1Human Factors in Aviation Maintenance
Human Factors
inAviation Maintenance
2Human Factors in Aviation Maintenance
Welcome
4Human Factors in Aviation Maintenance
1. What is human factors?
2. History of human factors
3. Human factors spectacles
4. The PEAR model
5. Human error
6. Maintenance accidents
7. Where to get information
8. Summary
Presentation Content
5Human Factors in Aviation Maintenance
1What is Human Factors?
7Human Factors in Aviation Maintenance
What is Human Factors?
This section shall:
• Define human factors as it relates to
maintenance
• Show specific examples of maintenance
human factors
• Show why the topic is important to you
8Human Factors in Aviation Maintenance
List “Human Factors” Related to Maintenance
10Human Factors in Aviation Maintenance
• Designing workplaces, tools,
procedures, and policies so people
can use them easily and safely
• Primary concern is for people in the
organization
• Combines elements from many
disciplines
• Critical to the overall flight safety
and personal safety
What is Human Factors?
11Human Factors in Aviation Maintenance
Ensure continuing safety and efficiency by paying
attention to issues that affect human performance.
Human Factors Goal — A Summary
12Human Factors in Aviation Maintenance
The Elements of Human Factors
14Human Factors in Aviation Maintenance
• Personality types
• Relating to other people
• Dealing with stress
• Coping mechanisms
• Self image
• Accepting criticism
Clinical Psychology
15Human Factors in Aviation Maintenance
• Study of human body part sizes
• Can the user reach controls?
• Ability to access aircraft parts and systems
• Designing for extremes, i.e., smallest female and largest male
• No such thing as the “average”person
Anthropometrics
16Human Factors in Aviation Maintenance
• Reinforcing desired behavior
• Observations in the workplace
• Statistical analysis
• Effects of stress on behavior
• Controlled studies of the effects of work policies and procedures
Experimental Psychology
17Human Factors in Aviation Maintenance
• Human-computer interaction
• User interface design
• Requirements analysis for
software-based tools and test
equipment
• Accommodation for range of
computer literacy
Computer Science
18Human Factors in Aviation Maintenance
• The “mental” parts of
perception
• Problem solving ability
• Things that affect
troubleshooting performance
• Effects of stress on mental
processing
Cognitive Science
19Human Factors in Aviation Maintenance
• Industrial safety
• Slips, trips, and falls
• Materials handling, e.g., lifting
• Toxic materials storage and
use
• Facility design and safety
• Warnings
Safety Engineering
20Human Factors in Aviation Maintenance
• Skeletal and muscular structure
• Biomechanics
• Physical structure of perceptual
elements, e.g., eyes
• Work physiology, e.g., heat
generation and dissipation
• Fatigue effects
Medical Science
21Human Factors in Aviation Maintenance
• Organizational structure
• Rewards and compensation
• Motivation
• Work teams and groups
• Union/management relations
• Equitable treatment
Organizational Psychology
22Human Factors in Aviation Maintenance
• Principles of learning
• Ways to help people to
remember
• Design of instruction
Educational Psychology
23Human Factors in Aviation Maintenance
• Organized approach to the
study of work
• Setting reasonable work
standards
• Making work tasks efficient
• Statistical analysis of work
performance
• Efficient facility layout
Industrial Engineering
24Human Factors in Aviation Maintenance
Ensure continuing safety and efficiency by paying
attention to issues that affect human performance.
Human Factors Goal for Review
25Human Factors in Aviation Maintenance
2History of Human Factors
27Human Factors in Aviation Maintenance
• Early military work on designing
weapons and uniforms
• Time and motion studies (Frank
and Lillian Gilbreth)
• World War II aircraft cockpit
controls and displays
• Establishment of Human Factors
Society (1957)
• Military systems and
consumer products
The History of Human Factors
28Human Factors in Aviation Maintenance
Maintenance Human Factors has Evolved in 20 Years!
29Human Factors in Aviation Maintenance
Human Factors Timeline
31Human Factors in Aviation Maintenance
Human Factors and Ergonomics
Society
• Established in 1957
• 5,000 members +/-
• 50/50, psychology/engineering
• In 49 states and 42 countries
International Ergonomics Association
• Established 1959
• 42 federated societies
Human Factors and Ergonomics Society and International Ergonomics Association
32Human Factors in Aviation Maintenance
Human Factors Spectacles3
34Human Factors in Aviation Maintenance
• Examples of the human factors
perspective
• You can see human performance
issues if you look
• The remainder of this presentation will show you what to look for
• Look at others
• Look at yourself
• Look at the environment that
surrounds you
Put on your “Human Factors Spectacles”
35Human Factors in Aviation Maintenance
• Sensitivity to human factors
• Knowledge of how human factors affect work and
safety
• Objectively examine your world
• Be willing to make suggestions and comments
Put on your “Human Factors Spectacles”
36Human Factors in Aviation Maintenance
• What was the premise of the human factors spectacles video?
• List 10 things that you see while driving with your human factors
spectacles
• List 10 things that you see in this class with your human factors
spectacles
• List 10 things that you see at work with your human factors
spectacles
• What do you see at home with the human factors spectacles?
• In the mirror?
What did you Learn about Human Factors Spectacles from the Introductory Video?
37Human Factors in Aviation Maintenance
A Reminder to Apply Human Factors Principles 24 x 7
38Human Factors in Aviation Maintenance
The PEAR Model4
40Human Factors in Aviation Maintenance
• Models make it easier to understand complex things
• Easy to remember
• Models can be 2-D, 3-D, or mental
Why Use Models?
42Human Factors in Aviation Maintenance
• Originally used for
pilot’s crew resource
management (CRM)
• Has served human
factors training well –
worldwide
• A bit abstract
The SHELL Model
44Human Factors in Aviation Maintenance
• S includes all documentation
• H is physical stuff, like tools and equipment
• E is for the physical and social environment
• L-1 is for individuals
• L-2 is for groups
The SHELL Model Explained
46Human Factors in Aviation Maintenance
• PEAR is easy to remember
• It works for maintenance
• It is matched with the SHELL model
The PEAR Model
48Human Factors in Aviation Maintenance
• People who perform the job
• Organizational and physical environment
• Actions (tasks) performed as part of the job
• Tools, procedures, and other resources
PEAR
49Human Factors in Aviation Maintenance
Physical
• Size
• Gender
• Age
• Strength
• The five senses
Physiological
• Health
• Nutrition
• Lifestyle
• Alertness/fatigue
• Chemical dependency
Psychological
• Experience
• Knowledge
• Training
• Attitude
• Emotional state
Psychosocial
• Interpersonal relations
• Ability to communicate
• Empathy
• Leadership
People
50Human Factors in Aviation Maintenance
Physiological
• Health
• Nutrition
• Lifestyle
• Alertness/fatigue
• Chemical dependency
Physical
• Size
• Gender
• Age
• Strength
• The five senses
Psychological
• Experience
• Knowledge
• Training
• Attitude
• Emotional state
Psychosocial
• Interpersonal relations
• Ability to communicate
• Empathy
• LeadershipLet’s review one
People — Fatigue
51Human Factors in Aviation Maintenance
• We live in
24x7x365 world
• Aviation does not
rest
• Humans need rest!
What Does This Mean?
53Human Factors in Aviation Maintenance
Overview of Fatigue
55Human Factors in Aviation Maintenance
PresentationTime!!
Is best when people
and presenters are
alert!
Timing is Everything?
57Human Factors in Aviation Maintenance
Chronic Fatigue (harder to fix)
•Frequent recurrence
•Long duration
•Slow recovery
•Often a physical
sickness or mental stress
causing chronic fatigue
Acute Fatigue
Intense
Short duration
Cured with a good night’s
sleep
Types of Fatigue — Acute Fatigue
59Human Factors in Aviation Maintenance
Chronic Fatigue (harder to fix)
•Frequent recurrence
•Long duration
•Slow recovery
•Often a physical
sickness or mental stress
causing chronic fatigue
Acute Fatigue
Intense
Short duration
Cured with a good night’s
sleep
Types of Fatigue — Chronic Fatigue
61Human Factors in Aviation Maintenance
• Get your 8 hours of sleep
• Proper sleep conditions
• Nutrition
• Exercise
• Hydration
• Moderate caffeine
Fatigue and Proper Rest
63Human Factors in Aviation Maintenance
An Excellent Website About Sleep
64Human Factors in Aviation Maintenance
• Fatigue is a human condition
• When you are very tired you
will not admit it (like a tired
child)
• Acknowledge fatigue and tell
co-workers
• Try to remain active
• Talk to others
• Use caffeine in moderation
Avoiding Error When Fatigued
66Human Factors in Aviation Maintenance
• Arrive fit for duty (rested)
• Move around, take breaks
• Alert co-workers if fatigued
• Have some caffeine
• Do boring tasks early, if possible
Promoting Alertness at Work
68Human Factors in Aviation Maintenance
Charles Lindbergh and Fatigue
70Human Factors in Aviation Maintenance
Physiological
• Health
• Nutrition
• Lifestyle
• Alertness/fatigue
• Chemical dependency
Physical
• Size
• Gender
• Age
• Strength
• The five senses
Psychological
• Experience
• Knowledge
• Training
• Attitude
• Emotional state
Psychosocial
• Interpersonal relations
• Ability to communicate
• Empathy
• Leadership
Let’s review one
People — Size — Anthropometrics
71Human Factors in Aviation Maintenance
The Study of Body Measurement
• User populations
• Why it’s important
• Male/female split
• Individual variation
• Use of “percentiles”
• The myth of the 50th percentile person
• 5th through 95th percentile
Anthropometry
72Human Factors in Aviation Maintenance
Anthropometry Percentiles
73Human Factors in Aviation Maintenance
Physiological
• Health
• Nutrition
• Lifestyle
• Alertness/fatigue
• Chemical dependency
Physical
• Size
• Gender
• Age
• Strength
• The five senses
Psychological
• Experience
• Knowledge
• Training
• Attitude
• Emotional state
Psychosocial
• Interpersonal relations
• Ability to communicate
• Empathy
• Leadership
The Five Senses
People — Vision and Hearing
74Human Factors in Aviation Maintenance
• European Aviation Safety Agency (EASA) requires an
understanding of the eye, the ear, and the nose
• FAA places more emphasis on protection
• The following slides show EASA-level details
People — Vision and Hearing
75Human Factors in Aviation Maintenance
• This animation reviews the
parts of the eye and how
they function
• Wear your safety glasses
• Have a regular eye exam
People — Vision
77Human Factors in Aviation Maintenance
• This animation reviews the
parts of the ear and how
they function
• Wear hearing protection
• Have an audio check-up
People — Hearing
79Human Factors in Aviation Maintenance
Sensors in the skin
perceive temperature,
pressure, and other tactile
information
People — Taste / Touch / Smell
81Human Factors in Aviation Maintenance
When you’re having your meal, you:
See
Smell
Taste
Feel
Hear
How to Remember the Five Senses
82Human Factors in Aviation Maintenance
Human SensesHuman Factors
Human Factors
Human Factors
Sensing Versus Perception
83Human Factors in Aviation Maintenance
As quickly as possible,
say the color of each word on the screen.
A Test / Example of…Volunteer Needed
84Human Factors in Aviation Maintenance
desk
rock
cat
spoon
book
Sensing and Perception
85Human Factors in Aviation Maintenance
dog
house
table
car
tree
Sensing and Perception
86Human Factors in Aviation Maintenance
red
blue
gray
purple
green
Sensing and Perception
87Human Factors in Aviation Maintenance
What is This?
88Human Factors in Aviation Maintenance
Both the letter “B” and the number “13” are the same figure. However,
the context determines how you perceive it.
(Coren, et al, (1994), Sensation and Perception, Harcourt Brace College Publishers)
What is This Now?
89Human Factors in Aviation Maintenance
PEAR — People — Summary: It Takes a Human to Adapt to this Kind of Work
90Human Factors in Aviation Maintenance
Physical
• Weather extremes
• Location (in/out)
• Workspace
• Lighting
• Sound levels
• Housekeeping
• Safety issues
Organizational
• Personnel
• Supervision
• Labor - management
• Size of company
• Profitability
• Job security
• Morale
• Corporate culture
• Safety culture
Environment
91Human Factors in Aviation Maintenance
• Exposure to noise is cumulative
• People cannot adapt to high
noise levels
• Noise interferes with
communication
• OSHA requires hearing
protection above 85 dbA (TWA)
• Ear protection devices can also
interfere with communication
• Noise increases the rate of errors
Noise
92Human Factors in Aviation Maintenance
• Safety is everyone’s responsibility
• Management rewards safe actions
• Everyone is empowered to stop
work for safety concerns
• Employees will enforce safety
practices
• Reporting unsafe acts or conditions
will be rewarded
• Employees work as a team
• Formal safety management systems
are due in 2009 (ICAO)
Organizational Factors — Safety Culture
93Human Factors in Aviation Maintenance
• What do you need to know?
• What skills are necessary?
• Steps to perform a task
• Sequence of actions
• Communication requirements
• Information requirements
• Inspection requirements
• Certification requirements
Actions
94Human Factors in Aviation Maintenance
• How do you communicate error events?
• Are there enough people to do the job?
• Do personnel understand the cost of aircraft damage?
• How can you motivate one another to care more?
• Are you responsible for the things that others do?
Actions — What Can You Do Today?
95Human Factors in Aviation Maintenance
• Identify the steps required to
complete a task
• For each step, identify the
information, tools,
communication links,
procedures, and so forth,
necessary to complete the
step
Task Analysis — It’s How We Do It
96Human Factors in Aviation Maintenance
• Lack of communication is a
major cause of errors
• Verbal and non-verbal
• Positive listening
• Communication protocols
• Affirm reception of information
(readback)
• Never assume the information
you transmitted is the same
information received
Communication
97Human Factors in Aviation Maintenance
• Technical documentation systems
• Test equipment
• Enough time
• Enough people
• Lifts, ladders, stands, seats
• Materials
• Portable lighting, heating, cooling
• Training
Resources
98Human Factors in Aviation Maintenance
• Are resources ever a problem?
• What are the solutions?
• Can you give an example?
• What advice can you offer?
Resources — Please Offer Your Examples
99Human Factors in Aviation Maintenance
• It’s how we get objective
information
• A “must have” for proper
diagnosis
• Can have a good or bad user
interface
• Can be misused
• Might require significant
training to use properly
Test Equipment
100Human Factors in Aviation Maintenance
• Everything in aviation
maintenance is proceduralized
• FAA regulations (part 43)
require aviation maintenance
technicians to follow approved
procedures
• Some procedures don’t work as
written
• Most common violation is
“failure to follow procedures”
Procedures
101Human Factors in Aviation Maintenance
Human Error5
103Human Factors in Aviation Maintenance
• Definition of human error
• Types of errors
• The “dirty dozen”
• Examples of errors
• Event investigations –Maintenance Error Decision Aid (MEDA)
Human Error
104Human Factors in Aviation Maintenance
Gravity
Humans
The Greatest Hazard to Aircraft is…?
105Human Factors in Aviation Maintenance
80% of Events are Caused by Human Error
106Human Factors in Aviation Maintenance
Only one way to
disassemble
40,000+ ways to
incorrectly
reassemble!
The Odds are Against Doing it Right!
107Human Factors in Aviation Maintenance
A human action with
unintended consequences
Definition of Human Error
108Human Factors in Aviation Maintenance
Types of Human Error
110Human Factors in Aviation Maintenance
Active and Latent Errors
112Human Factors in Aviation Maintenance
• Incomplete installation (33%)
• Damage on installation (14.5%)
• Improper installation (11%)
• Equipment not installed or
missing (11%)
• Foreign object damage (6.5%)
• Improper troubleshooting, inspection, test (6%)
• Equipment not activated or deactivated (4%)
Data from Boeing study of 276 in-flight
engine shutdowns (1994)
Why Things Go Wrong
113Human Factors in Aviation Maintenance
The Civil Aviation Authority’s List of Errors
115Human Factors in Aviation Maintenance
• Eliminate these causes and
you have conquered most
human errors
• Talk about each of these
• What are the causes in your
company?
• What are the corrective
actions?
The 12 Most Common Causes for Human Errors
117Human Factors in Aviation Maintenance
Dirty Dozen — Lack of Communication
119Human Factors in Aviation Maintenance
Dirty Dozen — Lack of Teamwork
121Human Factors in Aviation Maintenance
Dirty Dozen — Norms
123Human Factors in Aviation Maintenance
Dirty Dozen — Pressure
125Human Factors in Aviation Maintenance
Dirty Dozen — Complacency
127Human Factors in Aviation Maintenance
Dirty Dozen — Lack of Knowledge
129Human Factors in Aviation Maintenance
Dirty Dozen — Lack of Awareness
131Human Factors in Aviation Maintenance
Dirty Dozen — Lack of Resources
133Human Factors in Aviation Maintenance
Dirty Dozen — Distraction
135Human Factors in Aviation Maintenance
Dirty Dozen — Lack of Assertiveness
137Human Factors in Aviation Maintenance
Dirty Dozen — Fatigue
139Human Factors in Aviation Maintenance
Dirty Dozen — Stress
141Human Factors in Aviation Maintenance
Iceberg Model
143Human Factors in Aviation Maintenance
• Boeing’s event investigation
system
• Used by 500 airlines
worldwide
• Finds the contributing factors
Event Investigation — MEDA
145Human Factors in Aviation Maintenance
Anything that can increase or decrease the likelihood of human error.
Performance Shaping Factors
146Human Factors in Aviation Maintenance
MEDA Process
148Human Factors in Aviation Maintenance
MEDA Corrective Actions
150Human Factors in Aviation Maintenance
• Exposure to noise is cumulative
• People cannot adapt to high
noise levels
• Noise interferes with
communication
• OSHA requires hearing
protection above 85 dbA
• Ear protection devices can also
interfere with communication
• Noise increases the rate of
errors
Noise
151Human Factors in Aviation Maintenance
Maintenance Accidents6
153Human Factors in Aviation Maintenance
Fatal Accidents: Intl – 1998 to 2007
World Accidents World Fatalities
0
10
20
30
40
50
60
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Year
Fa
tal
Ac
cid
en
ts
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Fa
taliti
es
Source: US NTSB and Flight International, 8-14 January 2008
154Human Factors in Aviation Maintenance
Source: US NTSB and Flight International, 8-14 January 2008
Fatal Accidents: US/Intl – 1998 to 2007
US Accidents World Accidents US Fatalities World Fatalities
0
10
20
30
40
50
60
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Year
Fa
tal
Ac
cid
en
ts
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Fa
taliti
es
155Human Factors in Aviation Maintenance
Other
27%
Controlled Flight Into
Terrain
1%
Human Factors
45%
Technical/
Maintenance
27%
Intl Accident Cause Factors 2007
Source: Flight International, 8-14 January 2008
156Human Factors in Aviation Maintenance
21 Human factors
10 Engine failure
1 Mechanical failure
9 Probable cause unknown or
undetermined (NTSB
investigation not completed)
7 Weather
3 Structural failure
Published March 2006
Causes of Helicopter Accidents (1985 - 2006)
157Human Factors in Aviation Maintenance
• There are “opportunities for improvement”
• Maintenance and technical issues are areas of concern
• Technical documentation systems!!
• Human factors challenges are ever present
– Alertness/fatigue
– Communication (flight crew to maintenance)
– Inadequate use of lessons learned (event reporting)
• Challenges are similar for all aviation segments!
Implications of the Safety Statistics for Maintenance Human Factors
158Human Factors in Aviation Maintenance
• Maintenance errors cause accidents
• Accident statistics
• Common maintenance errors
• Examples of maintenance-related accidents
• Specific accidents
Maintenance Accidents
159Human Factors in Aviation Maintenance
Historic Maintenance-Related Accidents
161Human Factors in Aviation Maintenance
Mis-riggingSpectrum 33Spectrum AircraftJul 2006
Engine run-upB737-500ContinentalJan 2006
Trim riggingBeech 1900DColgan AirAug 2003
Trim riggingBeech 1900DAir MidwestJan 2003
In-flight break-up at 35K feetB747-200China AirlinesMay 2002
Fuel exhaustion over AtlanticA330Air TransatAug 2001
Reversed hydraulic check-valveDC-8Emery WorldwideApr 2001
Mis-wired side stickA320LufthansaMar 2001
Jackscrew for elevator controlMD-80Alaska AirlinesJan 2000
Recent Maintenance-Related Accidents
162Human Factors in Aviation Maintenance
• Beech 1900D
• Forward elevator trim control
cable replacement
• Reversed elevator trim
• Diagram in maintenance manual
depicts reversed trim cable drum
• Failure to perform functional test
• Flight symptoms mimic runaway
trim
Colgan Air Elevator Trim Mis-rigging
163Human Factors in Aviation Maintenance
Time for your “war stories”…
The rules:
No company names
No last names for the people
involved
Your Accident or Near-Miss Stories
164Human Factors in Aviation Maintenance
7 Where to Get Information
166Human Factors in Aviation Maintenance
www.hfskyway.com
Three Reference Manuals
167Human Factors in Aviation Maintenance
• Training
• Human Factors Guide for Aviation Maintenance and Inspection
• Human Factors Operator’s Manuals (one for aviation maintenance and one for airport operations)
• www.hfskyway.com
• FAA human factors resources
Where to Get Information: Sample Page from Operator’s Manual for Human Factors in Aviation Maintenance
168Human Factors in Aviation Maintenance
www.hfskyway.com
For More Information — Publications
169Human Factors in Aviation Maintenance
For More Information —www.hf.faa.gov
170Human Factors in Aviation Maintenance
FAA Human Factors Resources: www.hfskyway.com
171Human Factors in Aviation Maintenance
FAA (2005), Human Factors Policy, FAA Order 9550.8A, available at http://www.hf.faa.gov/docs/508/docs/HForder.pdf#search=%22faa%20order%209550.8%22
FAA (2005), The Operator’s Manual for Human Factors in Aviation Maintenance, Washington, DC,
available at Ops Manual HF in Aviation Maint.pdf
FAA (2007), The Operator’s Manual for Human Factors in Airport Operations, Washington, DC,
available at http://hfskyway.faa.gov/2007/OpsMan_Ramp_Final.pdf
FAA (1996), Human Factors Guide for Aviation Maintenance and Inspection, available at
http://hfskyway.faa.gov
FAA (2007), Maintenance Human Factors Training Program, Evaluate and Accept, FAA Order 8900.1,
available at:
http://fsims.faa.gov/wdocs/8900.1/V03%20Tech%20Admin/Chapter%2024/03_024_002.htm?opendocument
Hackworth, H., Holcomb, K., Dennis, M., Goldman, S., Bates, C., Schroeder, D., Johnson, W. (2007).
An International Survey of Maintenance Human Factors Programs (Report No. 07/25). Oklahoma City,
OK: FAA Civil Aerospace Medical Institute.
Hall, S., Johnson, W.B. and Watson, J. (2001). Evaluation of Aviation Maintenance Working
Environments, Fatigue, and Human Performance: Phase III. Washington, DC: Federal Aviation
Administration Office of Aviation Medicine. http://hfskyway.faa.gov
References
172Human Factors in Aviation Maintenance
Summary8