to the
industry. Individual evaluations of equipment and procedures are being made. All of this
information is being distributed in the form of Advisory Circulars as appropriate and ultimately
will be incorporated into the ND! Handbook.

A recent study by the Department of Trade and Industry of the United Kingdom focused on
small manufacturing organizations, including small repair stations. They found that these facilities
had limited NDI experience, usually residing in one person with outdated knowledge. These
persons were unaware of current methods, equipment, and practices. NDI equipment was
perceived to be expensive. ND! itself was viewed as an end-of-the-line inspection tool rather
than as a quality assurance adjunct. Surveys in the United States indicate these same problems
exist here. Smaller repair stations do have special communication needs which must be
addressed.

In conclusion, non-destructive inspection must be used increasingly by the aviation industry
to control problems with an aging fleet of aircraft. NDI equipment is becoming more and more
capable and sophisticated. This equipment can be of great value in the inspection process. For
maximum benefit, however, proper communications procedures must be established so that
the entire industry is fully informed concerning NDI and is fully capable of using this equipment
proficiently.

106

I ee


Not only has the complexity of aircraft increased, but the number of aircraft to be
maintained has grown. This growth has just begun. There is now a five year backlog for most
types of commercial aircraft. In fact, there are as many aircraft on order as there are in service.
There is a corollary push to extend the serviceable Tife of aircraft now in service. The term
“economic life" means that retirement of an aircraft is postponed until maintenance is

economically unfeasible. Given the price of new aircraft and shortage of aircraft in general,
retirement is rare.

At one time, most airlines could afford to keep a spare aircraft available to press into service
as a replacement for aircraft going in for maintenance. This, in combination with less rigorous
schedules, provided some breathing room for the maintenance of aircraft. Aside from the

heavier C and D checks, most maintenance on aircraft must now be done late at night or during
a handful of days on the ground,

So far we have established that the task of aircraft maintenance is becoming more
challenging because aircraft are more complex; the number of aircraft is increasing; the
timeframe to carry out maintenance is decreasing; and communication of hundreds of people is
essential. Needless to say, all of this would give us plenty to think about, but there is one more
dynamic. There will be almost a complete turnover in the workforce in the next ten years,

| am sure most people in the audience have heard the statistics. Over the next 10 years,
40,000- of the current 65,000-strong maintenance workforce will qualify for retirement. This is
the group of highly experience maintenance workers who joined aviation in the early boom
years of jet aviation in the late 50's and early 60's. All of these experienced workers will be lost,
while the need for maintenance technicians is expected to grow to 95,000 by the year 2000. At
one time this amount of loss might have been made up by experienced people from the
military, but now the military is expected to be the chief competition in recruiting people. What
this means is that the new work force will be young and inexperienced. There will not be

enough graduates of the A&P schools to meet the demands, so a large number of people will be
learning on the job.

This group of new maintenance personnel will have to make up in energy what they lack in
experience, and they will be far more dependent on Job Performance Aids than their
predecessors. On the other hand they will have some advantages over their more experienced
coworkers. They will be far more comfortable with technology and the use of the ever present
computer. | will talk about some of these systems and the future trends today.

The Youth Attack

Given my youthful appearance, | assume you may have wondered what a young fellow can
teach you about the future of maintenance. Well my introduction should give you a hint as to
what I can tell you. Although | am not as young as | look, | am definitely a representative of the
generation that will be ubiquitous in aviation in 10  yearstime. | can give you some indications of

what will be good and what will be not so good about having this type of transition in the
workforce.

Perhaps the youth of the workforce will help us in some ways. Even at my age | am “over-the-
hill" when it comes to computers. To give you some perspective on how fast technology is
progressing, consider that when | started college data entry was handled by punch cards.
Computer terminals were not widely available until 1 was a sophomore. Radio Shack was the big
computer supplier when | was a junior, and Apple did not come into prominence until | was
nearly finished, | was finished with my master's degree by the time IBM had the idea to market a
personal computer. Computers are basically a mystery to me compared to the entry-level
engineers who are starting with our company today. Can you imagine what growing up with

128



Another barrier to appropriate information exchange is occupational language.
Occupational language refers to specialty language used by different disciplines. Generally, it is
not necessary and may actually get in the way. For example, “hard-time replacement" and "safe
life" seem to mean the same thing, yet they are different terms in use by different groups.

The industry also is beset with imprecise use of terms. Various FAA documents and
manufacturer's recommended standards use imprecise terms. For example, for mechanics tools
or maintenance equipment, one may refer to "standard tools" or "common tools." Is there a
difference and, if so, what is it? Another example would be the difference between "light versus
“moderate” corrosion in the commuter fleet. At this time, the corrosion problem needs to be
addressed before it becomes moderate -- whatever that condition actually is.

Arcane language, such as that found in many places in the Federal Aviation Regulations, and
a multitude of acronyms also represent barriers to information exchange. Acronyms particularly
can be misleading. For example, "MISTS" means severe thunderstorms. Others have dual
meanings, such as "SID" which can mean either “supplemental” or "structural" inspection
documents. The idea of a standardized and simplified English for use in maintenance makes
more and more sense.

International communications is a topic of interest. | have noticed that international
Operators tend to have a sense of community that | believe is rare and not often found outside
this industry. They share a strong pride when it comes to aircraft safety. Also, the simple fact of
Possessing a national airline gives one pride in being part of a larger technological society.

Ironically, even with this strong community, information exchange between companies can
lessen. Interorganization communications has been affected by airline deregulation. In a
deregulated industry, subtle pressures can be placed on maintenance to reduce costs. Even
though one might like to communicate with other maintenance people in other places, the
Pressure to get the work out lessens one's ability to share information and to attend industry
conferences,

Intracompany communications is a particularly important topic. Aviation maintenance can
be described through the concept of functional "silos." In this instance mechanics and inspectors
are separated, for the good reason that one does not ‘want too much collaboration between the
group doing the maintenance and the group doing the “buy back." Functional silos, however,
generally do not represent good arrangements for effective communications. As a metaphor, it is
a powerful image to have people in silos who are trying to communicate with others by shouting
up and hoping that others elsewhere hear it.

The key to understanding information exchange and organizational barriers is in the idea of
system stability. We would all like to have an international system of air transportation which is
stable. This should be a system that is progressing and developing rather than becoming more
and more entangled in its own environmental complexities. System stability in a turbulent
environment is the goal.

How can organizational stability be achieved under present chaotic conditions? In such
environments, individual organizations, however large, cannot expect to adapt successfully
through their own direct actions. They depend on others in the industry. This solution is based
on the emergence of values that have overriding significance for all members of the industry.
These social values represent coping mechanisms and help overcome the barrier of complexity.
They are mechanisms that make it possible for the industry to deal with persisting areas of
uncertainty.

46

mai
out
tha

exc


An Integrated Maintenance Information System (IMIS):
An Update

Robert C. Johnson
Wright-Patterson Air Force Base

The Air Force Integrated Maintenance Information S stem (IMIS) is based on a concept
developed in 1979 in which computer technology would be applied to the growing volume of
information required in aircraft maintenance. At the FAA Human Factors Meeting in October
1988, | described the IMIS program in some detail. Today | will review mostly progress made
since that time and indicate out program plans for further development. This status update will
center on three ongoing IMIS activities:

1. F-16 diagnostic demonstration
2. Content data model specifications
3. IMIS requirements analysis

At the Air Force Human Resources Laboratory, where we are working on IMIS, we are
following a definite strategy in the development of this system. in the laboratory setting, we are
able to develop new ideas for computer-based maintenance information systems at relatively
low cost before making a major dollar commitment to a system. We can develop enabling
technologies to aid in our overall Progress. We also are conducting our studies with full focus on
the end user, i.e., the maintenance technician. System operations are planned from the
technician's point of view and field evaluations are conducted with Air Force technicians, A
major goal is to develop or recommend specifications and standards which others might use as
they develop information systems for their own Purposes. In this way we have been very much
involved in a number of Air Force rograms, such as the Advanced Tactical Fighter, the F-16, the
C-17, and the Air Force Technical Order Management Program. This latter program is the Air
Force attempt to digitize the massive amount of technical data Row required to support aircraft
maintenance,

The basic concept for the Integrated Maintenance Information System is shown in Figure 1.
IMIS provides through a portable maintenance aid all of the tec nical information that an
individual needs to perform maintenance on a daily basis. This includes technical data,
diagnostics, training, data collection, historical data, and i
There also is an aircraft interface. With IMIS, a technician can go to the aircraft, open a panel,
activate a switch, and a small screen will come on which will provide a self check of that part of _;
the aircraft. The portable maintenance aid, the computer, will plug into the maintenance bus |
on the airplane and through this bus be able to communicate witl any system that is handled by |
the Built-In Test (BIT) on the airplane. The final part of the system is the connection back with |
ground processing and data bases that already exist in maintenance. The maintenance
technician then will be able to plug into the airplane and get all available information from the
Built-In Test, run that against a diagnostic algorithm contained in the portable computer, make
the best diagnosis he can to reduce false removal at the flight line, and then proceed with the
appropriate maintenance.

89

maintenance management information. |



Commission (NRC), with expertise and information of value. Private sector groups, such as
professional and technical societies as well as academic institutions, also will be invited to
contribute. We also will use our own in-house activity at the Civil Aeromedical Institute (CAMI)
in Oklahoma City, Oklahoma. Behavioral scientists from CAMI will be responsible for the aging
fleet evaluation visits. We also expect to have the NASA Ames Research Center as well as others
connected with the Space Shuttle program as contributors, Finally, there are of course the

industry people who are most conversant with the issues of aviation maintenance and its
problems,

The Human Factors Research Program wiil draw on all of the above sources as we prepare
our handbook and other information products. Within the next year, | hope that we can begin
to make some of these products available to industry and thereby contribute to aviation safety

through improvements in the efficiency and effectiveness of aircraft maintenance and
inspection.

FEDERAL AVIATION ADMINISTRATION
AGING AIRCRAPT RESEARCH PROGRAM
HUMAN FACTORS RESEARCH

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Executive Summary

The Federal Aviation Administration sponsored a two-day meeting in December 1989 as
part of a continuing program to address issues of human factors and personnel performance in
aviation maintenance and inspection. Presentations were given by some 15 individuals
representing the full spectrum of interests in commercial aviation. Presentations also covered
related efforts from other fields and new technologies having possible application to aviation
maintenance. Each presentation, as well as the following question-and-answer period, was
recorded for transcription and study.

The focus of the December meeting was on issues of "information exchange and
communications." An earlier FAA meeting identified communication, in all its forms, as being
of great importance in aviation maintenance and a matter in need of attention. The primary
goal of the present meeting was to consider means of ensuring that the exchange of information
within the industry responsible for the maintenance of the U.S. air carrier fleet is accurate,
efficient, and responsive to the particular needs of this industry.

Recommendations presented to the Federal Aviation Administration are summarized as:

1, The movement toward a central data base to support aviation maintenance
should be expedited as feasible. The Service Difficulty Reports data base
maintained by the Federal Aviation Administration is a beginning, although this
data base is not truly responsive to air carrier needs at this time. In continuing
work toward a central data base, the FAA should consider carefully the strong
initiatives made by other agencies such as the U.S. Nuclear Regulatory
Commission.

2. The exchange of maintenance information will be improved significantly with
greater standardization and consistency in the development and presentation of
technical data, Data standardization projects should be encouraged.

3. Efforts to develop a Simplified English are excellent. However, care should be
taken to avoid multiple versions of Simplified English.

4, The time required for transmission of much maintenance information is
unsatisfactory. New and improved systems of electronic transmission should be
developed. A fully responsive data system will require that all transmissions of
maintenance information, particularly those with safety implications, be done
electronically.

5. Safety analyses and trend analyses using the FAA Service Difficulty Reporting
System must be improved to provide needed information more rapidly. Software
should be developed to allow trend analyses for industry upon request, with rapid
distribution of trend results.

6. The format for presentation of maintenance information is important, whether
the presentation is in paper or electronic form. The FAA should consider the
development and publication of a brief document containing an explicit list of
guidelines for the preparation of maintenance manual-type information. The
maintenance industry itself should consider incorporation of relevant parts of the
electronic presentation technologies being developed by the U.S. Air Force in its
Integrated Maintenance Information System.



The provision of excess inform

ation is not efficient. The greater challenge is to provide the
necessary information.

6 Conflict between short- and long-term business viability may create communication
problems.

7. Conflict between

an organization's norms and its formal policy may create communication
f problems.

8. "Information ownership" may adversely affect transformation.

F nizations, may withhold information for reasons
of power or prestige or misplaced career buil ing. Since deregulation, some may believe that
certain maintenance information is economically important, and that may be true. However, it

Makes forecasting and ultimate Support of operators more difficult not to have comparable
mation about maintenance programs or costs.

Some organizations, or individuals within orga
iT

9. The system may have current uses for which it was not designed.

10. An assumption of perfect communication (no feedback,
mperfect communication is not.

) is common; planning for
¢, We generally assume that a trained person will
gperson assigned to schedule will schedule;
None of these assumptions is always true.

perform correctly. We frequently assume that
a placard will be seen; or a manual will be read.

11, Mistaking inter-communication effectiveness fo

r system efficacy may be an unwitting
ifice.

,, This means that we can hold inter ersonal communication so important that we may
Acrifice a more effective system to hold on to that interpersonal communication. Systems in
the interpersonal factor has been abandoned can be very effective. The automated voice
Directory Assistance in telephone service and automatic teller machines are examples.
obile rental car systems which provide automated driving directions with standardized
‘age represent another. Here, the driver indicates his destination and receives a map that
je same language every time. It is quite effective. Only now, in my opinion, is the aircraft
dustry beginning to exploit simplified English with standardized terms. Words such as
semble," "lubricate," "shall," and "would" should have consistent meaning.

12. There is a normal (input) difficulty in specifying in advance what information will be
. This may create a problem in supplying information.

f A manufacturer may supply in
cause of the difficulty in specifyi
fofmation will be needed.

adequate information about maintenance of a new aircraft
ing -- before operational experience has been gathered -- what

F13. There is no magic in com

munication; it cannot offset poor planning at input,
Ormation, or output stages. ‘

any examples support this conclusion. A supplier cannot fix an incorrect part shipment by
ps alone; a manufacturer cannot correct a poor design with a sophisticated communications

if an operator cannot overcome a fundamental scheduling problem by generating

43



Criteria for Equating Human Tasks

We at the U.S. Nuclear Regulatory Commission, as | suspect is also true for the Federal
Aviation Administration, suffer from a Tack of appropriate and quality human performance data
to support some of the decisions we must make. There are many reasons. We work in a
regulatory environment; there are logistics difficulties in collecting data and we have superficial
data-gathering protocols; reporting systems do not emphasize human factors; there is limited
involvement of human factors specialists, and always the cost.

In order to make proper human performance data more available, the USNRC has
Contracted with the George Mason University to develop psychological and behavioral criteria
for equating human tasks within and between industries and the military. A taxonomy of data
from a variety of sources also is being prepared which we hope to use as part of our technical
basis for analyses and decisions. These criteria should be useful in many circumstances, For
example, an Army investigator studying maintenance on an Abrams tank might be able to make
good use of human performance data from the nuclear industry simply by being able to justify
equating the tasks.

As we are developing our taxonomy, we are soliciting any kind of human performance data
from any kind of environment that might be useful for inclusion in this taxonomy. Interested
persons may contact the USNRC or the Center for Behavioral and Cognitive Studies at the
George Mason University.

In summary, we are engaged in five major efforts at the U.S. Nuclear Regulatory Commission
to develop data management systems to improve operator and maintenance safety and
reliability at nuclear power facilities. The systems we have developed are not tailored specifically
to nuclear power operations but, instead, may be applicable to maintenance activities in many
other settings. We welcome inquiries from others who might wish to expand the use of these
technologies.

76



points, multiple indexes, and rich navigation support features like graphic maps and numerous
prespecified paths. CD-ROM provides the needed storage capacity to make these features
possible. In return, hypermedia provides CD-ROM with an excellent justification. Without a
good user interface, CD-ROM is just digital microfilm, and the enormous amount of storage
capacity it provides means more places to put information to make it inaccessible or unusable.

Problems and Prospects for Hypermedia and CD-ROM

Who can resist the vision of a hypermedia maintenance manual in which thousands of pages
of text, graphics, voice, and other diverse information sources are seamlessly integrated by links
with each other? The diverse set of projects in which hypertext concepts have already been
applied and the excitement in the popular press about hypertext is encouraging many more
hypertext projects in still other application areas.

Nevertheless, hypertext applications that make information more accessible, more useful,
and more entertaining are hard to design and build. Some of the problems result from the
design tradeoffs that are involved in creating hypertext units, links, entry points, and navigation
support features. But from a project perspective, there are more global obstacles that hypertext

roject managers and their organizations must overcome for their projects to be successful. |
ave presented in another paper some of these challenges in "Making the Hypermedia Vision
Happen (Glushko, 1990b). Here | discuss some of the problems that are most directly relevant
to the context of maintenance information.

Realistic Expectations

Most organizations that get interested in hypertext start with a small-scale demonstration
project. Typically, this demonstration project uses a popular hypertext program like HyperCard
and emphasizes user interface capabilities. A carefully hand-crafted system is built to show the
enhanced usability that hypertext features, like links and navigation aids, bring to a problem that
might previously have been handled in a traditional database or document archive with a less
user-friendly interface.

The apparent success of the demonstration project justifies the start of a full-scale
development program to convert the entire database or document archive to hypertext. But too
often this full-scale development is doomed to failure. The organization tasked to carry out the
follow-on effort often has. unrealistic expectations about how hard it is and about the capabilities
and resources needed to do it. Many demonstration projects "succeed" by using methods and
tools that are impossible to scale up (Alschuler, 1989). Often the demonstration project uses an
off-the-shelf software package that provides neither the capacity nor the performance to deliver
the bulk of information now managed by the traditional database or file system. Worse, the
information examples and links in the demonstration project may have been carefully hand -
crafted, an unworkable approach for a system several orders of magnitude larger. If a
demonstration project takes three months to convert five procedures from an manual into an
interactive hypermedia form, how long will it take to convert a thousand procedures using the
same techniques? Automatic or semiautomatic techniques are the only realistic option for large
conversion projects.

A related problem of expectations results with CD-ROM when people focus on the
duplication and distribution costs, which are negligible, and ignore the development costs,
which can be considerable.

Design Guidelines
Because hypertext is a relatively new design field, there are few detailed published case

studies or design guidelines that designers can readily use. Published reports about hypertext are
not representative, typically biased toward small-scale demonstrations or research projects.

84



Technical Report Documentation Page

T. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

DOT/FAA/AM-90/ 14

4. Title and Subtitle 5. Report Date

Human Factors Issues in Aircraft Maintenance November 1990

and Inspection: "Information Exchange and 6. Performing Organization Code
Communications”

; + - [B. Performing Organization Report No
7 Author!

James ‘F. Parker, Jr., Ph.D.
| William T. Shepherd. Ph.d,  ‘CovPdttors)
9. Performing Organization Name and Address . Work Unit No. (TRAIS)
BioTechnology, Inc.
Falls Church, Virginia Contract or Grant No.

. Type of Report and Period Covered

12, Sponsoring Agency Nome ond Address

Office of Aviation Medicine
Federal Aviation Administration
800 Independence Avenue, S.W. ~ Sponsoring Agency Code
Washington, D.C. 20591

15, Supplementary Notes

16, Abstract

The Federal Aviation Administration sponsored a 2-day meeting in December 1989 as
part of a continuing program to address issues of human factors and personnel per-
formance in aviation maintenance and inspection. This meeting focused on issues
of "information exchange and communications." The primary goal was to consider
means of ensuring that the exchange of information within the industry responsible
for the maintenance of the U.S. air carrier fleet is accurate, efficient, and
responsive to the particular needs of this industry.

Presentations were given by representatives of commercial aviation interests and
covered related efforts from other fields and new technologies having possible
application to aviation maintenance. Each presentation was recorded and trans-
cribed for purposes of study and publication.

Eight recommendations were made to the Federal Aviation Administration regarding

effective communications methodology among the various members of the maintenance
industry.

17. Key Words 18. Distribution Statement

Aircraft Maintenance This document is available to the U.S.

Aircraft Inspection public through the National Technical

Human Factors Information Service, Springfield,
Virginia 22161.

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No, of Pages | 22, Price

Unclassified Unclassified 139

Form DOT F 1700.7 (8-72)

Reproduction of completed poge authorized



a given technician) of once or twice a year. Obviously a technician cannot remember detailed
Maintenance information for all such tasks. This is a major reason why error in maintenance is
generally accepted as a given.

Information to support maintenance is of two broadly different kinds, as shown in Figure 2.
One is procedural, i.e., information to support operations. Procedural information usually is
oriented toward corrective and periodic maintenance. The other kind of maintenance
information is descriptive, which explains how a system (or equipment) works. This is the type of
information technicians use to generate their own procedures at the worksite. Bear in mind | that
before one can perform, knowledge must be transformed into procedures. Performance

problems start to appear when technicians use the descriptive, cognitive process to drive virtually
all their tasks rather than rely on manuals.

As a rule, technicians tend to rely on their memory or "cognitive" capabilities, or ask their
peers. Maintenance manuals tend to be used as a secondary source of information. Air Force
research has shown that those who do use manuals tend to be the most experienced. The
reason appears to be that the inexperienced can get information from their peers or supervisors.
The experienced technician has no other place to go, so he uses the manual.

Procedural information can be partitioned into a number of information items, as shown
below:

What to do

How to do it

Sequence -- the order of task performance

Location -- where work is to be done

Identifications/context -- the specific item to receive the action
Tolerance -- how the equipment is to respond to the task

eceoveoe

Descriptive information also can be considered in terms of smaller units, as shown:

Systems context -- how the system fits within a larger system

Functional relationships -- relation to other system components

¢ Physical-functional relationships -- the physical unit that is to be manipulated, adjusted,
replaced, or repaired

* Physical characteristics -- features relevant to diagnostics such as location of test points

oe

Use and Usability

The use and usability of information are two separate but closely related issues. Several
factors affect use of information. When emphasis is placed on accountability in performance,
technicians will tend to use information more than when accountability is not a factor.

if the usability of information is high, it will also foster (but not guarantee) usage. The less
energy required of a technician to use information, the greater the likelihood he will use the
information. This concept applies whether one is speaking of manuals or computerized
presentations,

Use policies also are important, with most policies so broad as to be of essentially no use. For
example, directives at some military facilities state that "All maintenance personnel are required
to use manuals." Experience has shown such directives to be of little or no use because
Management usually does not enforce such broad directives. Peer pressure is another major
reason why in most situations technicians do not use manuals, One tends to work as the others
around him work.

110



The process of implementing an expert system is shown by the Expert System Model chart
(Figure 1). You need a few "ingredients" for a successful implementation. First you need an
expert. The field of Knowledge Engineering has developed to handle the task of converting the
individual's experience into a series of rules. The rules have the following format: "if these
conditions are present, then the following conclusions can be made." It is surprising that our
knowledge can indeed be summarized by a rather small number of rules. A typical domain can
be modeled with on the order of 250 rules and very large systems rarely require more than 1000
tules. The knowledge of several human experts may be combined into a single rule system.

Additional rules are also created using the technical reference manuals that a human may
utilize in the course of his work.

These rules will be the knowledge of the final product. The expert system has two other
major components. The expert system must manipulate the rules based on current information.
This is achieved via a Strategy and Control Section. The control section simply takes current
information, including any measured data, and compares it to the rules,

The final section is a user interface. This puts information into a form that can be understood

by the user. In addition, the user interface provides the user with the line of reasoning that was
used to reach a conclusion.

Emerging Technologies ‘

A number of technologies that are now emerging that have not yet been integrated into a
system. There is a developing capability in the area of voice recognition and speech technology.
This is important for the maintenance world, because communication via speech is hands free.
One such system is called "Dragon Dictate," by Dragon systems. It is a board that allows automatic

transcription of speech into a PC. It has natural language speech recognition, adapts to any voice,
has unlimited vocabulary, and is easy to use.

Another technology that could be utilized to facilitate access of information is a portable
video display screen that fits over the user's eye. It can be incorporated into a baseball cap. It
provides the illusion of a 12" screen that is 18" from the eye. The screen is only about three
quarters of an inch square and is called the "Private Eye." It was designed by Reflection
Technologies and is now starting production. The key is providing the mechanic with
information at a remote location.

Still in the initial phase of our project, we are continuing to investigate and evaluate existing
and emergent job performance aids and the related systems. We are continuing to pursue
airline participation for our field research, and points of contacts within the airlines. Your
comments and questions will be useful, too, and | invite your remarks. Please feel free to contact
me at Galaxy Scientific Corp., Mays Landing, New Jersey.

Thank you.

Us, GOVERIMINIT PREETING OFFICE 1990/561-020/20466

133



The Information Environment in Inspection
Colin G. Drury, Ph.D. ..

Data Base Support for Maintenance Requirements
of the Nuclear Power Industry
Thomas G. Ryan, PH.D. srssssssssssssssessssssnssesssssstecssssssscesssnescesengsocsraseressensesssssnesseneesssins 71

CD-ROM and Hypermedia for Maintenance Information
Robert J. Glushko, Ph.D. cssssssscssssesssssssssssssssssssssessecscesnassesccsrsesnsssensensssneresscesnsesesssnse 77

An Integrated Maintenance Information System
(IMIS): An Update
Robert C. Johnson .

Communication and Transfer of
~ Non-Destructive Inspection Information
Stephen M. BODO esssssssssessesssssssseeesansesseessnssssecsersssssssseraresunssssseeeesaenssssssenanatt 96

Converting Technical Publications into
Maintenance Performance Aids
Kay Inaba, PH.D. sssssssssssssssssesssnsssnnnunnssscssssssesseeseneesesssestsnnnsnnnasanesescccentseeeannsnannstts 107

Growth of Job Performance Aid Utilization
Daniel J. Berninger....

vi.



A number of factors affect manual usability. A listing of the more important includes:

* Accessibility

- Work breakdown structure
- Package

Portability

Completeness

Accuracy

Flexibility of use
Presentation

eeeee

Most items above are obvious in their importance. However, a brief discussion is in order
about two of these: (10) Flexibility of use and (2) Presentation.

As a technician gains experience in a particular type of work, his need for information
changes. Information systems/packages should be designed so that they will fit the more
experienced person as well as the inexperienced. This is difficult to do with paper systems but
somewhat more manageable with computer-based systems.

Presentation principles deserve considerable attention. Such principles are perhaps the most
important factor underlying the effectiveness of technical manuals designed to be used on the

job. These presentation principles, or guidelines, are based on past research in four fields. These
are:

1, Short-term memory research. Short-term memory appears to last for 15 to 30 seconds.
Thus, if information can be imparted to a user in these 15 to 30 seconds, one will get an
accurate translation of that information into performance.

2. Scanning research. This research provided guidelines on the amount of information to
present on a page or in a graphic.

3. Audiovisual research, While we have learned that presenting information in an audiovisual
mode is generally not cost effective, the research did provide valuable data concerning the
relative importance of text versus graphics.

4. Learning research. This research gave valuable guidance concerning proper ways to treat
descriptive information.

Presentation principles are divided into two broad categories -- one for procedures and one
for descriptive materials. Most principles concern procedures, and we break these into principles
related to text-graphics, text, and graphics. Text-graphics will be addressed first.

A cardinal principle for the use of text-graphics is that the text material and the graphics
should be presented "together." This means, for paper, on the same page or facing pages. For
cost reasons, this principle at times is not followed. As a compromise, the graphics may be
placed at the end of a procedure. In some cases, graphics may be placed at the end of the
chapter. In either case, however, expect a degradation of usability. The rule remains: The more
energy required to obtain information, the less likelihood the information will be used.

The role allocation of text and graphics is important. The following listing presents the
optimum allocation of text and graphics material:

111



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91


Source Files

Many hypertext Conversion projects are plagued by the poor quality or availability of sour f
files. Many documents have no digital form, and even when one exists, unless a hypertext versi

was planned or contracted for when the documents were created, the existing digital form may
not be readily usable.

Optical character recognition (OCR) technology is rapidly improving, and new OCR devices
that output text in SGML form are especially promising. Nevertheless, error rates are non-
negligible, so proofreading is always required.

Taken together, potential problems with source files make it essential that hypertext projects
carefully investigate source quality and availability before committing to a project schedule. A

single ocument sample may not be representative; often a large document or document
lection (such as the complete set of manuals for a lar

Cost-effective to have a third-party text conversion service transform all of them to a common
format than to use project software resources to carry out the conversion.

Hypertext projects whose application involves periodic publication of text created elsewhere
should define formatting standards and quality contro! procedures for the organization that
produces the information. These measures can lead to substantial improvement in the

productivity of hypertext conversion by enabling the development of automatic conversion
software.

Software Tools

Most off-the-shelf hypertext software is oriented toward creating new hypertexts and is not
well-suited for converting existing documents (Alschuler, 1989; Glushko, 1990a). Demonstration
projects often use this software to create expectations about the look and feel of a full-scale

implementation, and it often comes as a harsh shock to discover fundamental limitations in the
software that jeopardize the viability of a project.

It may be worth waiting for the next generation of hypertext software that directly supports
conversion. Alternatively, some database Programs or expert system shells may better support
hypertext features than programs that call themselves hypertext.

Summary: Toward Hypertext Engineering

| end this paper with a summary of what | have tried to convey about hypertext and CD-
ROM. Elsewhere | have characterized this philosophy as "hypertext engineering" (Glushko,
Weaver, Coonan, and Lincoln, 1988):

* Hypertext is an attractive vision, but practical hypertext applications are hard to build.

* Hypertext is not a revolutionary idea; it is the natural extension of non-linear presentation

conventions from print documents now that enabling technology and user interface concepts
have arrived.

* Disciplined approaches to analyzin information, identifying constraints in its structure and
P! pp yzing 8

in the task environment, and using the appropriate implementation technology are required.

Current hypertext software technology is better suited for creating hypertext than for converting
existing documents.

86



Another problem relating to delays in processing of information concerns the Service
Difficulty Report data base maintained by the FAA. The purpose of the SDR system is to collect
information concerning aircraft difficulties on an industry-wide basis and then analyze this
information as a basis for appropriate corrective action. However, these analyses proceed too
slowly to serve their avowed purpose. By the time an analysis of significant SDR findings is
completed, the industry is aware of the problem and has taken corrective action. The value of
the SDR system could be increased significantly if it could work in a more timely manner.

Recommendations

1. New procedures to improve the flow of maintenance information must be
developed. Needed information should be prepared expeditiously and transferred
by electronic means. At this time, some 37 airlines obtain their maintenance
manuals, or some portion of these manuals, on magnetic tape from Boeing. This is
a beginning toward a complete electronic system. However, a truly satisfactory
system will require that all transmissions of maintenance information, particularly
those with safety implications, be done electronically. Movement in this direction
should be encouraged.

2. The Service Difficulty Reporting System must provide needed information more
rapidly. This is particularly true for analyses which show maintenance trends.
Software should be developed for the SDR data base which will perform a fixed
number of commonly required trend analyses upon request, with rapid distribution
of trend results.

Maintenance Manuals

The printed manual has been the mainstay for aviation maintenance for years. While the
format has changed little through time, the manuals have gotten bigger and more cumbersome
to work with. While manuals serve a worthwhile purpose as a repository for data and as a
reference source, they are not particularly useful for flight-line support. As a result, manufacturers
and operators have turned to alternate systems such as Automated Work Cards and
electronically generated copies of relevant portions of manuals. ATA has developed an
automated Aircraft Maintenance Task Oriented Support System (AMTOSS) in which each task
and subtask has a unique number identifier. Through use of this coding, an operator can collect
all appropriate and related tasks described in different parts of the manual into one grouping. He
can then build a basic work package.

The maintenance manual concept has been taken a significant step forward by the Air Force
in the development of the integrated Maintenance Information System (IMIS). This system
integrates diagnostic and maintenance information and presents it to technicians at the flight
line through a portable maintenance aid with a hypertext user interface. With this system, there
is no need for a maintenance manual. All technical data, diagnostic rules, aircraft-specific
information, etc. are presented as requested by the\technician.

Another approach moving away from the traditional maintenance manual concept is the
On-Board Maintenance Information System (OMIS) being explored by Boeing. This system will
provide all required data to support ramp and flight line maintenance on a given airplane. OMIS
also will carry information concerning the maintenance history of the airplane on which work is
being done. All necessary information for maintenance needs will be provided.

Recommendations

1. The movement toward electronic maintenance information systems represents a
significant advance and should be fostered by whatever means feasible. However,
the rules for effective presentation of information remain the same, whether the
presentation is in paper or electronic form. The FAA should consider the

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U.S. COMMERCIAL AIRLINE FLEET
Average Age: 12.7 Years

S to 10 Years (20%)

Oto S Years (19%)

10 to 15 Years (14%);

15 to 20 Years (20%) Over 20 Years (26%)

Total Aircraft: 3,671

NOFLTAGE. OG

Figure 2. Estimated age of the commercial airline fleet.

DESIGN GOAL VS, HIGH TIME AIRCRAFT
400 - \ Design Goa
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Figure 3. Comparison of design age with actual age of highest time aircraft
in fleet.

98



CD-ROM and Hypermedia for Maintenance Information

gs

Glushko, Ph.D.

is with Maintenance Information

aircraft are complex systems that require tens or hundreds of thousands of pages of
formation to operate and maintain them. This information is organized as hundreds
created by dozens of contractors and subcontractors. To make it easier to keep
accurate and up-to-date, this information is logically organized (perhaps according
her standards), which helps minimize redundancy. However, this means that many
e information from different parts of a manual or from more than one manual. In
lowing cross references to find needed information is a simple task: we all can
ing a bookmark or a thumb to hold our place in a book while we turn elsewhere. But
it is always time-consuming and error-prone for the maintenance mechanic to track
ded information that is spread throughout manuals, since thousands of pages of
f occupy dozens or even hundreds of "shelf-feet.". The mechanic might have with him
54 of four most useful manuals, since that is all he can carry, and important information
to be back at the hangar or maintenance depot in yet another manual. This means
nance must often be carried out without all the information that could conceivably

olution: An “Intelligent Electronic Manual"

Reently, many people have been proposing various realizations of an “intelligent manual"
these problems with locating and using information in large document collections. The
‘theme is to use a portable computer with enough storage capacity to contain all of the
ffon from the printed manuals. Typical features o! this intelligent electronic manual are:

amounts of storage for text, graphics, illustrations, and other kinds of information

Snort for familiar ways of finding information, using tables of contents and indexes
er entry points that are impossible on paper but made possible by the presence of the
, such as (1) full-text search through the information database for sections that contain
Gids or phrases or (2) interactive troubleshooting using intelligent assistance

play functions for viewing information page by page or for browsing by jumping many
a time

gressive display of detail, so that a reader can start with an outline view of the
ation (like a table of contents) and then "zooming in" to get details where they are

omputer-supported cross references or links between related information that can be
followed to display the cited information as if it were directly connected

embedded training and job aids, often using media like audio or video to optimize the
yctional transfer.

77



Table 1

COMMUTER AIRCRAFT VENDORS

AIRCRAFT VENDOR US GOV'T FOREIGN GOV’T
!) AEROSPATIALE FAA DGAC
| (Direction General
Aviation Civil)
2) BEECH FAA *N/A

3) BRITISH AEROSPACE FAA CAA
(Civil Aviation Authority)

4) CASA FAA DGAC
(Direction General
Aviation Civil)
5) DE HAVILLAND FAA MOT
(Minister of Transport)
6) DONIER FAA LBA

(Civil Aviation Authority)

7) EMBRAER FAA CTA/EC
‘Center Tech Aviation)
‘Certification Office)
8) FOKKER FAA RLD
(Bureau of Aviation)
9) FAIRCHILD/METRO FAA * NWA
10) SAAB FAA

CAA .
(Civil Aviation Authority)

CAA |
(Civil Aviation Authority)

11) SHORTS BROTHERS FAA
* U.S. Aircraft Manufacture

37



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Intracompany communications are beginning to be supported by new ideas concerning
teamwork in maintenance. In most maintenance operations, however, individuals still have
clearly defined job assignments and job roles and rigidly adhere to these. Expectations for these
people can be identified completely in terms of their job descriptions. This is not a flexible use of
personnel nor does it foster productive communications.

Using teamwork in maintenance, people retain specific job assignments but are given more
freedom to work with other units and to develop better procedures for cooperation. In one
instance, an organization determined that it was top heavy in the specific job of quality control
inspectors. Rather than continue with an inefficient organizational structure and organizational
staffing, some of the quality control inspectors were given a training role and assigned to work
with some of the less skilled mechanics. Now, rather than simply saying "this is wrong, do it over,"
inspectors guide the mechanics through the process and become what might be termed "allies
in maintenance." The improvement in maintenance could be attributed both to the
redefinition of roles and to the improvement in communications between specialties.

As a final point for your consideration, | would like to note that Japan Airlines now forms
maintenance teams for specific aircraft. These teams focus on one particular aircraft. This
approach is expensive since Japan Airlines has almost double the ratio of mechanics to aircraft
that we find with the American system. Their teams include specialists, for example in hydraulics,
electronics, and avionics, and the point is that they are willing to invest that. Whether this is a
good investment or whether it is the appropriate solution for the U.S. is debatable. However it
does maximize collaboration among maintenance personnel and certainly fosters good
communications between the maintenance team and the flight crew.

In conclusion, | would like participants at this meeting to seriously question the extent to
which there is collaboration and community within the air transport industry. Are our
communication systems as good as they might be? Can we find ways to deal with some of the
barriers to information exchange and instead use these features of our maintenance system as
means for facilitating information exchange.

49



Finally, two to three related actions per step will keep the instruction within short-term memory
capacity.

The term "related action" is important to understand. For example, the instruction "remove
ten bolts, remove cover" is acceptable even though it exceeds the two to three related actions
per step. The reason is that when the technician removes the ten bolts, the cover is loose and he
then remembers that he should remove it also. On the other hand, the instruction "close valve
236A and valve 767C" is not acceptable. By the time the technician finds the first valve and
closes it, the probability that he will forget the second valve is too high.

Figure 6, 7, 8 and 9 illustrate the use of the basic syntax. In Figure 6, the word "loosen" is the
command verb, with "clamp" the object, and “from scuppertube" the qualifier for this action. At
times, the qualifier can be eliminated since it may not add information. When the clamp is
shown in proper context in'an accompanying graphic, "remove clamp" is adequate. At times,
qualifiers are essential to the meaning. For example, in Figure 7, the qualifier “until oil level
indicator is at FULL" is essential because it qualifies the action. It tells you the tolerance.

The current list of action verbs we are using is shown in Figure 10. This list may be adjusted
somewhat from project to project but, in general, in its entirety would not exceed 120 action
verbs. We refer to these as required verbs. We do not allow synonyms. if we use the verb "raise"
for an action, it is always raise. It is never "lift;" it is never "elevate," It is always "raise." To work
with these verbs requires a different kind of discipline and a different style of writing, one closer
to programming computers than to writing text.

Figure 11 presents principles relevant to graphics. The key point in use of graphics is to
present a context and show the items in that context. This applies to the use of graphics in both
procedural and descriptive materials.

It is quite important to avoid clutter in graphics, which again raises the issue of fidelity. Many
designers of manuals try to use actual pictures, which of course have high fidelity. However,
studies show that line drawings are superior to pictures. The basic reason is the negative effect of
clutter found in pictures. For example, a line drawing of a circuit breaker board, holding a
number of circuit breakers, does not need to show circuit breakers as such. The illustration can
simply show circles. The key for the graphics is to provide some clue that the technician can use
to find a specific circuit breaker. The clue can be the right corner, the left corner, or a line
running through the center. The entire board does not have to be shown. The technician relates
relative position on the board (e.g., a specific breaker) to a known point (e.g., the upper right
corner).

Extensive use should be made of call-outs in graphic presentations of technical information.
Scanning principles should be followed in the use of call-outs. Figure 12 is a sample of a graphic
which is not particularly effective. | defy anyone to find the number 129 within a few seconds.
Yet this is not an unusual drawing for a manual

Presentation Principles for Graphics

© Provide context
* Show in context
(for !ocation and identification)
* Reduce items not relevant to task/subject
(Avoid clutter)
Figure 11


Better Utilization of
Aircraft Maintenance Manuals

Richard G. Higgins
Boeing Commercial Airplanes

The use of digital data to support aircraft maintenance Operations is a fact of life now.
Specification 100 of the Air Transport Association (ATA) Says we must use digital data. The
Boeing Company is firmly committed to such use and is moving rapidly in this direction.

The use of digital data systems is Necessary because of the tremendous documentation now
required to support aircraft maintenance. Boeing delivers about 70 manuals to support an
airplane. To illustrate this information overload, Figure 1 presents a partial list of maintenance

data deliverables supporting a single airplane. The list shown in this Figure is less than one-half of
the total number delivered.

The volume of maintenance documentation prepared by Boeing each year is massive. Figure
2 shows that the 1988 publishing activity at Boeing included maintaining 1,126 active manuals
for some 5,300 airplanes and 425 operators. The size of this data base gives us almost 20 million
Page sets to maintain, with each manual being revised on about a 120-day cycle. Some years
ago we used Mt. Saint Helens, about 8,000 feet tall, as a comparison for the height of the paper
stack we publish each year. Now we have passed the height of Mt. Everest for comparison

Purposes. Soon we will begin to make our comparison with the 100,000 foot tall mountain on
Triton, a satellite of the planet Neptune

Our paperwork volume is a problem because none of us can deal with these data in an
efficient way any longer. The person who can pick up a document and efficiently translate that
information into an airplane action is quickly disappearing. This is true even though that person
might have a support staff, Federal regulatory agencies, airframe manufacturers, and many others
trying to help him. The data are difficult to use because, for example, one might need three or
four of these documents at a minimum for a particular task.

Apart from the complexity of the documentation, there is the time factor in publication.
There is approximately a six-month turnaround time to get an issue into a document and

available for users. The existing production process is simply too slow to support customer
requirements.

In an attempt to better understand our documentation Process, some time ago we began
asking customers about the way these documents were used, particularly for maintenance
planning. As shown in Figure 3, maintenance data is received y the customer in paper or
microfilm form; the data undergoes some customization; and the information then is used in a
manual task-planning process to structure aircraft maintenance.

In 1980, one customer asked us for a magnetic tape of their maintenance manual. At that
time, we didn‘t quite understand why they wanted it, but since we could produce it from our
system we gave it to them. This continued for a few years and more customers started to ask for
Magnetic tapes. Thirty-seven airlines now get some of their maintenance documents in digital
form from the Boeing Company. They load these tapes onto their own computer, exercise
certain customization, and produce automated task planning for their maintenance.

As we move into increased automation in the delivery of maintenance data, the Air
Transport Association is developing requirements designed to standardize the manner in which
all of us approach this issue. The listing in Table 1 illustrates recent ATA requirements for

54



Information Needs of Aircraft Inspectors

Michael T. Mulzoff
Pan American World Airways

Predictions concerning the future role and information needs of aircraft inspectors can best
be made by first examining the evolution of that Position. Let's look back four decades at the
inspector -- how he has changed, and how his job has changed. We will begin in 1947, simply
because I first became an inspector in that year and can personally attest to that environment.

The 1947 mechanic and inspector had a different relationshi
today. In those simpler times, a mechanic was more than vaguely
of his aircraft and could essentially maintain most systems on his
(‘avionics" had not yet been born) was the one exception. Sti
aircraft had not yet arrived,

ip with their aircraft than exists
familiar with most components
‘own. Even in those days, radio
Il, the complexities of today's

In the 1940's, "HARD TIME" was the prevalent maintenance P
all major components were removed at Specified intervals, regardless of their condition or how

they were performing. These fompanents were overhauled after which they were considered
essentially new, and reinstalled with "zero time."

rogram. Under this program,

In addition to periodic component removals, these programs relied heavil
frequent maintenance performance checks of the aircra

involved in accomplishing these system checks (pressures,

ly on relatively
systems. Inspectors were most often
, temperatures, operation, etc.).

Inspectors were also responsible for determining condition of the aircraft Structure. Although
of serious concern even in those days, the task was relatively simpler with the absence of
Pressurized fuselages and fleets that were less aged than is common today. As a result of these
Maintenance program requirements and less demanding structural consi erations, the majority
of a typical 1947 inspector's time was Spent on aircraft systems rather than structures.

Inspection equipment was also much simpler when measured by today's standards. Dye
Penetrant and metal particle inspection methods were the main processes in use throughout
the 1940's and 1950's. X-ray was a dental tool not often seen at the airport.

Throughout these four decades of evolution, some form
used to outline the task to be done, and as a signature receipt for accountability. Early guides
Most often provided a general description of the task required, in most cases relying on the
mechanic's or inspector's knowledge for proper accomplishment. As the aircraft became more

complicated, the guides became more complex, and presently often contain detailed
instructions, specifications, and illustrations.

of work sheet or guide has been

was patterned after the military schools and
was excellent. This training provided the bulk of the airline workforce with their basic aviation

education into the mid-1970's, This training concentrated on detailed systems knowledge which
supported the "HARD TIME" maintenance Program reliance of maintenance system checks,

Now let's move forward to the maintenance environment of the 1990's. Along the way,
industry and the Federal Aviation Administration (FAA) recognized that systems could be best
maintained by monitoring the continuous Operating performance of the systems as reported by
the flight crews. This would provide immediate knowledge of deterioration and be more
effective than a later alert by a scheduled maintenance check. This ability to detect

50



Document Examiner Pegeenotton tebetace Fectictes

G
Reta-Presentation Arguments to Presentation
Inher tance of Presentation
thon types form the basis of the typing system tor user input Presentecton-Type Definition Fecit
ram output. A large number of predalined presentation types
‘aly few ace used for program W/O. This Is because every
fommon Lisp data type is alto a presentation
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‘ample, the Common Lisp types hash-table y 1d Date Types ae Pres
‘complie: /ou would not generaliy encounter these in inplor ing Presentation types
ond user-visible pl Show Wenalors For Types Connend
In this section, we list what we regard as the types most likely to be Presentation Inspector
used by application programmers. Some, Iike Integer, sting, and
ber ncountered frequently in all kinds of programe. Many
yaxcode-fragment and natinatwork, are more
uses.

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indows} atenderd-present at ion-types. tsp, where Bookmart

look for models when defining your own types. The dictionary a

Sry or ‘Sach type notes wheter Ais eo a onary Je Predefined Presentation Types Section
ie. tude

The documented types are divided lato thes groups:

1. Common Lisp Presentation Types

2. Symbolice Common Lisp Presentation Types

3. Other Prasentation Types

Qf course, the Common Lisp types form a aubset of the Symbolics

Common Lisp types, but for the pucposes of the present discussion,

wa Separated them out, The Other Presentation Types include the

Potentially useful types exported from packages other than Symbolice

Common Lisp; most of them are In the specialized-use category.

‘The following table Ilets the useful Common Lisp presentation types:

Predefined Presentation Types
Prose

‘etion Types
resentation

‘Common Lisp Presentation Types.
‘and

character
1 Standard (Reader)
Show Candidates Hele
© Show Overview Predefined Presentation Type: Show Documentation Select Viewer
Db Find Table Of Contents Presentation Substrate Facilities Show Overview Reselect Candidates
& Show Decunentation Predefined Presentation Types Show Table of Contents Private Document.

ma
ther commands, press Shift, Control, Meta-Shift, o Super.
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Figure 2, Document Examiner

online reference manual with 30,000 pages of documentation for an aluminum rolling mill (Van
Sickel, Sierzega, Herring, & Frund, 1988).

Engineering Data Compendium. The Engineering Data Compendium is a 3000-page
reference book containing over 1100 articles about various aspects of human perception and

performance, developed by the U.S. Air Force Armstrong Aerospace Medical Research
Laboratory at Wright-Patterson Air Force Base, Ohio (Boff & Lincoln, 1988). At first glance, it may
seem to be the perfect candidate for hypertext: it consists of highly structured articles designed
to stand alone, that are enhanced by a rich set of cross references, and that can be accessed
using several complementary entry points. These entry points include a scientific table of
contents, an extensive back-of-the-book index, and an alternate table of contents called the
design checklist. The design for a hypertext version of the Compendium (Glushko, Weaver,
Coonan, & Lincoln, 1988; Glushko, 1989) calls for hierarchical outline viewers for the existing
entry points, hypertext links for the explicit cross references, and derived hypertext links for
implicit cross references like embedded glossary terms and shared keywords.

Figure 4 (Glushko, 1989) depicts the original design for the hypertext Compendium. The
boxed "buttons" in the sidebar at the left are hypertext links to other entries. The "Bookmark"
function in the menu at the top of the screen is modeled after the bookmark panel in the
Document Examiner interface, but the small screen for which the former design was intended
turned a dedicated screen area into a menu function.

80



eae

IMIS - A CALS CONCEPT FOR MAINTENANCE

On-Board Diagnostics Ground Processing & DataBases
(Buitt-In-Test, Flight Data) (Job Control, Debriefing, Supply, History)

Se FA

‘Workstation Interface

ee \ ee”

Portable Maintenance Aid
Automated Tech Data, Diagnostics,
Training, and Data Collection

Figure 1

With IMIS, a technician will not have to worry about aircraft configuration. The airplane will
identify itself to the portable computer. Then the technician will be provided with individual
data that applies only to that airplane. He will not have to sort through data anymore to see
which data apply.

A technician working with IMIS will deal with one computer interface only. All data will be
provided through this interface. The technician himself should not care about this, as long as his
information needs are being met.

An operational IMIS system should improve operational capabilities of technicians through
more effective presentation of maintenance information. The quality of technical information
will be improved and tailored to meet the technician's needs. Time-consuming paperwork will
be reduced through automation. Improper parts removals also will be reduced through
improved diagnostics. The result, from the Air Force point of view, will be better utilization of
available manpower, an improved capability for maintenance in dispursed operations, and more
mission sorties with available resources.

Figure 2 illustrates the flow of data in and out of IMIS. The circle showing "flight data," for
example, refers to information obtained directly from the airplane. In the Advanced Tactical
Fighter, when a module fails, IMIS will be provided information about the altitude at which it
failed, the G-forces operating against it, pressures, vibration, and other information important for
maintenance. The important thing to note is that IMIS provides all of this information through
one interface. If IMIS were not available, the technician would have to interact with computer
systems for each one the outside circles on a daily basis.



numerous memoranda; and a regulatory agency cannot make a staffing problem go away by
widening its communication network.

Finally, | would like to offer a few recommendations. These are global recommendations, but
the topic itself is global.

1, There should be an ongoing program to solicit ideas for communication mechanisms to
support maintenance. People in all parts of our industry are involved in communications. They
have needs and they have certain ideas for answers.

2. Feedback should be used to improve communication processes. Feedback to improve any
process is a necessary step, and feedback often is ignored due to our assumption that the system
is working as it should,

3. We should intentionally focus on communication mechanisms. There are specialists who
know about communication and how it works. Studying what these people have to say or talking
with these people might provide new insights into means for improving or fixing problems in
given communication links.

4, We can evaluate communication mechanisms. Are they serving the purpose for which
they were intended in the first place? Are they truly effective? Regarding communication
effectiveness, | would like to relate an incident that happened as | was boarding a plane in
Orange County to come to Washington. At this time the John Wayne Airport is undergoing a
major building program and does not have jetways or other motorized conveniences for planing
and deplaning. Planes must line up on the apron or tarmac or gate area one-by-one and
passengers have to walk to the aircraft. Just before | boarded the flight, the boarding agent said
over the public address system, "Flight 1256 is in final boarding. Passengers should proceed
through Gate C. The plane is in the middle of the runway, it is facing south, and it's a Boeing."
Other than the experienced traveler, who would know where to go with these instructions?
How much of our communication in maintenance could take on similar tones because the
communication is not clear and the maintainer does not know where to go with the
instructions? There is still much to be learned concerning the communication process and ways
for making it most effective.

44


performance parameters observed. Some systems collect the information automatically and
record it, and recently American Airlines has set up systems for real-time collection and
transmission. Some systems require the flight crew to manually record the data that is then
analyzed when the aircraft is on the round? All of the systems use the information in the same
way, by continuously monitoring the trends to spot anomalies. The end result is increased
aircraft availability and lower overall engine maintenance costs. TEMS and its family of systems is
used by the U.S. Air Force to track its entire fleet of engines.

TEXMAS: Turbine Engine Expert Maintenance Advisor System. TEXMAS is utilized in
conjunction with monitoring systems like TEMs. Rather than having humans do all of the
analyses, TEXMAS uses human-like reasoning to achieve the same end. It takes the raw data and
carries out functions such as engine performance measurement, event monitoring, and life
monitoring. TEXMAS can also be used to walk an inexperienced mechanic through the process
of diagnosis. TEXMAS is based on expert system technology, which can be thought of as an
alternative approach to programming computers. | will talk about it in more detail at the end,
but in effect one comes up with rules that can be applied to different situations and when the
proper conditions are met.

VSLED: Vibration, Structural Life and Engine Diagnostics. VSLED is representative of the
latest generation of performance aids in that it is integrated into the aircraft itself. It is unusual
because it extends the familiar engine monitoring to the aircraft structure. This is done by
monitoring parameters and analyzing trends as with engine monitoring. In the case of the
structure, there are sensors on the aircraft that sense stress and vibrations. The goal VSLED has in
common with other systems is to reduce the overall maintenance hours. VSLED takes several
systems and brings them together. It continuously monitors parameters and has automatic
detection of limit exceedance. In addition, it can take the data and perform fault isolation.
VSLED is the on-board maintenance system for the new generation of V-22 Helicopters.

AIMES: Avionics Integrated Maintenance Expert System. AIMES takes the monitoring idea
and combines it with reat time diagnosis. This is important for avionics problems, because a
substantial percentage of the problems that occur cannot be repeated on the ground. Thus, the
knowledge of the mechanic is coded on the computer in the form of rules, and the AIMES
system does fault isolation while the aircraft is still in operation.

CITEPS: Central Integrated Test Expert Parameter System. This system was developed by
the U.S. Air Force Wright Patterson Aeronautical laboratory for the B-1B. CITEPS utilizes
information from the monitoring systems and built-in-test (BIT) systems to perform fault isolation.
It is also expert-system based, using rules that are developed from talking with experienced
maintenance personnel.

XMAN: Expert Maintenance Tool. This system was developed by Systems Control
Technology Corporation for the USAF A-10A. This was designed to be a user interface to the
maintenance database created by systems like TEMS. It is an aid designed to automate
diagnostic and trouble shooting procedures. Since it can communicate to the user the
sequence of conclusions in the diagnostic procedure, it can be used for training.

Most of these system and others such as the BIT systems for the new AIRBUS aircraft
underwent a rocky implementation process. It turns out that getting built-in-test to function
properly and the expert systems to make an accurate diagnosis is extremely challenging. To
make matters more challenging, even 90% accuracy is not sufficient when it comes to gaining
the confidence of the maintenance workforce. One can imagine that even if the machine is
correct 9 out of 10 times, spending a shift or two on a “wild goose chase" can make you think

131



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124



computers will mean to those going through school today. My three-year old daughter is already

laying with computers. She uses a Sesame Street program that | loaded on the computer at
ome.

Job Performance Aids

Now, | have said enough about the computer as a stand alone item. As many of you know, it
is not as easy as just giving everyone a terminal. During the 1980's, computers started to have a
presence on the maintenance floor. Although no one would be able to go back to the way
things were, it is not clear that everything about the introduction of the computer was positive. It
is also clear that data was often collected simply because the computer could provide it. In
some cases, it became unclear whether the computer was aiding the human or the human was
aiding the computer.

Our initial research has demonstrated that this is indeed the time for action, but by no means
is it a time for panic. From what we have seen, we have more reason for optimism than dread of
the future. This sense of optimism only comes after viewing all sides of the issues. | would like to
highlight one aspect of our findings that addresses another side of an issue that has come up
several times during this conference. The issue is still human factors, but not the human factors of
the worker, it is the human factors of the designer.

Several talks and subsequent questions addressed to speakers have raised concerns about the
integration of computers on to the maintenance floor over the past decade. A number of horror
stories were related and it was clear from the discussion that some of these systems were more
hindrance than help. First | will say that is, indeed, consistent with our findings. We have not
come upon a system that will be the "savior" of maintenance. Further we can confirm the finding
that the main problem is the lack of human factors consideration.

The next step is to understand why this is the case and how to avoid it in the future. We want
to answer the question of why the systems that have been implemented so far have such short
comings.

First one needs to understand the design process of these systems. It is easy to criticize
complex systems, once they are built and operational because limitations are self-evident.
Unfortunately for the designer, the entire design and implementation process must take place
with relatively little opportunity to observe operation. Even at junctions when observations can
be made, changes are impractical unless they relate to the basic functionality of the system.
These observations are typically known as “niceties" by designers, and are unaffordable, since it is
a struggle just to get the basics running. Although there are some exceptions, human factors
considerations are almost always put in the nicety category, and thus are missing from the final
product. It is now becoming apparent that for systems used by humans, nicety is probably not a
good definition of these elements.

It is a difficult problem to solve, because human factors issues are difficult to identify up front
and nearly impossible to implement midstream. The final product is almost entirely dependent
on the original effort at setting requirements. The requirements are made too early in the
process to be complete.

The message is that poor human factors design is not due to a conspiracy by equipment
designers. It is due to a limitation of the traditional design process and the body of knowledge
that they have to work with.

Where human factors has been taken up in places like Boeing and Douglas the proups are
treated more in an advisory capacity. Someone else designs the component and the human

129


Table of Contents

Page
EXECUtIVE SUMMAFY ....ssersnesneseestsnseststinsnntsenntntsttatntsssssntineeetinstntvatistiiusseesese 1
IMtrOGUCtiON..ssssssssssssssssssssssscsseecscssccceesesnecees 3

Meeting Presentations

FAA Overview of Maintenance-Related Information Exchange
Dennis Piotrowski wesessseusesnsenssneenisuesisiusiussanininsrisneriesuisiseees 15

Major Air Carrier Perspective
Clyde R. Kizer..

Mid-Level Air Carrier Perspective
Thomas F. Derieg.

Commuter Airline - Vendor Communications
A. Fred GilOS sesesseescsssssssssssssnssissetsssstiassissisissiousaiussiassiassiisisissssecs 32

Human Factors Issues in Manufacturers’ Maintenance-Related
Communication
Anthony Major0s, PR. Deressssssesussssessnssiussessstsssssisesisssisetiasssisssisssssssueees 39

Facilitation of Information Exchange Among Organizational Units
Within Industry
James Taylor, Ph.D. seossessesssssesesssneseeiasesisstissssusssssussssiunssiisssississessaeeesee 45

Information Needs of Aircraft Inspectors
Michael T. Mulzoff........000.

Better Utilization of Aircraft Maintenance Manuals
Richard G. Higgins.



In logic terms, we learned that roviding information usable on the job is necessary but not
sufficient. If you do not provide usable job information, your chances of improving maintenance
effectiveness are quite limited. But given that you do, you still need to do more. Usable job
information is very important, but the entire maintenance system must be addressed.

A second lesson is that higher level management attention to maintenance tends to be
cyclical. This attention appears to run in approximately ten-year cycles. The reason is that
maintenance is not a popular or glamorous subject. Maintenance is not a favorite subject of
corporate executives. However, periodically executive attention is focused on maintenance
because of the large cost consequences of ineffective maintenance. But the attention won't last

long. Thus, if you are involved in maintenance and find you have the attention of management,
take advantage of opportunity while it lasts.

When management does attend to maintenance, changes are often introduced -- some

good, some not so good. These changes usually are short-lived. The result is usually a temporary
improvement in some aspect of maintenance.

In order to make a permanent change, the change must be institutionalized. An example is
the introduction of ATA-100, which helped standardize manuals in the airline industry. But it
had its drawbacks in that institutionalizing also tends to stultify growth. Your manuals are now
standardized, but are they usable? Have your manuals grown in usability? One way to overcome

this resistance to growth is to make accountability an important item in maintenance because
accountability focuses on performance.

Before concluding this discussion on lessons learned, | would like to share my favorite
quotation regarding maintenance. The quotation is by Eric Hoffer, sometimes knows as the "blue
collar philosopher." He states, "There is a phase of the war with nature which is little noticed but
has always impressed me. To me there is an aura of grandeur about the dull routine of
maintenance; | see it as a defiance of the teeth of time. It is easier to build than to maintain.
Even a lethargic or debilitated population can be galvanized for a while to achieve something
impressive, but the energy which goes into maintaining things in good repair day in, day out is

the energy of true vigor." This expresses admirably why maintenance attention has such a short
half life.

Information and Maintenance
(Figure 1)

tenance is Information Demanding

Maintenance is a stochastic system
Frequent design changes

Impact on maintenance technician
-Large number of infrequent events
-Multiple configurations
-Numerous error opportunities

The role of information in maintenance is a function of the unique nature of maintenance.
Maintenance is a stochastic system driven by essentially random events. The combination of the
stochastic nature of maintenance plus frequent changes in aircraft Configuration result in a
tremendous amount of information required. One Air Force study showed that approximately
80 percent of the work assigned a given technician consists of tasks that occur on the average (for

108



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inspectors in the equivalent of a continuous retraining program. Also, specific recommendations
have not been made, as they require completion of the ongoing task analysis study of the
National Aging Aircraft Research Program. Eftects of other important task variables (e.g., lighting),
job variables (e.g., social pressures), and individual variables (e.g., inspector's basic ability) have
similarly been omitted.

Acknowledgement

The research reported in this paper was supported by FAA's National Aging Aircraft
Research Program. The contract monitor was Dr. William Shepherd, Federal Aviation
Administration, Office of Aviation Medicine.

References
Bloomfield, J.R. (1975). Theoretical approaches to visual search. In C.G. Drury and J.G. Fox,

Human Reliability in Quality Control, Taylor & Francis, London, 19-30.

Chaney, F.B., & Teel,K.S. (1967). Improving inspector performance through training and

visual aids. |. Applied Psychol., 51, 311-315.

Drury, C.G. (1982). Improving inspection performance. in G. Salvendy, Handbook of industrial
Engineering, Wiley, N.Y., Chapters 8.4.

Drury, C.G., & Addison, J.L. (1973). An industrial study of the effects of feedback and fault
density on inspection performance. Ergonomics, 16, 159-169.

Drury, C.G. et al. (1987). Task Analysis. In G. Salvendy, Handbook of Human Factors, Wiley,
N.Y., 370-401,

Drury, C.G., & Sheehan, J.J. (1969). Ergonomic and economic factors in an industrial
inspection task. Int. J. Prod. Res., 7, 333-341.

Drury, C.G., & Sinclair, M.A. (1983). Human and machine performance in an inspection task.
Human Factors, 25, 391-399.

Embrey, D.E. (1975). Training the inspector's sensitivity and response strategy. In C.G. Drury

and J.G. Fox, Human Reliability in Quality Control, Taylor & Francis, London, 123-132.

Gallwey, T.J., & Drury, C.G. (1983). Task complexity in visual inspection.

Gillies, J.G. (1975). Glass inspection. In C.G. Drury and J.G. Fox, Human Reliability in Quality
Control. Taylor & Francis, London, 273-288.

McKernan, K. The benefits of prior information on visual search for multiple faults.
Unpublished M.S. thesis, 1989, University at Buffalo.

Micalizzi, |., & Goldberg, J.H. (1989). Knowledge of results in visual inspection: implications

for training. Int. J. Ind. Engs.
Sheridan, T.B., & Ferrell, W.R. (1974), Man-machine systems, MIT Press, Cambridge, MA.

Shepherd, A. (1976). An improved tabular format for task analysis. |. Occup. Psychol., 49, 93-
104.

69



No prediction for the future would be

complete without some words about
computerization. Since the invention of the printing

Press, no event in history has had as great
i f bits and bytes now
iously prohibitive amount of retrievable data.

BITE") for many of the aircraft on-board systems. Further uses and advan

technology will certainly be with us into the 21st century, However
there is a debit side to computers,

In their early stages of development it was often proclaimed that for all practical purposes,
computers would make as a "paperless society." Are there any organizations that have adopted
computer systems that have not actually multiplied their use of paper by some X number?
Underutilized 50 and 100+ page statistical reports are often routinely published based on ease
of production rather than a legitimate distribution need. Hopefully, the 1990's will see a change

in the handling of this prodigal child with an insatiable appetite for data, and better
management of the ensuing waste.

A more serious consequence can result when the information system is insensitive to the
man factor environment at the mechanic and inspector level. In one actual case, an internal

, non-interchangeable parts so similar that the

commendation for a number change was
refused because the change would have deviated from the system standard. Only after the

robable error became reality, resulting in an in-flight incident, did the computer system
ecome subservient to the needs of the working level.

Another example, less obvious but no less im
airline, in data collection requirements for each aircraft log book entry. During li

will be minimized if Management recognizes that the effectiveness of an:
program will always depend on how well mechanics and inspectors accompl
regardless of how sophisticated computer systems may become;
serve rather than interfere with the accomplishment of these tasks.

Y maintenance
ish their tasks,
and that system design must

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27



Mid-Level Air Carrier Perspective

Thomas F. Derieg
Aloha Airlines

To understand my perspectives concerning information exchange and communications in
aviation maintenance you must know something about the kind of airline for which | work and
its particular maintenance requirements. The concerns and problems | have are very much a
function of my airline environment.

Aloha Airlines has been in business since 1946, although we have become well known to
most people only in the last two years. We fly 14 Boeing 737s in Hawaii, providing strictly inter-
island transportation between Honolulu and four outer istand airports. Two of our Boeing aircraft
are 737-300s. Twelve aircraft are 737-200s. Of these, nine are the advanced models and three
are basic models well known through the industry for their cold-bonded lap splices. Aloha
Airlines has 5,000 departures and carries approximately 350,000 passengers per month.

Aloha has an outstanding safety record. In its 43 years of operation, it has never lost a
passenger. We have had one well-known accident with a fatality in which we did lose a Senior
Flight Attendant. This was a real tragedy for all of us.

Communications in a smaller airline is different than in a larger carrier because of differences
in size, organizational structure, and organizational behavior. With a small airline, you know the
pilots; you know the mechanics; you know everybody in the company. The personal interface is
good and decisions can be made with relative ease since all persons directly concerned can be
in the same meeting.

The aviation industry, as noted earlier, operates as a three-legged stool. In our case, as shown
in Figure 1, the stool consists of the regulator, the FAA; the manufacturer, Boeing Airplane
Company; and the operator, Aloha Airlines. Since Aloha has a single aircraft manufacturer and
flies a single type of airplane, our relationship with the industry is relatively straightforward and
very much as shown in Figure 1.

In our dealings with the aviation industry, we find that the Air Transport Association has
almost made the three-legged stool into one with four legs, as seen in Figure 2. The Air
Transport Association, as an industry group, is very important for a company such as Aloha. We
are a long way from Washington and are not a big company, although rated as a national airline.
We do not feel that we have a lot of impact in the industry or much influence on regulatory
decisions, even those that affect us directly. The Air Transport Association provides this influence
for us. They provide it for the entire airline industry and through them we are able to make our
needs and desires known. The Air Transport Association has taken a leadership role in dealing
with problems of aging aircraft. Their activities, coupled with those of the FAA Aging Aircraft
Task Force teams, are making real progress. The combination of the knowledge provided by the
ATA and the industry, working directly with the FAA, has proceeded faster, in my opinion, than
would have been the case with the FAA working on its own.

The communication network within which Aloha Airlines conducts its maintenance
operations is shown in Figure 3. In the routine business of airlines, that involving Service Bulletins,
Service Letters, and other maintenance messages, we have direct communication between
Boeing engineering and our engineering department. This is primarily a one-way
communication channel, with considerable information coming in daily from Boeing.

On a day-to-day basis, we deal primarily through our Boeing local representative. There has
been a Boeing representative at Aloha since we started flying Boeing equipment in 1969.

23



Converting Technical Publications into
Maintenance Performance Aids

Kay Inaba, Ph.D.
XYZYX Information Corporation

Effective maintenance performance requires optimum use of maintenance information.
During the presentation, t will try to support the following arguments:

1. If you want to make maintenance effective, you must have usable information on the job.
Technical information required by technicians to do their jobs effectively must be usable and
available. But if that's all you do, you will have usable manuals but not necessarily any better
performance.

2. Accountability is the key to motivating technicians to use information. Maintenance
personnel must be held accountable for their performance. This means measurement and
feedback.

3. To make information usable, you must do considerably more than make the text readable.
The common measures of comprehension and readability of text address only a small portion of
the issue. There are many principles and guidelines for preparation of technical information
which should be followed.

Lessons from the Past

Much of what is done today in the development of job performance aids is based on past
studies and experience. For this reason, ! will review some lessons learned from the past and
discuss the peculiar and important role of information in maintenance. The initial set of studies
of job performance aids with which | am familiar started from a concern by the Air Force over
the high cost of maintenance. The studies indicated that the cost of manuals was miniscule
compared to the high cost of ineffective maintenance. These costs were in the hundreds of

millions of dollars per system. This is not the cost of maintenance; this is the cost of ineffective
maintenance.

Maintenance errors are major contributors to maintenance ineffectiveness. There are four
kinds of maintenance errors contributing to ineffective maintenance. These are (1) false
removals, which is generally high whenever there is time pressure, such as with turnaround
maintenance; (2) failure to isolate or failure to detect, which often occurs during inspection; (3)
damage during maintenance, which studies have shown to range between 10 and 30 percent;
and (4) time errors, which usually involves self-detected errors and simply extend the time to
repair.

Maintenance is a labor-intensive system. Thus, anytime there is a maintenance problem,
there will generally be personnel performance problems. Ineffective manuals and training are
usually major contributors to the problem. Periodically, because of the high cost of maintenance
and lack of understanding by higher management, these two (maintenance and training) are
often the target of cost cutting efforts. Such cost cutting efforts have helped to reduce the
usability of maintenance manuals.

Most important, manuals need to be usable on the job. Manuals that can be easily used on
the job will help reduce error rates. Studies have shown that job performance aids (integrated
with training) can reduce errors by as much as 90 percent of the existing rate. In addition, studies
have shown a reduction in required maintenance time by around 50 percent can be realized
with proper job performance aids.

107



Aircraft Vendor to Government

* Certification Approval Requests

* Proposed Engineering Changes

* Proposed Advisory Notices Data

* General Vendor Communications

We as commuter carriers have little involvement with the Government-vendor
communications leg. We can give our views on some aspects of these communications but
probably all we should do is simply try to understand the link.

To this point | have been describing “near perfect airline communications." | say near perfect
because | am describing communications with a U.S. manufacturer and the U.S. Government.
The value of these links depends on the quality of communications between the vendor, the
operator, and the U.S. Government. But what happens to the quality of these communications
when we deal with a foreign manufacturer rather than an American manufacturer?

Table 1 shows that commuter operators now deal with 11 major manufacturers, two of
which are in the United States. Table 1 lists these 11 aircraft vendors and shows that, whereas in
the United States there is one regulatory agency with which to deal, there is a different agency
for each different foreign government. This table clearly illustrates the odds of a commuter
carrier with more than one type of airplane having a foreign manufacturer within his hangar.

Use of an aircraft of foreign manufacture does not mean that communications simply shift
from the U.S. Government to the foreign government. The U.S. Government remains very
much in the picture. The major difference, as shown in Figure 2, is that the foreign government
now is interjected into the communications loop, principally between the aircraft vendor and
the U.S. Government. However, the requirement to deal with the foreign government very
much affects operations of the commuter carrier.

Let me provide an example of one of the communications issues we face on occasion when
dealing with a foreign vendor. In this instance, we received an Advisory Notice for an aircraft
modification which had an alternate means of compliance paragraph but did not show an
alternate means. This means, of course, that if you wish to use the alternate means of
compliance you must provide your own engineering data, which we did. Some time later, as a
function of the lag in communication with a foreign agency, we received a Service Bulletin
indicating a modification had already been approved. However, since we were so late in
receiving this, we had to deal with the alternate means of compliance. To avoid this, it was
necessary for us to write a letter to the U.S. Government stating that we planned to use this
Service Bulletin, which had been approved in another country. Needless to say, this is not an
expeditious way to do business.

Another problem we face with foreign vendors is that of getting paperwork for aircraft
procedures prior to required installation of modifications. The creation of predevelopment
procedures is not something foreign manufacturers do easily. In the case of one foreign aircraft,
the FAA indicated we should comply with all mandatory Service Bulletins, to which we
obviously agreed. The first Service Bulletin came and we made the necessary modification.
However, we could not find the required paperwork for the Flight Manual to describe related
procedures changes. After our call, the vendor said the paperwork had gone to his regulatory
agency. Initially, we tried to obtain this paperwork through the U.S. Government, but with no
success. | then called the foreign agency and found that the pages to the Flight Manual had been
sitting on the desk of a lady who was on vacation. However, they couldn't be released because
each page had to be perforated with punch holes which indicated the serial number of the
airplane. Unfortunately, the individual responsible for that task also was on vacation. Finally, we

35

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114



Plan for this Paper

Taken together, these features have come to be known as "hypertext" or “hypermedia," and
they provide a compelling vision of the how maintenance information might be delivered and
used in the future. Nevertheless, as with any new technologies, turning this vision into practical
applications is hard. In this Paper | will introduce the key concepts of optical storage and

hypermedia, review several examples, and suggest ways to overcome the problems that stand in
the way of successful applications,

Hypertext and Hypermedia

Definitions

In 1987 Conklin defined hypertext as “computer-supported links within and between
documents" (Conklin, 1987). My own definition of hypertext emphasizes its evolutionary
relationship to printed documents, rather than focusing on the new role of the computer.
Anyone who has carefully studied the structure of an encyclopedia, dictionary, regulation, or
maintenance manual is well aware of the Many non-linear presentation conventions these

documents use. Cross references, sidebars, footnotes, sidenotes, call-outs, and type sizes all signal
that texts need not be read in strict linear order.

From this perspective, hypertext is a concept for displaying information on computers that
exploits the non-linear conventions used in rinted information to make text easier to use on
computers. These conventions have evolved over hundreds of years and work well for short
documents, as anyone knows who has put a thumb in the back-of-the-book index and
sequentially browsed the separate topics pointed to by the index. The conventions begin to
break down for larger document collections because a proup of authors cannot use them as

consistently as a single author can, and because of physical limitations imposed by the sheer bulk
and size of documents.

Even more recent than the term "hypertext" is the term "hypermedia," which is generally
used to enlarge the hypertext concept to include other media, such as sound, video, or
computer animation/simulation. One consequence of a separate concept of hypermedia is that
it implies that hypertext includes only text. This seems to limit the notion of hypertext
unnecessarily, since any application that includes even the simplest figures or diagrams to
accompany text becomes hypermedia, making the hypertext subset of hypermedia an extremely
limited one. In particular, this means that a computerized version of a print document that
includes the graphic components becomes a hypermedia document. It is more useful to draw
the boundary between hypertext and hypermedia by saving the latter term for applications that

involve media that printed documents cannot incorporate. Hence, applications that contain text
and static graphics are hypertext.

Example Applications

| will briefly describe some recent applications of hypertext, beginning with one that is closest
to the vision of an intelligent maintenance manual with which | began this paper.

Integrated Maintenance Information System. IMIS, the Integrated Maintenance Information
System, is a concept and set of Prototypes for a portable computer that integrates diagnostic and
maintenance information and presents it to technicians via a hypertext user interface (Link, Von
Holle, & Mason, 1987). IMIS is being developed by the U.S. Air Force Human Resources
Laboratory and is funded as part of the Department of Defense CALS initiative.

IMIS is designed to use diagnostic information obtained directly from an airplane to configure

and customize the maintenance instructions provided to the maintenance technician. Field
trials of IMIS prototypes have demonstrated that this interactive combination of diagnostics and

78


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Communication and Transfer of
Non-Destructive inspection Information

Stephen N. Bobo
U.S. Department of Transportation
Transportation Systems Center

The inspection of aircraft, particularly aircraft structures, is increasingly dependent on non-
destructive inspection (NDI). There are four points | would like to cover concerning NDI
procedures in relation to communications in aircraft maintenance and inspection:

1. The preparation, recording, transmitting, and archiving of non-destructive inspection data.
2. The type of data required in non-destructive inspection.

3. The role of aging aircraft non-destructive research.

4. The future of NDI technology and the extent of data transfer.

Use of non-destructive inspection is based on an understanding of the probability of damage
to an aircraft as a function of normal operation. Figure 1 shows the incidence of failures in an
aircraft during its service life. Infant mortality is on the left and, as the aircraft goes through its
service life, the number of incidence of damage reports and damage revealed by inspection
increases to a point where the aircraft reaches its extended service life threshold. At this point
the aircraft must be studied and additional inspection methods, practices, and schedules
invoked to compensate for the increased likelihood of failure. This is the point on which the
Aging Aircraft Research Program will focus and it represents a threshold point for our use of NDI
inspection procedures.

To appreciate the demands being placed on non-destructive inspection technology, one
must understand the aging characteristics of the U.S. commercial airline fleet. Figure 2 shows
the number of aircraft and the age of the respective aircraft in our national fleet. There are nine

pes of major aircraft in this fleet and all of these except four have exceeded, on an average,
their designed service life. A large number of aircraft will require a very large number of
inspections in the future.

The aging aircraft issue is further illustrated in Figure 3. In this figure, the dark band shows the
number of cycles (one complete flight) for the aircraft in the fleet with the highest number of
cycles. The light band shows the number of cycles established as a "design goal" during the initial
development of the aircraft. As can be seen, each type of aircraft except the DC-10 and the L-
1011 shows aircraft which have exceeded their design service life.

Ominous signs have been present for some time that the structural integrity of commercial
aircraft is threatened as the fleet increased in average age. Three well-known events which
carried this message include:

1. Far East Airlines Boeing 737 accident in 1983
2. Japan Airlines Boeing 747 accident in 1985
3. Aloha Airlines Boeing 737 accident in 1988

In studying aircraft as a result of these events, the problem of greatest consequence was
found to be multiple site damage. This means that at some point in the aircraft's service life
there will be an onset of structural fatigue and multiple cracks will appear in the structure of the
aircraft. These cracks, when they link up, cause the potential for catastrophic failure to increase
at a more rapid rate than the nominal growth of individual cracks.

96


Conclusions and Recommendations

The exchange of information within the industry responsible for the maintenance of the U.S.
air carrier fleet must be accurate, efficient, and responsive to the particular needs of this industry.
Since deregulation of the airlines in 1978, the industry has grown rapidly and has become more
diverse. New aircraft types have been added to the fleet, with many coming from foreign
manufacturers. Older aircraft, which in former years would have been retired after 10 or 15 years
of service, are being kept in use. As a consequence, there is a new problem facing the
maintenance community, that of the "aging aircraft." All of these factors place new and growing
demands on aircraft maintenance organizations and on communication systems to support their
efforts.

Attendees at this two-day meeting represent all segments within the air carrier industry,
including regulators, manufacturers, and operators, During the two days, attention was given
exclusively to issues of information exchange and communications. Recommendations for
improvement were offered during formal presentations, during ensuing discussions, and during a
final "summing up" period. The following recommendations represent a grouping of attendee
suggestions according to broad topics, with specific recommendations included within each
topic.

Management of Maintenance Data

The documentation required for maintenance of the U.S. air carrier fleet is voluminous and
is growing. This documentation supports a triad consisting of the Federal Aviation
Administration, aircraft manufacturers, and airline operators. The flow of data within this triad is
complex and multi-directional. Manufacturers require feedback from operators to determine
acceptability and reliability of their product and its components. Airlines require product support
information from the manufacturer. The FAA requires data from both the airlines and the
manufacturers concerning product reliability and safety issues to support its industry surveillance
role. The Air Transport Association (ATA) plays an important role by coordinating the flow of
data among the three triad members.

The sheer volume of maintenance documentation is impressive. To illustrate one type of this
documentation, Boeing maintains some 1,126 active manuals for 5,300 airplanes and 425
operators. At these levels, the management of all forms of maintenance documentation --
Notices, directives, manuals, etc. -- becomes very challenging. For these data to serve their
intended purposes fully, a carefully planned and operated data management system is essential.
This system should include the collection, analysis, dissemination, and storage of technical
information supporting aircraft maintenance.

Database Development. A central data base for maintenance information would have many
values. It would serve as a central repository, thereby making maintenance information equally
available to those in both large and small aviation operations. It would offer immediate
accessibility to information needed on an urgent basis. Also, and of considerable importance, a
central data base, containing information from all segments of aviation, could support a variety of
safety studies and analyses of safety trends.

Aircraft manufacturers and airline operators maintain a number of computerized data bases
to support their individual needs. The closest to a national data base is that maintained by the
Federal Aviation Administration which contains Service Difficulty Reports. These reports are
required of airlines and detail events which occur in-flight or on the ground prior to flight. While
the SDR data base generally supports the needs of the FAA, it is not particularly useful for the
airline industry. By the time SDR reports become available, those airline operators with a



maintenance manuals can greatly reduce the amount of extraneous information presented to
technicians, while appropriately tailoring the information to the technician's expertise.

One proposed user interface for future IMIS prototypes is shown in Figure 1 (Thomas & Clay,
1988). Two steps of a maintenance procedure are shown on the screen, along with simple
diagrams of the equipment used to Carry out the steps. The numeric keys of the portable
computer can be redefined as shown at the bottom of the screen to provide hypertext functions
for using the IMIS maintenance manual. For example, selecting "1" moves to the next screen, "2"
moves back to the previous screen, and "5" jumps to a table of contents.

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Document Examiner. In 1985, Symbolics began delivering the complete reference manual
for its Lisp workstation software in an online hypertext system called the Document Examiner
(Walker, 1987). The initial release consisted of 10,000 text modules called records,
corresponding to 8000 printed pages. The Document Examiner takes full advantage of the
enhanced display resolution and large screen on the workstation to display pages much as they
appear in the printed manual. Figure 2, from (Walker, 1987), shows that the Document
Examiner screen display of a section of the online manual resembles a printed manual. Of
course, the Document Examiner also takes advantage of the workstation's Processing power to
support other features not available in the printed form. On the right side of the Document
Examiner display are candidate text units located using full-text search and a list of "bookmarks"
created for any unit previously viewed. Selecting a bookmark for a unit re-displays the unit.

Figure 3, from the same article, shows an automatically generated graphic display that is a
logical map of the parts of the manual that are logically connected to the currently-displayed

record, Selecting the name of any of the records in this graphic map causes it to be displayed on
the screen.

\n 1987 some of the software tools that had been developed by Symbolics to support the
development of the Document Examiner were released as the Concordia hypertext authoring
environment (Walker, 1988). Concordia is probably the most powerful and comprehensive
hypertext authoring toolkit today; one of the applications being developed using Concordia is an

79



While hypertext applications of practical scale have been successfully designed and
implemented, in general such projects are not documented in the open literature because of
resource constraints in development organizations or Proprietary considerations.

While there is a growing body of empirical research evaluating particular hypertext systems or
specific design options, this work does not usually generalize well. In addition, what formal
experiments have been able to establish is that most of the design choices, when considered in
isolation, have only small percentage impacts on system usability (Nielsen, 1989). Far more
important are individual differences in users, especially motivational differences, and the effects
of different tasks. Yet who the users are and the tasks they want to carry out are often not
something the hypertext system designer can control.

However, designers of hypertext systems can take steps to ensure that their systems are
acceptable and effective for their users. While empirically validated design guidelines remain
some way off, design methodologies for hypertext are being proposed; the most comprehensive
of these is that of Perlman (1989). Other less ambitious statements of hypertext design methods
for certain classes of hypertext applications or particular design problems have been proposed
(Hardman, 1988; Jonassen, 1986; Lacy & Chignell, 1988; Landow, 1987; and Walker, 1988).
General guidelines for user interface design can be successfully applied to hypertext
(Department of Defense, 1989; Smith & Mosier, 1986) if they are made explicit goals and
compliance with them is monitored during the design process

Any design feature can be the basis of or contribute to a future guideline if the system is
instrumented to collect data on its use. When coupled with observation of users, objective data
about the use of various system features can lead to design improvements if the system is
designed to support easy modification (Egan, Remde, Landauer, Lochbaum, & Gomez, 1989;
Hardman, 1989; and Perlman, 1989).

Installed Base Constraints

Hypertext demonstration projects are often done in research organizations that have
advanced technology, including workstations and high-resolution 19-inch monitors. HyperCard
on the Macintosh personal computer is also a very popular environment for demonstration
projects.

In contrast, the users for whom full-scale versions of these demonstration systems must be
targeted often work with an older installed base of computing equipment. This installed base
may consist predominantly of IBM AT-compatible processors with small display screens having
limited graphics resolution.

This situation often poses a dilemma for hypertext projects. Advanced technology may be
needed to demonstrate the benefits of hypertext capabilities, but the presentation of these
capabilities in the demonstration projects exceeds what the installed base will support. It is
essential that the funding or marketing organization promoting the project knows the costs and
tradeoffs implied by various technology alternatives. Which is more successful, a project that uses
less-advanced technology to create lower expectations that can be met, or a project that uses
state-of-the art technology that is not readily available for the average user? There is no right
answer, but it is essential to ask the question when project goals are being established.

Temporary constraints in processing power for installed base computers can be overcome by
exploiting space vs. time tradeoffs in hypertext designs by using the enormous storage capacity of
CD-ROM to store indexes and features like navigation maps instead of computing them in real
time (Oren, 1987).

85



difference between something being "prescribed" and something being "proscribed?" 1 would
venture to say that not a high percentage do. This is of real importance when you consider the
kind of accuracy we want in aviation maintenance. We hear about this all the time from airline
operators. It is up to us in the FAA and to us in industry to do something about this problem. The
attendees at this meeting can be very helpful by giving us some direction as to the best things for
us to do to improve this situation.

Maintenance information must be understandable. Maintenance information also must be
easily accessible. If it is not, people just aren't going to look for it. It is not a responsible act to
place critical maintenance information into thick binders and assume that this information will
get to the people who need it. If it does, it is likely to be torn out of the book and become so
dirty that one cannot read it. We have an obligation not only to deliver messages, but to deliver
them in a usable form and in a user friendly manner. Of the many new technologies available
today, certainly some can be adapted for problems of the shop floor. These technologies should
become standard rather than unusual in maintenance operations.

The fact that we need to implement new information transfer technology in maintenance
| does not mean that we need to move away from personal relationships. At one time,
maintenance staffs were relatively small and so was the fleet size. It was possible for a given
mechanic to work on a particular airplane enough to actually understand its history and to have a
real sense of the problems with that aircraft. The advantages to this are such that at least one
airline, in Japan, is reinstituting a program to reconnect aviation personnel with specific
| airplanes.

1 Today, maintenance operations for U.S. and international airlines are big and specialized.
| Maintenance for a given airplane may be done at many places. Implementation of
| communications and database technology will provide an opportunity for maintenance
personnel to be more closely coupled with the aircraft they maintain. There is no reason this
cannot be done, in concept, with the computer technology available today.

Current technologies can give maintenance workers access to training, technical, and
i procedural information without a need for tons of paper and can present this information in a
\ way more interesting to those who must use it. The repair histories of individual airplanes can be
followed and needed information quickly provided. All of this can be done today and, indeed,
some airlines are beginning to do it. A system that lets a worker know the status of the airplane
he or she has worked on will increase his or her personal involvement with the process. It seems
to us that this sense of personal vesting in an airplane and its status would be of benefit for the
worker. In turn, the increased worker involvement should be of benefit for the airline. Finally,
this tracking technology would be of value for us in the FAA to support our Service Difficulty
Reporting System. Since the benefits seem so obvious, and the technologies are available, it is
time for us to work together to bring these maintenance communication technologies online
within the next decade.

The adoption of advanced communication technologies, procedures, and philosophies has
the commitment of the Federal Aviation Administration and, | believe, the senior management
in U.S. airlines. What we need to do now is build some momentum behind the program. Over
the next two days, you who are attending this meeting will be discussing issues of information
exchange, hearing presentations, and, | hope, beginning to build that momentum. By so doing,
you will be making a valuable contribution to the entire aviation maintenance community.

Finally, | would like to note that | recognize the difficulty many of you have in taking time
from your busy schedules to attend these meetings. | appreciate your interest and your efforts



NOTE

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Figure 3

113



Figure 6, HyperCard Help - Graphic Map

CD-ROMs can be installed as another disk drive on standard DOS computers,
scenario for using a CD-ROM drive is as a file server from which needed informatio:
and possibly printed on demand.

and a typical
nis retrieved

Example Applications

Lotus One-Source. Lotus Development, the makers of the Lotus 1-2-3 spreadsheet, is also
the world's largest publisher of CD-ROMs. Lotus One-Source (Lotus, 1989) is an information
subscription service for the business and financial community; One-Source CDs contain

Company reports, financial data, and other information needed by investment analysis and
forecasting.

Subscribers to One Source pay thousands of dollars annually for updates, but they clearly

perceive that the increased availability and timeliness of the financial information they receive is
worth it.

Hewlett-Packard LaserROM. In 1988 Hewlett-Packard began distributing its system support
documents, including user manuals, using a CD-ROM application they market as LaserROM
(Rafeld, 1988). A couple of CDs that are updated monthly can contain all of the documentation
Hewlett-Packard produces, and Hewlett-Packard has found that it much easier to ship every
major customer everything rather than configure specific shipments for each customer.

How CD-ROM and Hypermedia Complement Each Other

CD-ROM technology is not limited to hypertext applications but is made significantly more
useful because of them. Many hypertext and hypermedia applications seem especially
complementary to CD-ROM, especially those that are inherently static like reference manuals,
dictionaries, or encyclopedias (Carr, 1986; Oren, 1987; and Rafeld, 1988). Hypermedia systems,
especially heavily graphic ones, tequire more storage space than traditional forms of information
Presentation. In addition, hypermedia applications typically include multiple views and entry

83



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IMIS PHASE It: FLIGHT LINE DIAGNOSTICS

+ Flight Line Diagnostic System
+ Portable Maintenance Aid (PMA)
* 1553 Alrcrait Intertace
+ Integrated Diagnostics / Tech Data Software

+ Authoring System for “Type C* Data

+ Filght Line Field Teats

+ tnitlal PMA Demo at Shaw AFB 1988
+ F-16 Test at Homestead AFB 1989
+ F/A-18 Test at Patuxent River 1990

+ Content Data Modet (CDM) Spec

Figure 5

of data were to be used in three different manuals, it would not be necessary to update all three

when the data item changed. A simple update of the data item itself would accomplish all
necessary changes.

There are many advantages to use of Type C data. For one, technical data to support a
vehicle is contained in an integrated data base rather than a collection of manuals. The data
base itself can be used to support many devices and many presentation layouts. The biggest
advantage, of course, is that a neutral technical data system, using Type C data, allows the

development of an integrated flight line maintenance system rather than one requiring a
number of technician interfaces.

-C

* DATA BASE
+ AD HOG
+ PAPER,

8
« DOCUMENT
+ FIFO
PAPER
OUTPUT ELECTRONIC
OUTPUT

+ INTEGRATED

AS DATA MOVES LEFT TO RIGHT:
+ LESS DATA REDUNDANCY
+ LESS DATA VOLUME
+ LESS HARDWARE SPECIFIC
+ LESS APPLICATION SPECIFIC
+ EASIER TO INTEGRATE

Figure 6

94



The Information Environment in Inspection

Colin G. Drury, Ph.D.
University at Buffalo

Introduction: Airframe Inspection

Inspection is information processing. Other aspects of the inspector's task, such as physical
access to the work and body posture during work, are subordinate to this central task. The
human as information processor has been studied for many years (e.g., Wickens, 1984 for review)
and, indeed, the whole foundation of experimental psychology between the 1940's and 1970's
has been on this model.

if information is the essence of inspection, we must examine the sources of information used
{and not used) by the inspector: how information is received, processed and generated. Hence,
we consider the inspector's information environment.

To provide structure for examining a job as complex as that of the inspector, a generic Task
Description of inspection will be used. Task Description is a listing of the tasks involved in a job,
but it also includes any rules for how tasks are sequenced within the Job (Drury et al., 1987;
Shepherd, 1976). From such a Task Description we can determine how the demands of the
tasks compare with human capabilities to meet those demands. This comparison is Task Analysis,
which is one way to consider this paper: A Task Analysis of the inspector's information
processing. Although task descriptions of inspection have been proposed many times for
manufacturing inspection (Bloomfield, 1975; Drury, 1982), we will need to modify these to be
specific to airframe inspection. Table 1 shows a generic task description of the inspection
performed when an aircraft arrives for service. Examples are shown of both visual and non-
destructive testing (NDT) tasks. Note that only if a defect is found will the final two tasks occur:
Repair and Buy-Back Inspection. Each of the first five steps will be considered in turn to cover
incoming inspection.

Any system involving a human is typically closed-loop (Sheridan and Ferrell, 1977). Obvious
examples are in flying an aircraft or driving a car, but the concept applies equally to inspection
tasks. As shown in Figure 1, the human in the task receives some instruction or command input
to use systems terminology. The operator and any associated machinery transform this command
input into a system output. To ensure stable performance, the system output is fed back to the
input side of the system, where it is compared against the command input. If there is any
difference (command minus output), the system responds so as to reduce this difference to zero.
Thus, in flying aircraft the command input may be the heading given by air traffic control. The
system (human plus aircraft) compares the output of current heading (from, for example, the gyro
compass) to the command heading, and uses aileron and rudder to make the output match the
command. A closed-loop model of the inspector (Figure 1) will be applied to the generic task
description of inspection (Table 1) to locate and evaluate the sources of input (command) and
output (feedback) information.

Information in Inspection

From the model in Figure 1, it is obvious that two types of information can be distinguished.
The input is command information, while the output is feedback information. Both have been
shown to be amenable to manipulation to improve system performance. Not obvious from
Figure 1 is that the command input may be complex and include both what needs to be
accomplished and help in the accomplishment. Input may give both directive and feedforward
information. Thus, a workcard may contain "detailed inspection of upper lap joint" in a specified
area (directive) and "check particularly for corrosion between stations 2800 and 2840" (

63



In addition to providing a limited and standard vocabulary, Simplified English also provides a
set of writing rules. These rules serve to clarify the presentation of maintenance instructions. At
Boeing, an artificial intelligence unit provides a checker which reviews the writing rules and saves
an engineer from having to do this review himself. It tells the engineer where writing violates the
set of rules and allows him to make immediate corrections.

Airline/Boeing Partnership

Boeing is now undertaking a program to rewrite its maintenance documentation in digital
format using the new standard for production airplanes. AMTOSS tasking, PMDB, and simplified
English are being employed in this program for several aircraft including the 737-300/-400/-500
series, the 747-400, and the 757/767 aircraft. We also plan to digitize our maintenance board
files for out-of-production aircraft such as the 727 and earlier 737 and 747 series.

The Boeing Company wants to ensure that all changes being made are acceptable to the
customer. All new formats and standards need to be validated by the airlines. If changes are
required, we have pledged that we will not go in an individual Boeing direction. Results of the
Boeing-airline interactions will be presented, as required, to committees of the Air Transport
Association/Aerospace Industries Association of America. We will request approval from these
committees before proceeding. In this manner, we hope to ensure that smaller airlines which
might have a different view of what is effective in maintenance are not left out of the picture.

At this time, Boeing is using the 747-400 as a "pilot" model for checking our new digital
maintenance data efforts. In this pilot effort, use of AMTOSS tasking procedures for the
identification of maintenance tasks was completed in the fourth quarter of 1988. Validation of
the Production Management Data Base and Simplified English both are ongoing at this time.
Since we feel that the specification dealing with PMDB will change through time, we have
issued a test tape and are asking for feedback from the airlines. We also have built a
demonstration PC computer program illustrating PMD8 which is available for those interested in
learning about this effort.

To conclude our discussion of the development and implementation of digital programs for
the delivery of maintenance data, | would like to make the following points:

New technical standards for maintenance data are essential to program success.
ATA/AIA Task Group members have made substantial contributions to these standards.
ATA/AIA cooperation has been very good.

Boeing is committed to this program.

Airlines must become involved

- The program must be given priority

- The program must receive high-level management attention

eoeeee

On-Board Maintenance Information System (OMIS)

Boeing is exploring the uses for an On-Board Maintenance Information System (OMIS). The
purpose of an On-Board Maintenance information System is to provide all required data to
support ramp and flight line maintenance on an airplane. It contains necessary maintenance
information to correct airplane faults reported by the Central Maintenance Computer. In a
sense, OMIS provides the intelligence to support ramp and flight line maintenance and allows
an airplane to become self supporting. As long as maintenance personnel are available, this
system provides all necessary information for these people to respond to maintenance needs.
For aircraft structures which do not have a monitoring system, OMIS provides access to fault
isolation and maintenance procedures.

59

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We frequently speak of the three-legged stool in the air transport system which involves the
manufacturer, the airlines, and Government regulatory agencies. Indeed, this three-legged stool
exists in all countries involved in air transport. Each leg of the stool has a responsibility. Each is
answerable to its own constituency, be they the Government or the stockholders or the traveling
public. Each must know and respect the responsibilities of the others and ensure that we do not
deviate too far in any one direction in terms of over regulation or over liberalization of control.
The members of that three-legged stool must communicate with each other at all levels on a
frequent basis.

Manufacturers depend on airlines to provide data to support the design and performance
characteristics of aircraft. Airlines must indicate the distances they want to fly, the seatin;
capacity they need, and other design-related data. Airlines also must provide data on aircraft
reliability. Manufacturers need to know how their systems work. is one hydraulic actuator more
reliable than another type of hydraulic actuator? Particularly in avionics, manufacturers must
understand the reliability of a product they put in the field. Certain of this information is provided
through the services of manufacturer's factory representatives who work directly with the airlines,
frequently on the premises to ensure day-to-day communications.

Both manufacturers and the FAA depend on the airlines to provide in-service difficulty
teporting. Both need to know the kinds of problems that occur with an aircraft that cause service
interruption or safety concerns. They depend on this information from the airlines so that both
the safety and reliability issues can be addressed properly.

Airlines depend on the manufacturer to provide product support information. Individual
airlines require fleet reliability data so that each airline can determine whether its reliability is
deviating significantly from the industry norm. They also require maintenance action and
information documents, such as Service Bulletins, to provide information from which to base
aircraft repair once a problem has been found.

The Federal Aviation Administration depends on the airlines and the manufacturer for data
concerning in-service difficulties and product reliability. Such data form the basis for regulatory
actions and general oversight of the transport industry. The industry depends on the FAA's
awareness and surveillance capabilities to provide the safety net that the nation needs in air
transport.

The Air Transport Association (ATA) serves a <oordinating function in this three-legged stool
arena. It is ATA's responsibility to keep the Government, be it the regulatory agency or the
legislative bodies, aware of the technical capabilities and limitations of the industry.
Congressmen, senators, and their technical staffs, must be aware of where industry limits are, as
must the FAA. By the same token, airlines must be cognizant of regulatory and legislative
requirements being imposed on them and what these will mean in terms of economic, safety,
and operational impact. ATA serves to coordinate these activities and to bring the proper body
of people together to address these issues.

Again, as stated earlier, one can never resolve a technical issue without understanding all
ramifications of that issue. The manufacturer, if he has to solve a problem dealing with some
technical aspect of the aircraft, will generally resolve that problem in a manner which will allow
greatest manufacturing productivity. The airlines will Benerally resolve an aircraft technical
problem with a means that will provide reliability in off-the-gate or out-of-the-dock capability for
that aircraft. The FAA, if they had no other concerns, would resolve a technical problem to
ensure the very safest system to a point where you might not be able to fly the aircraft. We all
want the maximum, but there has to be compromise at all times. Compromise requires effective
communication.

19



The third requirement for enhancing communication is focus on product. Human effort,
coupled with instructions, machines, and tools forms the technology of aircraft maintenance.
Safe aircraft in commercial service are the throughput, or product, of the maintenance and
inspection function of the air transportation industry. The technical systems analysis focuses on
what happens to these aircraft (the product), as they pass from manufacturing to flight and to
engineering and maintenance systems again and again. Does everyone hold a consistent view
with respect to this industry product? If the industry purpose is to safely put as many people in
the air at the lowest possible price, industry views and values may not be consistent concerning
maintenance values. One segment of the industry is looking for maximizing short-term profits:
another segment is looking for maximizing size of market. Are members of the maintenance
community aware of those differences?

The fourth item in the listing of requirements for facilitating communication is “using a
common language." Common language comes from the product, but the common language
also comes from a conscious attempt to share information in a way that is unequivocal. There are
many examples of imprecise use of language in the maintenance industry. When one includes
international carriers, the issue becomes even more difficult.

The final requirement for facilitating communication discussed here is the conscious and
collaborative expectations by members of the maintenance community. In the maintenance
social system, the web of relationships among all parties involved comes into focus. What
significance does this network have for communication? For One, it means that, depending on
his expectations at work, a mechanic or inspector can respond in a number of different ways toa
maintenance problem. For example, if a mechanic discovers a possible flaw and expects to learn
from this occurrence, he will welcome help from a supervisor. However, if he expects the
supervisor to trust him and leave him alone, he will resent the supervisor's intervention. From the
supervisor's point of view, if he is expected by his superiors to know at least a little more than his
subordinates, his intervention may be normal and proper for him despite how it appears to the
mechanic. Thus the social system is.a set of expectations sometimes positive and constructive,
and sometimes not so constructive, with others in the workplace, with others elsewhere in the
organization, and with outsiders as well. Depending upon the context, and organizational and
individual history, such expectations will lead to different behaviors.

Appropriate behaviors are what we are concerned with ultimately. These behaviors include
flexibility in the application of maintenance technology, cooperation and coordination. All of
these behaviors are linked to the product -- in this case safe aircraft.

A common focus on the product -- a safe aircraft -- should be a straightforward matter for
maintenance personnel. However many factors can serve to distort this focus such as pressures
from the regulators, pressures from the marketplace, pressures from the competition, and other
factors, The fact that we may not have a common language, the fact that we may have multiple
(if not conflicting) maintenance philosophies, the fact that we may have arcane technical
language, the fact that we may have imprecise use of terms, are all things that can cause loss of
product focus and consequent problems in the maintenance system.

Another communication concept now in use in aviation is cockpit resource management
(CRM), introduced by NASA about 10 years ago and now being increasingly adopted by air
carriers. In its simplest form, cockpit resource management posits that flight deck personnel
should be working together more than simply operating as a fixed military hierarchy where
someone at the top gives orders and others follow them. This recognizes that give-and-take
information and different perspectives are important on the flight deck. CRM applied to flight
crewmembers is being accepted among the air carriers. The concept has begun to be applied to
maintenance departments.

48

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52



HyperCard Help. HyperCard is an extremely popular hypertext program that has been used
for literally thousands of different applications in the three years it has been marketed by Apple
Computer (Apple Computer, 1987). The basic unit in HyperCard is often presented as a card;
hypertext applications are often designed as a “stack" of cards connected by links between
related cards that are shown by link markers typically called "buttons."

The HyperCard software contains its own help system that illustrates how familiar metaphors
in hypertext systems can enhance the usability of online information while hiding irrelevant
detail. Figure 5 shows the "flip chart" that appears to users when they select help. Users view
different parts of the help manual by selecting the tabbed divider buttons at the bottom of the
Screen. Since users see details only in the locations they select, few realize that the help system
contains over 400 different cards.

A secondary metaphor used by HyperCard help is that of a map that represents the logical
structure of the help manual, shown in Figure 6. When users select (using a mouse) an icon
representing a specific stack of cards in the help manual, it is as if they "zoom" through space to
view the list of cards within that part of the manual.

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Definitions

CD-ROM, or compact disc read-only memory, is a storage format for optical discs that is a
cousin of the familiar audio format (Chen, 1986). The storage capacity on CD-ROM is roughly
660 megabytes, which can be thought of as the equivalent of 250,000 pages of typewritten text,
or a combined 10,000 text pages, 2000 diagrams, and six hours of telephone-quality audio.

An important benefit of CD-ROM is that disks are inexpensive to duplicate and distribute.
Once a master disk is prepared, it costs only a dollar or two to create additional copies, and it
costs only another dollar to ship a disk anywhere in the country. When compared to the
production, shipping, and storage costs for printed information, CD-ROM wins by orders of
magnitude.

82


development and publication of a brief document containing an explicit list of
guidelines for the preparation of maintenance manual-type information. This
document should be based on the guidelines discussed at this meeting and should
be distributed to aircraft manufacturers and interested documentation specialists
for review and coordination with recent ATA requirements.

Coordination with Air Transport Association

The Air Transport Association formed the Airworthiness Assurance Task Force to address
problems of the aging airliner fleet. Within this Task Force is the tmproved Airworthiness
Communications Systems Committee. This Committee, which includes representatives from the
Federal Aviation Administration, has been concerned with many of the same items addressed as
Conclusions and Recommendations here. For example, one goal of this Committee is to
develop a standardized technical data system. Another goal is to address the role of human
factors in aircraft maintenance. As one can see, the goals of the ATA Committee and those of
this meeting are closely allied.

Recomm ion

1, The FAA Program on Human Factors and the ATA Committee on
Communications maintain close coordination. Others interested in specific topics
addressed in this meeting should contact the ATA Communications Committee to
learn of its agenda and its conclusions to date.

Human Factors

Topics of interest at this meeting focused on maintenance data, technical documentation
and industry communications procedures. While human factors are very much a part of each of
these topics, little reference was made to some of the more traditional areas of interest within
human factors, such as:

Use of visual displays
Information processing
Performance measurement
Feedback requirements
Decisionmaking

The extent to which topics such as these affect maintenance performance and are related to
maintenance communications is not known. One can assume that each topic represents a
variable underlying maintenance proficiency.

As reported at this meeting task analyses are being performed for an array of maintenance
actions as part of the FAA Human Factors Program. At the conclusion of these studies,
considerable information will be available concerning the role and influence of traditional
human factors variables in maintenance performance.

Recommendations

1. Results of the Human Factors Task Analyses should be reviewed as studies are
completed to assess the manner in which any of the recommendations presented
here should be modified or expanded to incorporate the new findings.

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7. The Federal Aviation Administration and the Air Transport Association both have

programs considering information exchange in aircraft maintenance and
inspection. Coordination between these Programs is excellent. Anyone
interested in the topic of information exchange should be familiar with each of
these programs.

. Traditional topics in human factors such as (1) use of visual displays, (2) information
processing, (3) performance measurement, (4) feedback requirements, and (5)
decision making were given little reference during this meeting. However, one
can assume that each of these topics plays some role in determining
maintenance efficiency. As the FAA Human Factors Program proceeds and more
direct human factors data are developed, findings of these efforts should be
incorporated into new procedures and systems to improve information exchange
in aviation maintenance.

¥


in complex system settings. CES generates the intentions or the decisions that might be made
ven a specific set of circumstances. The system is currently on a symbolics computer.

Operation of CES requires certain inputs. First, the system must be provided a knowledge
ase describing the decision maker or decision-making group. What do they know? Next, a set
f process mechanisms must be provided. These are the rules we would expect these people to
use as they apply the information in their knowledge base. Finally, some well-defined scenario
used to initiate a decision-making sequence must be provided. In a decision-making sequence,
it is most important that some kind of algorithm be provided that will illustrate to CES the impact
of earlier decision making.

CES outputs include housekeeping information concerning the knowledge base and
scenario parameters. It prints out an entire sequence of the decision-making process. As the
situation becomes more complicated and no reasonable decision can be made, CES will print
out information concerning all attempts that were made through hypothesis development,
information search, verification attempts and other processes in a decision effort. There is a
complete audit of everything that the simulation does.

CES can be used for analyzing cognitive errors of commission and omission and to support
tisk (safety) assessments. The simulation itself does not produce error probabilities. To achieve
this, we developed another "tool" called CREATE, the Cognitive Reliability Evaluation
Technique. Using the two together, we can generate the likelihood that a decision-making error
might be made. CES also can be used to study decision-making behavior per se. For example,
under certain stressful situations, we have found that both operators and maintenance personnel
may regress in their behavior. Where normally decisions would be made using a series of
hypotheses, in these cases individuals regress to that which is familiar. They regress to decisions
used in the past.

Another type of decision-making process being studied is one which we call "going down the
primrose path." Again, this occurs under conditions of serious stress. Here individuals generally
are required to make a series of interdependent decisions. We find that stress effects cause
individuals to commit themselves to an initial decision and try thereafter to confirm that decision
even in the face of conflicting information. They may even block out new information in order to
maintain the validity of their initial decision. We have seen this happen in many of the accident
situations that have occurred in our industry. Using CES, we attempt to simulate and understand
these two decision-making processes. We then may be able to build into the simulation certain
factors, that later could be put into actual equipment, to force people to maintain a more
orderly decision-making process.

The Cognitive Environment Simulation also is used for intellectual augmentation. We have
concluded that automation is not a complete solution for many task requirements. Automation
takes tasks away from people. Then vigilance and motivation both become problems. In fact,
nuclear power plants Pave been closed because people were sleeping on the job. In order to
combat this, we are using an expert system in an attempt to have this system perform the more
mundane tasks and thereby augment the ability of an individual to make the kinds of decisions
he should make.

A final use of CES is for previewing the effects of decisions taken but not yet implemented.
We feel this preview function of tactical decisions will improve the planning phase, the decision-
making phase, and final implementation.

75



Airworthiness Directives are not always clear-cut and easy to understand. When we receive an
AD, we make copies and spread them through the organization to Quality Assurance,
Inspection, and Maintenance. We then have a meeting until we come to a conclusion as to
what the AD really requires of us. After this, we normally call Boeing engineering to see if they
agree with our conclusion. Once Boeing concurs, we then talk to the Northwest Region, and
say, "We think this is what the AD says; this is how we intend to meet it; do you agree with our
approach and does it meet the needs?" Generally, the Northwest Region agrees; sometimes
they don't. As this communication loop is proceeding, we also keep contact with our Principal
Maintenance Inspectors at the FSDO. They are equally interested in ensuring that we comply
with these Airworthiness Directives.

Every Airworthiness Directive, as | said, tells you how to accomplish a repair. However,
sometimes the AD does not cover every aspect of repair, and you must go to the FAA for
approval of an alternate compliance, For example, on ADs dealing with the Boeing 737 lap
joints, you always need an alternate compliance. tn this case, we contact the Northwest Region
for approval for the repair we plan to make. We also go to Boeing engineering to be certain they
concur with our approach. Finally, we may contact our Principal Maintenance Inspector at the
FAA FSDO. So, as you see, there can be a considerable paperwork flow and a lot of personal
interaction in our communications with the FAA and the manufacturer concerning repair plans.

At Aloha Airlines, our maintenance program is controlled through a well-defined planning
process dominated by the Engineering Department, as shown in Figure 5. Inputs from the FAA
FSDO come in through our Quality Assurance Department. Other outside inputs come through
our Engineering Department, from Boeing or the FAA Northwest Region, It is also through
Engineering that we communicate with the Air Transport Association. When a Service Bulletin
or a Service Letter or similar document arrives, Engineering reviews it and gives copies to all
other departments for their review. On a monthly basis, we meet to go over these Service
Bulletins and Service Letters and determine which apply to us, what the requirement is, if we
need to act on it, and how to accomplish it. If we decide we want to do it, Engineering creates
an Engineering Change Order to accomplish the inspection or modification. The Planning
Department then coordinates all other required activities such as acquiring the necessary
material, coordinating this activity into our Maintenance Plan, coordinating with production and
inspection activities, and scheduling the work to ensure that it is accomplished on time.

We meet on a daily basis to review the previous day's operations, to determine what our
problems are, and to plan for the remainder of the day and the next few days. Our Boein
representative sits in on these meetings and is well informed as to what we are doing. Althoug!
he is a Boeing employee, we consider him part of the Aloha family and maintain a very open
line of communication with him.

Each afternoon, we have another meeting. At this time we review current repair efforts, our
manpower requirements, deadlines for various jobs, and any additional work we foresee. At this
time, we plan the evening's maintenance work. One nice feature of a small airline such as ours is
that every airplane is in maintenance at our home base every night. This is a luxury not many
airlines have and it certainly eases our communication requirements.

‘ have described the communication procedures used at Aloha Airlines. As a final point, |
would like to discuss briefly communications between the FAA and airlines in general. For the
most part, | feel these communications have improved greatly over the last several years, In the
1985-86 period, large fines were being imposed on airlines for non-compliance and other

28



Part 1 - User's Guide
Part 2 - Human Performance Data Store
Part 3 - Hardware Performance Data Store
Part 4 - Aggregated Data Store (human performance
combinations, hardware combinations, human/hardware combinations)

Data for NUCLARR are prepared by an Idaho National Engineering Laboratory management
team, which collects the data and prepares it for input into the system. About every two months,
a Quality Assurance Team is sent to Idaho Falls to review the collected information to determine
its appropriateness, where it goes in the system, and whether or not the data distributions will
allow for any kind of aggregation. This review team contains individuals from the nuclear industry,
the military, NASA, and other appropriately qual- ified organizations.

NUCLARR is updated quarterly. Those having the hard copy version receive updates at that
time. Those having the automated system receive a new set of floppy diskettes.

The NUCLARR library is available to all interested agencies, groups, or individuals. The hard
copy version is available at no cost to those who apply. The automated version is available on a
data-exchange basis. Since the USNRC is a Government agency, we cannot sell this technology.
Therefore, our management and legal counsel have established a procedure where the
automated version is available to industry and universities on this information- exchange basis.
Details are provided upon written request to the USNRC.

Nuclear Plant Reliability Data System (NPRDS)

The Nuclear Plant Reliability Data System is a voluntary reporting system sponsored and
maintained by the U.S. commercial nuclear power industry which includes data on
maintenance events, usually hardware failures. The data system contains approximately 500,000
event reports dating back to 1974, NPRDS data can be recalled by hardware description,
vendor, plant, type of failure, source, timeframe, or combinations for use in risk assessments,
establishing trends, and for comparisons between facilities. NPRDS is managed by the Institute of
Nuclear Power Operations (INPO), in Atlanta, Georgia. Users include the nuclear industry,
USNRC, vendors, and design engineering companies. Access is by request to the NPRDS
Operations Office at INPO.

Maintenance Personnel Performance Simulation (MAPPS)

Maintenance Personnel Performance Simulation is a stochastic task networking computer
simulation which focuses on overt behavior. Its output can be systematically influenced by up to
24 personal, task-centered, and environmental factors that might reasonably be expected to
influence performance. It allows one to simulate a particular situation of interest at a very
detailed level.

MAPPS is capable of simulating the behavior of maintenance mechanics, electricians,
instrumentation and control technicians, operations controllers, and supervisors, in teams of two
to eight, in complex high-reliability systems settings.

The output from MAPPS includes some 70 housekeeping and evaluation. indices.
Housekeeping indices include general information about the subtasks making up the task
sequence being simulated, the task sequence itself, characteristics of the personnel involved,
protective clothing, and shift change information. Evaluation indices include performance of
individuals being simulated, performance of the team simulated on each subtask, and
performance on the overall task.

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The Steering Committee would like to take the informal system and institutionalize it in
some formal method so that we can (1) get the information disseminated quickly and (2) have a
formalized and rigid analysis program that will allow us to determine not only the extent to
which the problem exists throughout the fleet, but also the best resolution for the problem. At
this time, if only one or two carriers have a problem it generally is resolved between the carrier
and the manufacturer or between the FAA, manufacturer, and the carrier. A goal of the
Steering Committee is to use the SDR system as it exists today and extract the data, of which
there are vast amounts stored in the system, and create an analysis loop for the system that is
geared specifically toward the needs of the airline industry. Analyses are conducted on data
collected now and it is used for the FAA and for general aviation, but analyses of the data are not
of great use to the air transport industry. Information comes about too slowly. By the time the
FAA produces an analysis of significant findings from the SDR, everyone in the industry is aware
of the problem and has already taken action to correct it. So that part of the SDR loop does not
work well for the airlines. We need to determine means of formalizing that part of the analysis
loop to make it indeed work for the airlines.

Another goal for the Steering Committee is to pursue means for developing a standardized
international system for collecting, storing, analyzing, and disseminating technical data. Again,
we have concentrated on the Service Difficulty Reporting system, but the effort has far greater
ramifications than SDR. A short-term objective was to see how the existing SDR system might be
improved. In the long term the objective is to design a technical data system from the ground up
that will be acceptable internationally and will ensure that all carriers report the same
information to their regulatory agencies or manufacturers in the same format. If this can be
achieved, we will have done a great deal not only for the study of reliability but for the capability
to detect safety trends with far greater clarity, accuracy, and speed than is the case now.

The format for a new system should ensure consistency not just for SDRs but also for’ data fed
back to manufacturers based on reliability factors, or based on problems detected during normal
maintenance inspections. In all, we need a single document that will go to all agencies and into
a data base accessible to the industry in order that we have the most comprehensive data
analysis program possible, whether one is concerned with reliability or with safety. This is an
ambitious program and we anticipate a period of several years before we achieve an
international standard, let alone a standard acceptable among the airframe manufacturers and
to the FAA as well.

Another objective of the Committee is to specify electronic means for transferring data. At
this time, if a manufacturer's engineering representative decides that a change is necessary to
technical data relating to the systems of his aircraft, an average of about six months is required for
the engineer to make the changes necessary and see that the information gets into the hands of
the operator with the equipment. For instance, if he wants to change a reference or a part
number on a hydraulic actuator because it has been modified, it takes about six months from the
time the engineer recognizes the need to make a change before the engineer or manager at
the airline receives that change in his hands. The airline itself then has a lag time generally on
the order of about three weeks to three months before the information received from the
manufacturer is incorporated into all of his manuals. The timeline for this data flow is of course
too long. We need to reduce the time factor to hours or days. The only means to do this is
electronically with a standardized communications system shared back and forth between the
airlines, the FAA, and manufacturers. We must have a common format if this is to be achieved.

An additional activity of the Communications Committee, one quite important for airline
operators but also of consequence for the FAA and for manufacturers, is to provide
recommendations concerning changes needed in the aircraft of our older fleet airplanes over
the next four or five years. It is critical to the industry that these recommended changes not be

21



LESS “PERFECT AIRLINE COMMUNICATIONS”

AIRCRAFT

COMMUTER
OPERATOR

Figure 2

38



Figure 4 shows the different areas of information included within the OMIS data base. As you
can see, it includes spares information, maintenance information, minimum equipment list
information required for aircraft dispatch, and other needed items.

The small boxes within the larger hatched boxes at the bottom of Figure 4 indicate that only
that portion of a data base may be carried which is required by a particular airplane.
Theoretically, OMIS is smart enough to know on which airplane it is being carried. The tail
number of an airplane determines what is in the data base.

Ina full on-board maintenance system, the Central Maintenance Computer is the key entity
for support of the airplane. This computer continuously monitors the airplane. It also contains
information concerning all preventive maintenance schedules. As shown in the lower left of
Figure 5, the on-board maintenance system works with the Central Maintenance Computer to
exchange information concerning maintenance probabilities. For a given event, OMIS might tell
the Central Maintenance Computer that there is an 80 percent probability that the problem lies
with one certain component. With this information, the Central Maintenance Computer can
use ACARS, the down link radio system now in use with some airlines, to radio the data ahead
so that a mechanic and the part are waiting at the ramp to support that maintenance
requirement.

Note that Figure 5 shows that man, the human operator, remains as a component within the
on-board maintenance system. Man must look at systems that are not monitored or that he has
flagged as safety concerns. He also must remain within the system to provide a monitoring
function to ensure that the complete system is operating appropriately.

We anticipate a number of benefits when the On-Board Maintenance Information System
becomes fully operational. Maintenance data then will be easily accessible with the on-board
system right at hand. There will be centralized storage of data for easy retrieval. Fault isolation
and correction also should be improved. Finally, and of considerable importance, maintenance
time will be lessened and we should reduce the requirement for retesting of good components
incorrectly flagged as possibly defective.

In summary, the Boeing Company is firmly committed to the development of systems for the
delivery of digital maintenance data. Within the next ten years, we hope to see all of our current
developments in operational use. For this to be accomplished, Boeing and the airlines, in
concert with industry committees, must work together to ensure that the new maintenance
data systems are effective and responsive to the needs of all users. In any event, it is apparent that
the day of hard-copy maintenance documentation is ending. The future of digital maintenance
data systems is now.

60



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The phased approach being followed in the development of IMIS is shown. in Figure 3. In the
first phase, concluded in 1987, concern was only about data content, user requirements, user
presentation formats, and similar issues. Little attention was given to computer hardware. In
Phase Il, which is ongoing at the present, we are concerned with diagnostic presentation,
development of maintenance algorithms, and the integration of technical data. When flight line
diagnostics are in process, and technical data are required, the technician should be able to
access the data immediately. Phase III, scheduled for completion in 1993, will be a formal
engineering analysis of the requirements for an Integrated Maintenance Information System and
a full field test of the system as developed. The principal activities and results of Phase |, the
development of electronic presentation techniques, are shown in Figure 4. Initially we worked
with a small off-the-shelf computer. Even so, we were able to link it with multiple data sources so
that a technician could go from the task to diagnostics to historical data to remedial background
information as he worked with the computer. We also worked extensively in the development
of efficient presentation formats for the computer interface.

Three in-shop field tests were conducted to evaluate our electronic presentation
techniques. Two were at Air Force facilities and one was an independent Navy test. In a
comparison test, we found 100 percent fault isolation success with the electronic system versus
75 percent success with a paper presentation system. In addition, we found that fault isolation
time with electronic presentation generally ran about one-half that with a paper-based system.
With the electronic system, there were no false removals, which is a tribute to the ability of IMIS
to provide diagnostic information. Finally, technicians liked the electronics system. Acceptance
scores were high.

In our electronic presentations, two levels of detail for maintenance information were
provided since both novices and experts worked with the system. Developing maintenance
information for a dual-track system was not a simple matter but it was done. This approach was
successful in making the system useful for technicians at different levels of experience and

capability.

The principal activities of Phase II, Flight Line Diagnostics, are listed in Figure 5. As we began
this phase, it was apparent the small off-the-shelf computer used previously no longer was
satisfactory. Consequently, a Portable Maintenance Aid (PMA) was constructed in-house with
appropriate features to allow use at the flight line. We also began an authoring system for "Type
C" data, about which more will be said later. In flight line tests to date, the F-16 has been used as
the test aircraft. In May 1989, we completed our diagnostics tests for the fire control radar in the
F-16. In 1990, the Navy F/A-18 aircraft will be used as a test vehicle since it has a more extensive
maintenance bus and will represent more of a challenge for our diagnostic system. The final step
in Phase II will be the preparation of a Content Data Model Specification which will detail
software requirements for our authoring and presentation system.

The F-16 flight line test was conducted to demonstrate the feasibility and utility of flight line
diagnostics. In this test, the Portable Maintenance Aid was loaded with the F-16 Fire Control!
Radar data base. Into this data base were inserted six radar faults. Twelve F-16 technicians then
attempted to isolate and repair these faults using the PMA as a diagnostic system.

The diagnostic logic of the PMA optimized the isolation and repair sequence. Technicians
indicated they preferred the IMIS diagnostic system over a handbook approach. The technicians
commented positively about (1) the graphical depiction of diagnostic logic, (2) the diagnostic
sequence controlled by the technician, (3) easy access to required data, (4) the expert/novice
levels of detail, and (5) the automatic maintenance data collection feature. One problem noted

92



Facilitation of Information Exchange Among
Organizational Units Within Industry

James Taylor, Ph.D.
University of Southern California

Introduction
In these remarks | will discuss some of the barriers to communication between organization
units, and | will introduce concepts which may offer insight into coping with these barriers.

First, | would like to emphasize that the air transport industry is living in an environment that
is becoming increasingly complex. Indeed, we might call it "chaotic." Today's maintenance
environment includes an increasing passenger load, increasing international competition, a short
supply of new passenger aircraft, more short-term cost concerns, increasing fleet size of aging
airplanes, more complex technology (both in aircraft and tools), heightened concern over the
curriculum of A&P schools, and a re juced supply of applicants to those schools.

If we want people in maintenance and inspection to be able to adapt to this complexity,
rather than merely react or succumb to it, they must have a greater understanding of their place
in their environment -- a complex international system of air transport. My remarks today will
address ways that exchanging information affects understanding, and in turn improves that

adaptability.

Barriers to Communication
What follows are some barriers to information exchange in aircraft maintenance. An
understanding of these barriers offers ways to think about successfully adapting to complexity.

Aircraft design philosophy has changed over the past 15 years, This change has direct effects
on maintenance practice and philosophy. First there was “fail-safe” philosophy which relies on
redundant parts; if one component breaks there is another component in line ready to carry its
load. Therefore the failure is not threatening, ‘and maintenance can be “after-the-fact" in
repairing what has broken. Another philosophy is "safe life," in which individual components and
parts can be tested to failure before manufacture. With these test data, plus an appropriate time
added to be conservative, replacement time for those parts can be predicted. When the
component has operated for that time, the maintenance task is to simply replace the part
regardless of its condition. A third maintenance philosophy is "condition monitoring." This has to
do especially with the problems of aging aircraft, and to the situation of the pressure cabin -- for
which there is no redundant part. In condition monitoring it is necessary to monitor sheet metal
skin to determine whether design life can be extended. Using condition monitoring, cabin life
can be theoretically extended without limit. The result is that older airplanes become harder to
work on, and mechanics become less experienced. In short, the older mechanics don't know
the new sheet metal techniques very well, and the younger mechanics don't know commercial
airliners very well.

Condition monitoring generally involves supplementary structural inspection documents
(SSIDs) which call for new inspection procedures. "Damage tolerance analysis," which specifies
crack growth rates, allows one to program inspections at times when crack damage has
progressed, but has not yet produced an unsafe flight condition.

These are fairly new ideas throughout the industry, and different people have different
meanings for these terms. For example, some maintenance people simply do not know what
damage tolerance is; while others believe that any added inspection policy is a SSID. Obviously
such confusion does not facilitate information exchange.

45

'
i



* CD-ROM and hypertext are complementary. Hypertext systems, especially those involving
extensive graphics or other media, require more storage space

than traditional forms of
information presentation. The innovative user interface concepts of hypertext and hypermedia
make CD-ROM something besides digital microfilm.

* Successful hypertext projects are those that take a cautious approach to problems of scale
and that make the right tradeoffs along the way.

References

Alschuler, L. (1989). Hand-crafted hypertext: Lessons from the ACM experiment. In £. Barrett

(Ed.), The Society of Text: Hypertext, Hypermedia, and the Social Construction of
Information (pp. 343-361). MIT Press.

Boff, K. R., & Lincoln, J. E. (1988). Engineering Data Compendium: Human Perception and
Performance. AAMRL: Wright-Patterson AFB, OH.

Carr, R. (1986). New user interfaces for CD-ROM. In S. Lambert and S. Ropiequet (Eds.), CD
ROM: The New Papyrus (pp. 185-196). Microsoft Press.

Chen, P. (1986). P-S The compact disk ROM: How it works, IEEE Spectrum, 23(4), 44-49,
Conklin, J. (1987). Hypertext: An introduction and survey. Computer, 20(9), 17-41.

Department of Defense (1989). Human engineering design criteria for military systems,
equipment, and facilities (MIL-STD-1472-D). Washington, DC.
Egan, D., Remde, J., Landauer, T., Lochbaum, C., & Gomez, L. (1989). Behavioral evaluation

and analysis of a hypertext browser. Proceedings of the 1989 CHI Conference on
Human Factors in Computing Systems, 205-210.

Glushko, R.J. (1989), Transforming text into hypertext for a com

Proceedings of the ACM Conference on Computer-Human Ini
298.

pact disc encyclopedia.
teraction - CHI '89, 293-

Glushko, R.J. (1990a), Using off-the-shelf software for a hypertext electronic encyclopedia.
Technical Communication, 37(1), 28-33.

Glushko, RJ. (1990b). Visions of grandeur? Unix Review, 8(2), 70-80,

Glushko, R.J., Weaver, M.D., Coonan, T.A., & Lincoln, J.E. (1988). “Hypertext en,

Practical methods for creating a compact disc encyclopedia. Proceedings of

pineering’:
Conference on Document Processing Systems, 11-19.

the ACM

Hardman, L. (1988). Hypertext tips: experiences in developing a hypertext tutorial. In D.M:

Jones and R. Winder (Eds.), People and Computers IV, (pp. 437-451). Cambridge:
Cambridge University Press.

HyperCard User's Guide (1987). Cupertino, CA: Apple Computer.

Jonassen, D. (1986). Hypertext principles for text and courseware design. Educational
Psychologist, 21(4), 269-292.



forward). There are really three potential parts to the information environment: directive
mation, feedforward information, and feedback information. All are known to have a large
fect on manufacturing inspection performance. A short review of this data is needed before
e can consider aircraft inspection in detail.

Directive Information involves the presentation of information in a form suitable for the
uman. This is the basis of good human factors. An example from inspection is the work of
haney and Teel (1967) who used simplified machinery drawings as an aid to inspectors. These
lrawings of machined metal parts were optimized for inspection rather than manufacture, with
imensions and tolerances in the correct placement and format and with similar characteristics
grouped together to encourage systematic inspection. Compared to a control group with the
Orginal drawings, inspectors using the optimized drawings found 42 percent more true errors in
atest batch.

Feedforward Information can consist of two parts: telling the inspector what defects are
expected and providing the probability of the defects. Because there are typically a large
‘number of potential defects, any information made available to the inspector is valuable in
focusing the search subtask in particular. Many investigators (Gallwey and Drury, 1985) have
found that looking for more than one type of defect simultaneously can degrade detection
performance, so that focusing on likely defects can be expected to result in more detections.
Drury and Sheehan (1969) gave feedforward information on fault type to six inspectors of steel
hooks. Missed defects were reduced from 17 to 7.5 percent, while false alarms were
simultaneously reduced from 5.5 to 1.5 percent. Information to the inspectors on the
probabilities of a defect being present has not led to such clear-cut results (e.g., Embry, 1975)
and, indeed, a recent experiment (McKernan, 1989) showed that probability information was
only useful to inspectors for the most difficult to detect defects.

Feedback Information has had consistently positive results in all fields of human performance
(Smith and Smith, 1987) provided it is given in a timely and appropriate manner. Indeed, it is the
basis of most training schemes: trial and error does not result in learning without error feedback.
Wiener (1975) has reviewed feedback in training for inspection and vigilance and found it
universally beneficial. Outside of the training context, feedback of results has had a powerful
effect on the inspector's ability to detect defects. Embry's laboratory studies (1975) showed a
large effect, but so did Gillies (1975) in a study in the glass industry where missed defects were
reduced 20 percent when feedback was implemented. Drury and Addison (1973), another glass
industry study lasting almost a year, showed a reduction in missed defects from 15 to 8.8 percent
after rapid feedback was introduced. More recently, Micalizzi and Goldberg (1989) have shown
that feedback improved the discriminability of defects in a task requiring judgement of defect
severity.

Information in Aircraft Inspection
Each task inspection will be considered in turn.

Task 1: Initiate. Here, the command information predominates. For visual inspection, the
workcard gives the location, type of inspection to be performed and, at times, feedforward
information of use in the search and decision phases. Typically, however, this information is
embedded in a mass of other, necessary but not immediately useful, information. Often the
information contains attached pages; for example, with diagrams of parts to be inspected. While
laser printers making a new copy for each workcard have helped diagram quality, inspectors still
find some difficulties in interpreting this information. Supplemental information is available in
manufacturers' manuals, FAA communications, and company memos/messages, but these
sources are typically not used at inspection time. This places a large burden on the inspector's
memory.

65



Lacy, R., & Chignell, M. (1988). Authoring hypermedia for computer-based instruction.
Proceedings of the Human Factors Society 32nd Annual Meeting (Vol. 1), 313-317.

Landow, G. (1987). Relationally encoded links and the rhetoric of hypertext. Hypertext '87
Proceedings, 331-143.

Link, W., Von Holle, J., & Mason, D. (1987). Integrated Maintenance Information System
(IMIS): A maintenance information delivery concept. AFHRL Technical Paper 87-27,
Wright-Patterson Air Force Base, OH.

Lotus One Source brochure. Lotus Development Corporation, Cambridge, MA. (800-554-
5501, operator XXXX).

Nielson, J. (1989). The matters that really matter for hypertext usability. Hypertext '89
Proceedings, 239-248.

Oren, T. (1987). The architecture of static hypertexts. Hypertext '87 Proceedings, pp. 291-
306.

Perlman, G. (1989). Asynchronous design/evaluation methods for hypertext technology
development. Hypertext '89 Proceedings, ACM: New York, 61-81.

Rafeld, M. (1988). The LaserROM project: A case study in document processing systems.
Proceedings of ACM Conference on Document Processing Systems, 21-29.

Smith, S., & Mosier, J. (1986). Guidelines for Designing User Interface Software. Bedford,
MA: MITRE.

Thomas, D., & Clay, J. (1988). Computer-based maintenance aids for technicians: Project
final report. U.S. Air Force Human Resources Laboratory Technical Report AFHRL-TR-
87-44, Wright-Patterson Air Force Base, OH.

Van Sickel, P., Sierzega, K., Herring, C., & Frund, }. (1988). Documentation management for
large systems of equipment. User-oriented content-based text and image handling.
Proceedings of the RIAO Conference, (pp. 124-137). Boston, MA.

Walker, J. (1987). Document Examiner: Delivery interface for hypertext documents.
Hypertext '87 Proceedings, 307-323.

Walker, J. (1988). Supporting document development with Concordia. IEEE Computer,
21(1), 307-323.



CARGO .
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Figure 13

123



The final principle is that of language control. The material should be described in terms
known to the reader. Technical jargon should be avoided, unless the terms are defined as part of
the learning/descriptive process. Unfortunately, there is not much by way of guidance in the
literature concerning how to curtail "language" of technical materials in a systematic manner.
Therefore, one must rely far more on writing skills of those preparing the descriptive parts of
technical manuals than we like. We find that it helps to start with a limited number of basic
words and then use these words to describe new words as the needs arise. In this manner, you
can achieve a measure of standardization of the "language" in the manual.

Measurement and Development

Common measures of readability are not very useful for measuring the effectiveness of
technical information. As indicated in this presentation, there are numerous factors that
contribute to the acquisition and retention of technical information. You will find that only a
small portion are covered by common measures of readability such as the Flesch count. While
use of the Flesch count should not be discouraged, improving the usability of manuals and
technical information requires more than simply fixing the text. What needs to be
communicated cannot be accomplished effectively by text alone.

A recommended procedure for measuring the effectiveness of technical documents is to first

use specifications based on the presentation principles just discussed. Then, determine the
extent to which a communication or manual complies with the specification.

Deviations from the specifications should be allowed. As noted, a major problem with
specifications is that they stultify growth. Too often authorities demand 100 percent compliance
to specifications because it is simply too hard to train people to be flexible. The consequence, |
believe, is far worse than trying to train people to be flexible.

Deviations from the specifications (in the preparation of technical information materials)
should be based on the principles described above. However, the final judge of usability should
be whether the technicians can actually use the information on the job. A measured
relationship between maintenance information and performance on the job should be
determined. Only with such a measurement capability can we realistically evaluate the
information systems being used and/or considered in aviation maintenance.

126

———_----—-—


Commuter Airline - Vendor Communications

A. Fred Giles
Continental Airlines Commuter Division

The communications network to support aviation maintenance, whether one is referring to
the major carriers or to commuter airlines, exists as a three-way operation. Information moves,
with greater or lesser efficiency, among the three major elements in the network -- the corners
of the familiar industry "triad," as shown in Figure 1. The driving force behind a major part of
these communications is purely economic. Manufacturers need to make money. Airlines need
to run a profitable operation. Overriding these economic forces, however, is the regulatory
issue. The Federal Government regulates and oversees the air transportation industry and the
motives here are not economics but safety. Communications to and from the Government deal

largely with matters of compliance. In the interest of safety, regulations are prepared. The
industry must comply.

Compliance for a major carrier and compliance for a commuter airline are the same. All
operators must comply with the regulations. However, there are realities which must be taken
into account. The commuter industry is one which has grown in some instances from one and
two man businesses to a Part 135 operation or a Part 121 operation with multiple airplanes.
Thus, with commuters, there is not the same structure, authority, and research capability found
with the major carriers. A director of Quality Control might be one person who does everything.
However, he must contend with the same regulations and communications as the large carrier
and must comply in the same manner.

Compliance is a matter both of procedures and of paperwork. A regulation will mandate
some particular action or procedural change but it also inevitably requires accompanying
- paperwork. Large carriers deal with the requirement through a Technica! Publications
Department. Commuters deal with the requirement in the same manner, except that the
Technical Publications Department may be only a single person. This person is responsible for
the paperwork and, in large measure, the communications link that is essential for continued
operation of his airline. He is also responsible for the quality of publications underlying his
operation. if these technical publications are badly written, that is how the airline will be run.
Correspondingly, if publications are handled well, the airline will be a better operation.

Technical communications operate along the three dimensions described in Figure 1. From
the point of view of economics, the most important of these is the "Airline Operator-Airline
Vendor" dimension. Typical types of communications here include:

Aircraft Vendor to Operator

Service Bulletins

Information Letters
Recommended Repair Schemes
Modifications Update
Publications Revisions

General Vendor Communications

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Operator to Aircraft Vendor

* Completed Repair Schemes

* Modification Compliance

* General Operator Communications

32



also is a crucial issue and is one which requires careful review if we are to develop a training
strategy which best supports present maintenance needs. As a start toward optimum working
environments for maintenance personnel, we are sending people to various air carrier
maintenance sites and looking at environmental parameters such as lighting, noise level, and
other factors which might be either helpful or detrimental to the process. Other topics of
concern for our program include the kinds of equipment and job performance aids required for
maintenance and inspection as well as studies of vigilance and variables which might lead to
boredom and complacency on the job.

A number of initiatives already are underway as we build our research program. As part of
the FAA's aging fleet evaluation program, we send a human factors specialist on each site visit
and use that as an opportunity to collect information concerning work environments and
working conditions. We also are sending research teams to conduct task analyses of
maintenance activities at different air carriers. To date the teams have visited Pan Am facilities at
Kennedy and Miami airports. A number of other visits are planned both for air carriers and for
repair stations.

Another activity just starting is a study of the application of intelligent tutoring systems and
computer-based instruction in maintenance training. These interactive technologies have
developed considerably in recent years and now may be of real value as systems to improve the
effectiveness of maintenance training.

We plan to use the findings of our various research activities to develop an information
source, a handbook available to industry and others concerned with maintenance. At this time
we do not know exactly the contents of this handbook or the form which it might take.
Ultimately it might be a‘printed handbook supported by such things as video tutorials and other
types of machine oriented media. But, again, | want to emphasize that our product is going to
be information.

While we do not have a firm set of chapters for the Human Factors Handbook at this time,
some chapters that we anticipate might be included will cover:

Information transfer/communications

Work environment

Selection/training

Equipment/job performance aids

Inspection methods

Human limits

Problems of vigilance/boredom/complacency
Reliability of NDI activities

eooeeeceee

Just as the present meeting focuses on matters of "information exchange and
communications," we plan another meeting for June 1990 which will focus on "training issues."
At that time we will discuss some of the initiatives | have just described, such as intelligent
tutoring systems, computer-based instruction, and other new training techniques. The June
conference will be held under auspices of the FAA Technical Center in Atlantic City, New
Jersey. Detailed information concerning this meeting will be available in the near future.

The Human Factors Research Program | have just described is organized as shown in Figure
1, The top of this figure indicates that we are seeking input from industry, the Federal
Government, and any others who can contribute. Within the Government, we plan to deal not
just with FAA facilities but to include the Department of Defense (DoD), the National
Aeronautics and Space Administration (NASA), and others such as the Nuclear Regulatory



Coping with Communication Obstacles

To understand the importance of coping with communication barriers, let us view the
maintenance community as a sociotechnical system. This is a system which delivers a technical
output achieved through cooperation and coordination among its members -- and of course
that is where the communication comes in. The key requirements to facilitating information
exchange in a socio-technical system are:

* Understanding the larger system

* Choosing appropriate philosophy and values "for the industry"

* Taking a product focus

¢ Using a common language

* Holding conscious and collaborative expectations

The first requirement is to understand the larger system. What is the nature of the
environment? Since the commuter airline fleet has not had the same well-publicized accident
as the larger carriers, one could say that the same aging aircraft problems do not exist with the
commuter carriers. However, commuters are part of the larger air transport system and one
should find the same generic maintenance issues and problems there.

The second requirement for facilitating communication -- "choosing appropriate philosophy
and values," is a key topic for this discussion. Social values really represent coping mechanisms.
This mechanism makes it possible to deal with persisting areas of uncertainty by providing a
common vision or focus. If a single large organization cannot successfully adapt by itself, what can
itdo? To the extent that effective and appropriate values emerge, large classes of events can be
addressed through this ethical code of values. Given the right set of values, we can come to
understand more about and cope with the complex environment we are facing. This
organizational transformation will be either regressive or constructively adaptive according to
how far these emergent values adequately represent the new environmental requirements. In
other words, we have to understand the environment in order for our system's values to really
make sense.

The value of collaboration among members of the maintenance industry is crucial. There is,
in fact, considerable collaboration at this time. Certainly there is more collaboration in the
maintenance departments of the airline industry than one perhaps would find in the marketing
departments. In marketing, some information might be proprietary, but in maintenance the
value system supports collaboration. Collaboration in safety can lead to a conscious agreement
on common maintenance philosophies and to ways to communicate common values to every
member of the system. There may be more sense of cooperation between different company's
maintenance systems than between the departments within a single company.

Information exchange can be used to reinforce the understanding and the utility of common
industry values. As noted, collaboration is one such common value. However, there are some
maintenance philosophies that may or may not be shared by many members and certainly are
not shared by most members of the larger international air transport system. Examples include a
commitment to "condition monitoring," and to the frequent inspection required by 'SSIDs."

An analysis of a sociotechnical system not only discusses important elements in the
environment and the kind of values that help make the environment make sense, but it also says
that the technical system is important. A technical system analysis is undertaken only when we
understand the importance of the appropriate values in adapting to environmental chaos.
Further comprehension of the technical and social aspects of the system then is in order.

47



and urge you to continue working with us as we strive to build an aviation maintenance system
suitable for the demands of the 21st century. Thank you.

Meeting Objectives

William T. Shepherd, Ph.D.
Federal Aviation Administration

The Federal Aviation Administration is sponsoring today's meeting as part of a broad effort to
enhance communications between the FAA and industry as well as among different groups
concerned with human factors and personne! issues in aircraft maintenance and inspection. Our
Human Factors R&D Program within the FAA requires a continuing flow of information from the
outside world if the program is to be effective. The FAA has held a number of meetings
concerning maintenance and inspection, including one last year which specifically addressed
human factors issues - a meeting attended by many of you here today. These meetings are a key
part of our communications process and we plan to continue them into the future.

An important part of the communications process is the identification of human factors R&D
requirements. We want you to tell us what you think we should be doing in FAA. What kinds of
problems should we address in our R&D program? For our program to be successful, we must
target the R&D activity toward industry needs. That is where the payoff will be. To this end, all of
the presenters in the program, with one exception, are from outside the FAA.

The catalyst for the FAA's current program dealing with aircraft maintenance and inspection
was the Aloha Airlines accident in April 1988. Shortly after this accident, the FAA convened an
international conference at which human factors were identified as a crucial issue underlying
effective maintenance and inspection. The more we looked at problems in maintenance
operations, and particularly those of aging aircraft, the more we saw human factors as some part
of the problem. At this international conference, the FAA Office of Aviation Medicine was
assigned responsibility for the development and management of a research program concerning
human factors in aircraft maintenance and inspection.

As one of our first activities, in October 1988 we held our first human factors conference with
a wide spectrum of industry, Government, and academic interests in attendance. The purpose of
the meeting was to develop a listing of human factors issues and to establish priorities whereby
these issues might be addressed by our R&D program.

In developing the Human Factors Research Program, we believed that a major
accomplishment would be to provide compendiums of information that would be useful to
various aspects of the aviation maintenance industry. We hope to provide information of value to
those involved in maintenance training, people responsible for establishing and monitoring
workplace conditions, and those who prepare written documents to support maintenance work.

As another goal, we want to identify experts who can help industry and the FAA incorporate
proper human factors concepts in their activities. Target groups for our R&D activity include
aircraft designers, individuals working in the manufacturing environment; manufacturers
themselves; air carriers and their maintenance operations; repair stations; and of course our own
people within the FAA.

A number of research topics for our R&D effort have been identified, many developed
through our first conference held last year. At that meeting, information transfer/communication
was identified as the most important issue facing the aviation maintenance community. Training

6

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As important as it is, communications among the members of the three-legged stool does
not cover all communications requirements. Communicating with the public is equally
important, | firmly believe that the industry is best served when technical experts speak for the
industry. Any portrayal of technical data by someone other than a technical expert, even if he is a
professional communicator, is a veneer. In such cases, serious questions concerning technical
issues can only be answered by those with the best technical understanding of those issues.
Fortunately, in the past few years the industry has become considerably more effective in
communicating with those outside the industry. However, we must continue to ensure that our
technical experts are well schooled in the art of communication and can speak ably for the
industry.

When the Airworthiness Assurance Task Force was initiated, we were charged to address
certain short-term issues that affected the reliability of the fleet, such as structural integrity and
corrosion prevention. We chose five short-term objectives which are being pursued now by
three Task Force Working Groups and should be resolved in the very near future. Longer-term
issues came under the direction of the Task Force Steering Committee. This Committee, in
addition to being responsible for defining issues and ensuring consistency among working groups,
has the responsibility of pursuing the longer-term objectives. One of these longer-term
objectives is to address the role of fuman factors in aircraft maintenance. Another longer-term
objective is to develop a standardized technical data collection, storage, analysis, and
documentation system.

One of the first actions of the Steering Committee was to examine the Service Difficulty
Reports of the FAA to determine if changes could be made that would provide more
meaningful data in a more responsive time. At this time, airlines are required to report certain
events specified by regulations every time these occur in flight or on the ground incident to
flight. The intent is for a data base to be developed which would be analyzed for safety trends. If
trends develop, the FAA is required to alert the field as to potential problems, either with a fleet
of airplanes or with the overall air transport fleet.

Unfortunately, the Service Difficulty Report System does not work in the manner originally
intended. Information is gathered and is disseminated and the industry is aware of problems as
they develop, but generally not through the formalized system of the SDRs. Industry learns
through an informal system that exists among those responsible for the safety of the industry or
the airworthiness of the fleet.

As noted earlier, airframe manufacturers have representatives on-site at most airline facilities,
as does the FAA. FAA inspectors oversee activities on-site at maintenance activities of the air
carriers. The airlines, the airframe representatives, and the FAA representatives form the
informal communications link that detects problems as they occur in real time and reports them
back to responsible agencies, in this case the FAA and the manufacturer. The FAA, the
manufacturer, and generally the airlines then gather to determine how widespread the problem
is. The manufacturer alerts the field to the potential problem through a Service Bulletin or a
Service Letter which describes the problem, asks operators to examine their aircraft to
determine if they have the problem, and then describes means for correcting it. If there is a
safety implication to the roblem, the FAA takes the Service Bulletin, generally an Alert Service
Bulletin in that case, and publishes an Airworthiness Directive. This is how the information is
disseminated. The alerting and signaling of potential safety problems are geared so that we get
information to the field in an expeditious manner. But it is not done under the formalized
system.

20

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menu


Presentations

FAA Overview of Maintenance-Related
Information Exchange

Dennis Piotrowski
Federal Aviation Administration

Human factors issues in information exchange were with us long before the Aloha accident.
In all of our aircraft development programs, both industry and the Federal Aviation
Administration have faced real problems in establishing communication channels among the
various groups working in the development programs and in deciding the kinds of information to
be distributed through these channels. For example, in the YC-15 flight test program, data-link
channels were established between the Long Beach manufacturing facility and the Yuma Flight
Test Center. This allowed aircraft design engineers to obtain quickly information that came from
the flight test vehicles and to ask questions directly of the flight test crew concerning results of
each test. At the same time, we were conducting a flight training program for Kuwait in which
information generated concerning flight characteristics and aircraft maintenance needed to be
passed to a foreign flight and maintenance team. In all of this, we became quite sensitive to
issues of information exchange and communication.

Lessons learned in programs such as those | just mentioned have been of value to the FAA as
we try to maintain an effective communication network with the aviation maintenance
community. Before we look at the FAA communications system, however, | should call
attention to the many different groups with which we must communicate. Ours is by no means a
single-channel system. Information concerning an airplane and its maintenance requirements
must be transmitted to those with inspection authority, aircraft manufacturers, airline operators,
maintenance personnel, pilots, those in the training establishment and many others, With the
international flavor of aviation today, the list becomes even longer. The back-and-forth
requirements of communication within and between these groups generate any number of
unique communications issues.

The communications system used by the FAA for a specific airplane begins with a single
piece of paper called a Standard Airworthiness Certificate. This signifies that the airplane
conforms to its engineered type design and that it is safe for operation or it is airworthy. At this
point, we are trying to communicate the status of a product with a single piece of paper.

When the Airworthiness Certificate is issued, it is supported by the aircraft Maintenance Plan
(Instructions for Continued Airworthiness). The Maintenance Plan is developed through the
activities of Broups from the manufacturer, operators, and the FAA. All of these individuals work
together within the Aircraft Evaluation Group (AEG) and through a Maintenance Review Board
(MRB) to develop the first maintenance program. This program specifies recommended
maintenance intervals and other aspects of the program needed to provide a full maintenance
capability from the first day of commercial use.

The Maintenance Plan is supported by appropriate Federal Aviation Regulations which
communicate the minimum standards for design and operation of the aircraft. Additions or
changes to the Federal Aviation Regulations involve a complex process in which a proposed new
rule is published by the FAA for review by the industry or any others with an interest in that topic.
After about a two-year period of review, discussions, and revisions, the new rule may become
effective. At this time we then need to communicate this change to all impacted parties.

15



Second Federal Aviation Administration
Meeting on
Human Factors Issues in
Aircraft Maintenance and Inspection
“Information Exchange and Communications"

Report of a Meeting

13 - 14 December 1989
Alexandria, Virginia

Introduction

The Federal Aviation Administration (FAA) sponsored a two-day meeting in December 1989
to address issues of human factors and personnel performance in aviation maintenance and
inspection. At this meeting, particular attention was given to "information exchange and
communications" in maintenance operations. Presentations were given by some 15 individuals
representing the full spectrum of interests in commercial aviation. Presentations also covered
related efforts from other fields and new technologies having possible application to aviation
maintenance. Each presentation, as well as the following question-and-answer period, was
recorded for transcription and study.

The broad objectives of the meeting were to (1) develop an improved understanding of the
role of communications in aviation maintenance, (2) identify specific problems of
communication, and (3) review new procedures and technologies which might improve the
exchange of maintenance information. An elaboration of the objectives of the Federal Aviation
Administration in sponsoring a meeting such as this is described in the two presentations
immediately following.

"Conclusions and Recommendations" of the meeting are presented just after the FAA
Meeting Welcome and Meeting Objectives. These Conclusions and Recommendations are
based on a “summing up" session held at the end of the meeting plus a careful review of the
transcripts of each presentation. Recommendations have been reviewed for intent and for
accuracy by each of the presenters.

An edited version of each presentation, taken for the most part from the tape transcripts, is
presented.



Information Type __ Presentation Type
What

Text
How Text
Sequence Text
Location Graphic
Identification/Context Graphic
Tolerance Text

The what, how, and sequence are best presented in text form. Attempts have been made to
present what and how graphically, but we have seen no data to indicate that this helps the user.
The best allocation is to use text to show what, how, and sequence, and use graphics to present
location of equipment items and its identification. Tolerance should be in text form.

Figure 3 shows an attempt to present location and identification information ‘by straight text
alone. This approach has two disadvantages. First, considerable text is required to describe the
location and appearance of the equipment. Second, the instructions themselves get quite
extensive,

Figure 4 shows the same information presented in Figure 3, but in a text-graphic format.
Note that only a very simple text statement is required. Most of the information is presented by
the graphic.

Use of graphics, however, raises another issue. This is the issue of fidelity of graphics. The
greater fidelity one attempts to introduce, especially in black and white presentations, the more
expensive the manual. We have found that fidelity itself is not the key item. For instance, in
Figure 4 the call-out of No. 2 tells you the shape of the tool to be used. No. 1 shows where it
should be placed. This call-out is not entirely clear, but the important feature is that if the
technician is located beside the equipment item, the shape of the equipment itself will tell him
exactly where the tool is to be placed.

Several clear-cut principles apply to the Presentation of text, shown in Figure 5.

Syntax is simple. For procedures, use the command form. The reader is always the "you," so
the subject (for the sentence) can be eliminated. Key components of the syntax are the action
verb, (i.e,, the command verb) and the object of the action verb. For the principle of "minimal
number of words,” we allow 25 words at most. If more than 25 words is required for one
sentence, something is wrong.

Presentation Principles for Text

* Fixed syntax

* Minimal number of words

* Standardized command verbs

* Standardized nomenclature

* Two - three related actions per step

re 5

For standardized command verbs, a maximum of 100 should be completely satisfactory. Even for
complex sets of maintenance tasks, we find 80 percent will be covered with 20 verbs or less.
Standardized nomenclature obviously is important in text. While not as important with graphics,
we recommend standardized nomenclature to improve acceptance and reduce ambiguity.

112



perform a probabilistic risk analysis. As we license a nuclear power plant, the operator is required
to analyze all sequences that could possibly lead to a melt- down followed by a massive release
of radiation. As these analyses were conducted, it became apparent that we needed to attend
much more to our maintenance and surveillance activities, These literally turned out to be
precursors or initiators of some potentially catastrophic events.

In setting the stage for a review of the development of our human factors data bases, | should
mention the particular sensitivity of our industry. With any regulatory agency, there is some
controversy between the agency and the industry it regulates. With both highway transportation
and aviation, there is controversy but it is muted by the fact that we all must ride in the same
vehicles. When one considers the generation of electricity by means of nuclear power, matters
are much different. There has been a real gulf between Government regulators and the industry
itself in terms of information exchange, especially in the area of human performance.
Nonetheless, we have been able to proceed with the development of various data base systems
to support our human factors program.

Maintenance requirements of the nuclear power industry are supported by five principal
data management systems and analytic tools. These are:

* Nuclear computerized library for assessing reactor reliability (NUCLARR)

* Nuclear plant reliability data system (NPRDS)

* Maintenance personnel performance simulation (MAPPS)

* Cognitive environment simulation (CES)

¢ Criteria for equating human tasks within and between jobs within an industry and between
industries

Each of these developments will be described next in some detail.

Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR)

NUCLARR is a data management system containing human and hardware reliability
information. The system is constructed in a series of matrices that bring together the individual,
whether on the operations side or the mainten- ance side; the kind of action the individual is
involved in, whether a single action or an action sequence; shaping factors, those factors
associated with the individual, the task, or the environment which influence the particular
behavior; and finally the equipment, whether it be an individual display or control or the entire
system itself. This information is presented both in probabilistic form, the likelihood that a
particular error will be committed, and in the form of the raw data used in the calculation of the
error probability. The library also contains information concerning failure rates for hardware
components.

NUCLARR comes in two forms, an automated version for a personal computer (PC) and a
hard copy version. The PC version is menu driven and also uses ad hoc commands in order to
locate human error and hardware failure rate and causal factor data. The system then aggregates
these data using certain rules and will format the information for processing through a statistical
package. The desired reliability information then can be presented either on the computer
display or in hard copy form. Inasmuch as documen- tation is maintained for all failure rate data,
the system acts as a clearinghouse for documentation on controlled studies, field data collection
programs, and system risk assessments.

NUCLARR also comes in a hard copy format, called a NuReg Report. This is a five-volume

document, actually broken into four parts, which is updated every three months. The four parts
consist of:

72



He is aware of our problems and serves as our primary communication channel to Boeing
Customer Service.

Boeing Customer Service is very helpful for us and serves us in two ways. One is to assist in
some particular troubleshooting problem. A larger part, however, is to provide us with
information on repairs for which we do not have FAA-approved data. As those in the industry
know, any repair classified as major must be accomplished using FAA-approved data. Primarily
this information comes from your Structure Repair Manual or your Maintenance Manual or a
Service Bulletin, if it has a repair listed. All of these provide FAA- approved data.

In the event we have a repair without FAA approved data, we go to Boeing Customer
Service to develop a repair scheme. The best example is any repair we make now in the lap
splice on an airplane in an AD area. Such repairs require FAA approval before being made. The
engineer prepares a repair scheme, gives it to the local Boeing rep, and it is then transmitted to
Boeing Engineering for review. Based on their review they either approve the repair or
disapprove it and suggest an alternative scheme. If this requires FAA approval, we then go to the
Boeing Designated Engineering Rep (DER), who evaluates the repair. If the repair meets FAA
requirements, the DER issues what we call an 81103 and files it with the FAA. This becomes our
approved repair data as long as we effect the repair as described by the DER.

The procedures just described are straightforward but do not always work that way. At times,
when we request repair approval from the Boeing DER he may say, "We don't consider this a
major repair. This is a minor repair since it is in secondary structure." With this, we face a
problem which, in fact, is industry-wide. There is no good definition of a Major or a minor repair
in the industry, although there are definitions in FAR Part 1 and FAR Part 43. How- ever, anyone
in the industry recognizes that there are problems with these definitions,

Every airline has its own definition of a major repair in its Operating Manual. This Operating
Manual has been approved by the FAA and, although the definition may not be exactly as in
FAR Part 1 or FAR Part 43, the definition is approved and we must abide by it. Therefore, even if
Boeing tells us it is a minor repair, if our Operating Manual says it is major, we must deal with it as
such. The FAA holds us accountable to administer our own Program and follow our own
approved manual. So we must proceed to get the FAA approved data.

The final point noted on Figure 3 is that Boeing Customer Service and the Boeing local
tepresentative help us with logistics matters, particularly if there is a requirement for Aircraft On
Ground (AOG) parts. The local rep provides a great service in obtaining these parts.

We have two ways in which we communicate with the FAA, as shown in Figure 4. Primary
FAA contact is through our local Flight Standards District Office (FSDO). In our FSDO, we have a
Primary Operations Inspector who oversees our flight activities, and a Principal Maintenance
Inspector, who oversees our maintenance program. These individuals look primarily for
compliance. Does the conduct of our program comply with FARs and does it comply with our
own program? FAA provides basic requirements in the FARs, in our case FAR 121. We then
develop our own programs to demonstrate to the FAA how we will satisfy these requirements.
They then accept our program and subsequently audit us to ensure that we are complying.

The other way in which we communicate with the FAA is through the Northwest Region.

Airworthiness Directives (ADs) for the Boeing 737 airplane come from the Northwest Region.
These are the documents that affect the engineering and maintenance of our airplanes.

25



particular interest in a problem have learned of the issue through an informal and more
expeditious system. Also, the output at present is somewhat weakened as it is non-specific. A
user needs to be able to query the SDR data base for specific information rather than having to
peruse an enormous print-out. If the central SDR data base of the FAA is to achieve its full
potential, it must be expanded and improved to a point where the informal data exchange
system no longer is needed and where airline or aircraft-specific information can be obtained.

An improvement program for the SDR data base also should consider issues of data capture
and data consistency. At this time, a problem indication below the legal reporting threshold may
be lost. Thus, (1) the next inspection must rediscover the problem, if it can, and (2) other
interested parties are unaware of the problem. In addition, there is a measure of inconsistency in
the way in which operators interpret SDR data reporting requirements.

The need for an efficient database structure by the airline maintenance community has its
parallels in the nuclear power industry. Under the auspices of the U.S. Nuclear Regulatory
Commission, considerable progress has been made in the development of data bases to support
nuclear power operations. One such data base, the Nuclear Computerized Library for Assessing
Reactor Reliability (NUCLARR), contains data concerning both equipment and personnel and
deals with both operations and maintenance. This system contains raw data describing both
equipment and personnel performance and probabilistic data describing error likelihood under
specified circumstances. The logic and procedures used in developing the NUCLARR data base
could be of considerable value in any expansion of the FAA SDR data base.

- Recommendations
1. The movement toward a central data base to support aviation maintenance should
be expedited as feasible. The Air Transport Association, operating through its
Improved Airworthiness Communications Systems Committee, has as one goal
using information within the FAA Service Difficulty Reporting System to create an
analysis loop for the airline industry geared specifically toward maintenance needs.
This is a valuable initiative.

Certain requirements and cautions are in order in the development of a central data base.
Access must be immediate and available to all individuals and organizations concerned with
aviation maintenance. Data should be in a form so that safety and trend analyses can be done
quickly and without major data transformation. The data base should include human factors data
describing human reliability in various maintenance activities. Finally, developers of the data base
should always be cognizant of a basic !aw presented by one of the meeting attendees: "The
effectiveness of a maintenance program is in direct proportion to how well the mechanic
accomplishes his task -- independent of the associated computer system." The data base must be
oriented to the needs of maintenance personnel and not to the underlying computer system.

2, The FAA should examine in detail the logic and procedures used by the U.S.
Nuclear Regulatory Commission in its development of the NUCLARR data base.
Insights obtained by doing this could be of considerable value in an expansion of
the FAA Service Difficulty Reporting System. This is particularly true concerning
the manner in which human performance data are entered and procedures for
establishing probabilistic descriptions of human reliability.

Quality of Maintenance Data

Maintenance data must be usable for all maintenance personnel, whether they be managers
planning for a "heavy check," or mechanics doing a flight-line repair of a hydraulic system.
Maintenance information also must maintain a consistent format as it proceeds through the
system. Data generated by a manufacturer to describe a maintenance action should not be
changed in format or meaning as it works its way to the mechanic on the floor.

10



problems. At that time, when we saw an FAA inspector arriving, we did not want to talk to him.
Rightly or wrongly, many of us felt that he was there to make a profit. While | know that was not
the case, that was the feeling. As a result, the industry "clammed up" on talking to the FAA and
problems were not being solved. This is no longer the case. Problems now are being solved.

The task forces set up by the Air Transport Association and the FAA Aging Airplane Group
represent forces which are improving our lines of communication. When the FAA group met
with us recently, | felt it was the first time we could just sit with these Airworthiness Inspectors
and other experts and talk over what we were doing and trying to accomplish. The FAA group
was very knowledgeable and provided considerable feedback into what was a problem-solving
session. We need more of that in the industry to improve communications and maintenance
performance. Our industry functions better when we work directly with the FAA to examine
problems and arrive at solutions as opposed to simply being inspected for compliance. The
Current changes represent a positive move.

30



PROBABILITY OF DETECTION

vs.
FLAW LENGTH
10 OPE LETTE
- ——— EDDY CUNNENT
0.8 wees PENETAANT
RADIOGRAPHY
NO. OF ULTRASONIC
DETECTED °* | —
FLAWS/ - al
TOTAL
rraws OT
02
rod ”
0 LE DA eater Tal 1 L 4 1
o. 0.100 0.200 0.300 IN,
t L L L 1. 1 1 1 J L 1 L Lt 4 i i j
o 1.00 2.00 3.00 4.00 5.00 6,00, 7.00 8.00 9,00 mm

LENGTH OF THIN SPECIMEN FLAWS, 2c

Figure 5. Detection probability curves for four NDI procedures.

interval based on the size of the crack that can be detected by NDI. The Federal Aviation
Administration establishes the procedure and the frequency of inspection and then submits this
information to air carriers who in turn are responsible for preparing a procedure to carry out
these inspections. In addition to the carriers, there are some 4,000 repair stations which also
receive these notices. Oversight of this community of repair stations and individuals maintaining

these airplanes is accomplished by some 3,600 inspectors covering the three areas of
manufacturing, maintenance, and certification.

The base document for non-destructive inspection is the NDT Manual. Figure 6 is taken from
a page in the Boeing NDT Manual describing eddy current inspection for the lap joint found to
be a problem with the 737 aircraft. This illustrates the transformation of an engineering drawing
into an inspection drawing. Drawings such as this are available at the technician level. The
technician will get a sheet of these instructions when he goes to look at the airplane.

Figure 7 shows three graphs, prepared by Douglas Aircraft, depicting the presentation on the
cathode ray screen for two eddy current probes inspecting for aircraft corrosion. These particular
signal patterns are for exfoliation corrosion found around fastener holds in wing skins. This is the
type of information that must be present in the NDT manuals,

100


IMIS PHASE I: ELECTRONIC PRESENTATION

PHASE I:
Electronic Presentation | - Electronic Presentation System
} of Tech Orders + Off-The-Shelf Computer

* Presentation Formats for Interactive Display

+ In-Shop Field Tests
+ Initial Test at Offutt AFB 1984
+ Retest at Grissom AFB 1985
+ Independent Navy Test 1986

+ Performance Results
* 100% FI Success vs. 75% with Paper
+ Average Fault fsolation Time Halved
+ No False Removals
Technicians Preferred Electronic System

Figure 4

was with the weight of the PMA, which now is about 13 pounds. Within the next several years,
plans call for the PMA to be reduced to a size essentially defined by the size of the display.
Including batteries, this should weigh approximately six pounds.

A separate effort within the IMIS program is to examine the potential of this system for
training maintenance technicians. Logic indicates that the same data base could be used both
for training and for maintenance support. When used in this manner, a trainer can examine a
trainee's logic as he attempts fault isolation. Since the trainee's attempts are recorded, the
trainer does not have to observe all activities. Simulated faults and systems can be programmed
as well as "what if" logic. One advantage is that the system could be used to preview little used
tasks, It also has the advantage of providing multi-level presentations (expert, novice, trainee).

IMIS technology is being evaluated at this time in a study of its impact on Rivet Workforce
training. The Rivet Workforce is a program in which the Air Force is attempting to expand the
technical capabilities of individual technicians. The Air Force is trying to broaden these
individuals so they are not entirely vertical specialists. The objective is to do this without greatly
increasing training costs. In this program, which will be completed in 1990, various approaches
are being taken to determine the training potential of IMIS. Subject matter experts are being
interviewed at the Air Training Command and in the field. Opportunities for use of IMIS
technologies are being described. The result will be recommendations for use of IMIS,
development of a test plan, and demonstration of a test protocol.

The development of IMIS is working toward use of "Type C" data. The advantages of moving
in this direction are shown in Figure 6. Type C allows a neutral-format free data base. In this
approach, when data are entered into the data base, the data can be used to support many
applications. When a data item is updated, all applications are updated. For instance, if a piece

93



tation takes place at many points in the
ystem and involves many individuals of varying backgrounds and skills. At the
cturer, engineers and documentation specialists prepare Service Bulletins, changes to
nual, and other messages for airline Operators. Working with the Federal Aviation
istration, Airworthiness Directives are prepared. Since ADs require a legal review, lawyers
e involved in the writing process. As a result, according to one operator undoubtedly

fecting an industry consensus, "Airworthiness Directives are not always clear-cut and easy to
enderstand."

One approach being taken to improving the readabilit
Scuments is the development of "Simplified English." Interest has been expressed by
Manufacturers, operators, and the FAA in the development of a limited vocabulary for technical
friters and engineers which is accepted through the industry. A standardized language would
a much to remove elements of confusion from technical documentation. in an example
rovided by Boeing, a "hatch" is always a hatch. Technical writers and engineers cannot refer to it

# a "door," a "panel," a "limited access area," or any of the many other designations. Under all
pircumstances, access is through a "hatch."

y and understanding of technical

Boeing Commercial Airplanes is using a limited and standard v:
AECMA for its documentation activities. Other organizations are pursui
Poeing, the Writing Guide includes an artificial intelligence unit whic!

ing, also reviews writing rules a
peal step forward in the improve
aintenance data elements.

Recommendations

While "established" ways exist for the preparation of most maintenance
documentation, there are no standards. In recognition of this, the Communications
Committee of the Air Transport Association has, as one long- term objective, the
development of a standardized technical data system. Such a system offers much in
terms of improving communications and maintaining a high level of reliability in
maintenance operations. The FAA should support the development of this system
and consider specific projects to develop and evaluate standardization procedures.

ocabulary developed by
ing a similar approach. At
h, in addition to checking
ind saves an engineer from having to do this review. This isa
ment of maintenance documentation and the quality of

2. A number of initiatives are underway to establish a Simplified English for use with

maintenance documents. Aircraft manufacturers have done some of this; research
Sponsored by the Air Force has prepared other lists. The FAA, possibly working
through the ATA Communications Committee, should give impetus to the
development of a single Simplified English. This list then could be distributed
through the U.S. industry and also through foreign manufacturers, where it would

be quite helpful. In any event, every effort should be made to avoid multiple
versions of Simplified English.

s; Transmission Efficiency

i. Maintenance information must move swiftly through the system if it is to serve its purpose

fully. Delays in generating or transmitting maintenance documents impact maintenance

F gettormance and reduce effectiveness. Several speakers commented on the length of time
fequired to get technical data to an operator. if a Designated Engineering Representative

decides that a change in technical data is Necessary, an average of about six months is required

f for the changes to be made and the information then sent to the operator using the aircraft.

Once at the operator level, there is another delay before the manufacturer's information can be
incorporated into his manuals.

W



REG. NO. N7286 (Line Position 342) - 1961
-Flight Hours Not Available
-Flight Cycles 39,523

Cracks
Analyzed

fo) °° roo. 0K ondlnowos0- O-B-ao- 9]

fe)
colo 000000000 00000000)f0 0 Stringer
°o

4
(sy ° 0000000000000 00 0 0 [0 OF f=

q T
STA 300 STA 360

Figure 4. Example of multiple crack elongation.

Following the transmission of the initial bulletin, a more detailed inspection procedure was
defined and transmitted as an Airworthiness Directive. Airworthiness Directives were sent for |
Boeing 727, 737, and 747 aircraft. To illustrate this process, the actions required of the operator
by Boeing 727 Airworthiness Directive include:

* Within 2500 landings, conduct High Frequency Eddy Current (HFEC) inspection for
cracks at stringer-4 and stringer-10

* Perform subsequent detailed visual inspections of all fuselage lap joints at intervals not to
exceed 5 months

~ i corrosion is found, conduct a Low Frequency Eddy Current (LFEC) inspection and repair if
necessary
~ If cracks are found, perform a High Frequency Eddy Current inspection and repair

¢ Carry out terminating repair at stringer-4 and stringer-10 within four years
Similar Airworthiness Directives were sent for the Boeing 737 and 747.

The preparation of an Airworthiness Directive of this type requires an extensive analysis of
flaw characteristics for a given aircraft. To do this, for a given NDI inspection method a
determination is made through statistical analyses of the minimal size of a flaw which can be
detected by the individual and the specific type of equipment he is using. This gives you the
probability of detection of a flaw as a function of flaw length. Figure 5 shows detection probability
curves for four non-destructive inspection procedures in general use in the industry. These are
eddy current, dye penetrant, radiography, and ultrasonic inspection. Based on a determination
of the rate of flaw growth during experiments, we can establish an appropriate inspection

99


TYPICAL

UPPER ULTRASONIC.

SKIN INSPECTION

PANEL AREA
CONSTANT
SECTION

LOWER SKIN

LOCATION ALL

LOWER PANELS
TYPICAL

ULTRASONIC
INSPECTION AREA

TYPICAL CRACK
LOCATION La
ALL UPPER

PANELS

Figure 9. Typical crack environment for ultrasonic inspection,

Figure 8 is another example of the type of information contained in NDT manuals. This figure
shows ultrasonic cathode ray tube responses from a non-corroded region of the aircraft and from
a corroded section.

A typical crack environment for ultrasonic inspection is shown in Figure 9. This is an element
of the Special Inspection Document (SID) for the McDonnell-Douglas DC-10. This procedure
requires an inspector to climb up into the elevator structure, lie on his stomach, and look at the
video presentation shown in Figure 8. This is a very difficult inspection and is one that requires a
real measure of dedication on the part of the inspector.

There are many interconnecting documents, Messages, and other communications which
send information among the Federal Aviation Administration, the aircraft manufacturers, and
the air carriers. Listed below are some of the more important of these communications and the
particular segment of the triad having major responsibility for the communication:

Federal Aviation Administration

1, Federal_Aviation Regulations - FARs represent the overriding document in the

communications network. These regulations take precedence.

2. Advisory Circulars - ACs provide non-mandatory guidance for the control of inspection
processes.

3. Airworthiness Directives - These directives are mandatory and are issued to control some
specific problem. Some say that ADs are used only following a severe accident; the
FAA is not being proactive with respect to the issue. However, the FAA does not like
to place additional burdens on the aviation industry unless it can be conclusively
proven that a problem exists,

104


add
allow
apply
ask
avoid

be
bend
blow

carry
check
clean
close
compare
connect
continue
cover
cut

decrease
deflate
determine
dip
discard
disconnect
do (not)
drain

dry

estimate

feel
fill
find
follow

go
get
guide

handle
have
hold

increase
inflate
inspect
install

keep

listen
look
loosen
lower

make sure

mark
measure
mix
move

note
notify
open

perform
place
polish
pour
press
pull
push
put

raise
read
release
remove
repeat
replace
return
rinse

Figure 10

120

save
scrape
see
set...to
shake
soak
start
stay
stop

take
tap

tie
tighten
touch
try
turn

use

wait
wash
watch
wear
wipe
wrap
write



standards. It has long been known that comparative judgement (against an available standard) is
more accurate than absolute judgement (against a remembered standard), but this data does
not appear to be used consistently in airplane inspection. The closest we come to a standard in
visual inspection is to use adjacent areas (lap joints, rivets) to make the comparison; adjacent
areas are not a reliable standard. Similarly, with NDT inspection the inspector must judge the
deflection of a meter as the transient shape of an oscilloscope trace by absolute rather than
comparative judgement. At times the calibration specimen is carried to the workpoint, but it is
not often used there, for a variety of reasons.

Feedback to the inspector in the Decision Making task is not rapid or obvious. If an inspector
marks a defect (and writes it up), it will be repaired and go to a buy-back inspection. Because of
scheduling constraints and shiftwork, it will rarely be the same inspector who gets to reinspect
that repair. Only by chance or individual initiative will the inspector talk to the repairer or the
buy-back inspector. Thus, an opportunity for feedback is being missed. In addition, some repairs
will destroy the defect without confirming it, e.g., drilling an oversize hole to take a larger rivet
when Eddy Current inspection has indicated a small crack in the skin by that rivet.

Task_5:_Response. The physical response made by the inspector represents the output
information from the inspector to the system. It is as much a part of the information environment
as input and feedback. In order to report correctly, the inspector must both make physical marks
on the aircraft and issue a work order for repair, or at least further inspection, of each defect.
Typically, more than one defect may be found in a job, so that memory is required to store these
defect locations and types until a formal report can be filed, usually at the end of the workcard.
Inspectors often carry a small notebook to aid this memory, but there is no formal system to
prevent forgetting or mis-remembering. All of this becomes more problematical when the
inspector is interrupted. These interruptions have to do with both scheduling (e.g., an extra
inspector is required on another job) and unscheduled events such as more cleaning being
required before an inspector can complete a workcard. In addition, maintenance operators
have to interrupt the inspector to buy-back any repairs which have been completed. Again
there is potential for error.

Feedback as a result of the Response is rare. Only a small sample of work is audited, and an’
feedback from this is typically negative rather than positive. If a defect is reported, then feedbac
to the inspector who reported it can be arranged. However, if the inspector does not report the

defect (either search failure or a wrong decision), only an audit or subsequent inspection will give
feedback.

For many defect types, a defect may only be an indication, and hence not reported.
Unfortunately, the information that the inspector found an indication is then lost forever, as the
chance of the same inspector being assigned to the same part of the same aircraft months in the
future is small. Capture of some of these indications may be a way to provide more detailed
feedforward for subsequent inspections.

Conclusions

The information environment has been shown to be a particularly powerful determiner of
human, and hence system, performance in inspection. Applying these ideas in a systematic
manner to aircraft inspection has revealed places where the current system is working well, e.g.,
some aspects of directive and feedforward information using the job cards. It has also shown that
there is room for improvement in integrating information at the inspection point and in
providing feedback to the inspectors.

In this paper, many areas have obviously been ignored. The use of information in the training
process has not been analyzed nor the concept of using feedforward and feedback to keep

68

ane e


po

Evaluation indices are both probabilistic and non-probabilistic and can even deal with impact
of supervision on operator performance as well as factors having to do with organizational
climate. In fact, in our reviews of every major incident which has occurred in the nuclear arena
we have concluded that it was not so much what the maintenance man did or did not do, or
what the operator did or did not do, but rather the climate in which these people were
operating. The organizational! climate seemed to be a primary determiner as to whether
operators recovered from a situation or exacerbated it.

MAPPS is housed at the National Institutes of Health (NIH) Computer Facility in Bethesda,
Maryland, and, for European users, at the EURATOM Computer Facility in Ispra, Italy. A PC-based
version "Micro-MAPPS" is scheduled for completion at the end of FY 1990.

In the initial construction of MAPPS, concern was expressed over its ability to dissect a task
sufficiently to really understand the task. The current capabilities of MAPPS dispels such
concerns. MAPPS now has the following features:

Maximum number of subtasks (per task)
Types of subtasks (by action statement)
Maximum task duration (days)
Number of shifts

Categories of protective clothing
Maximum number of tasks on-call in the MAPPS library

There are two features of the MAPPS simulation that should be of interest to those
concerned with aviation maintenance. First, we spent a considerable amount of time in
developing operational definitions of action words. We now have a list of some 28 orthogonal
action words derived from the many hundreds of terms people use. These action words are used
to characterize the maintenance task with great impact on the way the simulation progresses.
Also, we have developed a task analysis library. As a task is completed it is fed into the MAPPS
library so that an investigator at a later time, who may not have time to do a complete task
analysis, can simply call up an earlier task and modify it somewhat for his own particular needs. A
regular simulation then may be conducted.

The USNRC is using the MAPPS simulation capability for a number of purposes. One use is
to supplement data management systems. For example, we may find there are some
combinations of operators, actions, environmental factors, and equipment that we simply can't
study directly because of political reasons, logistics reasons, cost reasons, or other issues.
However, these tasks are important when we need to perform more broad analyses of reactor
maintenance. In this case, we use MAPPS to simulate the unavailable actions.

MAPPS also can be used to provide probabilistic inputs to risk (safety) assessments, somewhat
in the manner in which NASA developed its safety assessments after the Challenger accident.
The system also can provide non- probabilistic inputs to licensing reviews and inspections. It can
be used to preview effects of remedial actions. Finally, the system will provide design information
concerning maintenance schedules, staffing, and function allocation requirements, and for
development of performance aids such as written procedures. MAPPS is available on an
information-exchange basis through the USNRC.

Cognitive Environment Simulation (CES)

Cognitive Environment Simulation is an automated artificial intelligence system for analyzing
the decision-making behavior of individuals and groups under normal and abnormal conditions

74



one's thoughts with the idea of resolving a problem and not with the idea of winning a point? It
is certainly true in aircraft maintenance that effective verbal communications are most
important.

As we address the issue of effective communications, one issue comes immediately to mind.
As | travel around the country and participate in meetings with industry and the public, |
recognize that all of us are not communicating as effectively as we might concerning the safety
factor in commercial aviation today. However many statistics we present to support the safety
issue, we still find a considerable body of the flying public that does not feel that way. All of us
will benefit if we can develop communication procedures which reinforce the perception of
safe travel rather than the opposite. We must be able to discuss the aging aircraft program,
Service Difficulty Reports, and similar issues in such a manner that we do not undermine the
proper perception of aviation as an extremely safe mode of transportation.

Another communications issue to note is that of getting information from foreign
manufacturers who are providing a number of aircraft for U.S. aviation, particularly for regional air
carriers. Establishing effective communications here, particularly with respect to maintenance, is
an important problem and one about which you will hear more today. Aircraft Evaluation
Groups are more actively involved in foreign maintenance programs today than in times past.
Current regulations do address the manner in which maintenance programs will be constructed
and the language in which they will be presented. At this time, bilateral apreements are in place
to require maintenance programs to be delivered with the first airplane that is shipped.
However, | realize that these agreements in themselves by no means solve the problem. We
recognize that the Federal Aviation Administration in many instances can only establish a
minimum standard. It is necessary for industry to work beyond these minimum standards to
develop communication links and maintenance documentation that truly meets industry's
needs. Industry must work directly with the foreign manufacturers to define exactly the type of
documentation needed to develop a rigorous maintenance program.

The Federal Aviation Administration recognizes that today's aviation maintenance requires
effective communication systems at all levels. We in the FAA are working to develop improved
communication procedures with our own personnel and hope to contribute to improved
communications throughout the maintenance community.

17



>
COMMERCIAL JET
NONDESTRUCTIVE TEST

RITICAI A
CRITICAL UPPER CRITICAL FORE AND AFT

, ROWS OF FASTENERS
ROW OF FASTENERS OUTER OR
TYPICAL FATIGUE UPPER SKIN
CRACK LOCATION r 4
¢ :

iw r | ADHESIVE
HS cgloye = off -
\lgo o ¢ oo of
'E ©2008 6 oF

{ STRINGER

Up  INNEROR LOWER SKIN TYPICAL FATIGUE CRACK LOCATION

LONGITUDINAL LAP JOINT CIRCUMFERENTIAL BUTT JOINT
CRACK ORIGIN a SURFACE
TYPICAL CRACK
a
PROPAGATION
SECTION A-A

Figure 6. Typical fuselage skin joint configuration and crack orientation .

101



impeded as a result of lack of material, lack of manpower, or lack of facility. We must develop a
coordinated industry plan which shows the schedule we are going to use to make these changes
so that we don't all do 747 Section 41's in January of 1999, fr instance, knowing full well there
will never be enough material, there will never be enough manpower, and facilities will not be
adequate if everyone decides to make the changes on the same day. The schedule must clearly
show the implementation plan. This is crucial so that manufacturers can gear their production
requirements so that material will be available when needed by the industry. It is also crucial for
the FAA so that they know both their manning requirements for inspection and the regulatory
requirements to ensure compliance. If successful, the plan should ensure that the AATF
recommendations can be implemented without a hitch, without running into constraints of
manpower, facilities, or material.

If the reporting and scheduling initiative is carried to its extreme, we might be able to use it
to control the maintenance of an entire airplane from the time it is received from the
manufacturer until the time it is retired from service. The program would record all routine and
non-routine maintenance. At this time, although airlines themselves develop data of this type,
there is no industry-wide sharing of that data. We do know that on the average approximately an
hour and a half of unscheduled maintenance is required for every hour of scheduled
maintenance. But we still need to know at the time an airplane is received on the line what its
routine maintenance, non-routine maintenance, and material requirements will be throughout
its lifetime. Given that, the operator can plan maintenance activities better and ensure the
resources necessary for those activities. They will know, for instance, that the next time this
airplane comes in for a C or a D check it will have 35,000 cycles on it and the data show that at
35,000 cycles on the average 5,000 hours of non-routine work will be required, which will be
concentrated in certain areas of the airplane. The manufacturer then can make a long-term
projection concerning his requirements for producing the material and the industry can save
money by having proper resources available. Spot buys will not be necessary; overtime work may
not be required; and dock scheduling conflicts can be avoided. From a planning standpoint it
should reduce the cost of maintenance because the airline will not have to pay to store
materials from the manufacturer to be on hand when not needed. However, he will have the
materials when they are needed. Such planning also will give the FAA a far better projection of
maintenance fequirements for our various fleets of aircraft as they progress through their
ifetime.

A data management and planning program as just described is ambitious but, if we are to
ensure that changes to aircraft required to meet the AD's attendant to the AATF
recommendations can be done within two or three years, this program itself, at least the first part
of it, must be on-line also within two to three years.

The Communications Committee is pursuing many initiatives designed to improve the
communications process as it affects the maintenance, engineering, and safety aspects of the air
transport fleet. Many other activities are being undertaken in a cooperative industry effort. Every
one of them is geared toward the absolutely essential need for open, honest, and responsible
communications.

22



deterioration at an early stage also provided the means to allow components to operate until
deterioration started rather than having a fixed removal time. With these revelations, "HARD
TIME" programs gave way to "ON CONDITION" maintenance programs and Reliability Analysis
Control.

The movement from "HARD TIME" to "ON CONDITION" maintenance programs has had a
major impact on the inspection function. As previously stated, system checks with inspector
involvement were a large part of the "HARD TIME" program. Most system checks now are
accomplished by operational monitoring with little or no inspector involvement. The inspector's
requirement for detailed systems knowledge and background became less essential than
previously required. This factor does not imply that the need for systems knowledge has been
eliminated. An inspector still requires a respectable knowledge of all systems that cause the
structure to operate as a unit. However, today's maintenance programs no longer rely on the
inspector to determine system condition, whereas his surveillance of structural condition is
critical to the program.

The development of pressurized fuselages has been a balance to the inspector's functional
change brought about by the "ON CONDITION" maintenance program. Where the "ON
CONDITION" program reduced inspector responsibility for systems monitoring, the pressurized
fuselage has generated an at least equal demand. Additionally, application of the "Supplemental
Structural Inspection Program" created specifically for aging aircraft has added additional
requirements to the inspection function. At this point, it is certain that the size of the aging fleet
will increase in the next decade and with it the demand for structural attention by the inspector.

As the aircraft structure was becoming more complex and aged, the inspection methods and
devices used to monitor airworthiness integrity of the structure also were developing. X-ray is
now in common use and seen on most every heavy aircraft service. Ultrasonic and eddy current
equipment are now considered basic tools for inspectors. The knowledge needed by inspectors
for proficiency in Non-Destructive Inspection (NDI) in many cases exceeds aircraft systems
knowledge that previously was considered the backbone of an inspector's education.

Figure 1 shows that in 1947 the career path of most inspectors traced back to the aircraft
mechanic position. This served the inspection function well since it carried a strong background
in aircraft systems to the position, and provided the type of knowledge best suited to support the
"HARD TIME" maintenance program.

Figure 1 also compares the 1990 inspector career path with the 1947 era. The shift from
mechanic to the metal specialty evident in this figure, as a career path for inspectors, lags the
functional environment change that has occurred during this period. As Figure 1 indicates, the
education and experience background of the majority of inspection recruits is still best suited for
a 1940's environment. Ideally, the 1990's inspector should have detailed knowledge of aircraft
structures, with experience in metal repairs. He should also have a general knowledge of
structural design philosophy, and the maintenance program concept. In addition to all this, the
1990's inspector should be proficient with most types of NDI equipment.

Unfortunately, the knowledge disciplines previously listed as ideal for a 1990's inspector are
not yet generally available in most training curricula except within individual Inspection
Departments. NDI familiarization is not yet a requirement in FAA-approved FAR 147 schools
and usually not covered in those courses (except for 1940 era dye check and metal particle
inspection methods). Structural design concepts such as Fail Safe and Damage Tolerance are not
yet generally recognized as beneficial to the metal repair specialist or inspector. The 1990's
should see a change in this attitude with training in these subjects displacing some systems
training.

51



—
SUPPLEMENTAL INSPECTION
____________

Al
NORMAL MAINTENANGE SAMPLING (IF NECESSARY)
~ FAILURE EXTREMELY IMPROBABLE:

INCIDENCE I
OF I
DAMAGE
ESL INSPECTION THRESHOLD
- INFANT EXTENDED-LIFE PHASE —-~-
° | ~—" PHASE MH

TIME: t

Figure 1. When in the life of an aircraft does damage occur?

An example of multiple site damage is shown in Figure 4, This is an instance in which
individual cracks around rivet holes started to Propagate and resulted in a single crack about 18
inches long which depressurized the cabin to the extent that Passengers were aware of the
condition. The bottom drawing in Figure 4 shows the manner in which the multiple cracks
joined to form the single long crack. This incident occurred in 1987 and caused a Service
Bulletin to be issued in an attempt to preclude such events in the future.

After the Aloha accident, a review was made of airplanes in the commercial fleet with cold
bond lap splices, believed to be the condition underlying the development of multiple cracks.

This review showed that multiple site damage might be present on over 1600 aircraft to some
extent. The number and type of aircraft involved were:

Boeing 727 .
Boeing 737.
Boeing 747 ..

An immediate problem faced after this review was that of transmitting information

concerning potential damage in these aircraft to individual Operators to ensure that timely
inspections could begin.

One week following the Aloha Airlines accident, a Message was sent to all operators of
aircraft believed subject to this kind of damage. This first message gave the inspections and other

procedures believed necessary to ensure the continued airworthiness of aircraft that were flying.
Specific items in this message included:

* Cabin pressure differential limited to 5 psi
* Visual inspection required of all lap joints
* Eddy current inspection required of stringer-4 and stringer-10 lap joints

97



The first part of the above communications link, that flowing from the vendor to the operator, is
driven by compliance requirements but also by financial considerations. The vendor has a
product to sell and the operator a product to use. For the vendor to remain in a competitive
position, re must keep his airplane flying and flying well. This communication channel supports
these goals.

The flow of information from the operator to the aircraft vendor varies, in the case of
commuter airlines, with the relationship that exists between the vendor and the operator. In my
experience with different commuter carriers, | have seen this link be sometimes cool and
sometimes very active.

The next leg of the three-way communications system involves the operator and the
Government, the regulating body, and contains the following types of communications:

Government to Operator

* Regulations

* Advisory Notices

* Notices of Proposed Rules

* Approval and Disapproval of Compliance Techniques
* General Government Communications

Operator to Government

* Proposed Compliance Techniques

* Response to Proposed Rules

* Proposed Alternate Means of Compliance Required by Advisory Notices
* Discussion of Regulations

* General Operator Communications

Communications from the Government to the operator deal with the regulatory
environment in which all operators work. These regulations establish procedures and standards
for our maintenance program to ensure that we achieve the desired safety goals. Our problem
here is one of ensuring that we understand completely the meaning of the different directives
from the Government. It is imperative that this link be clear, concise, and well understood by
those persons using it.

The return flow of information from the operator to the Government generally deals with
the manner in which the operator will meet the regulatory requirements. This part of the
communications link is not as clear as that from the Government to the operator and frequently
is subject to miscommunications. | have seen misdirected communications from the operator
back to the Government which were sent to the wrong office, thereby greatly reducing the
effectiveness of the communications.

The final leg of the three-way network deals with Government-vendor communications.
The principal messages sent in this leg include:

Government to Aircraft Vendor

* Certification Approval

¢ Engineering Requirements

* Advisory Notices

* General Government Communications

34



Major Air Carrier Perspective

Clyde R. Kizer
Air Transport Association

This presentation will describe, in general terms, communications in the aviation
maintenance industry and some things being done in the industry in conjunction with
manufacturers, the Federal Aviation Administration, and international organizations. It has been
said that truth is the first casualty of war. If so, then communications is the first casualty of human
endeavor. No matter what the institution, be it marriage, business, or tennis, one of the biggest
problems we have is either miscommunications or failure to communicate. As was stated so
nicely by the chain gang captain in the movie Cool Hand Luke, "What we have here is a failure
to communicate." That generally is one of our major problems with regard to maintenance and
engineering activities in the air transport system.

| found communications to be a problem in the military, and | again found it to be a problem
when | came to industry. We either misunderstand one another or we don't talk to one another.
Bob Doll is fond of quoting Winston Churchill who said that the United States and England are
two nations of similar heritage separated only by their common language. Unfortunately, this is
frequently one of our most common problems in aviation. Many communication problems arise
because you think you understand the system, since it is similar to a system you do understand. In
fact, there may well be a little nuance or a slight difference in the system that you do not fully
understand. Such differences may well be more difficult to comprehend and to clear up than
large differences between systems. As a result, communications suffer.

In this presentation | will provide a brief review of the general communications requirements
of our air transport system, including the network between the airlines, the manufacturers, and
the Federal Aviation Administration. | also will note the interaction of the Air Transport
Association with that network. In particular, | will discuss current efforts of the Improved
Airworthiness Communications Systems Committee, which falls under the auspices of the
Airworthiness Assurance Task Force. This Task Force was developed to attack the problem of the
aging fleet of commercial airliners, not just in the United States but throughout the world. The
Task Force represents 42 international carriers, 32 U.S. carriers, the U.S. Navy and the U.S. Air
Force. Also represented are seven regulatory agencies and five airframe manufacturers.

My experience with the Airworthiness Assurance Task Force indicated that it took about
three months of meeting and talking candidly to one another before we began breaking down
the barriers within which we were all confined. These included organizational barriers and/or
institutional barriers that had developed over the years. After about three months, members
became more serious in their attempts to really communicate in an honest, open, and
responsible fashion. This seems to me to be the most important aspect of group activity. To
achieve the objectives of the Task Force, all of the issues and hidden agendas must be honestly
explored. Every organization that interacts with another organization has responsibilities for
which it is answerable. When we communicate in an attempt to resolve problems, a major part
of the endeavor involves breaking through these parochial concerns so as to get all of the
information on the table so that we can truly understand the problem. We also must understand
what everyone's responsibilities are, be- cause when it comes to compromise there are positions
for each institution or each organization where compromise is not possible. We must know what
these limits are for each participating organization. The only way to do this is through open,
honest, and responsible communication.

18



Visual NDT
Task Description Example Example
1. Initiate Get workcard, read Get workcard and.
and understand area eddy current
to be covered equipment, calibrate
2. Access Locate area on Locate area on
aircraft, get into aircraft, position
correct position self and equipment
3. Search Move eyes across Move probe over each
area systematically. tivet head. Stop if
Stop if any indication. any indication.

4. Decision Making

5. Respond

6. Repair

7. Buy-back Inspect

Examine indication against
remembered standards.

eg. for dishing or corrosion.

Mark defect, write up
repair sheet or if no
defect, return to search.

Drill out and replace
rivet.

Visually inspect
marked area.

Re-probe while
closely watching
eddy current trace.

Mark defect, write up
repair sheet, or if
no defect, return to
search.

Drill out rivet, NDT
on rivet hole, drill
out for oversize
Tivet.

Visually inspect
marked area.

Table 1 Generic Task Description of Incoming Inspection, with examples from

Visual and NDT Inspection

64



twice about using the system next time. In the world of aircraft maintenance there are few
simple procedures, so accurate diagnosis is essential.

Expert Systems

Expert Systems will be an essential part of aiding a young maintenance workforce. It is not a
coincidence that most of the system listed previously utilize this technology to some extent. The
reason is that maintenance is dependent on knowledge. Knowledge of history, condition, failure
mode, and remedies. Expert systems were developed for this purpose.

Expert System technology is one of the few widely successful products of the field of Artificial
Intelligence. Expert systems were first proposed over 15 years ago, and commercial applications
have Been appearing in bulk for 5 years. The basic technology is about as mature as any
computer technology. The expert system is well suited for applications where performance is
dependent on a very narrow body of information. Expert systems work well in areas of aircraft
maintenance and medicine, but not so well in modelling common sense.

| '
HUMANS: i) COMPUTER | INSTRUMENTATION

—_—_ ' t
| Human Expert f—— 1 1
eS fl 1
r—+— | Codified |
| xnowledge | | Knowledge Data | | specific |
| Engineer /}-————7. -—— I Measured |
—_— | ! | 11 pata |
a | I | r : 4 1 i} \ 4
| engineering & ee I | knowledge | 1
Maintenance Manuals | i Base |
\ —|— |
\ | !
I | |
{ (oes |
| | strategye | 1
1 | contro 1
{ (
\ | |
1 | I
| \ ——_~— 1
|oend oF H 1 user | I
| user Questions, | | interface | I
Answers, & | Ln |
Explanations} H
1
1 t

Figure 1. Expert Systems Model

132



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Meeting Welcome

Anthony J. Broderick
Associate Administrator for Regulation and Certification
Federal Aviation Administration

| would like to welcome all attendees to the Second FAA Meeting on Human Factors Issues
in Aircraft Maintenance and Inspection. | particularly appreciate your attendance in view of the
snowstorm we are having just now.

1 was able to address this group at last year's meeting and, at the conclusion, made one strong
recommendation to Dr. Shepherd. This recommendation was that more of these meetings be
held and that they be at frequent intervals. | am pleased to see that this recommendation is
being followed and that human factors meetings will become frequent and regular events. |
think that it is very difficult to overstate the value of getting people together in a relatively
informal setting such as this to discuss problems of common interest from the perspectives of
different disciplines.

The topic of today's meeting is "communications and information exchange" because this
was identified as a crucial factor at last year's meeting. Communication ties the maintenance
operation together and, in fact, is the thread that runs through aviation safety from any point of
view. Personally, | am concerned about whether our approaches to communication and
information exchange are really working well today. Are we making best use of existing
knowledge and technology? In point of fact, | should say that | am convinced that we are not
making the best use of new technologies. That being the case, as the aviation fleet grows and
the industry expands, how will we meet our communications needs in the 1990's and into the
next century?

Anyone who reads the Airworthiness Directive and the associated Service Bulletins for the
cargo door on the Boeing 747 airplane will be convinced that we need help with
communications. Aircraft systems are growing much more complex and maintenance needs are
growing exponentially. We talk today about-- mechanical, electromechanical, and
hydromechanical components. We also have fly-by-wire systems and soon perhaps will have fly-
by-light, with all the computers and complex interfaces associated with such equipment. On top
of this, inspection and maintenance problems for air carrier aircraft that are aging present special
information problems.

A major issue concerns the interface with the person we must address. Repair and service
details for all of these airplanes and systems have to be communicated to maintenance
organizations in a timely manner and, above all, in an understandable manner. We must make
good use of the experience that we have gathered, the mistakes we have made in civil aviation,
and draw on progress made in the military and space fields. As | said earlier, for those who have
not done s0, it will be interesting to read an actual Airworthiness Directive and the Service
Bulletin that goes with it. Pick one at random, read it, and you will be convinced that we need
to do a better job.

Much maintenance documentation today looks like it was written by a lawyer. The reason for
this is that it was. The process that the Federal Aviation Administration and aircraft
manufacturers go through in writing an Airworthiness Directive requires a legal review. While
the legal review serves useful purposes, it can introduce problems. For example, words like
"proscribed" appear. How many people working in aircraft maintenance understand the

differe
ventul
kind ¢
opera’
attenc
us to


+ INTERMEDIATE LEVEL TO DATA FIELD TEST-GRISSOM AFB, IN.......1985,
+ NAVY/AF/MARINES LEVEL FIELD TEST......scscscsccosceceensese wessacnvrreevoneseee 1986,

+ ORGANIZATIONAL LEVEL TO DATA FIELD TEST-MACDILL AFB, FL.1988

-F-16 FLIGHT LINE DEMO AT HOMESTEAD AFB.......ss-esnssceceneeserenners3 989,

+ PORTABLE COMPUTER, AND UPGRADE... ae--swssscsccueeceseeree 1987-3990
+ AUTHORING SOFTWARE TESTS BY INDUSTRY, GOV'T ......_.......1987-1991
+ OATA INTERCHANGE STANDARDB......
+ CONTENT DATA MODEL DEVELOPMENT AND TEST...
+ F/A-18 FIELD TEST
+ MAN-MACHINE INTERFACE...
FULL UP SYSTEM DEMONSTRATION .....

wsevernneee 1988-1990

Figure 7

The movement toward use of Type C data is not just in the Air Force. The Technical Manual
Technology Exchange Subcommittee of the Department of Defense recently formed a tri-
service working group to develop an initial set of DoD specifications for "Type C" data. The Army
is represented by the Army Materiel Command, the Navy by the David Taylor Research Center,
and the Air Force by the Air Force Logistics Command and the Air Force Human Resources
Laboratory.

The Phase I! activity of IMIS is working toward a full integration of the system, with a 1993
deadline. The Portable Maintenance Aid will interface with al maintenance work stations, with
all supporting software systems, and with Air Force aircraft. A detailed requirements analysis will
be completed to ensure that the system supports all maintenance functions and that all required
information elements are taken into account. There will be additional field testing of the IMIS
prototype at the Air Force Base level. Finally, functional specifications will be leveloped to
support full implementation of IMIS.

The progress of IMIS from 1985 until its scheduled completion in 1993 is shown in Figure 7.
Upon completion, the Integrated Maintenance Information System (IMIS) should allow the Air
Force to take a quantum step forward in aviation maintenance. Use of an integrated system will
make maintenance technicians more efficient, lessen the number of false removal of parts, and
make the entire activity a more cost-effective effort.

As an update of my presentation last year, | would like to note in summary the following key
accomplishments of IMIS:

«The F-16 test demonstrated the feasibility and utility of interactive, on-aircraft diagnostics
using "Type C" data.

*The Content Data Model specification development is proceeding and will provide a
framework for "Type C” data.

The IMIS Requirements Analysis will soon produce a detailed model of the information
and functional requirements for a fully integrated IMIS system.

95



Human Factors Issues in
Manufacturers' Maintenance-Related Communication

Anthony Majoros, Ph.D.
McDonnell-Douglas Corporation

The inter-organizational communication system of an aircraft manufacturer can be described
as a network of links that evolves over time to accommodate regulatory, market, and efficiency
feeds. A communication itself can be just about anything that transmits information. A
communication episode, which can take all forms, is started by asking or by telling or by
recommending something. A research report is one example; a drawing is another; others
include telephone conversations, contracts, regulations, training manuals, maintenance
Manuals, a paint scheme on an aircraft, and so on. For business purposes, | would not include
matters such as rumors, social greetings, and casual conversations. Here we are concerned with
4) intent to transmit information.

| would now like to show examples of regulatory, market, and efficiency concerns expressed
types of communication. One should recognize, of course, that these examples represent but
few of what could be quite a long listing. The following listing provides examples of
ommunication processes that | believe capture regulatory concerns:

._* Federal Aviation Regulations

_ * Maintenance Review Board

* Airworthiness Directives

* Designated Engineering Representatives
. © Supplemental Inspection Documents

‘ The Federal Aviation Regulations and the Maintenance Review Board establish, or
Eommunicate, the original maintenance planning for a new aircraft model. The Airworthiness
Pirectives, DERs, and Supplemental Inspection Documents, address regulatory concerns as an
[craft proceeds through its useful life.

This next listing provides examples of communication processes oriented to market
ncerns:

Customer Service Representatives
Field Service Representatives
Service Bulletins

Maintenance Manuals

B ¢ Customer Training

Customer Service Representatives may number in the many hundreds. Possibly a thousand
fore would not be unusual for a large manufacturer. Field Service Representatives are those
ents of the manufacturer who are on site at large repair facilities of the operator. They
gsent a direct maintenance communication link. Service Bulletins play an important part
ay be mandatory, such as those that might apply to aging aircraft. Maintenance manuals
B the backbone of communication concerning aircraft maintenance and are being given
ing attention today. Focus is on procedures for automating maintenance manuals and/or
ing them in a way stressing ease of use, access, and resistance to destruction during field
Finally, customer training represents a form of communication oriented to market concerns.
Homer training, Customer Service Representatives, and Field Service Representatives are
Poftant factors in the buy decision for operators since the strength of customer service may
fan important par in an operator's success in using an aircraft and keeping it in the air for ten
Ive or more hours a day.

39



Growth of Job Performance Aid Utilization

Daniel J. Berninger
Galaxy Scientific Corporation

Introduction

! am not sure what to call this talk and "Growth of Job Performance Aid Utilization" is a
compromise that | am still not entirely happy with. We are conducting a study on behalf of the
Federal Aviation Administration of what we call Job Performance Aids (JPA). Initially we set out
to survey the state of the art in these systems. The long term objective of the research is to help
integrate existing and future systems with human factors considerations. We seek to develop an

awareness of the applications of JPA's, and address some of the reasons these systems are often
unpopular and ineffective.

The term Job Performance Aid has been mentioned several times during this conference
and it seems to mean different things to different people. We learned from Mike Mulzoff of Pan
Am that in 1945 the mechanic had little more than a pen knife to work with. In a strict sense
that pen knife was a JPA. In the initial phase of our research we are focusing on computer
processing based JPA's. It is a type of JPA that seems to have a lot of potential, but also seems to
Cause the most consternation among users. Most airlines have utilized the computer for some
aspect of their maintenance effort, from parts tracking and maintenance scheduling to on-line
databases with aircraft procedures. There is a whole new generation of systems that have be
developed for the military that will lead to the use of computers for many more elements of
maintenance. Our research effort is designed to facilitate the transition of this technology to civil
aviation, and identify the changes that will be necessary before that can happen.

| said | was not entirely happy with the title of this talk. The reason is that although we have
seen a growth in the use of JPA's in the last 10 years, what has struck us the most about our initial
research are the challenges facing maintenance in the next ten years. It seems likely that these
challenges will make JPA's an essential part of all maintenance operations.

Challenges of the Coming Decade

Let me talk briefly about this sense of urgency that we have observed. At one time the
maintainer of the aircraft was the pilot and the designer as well. He was a single resource for
information on design, flight conditions, service history, diagnosis and repair procedures.
Importantly, since that person was the pilot, he was able to get immediate feedback on his
performance as a maintainer. All of these factors are still very important in aircraft maintenance,
but no single person is capable of handling the bulk of information that is required to adequately
maintain an aircraft. The sheer volume of informati&# has increased so much that hundreds of
people are required to perform the task of maintenance on a single aircraft today. Yet it is
desirable for these hundreds of individuals to act as one, each sharing information as required.

Today's maintenance technician can only know a small subset of the information that is
needed overall; not giving him a lot of unnecessary information becomes important, as does his
ability to communicate what he knows at the appropriate times. Maintenance technicians are
very much dependent on their coworkers and the equipment (job performance aids) that are
available. This is the dynamic that is the focus of my talk, and, in fact, the focus of this conference.
The tasks that one person performed at the outset of aviation now require hundreds, and the
task of maintaining the flow of communication between those people is daunting.

127



PT? | I |
LT E pnoge'on flit |
Pirie LiL
ae
VATE:
LiTOFF | | i] WAZ zi
| Hl es ain | mil j We ]
(A). EDDY CURRENT RESPONSE (B) EDDY CURRENT RESPONSE
NO CORROSION FROM CORROSION USING:20

KHz, 1/2-IN.-DIAMETER PROBE

L | EDDY: CURRENT PROBE ~J]
|

Fal

reve) revr) (Ty)

(C) EDDY CURRENT RESPONSE
FROM CORROSION USING
50-kHz, 1/4-IN.-DIAMETER
PROBE cfc

Figure 7. Eddy current impedance-plane responses for exfoliation corrosion around
fastener holes in wing skins.

102

co


a two-year hiatus. When publication stopped, many protests were received and it is now
republished. This particular publication is dispatch-oriented. it discusses specific probl
are keeping aircraft on the ground.

The attributes shared by the diverse forms of communication described above are thi
enable organizations to (1) understand the needs or requirements, (2) predict the consequi
of a message, or (3) control events as may be appropriate.

Communication systems can be modeled, as shown in Figure 1. Basically, the model r
energy entering the system, being transformed, and leaving the system in a different form,
possibly a feedback to change the energy flow for the next message. For a communic
system, there is a communication requirement, or question, which triggers the system.
transformation process might involve policy or ownership decisions applied to
communication media. The scope and structure of the communication could be Cefined du
the transformation stage. How shall the communication be done? At the output, we wa
product, an answer, or an action of some kind. Also, feedback is often part of this system
The inter-organizational communication system used today is open because boundaries are

rigid. Output actions can serve to modify the communications system to make it more effic
or more responsive.

Here are a number of problems and characteristics of inter-organizational communicati

taken from the communication literature. They are presented with comments to relate them
our present discussion.

1, Communications efficient at one level may be inefficient at another.

Federal Aviation Regulations and Airworthiness Directives, for example, may be efficient

an upper or management level of maintenance and not be so efficient at a lower or worki
level.

2. Some systems may be over- or under-rationalized.

By rationalize, | mean a deliberate and systematic attempt to organize communicati

Some systems work best when highly structured or organized; others work best when loos
structured.

3. Communication "on the behalf of . . ." can lessen an agent's involvement.

4, Perceptions of communicative functions may limit the value of the system (transformatio
affected by perceptions).

Differences in employees' perceptions of their responsibilities can create differences in
output. As an example, a person in the manufacturer realm might think that his job is to report
company policy. A second person, with essentially the same message to deliver, may feel that his
job is to satisfy customer needs. Airline operators obviously would rather talk to the second
person.

5. "Full and complete" communication is not a cure-all.

Here | mean that one should not necessarily try to be open and complete in every
communication. There is always something more to say about a particular question. However,
there comes a point at which the person seeking information does not need more information.

42