human factor

1Human Factors in Aviation Maintenance

Human Factors

inAviation Maintenance


Welcome


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


1What is Human Factors?


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


List “Human Factors” Related to 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?


Ensure continuing safety and efficiency by paying

attention to issues that affect human performance.

Human Factors Goal — A Summary


The Elements of Human Factors


• Personality types

• Relating to other people

• Dealing with stress

• Coping mechanisms

• Self image

• Accepting criticism

Clinical Psychology


• 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


• 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


• Human-computer interaction

• User interface design

• Requirements analysis for

software-based tools and test

equipment

• Accommodation for range of

computer literacy

Computer Science


• The “mental” parts of

perception

• Problem solving ability

• Things that affect

troubleshooting performance

• Effects of stress on mental

processing

Cognitive Science


• Industrial safety

• Slips, trips, and falls

• Materials handling, e.g., lifting

• Toxic materials storage and

use

• Facility design and safety

• Warnings

Safety Engineering


• 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


• Organizational structure

• Rewards and compensation

• Motivation

• Work teams and groups

• Union/management relations

• Equitable treatment

Organizational Psychology


• Principles of learning

• Ways to help people to

remember

• Design of instruction

Educational Psychology


• 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


Ensure continuing safety and efficiency by paying

attention to issues that affect human performance.

Human Factors Goal for Review


2History of Human Factors


• 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


Maintenance Human Factors has Evolved in 20 Years!


Human Factors Timeline


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


Human Factors Spectacles3


• 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”


• 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”


• 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?


A Reminder to Apply Human Factors Principles 24 x 7


The PEAR Model4


• Models make it easier to understand complex things

• Easy to remember

• Models can be 2-D, 3-D, or mental

Why Use Models?


• Originally used for

pilot’s crew resource

management (CRM)

• Has served human

factors training well –

worldwide

• A bit abstract

The SHELL Model


• 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


• PEAR is easy to remember

• It works for maintenance

• It is matched with the SHELL model

The PEAR Model


• People who perform the job

• Organizational and physical environment

• Actions (tasks) performed as part of the job

• Tools, procedures, and other resources

PEAR


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


Physiological

• Health

• Nutrition

• Lifestyle



Physical

• Size

• Gender

• Age

• Strength

• The five senses

Psychological

• Experience

• Knowledge

• Training

• Attitude

• Emotional state

Psychosocial



• Empathy

• LeadershipLet’s review one

People — Fatigue


• We live in

24x7x365 world

• Aviation does not

rest

• Humans need rest!

What Does This Mean?


Overview of Fatigue


PresentationTime!!

Is best when people

and presenters are

alert!

Timing is Everything?


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


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


• Get your 8 hours of sleep

• Proper sleep conditions

• Nutrition

• Exercise

• Hydration

• Moderate caffeine

Fatigue and Proper Rest


An Excellent Website About Sleep


• 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


• 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


Charles Lindbergh and Fatigue


Physiological

• Health

• Nutrition

• Lifestyle



Physical

• Size

• Gender

• Age

• Strength

• The five senses

Psychological

• Experience

• Knowledge

• Training

• Attitude

• Emotional state

Psychosocial



• Empathy

• Leadership

Let’s review one

People — Size — Anthropometrics


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


Anthropometry Percentiles


Physiological

• Health

• Nutrition

• Lifestyle



Physical

• Size

• Gender

• Age

• Strength

• The five senses

Psychological

• Experience

• Knowledge

• Training

• Attitude

• Emotional state

Psychosocial



• Empathy

• Leadership

The Five Senses

People — Vision and Hearing


• 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


• This animation reviews the

parts of the eye and how

they function

• Wear your safety glasses

• Have a regular eye exam

People — Vision


• This animation reviews the

parts of the ear and how

they function

• Wear hearing protection

• Have an audio check-up

People — Hearing


Sensors in the skin

perceive temperature,

pressure, and other tactile

information

People — Taste / Touch / Smell


When you’re having your meal, you:

See

Smell

Taste

Feel

Hear

How to Remember the Five Senses


Human SensesHuman Factors

Human Factors

Human Factors

Sensing Versus Perception


As quickly as possible,

say the color of each word on the screen.

A Test / Example of…Volunteer Needed


desk

rock

cat

spoon

book

Sensing and Perception


dog

house

table

car

tree



red

blue

gray

purple

green



What is This?


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?


PEAR — People — Summary: It Takes a Human to Adapt to this Kind of Work


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


• 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


• 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


• 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


• 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?


• 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


• 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


• Technical documentation systems

• Test equipment

• Enough time

• Enough people

• Lifts, ladders, stands, seats

• Materials

• Portable lighting, heating, cooling

• Training

Resources


• Are resources ever a problem?

• What are the solutions?

• Can you give an example?

• What advice can you offer?

Resources — Please Offer Your Examples


• 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


• 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


Human Error5


• Definition of human error

• Types of errors

• The “dirty dozen”

• Examples of errors

• Event investigations –Maintenance Error Decision Aid (MEDA)

Human Error


Gravity

Humans

The Greatest Hazard to Aircraft is…?


80% of Events are Caused by Human Error


Only one way to

disassemble

40,000+ ways to

incorrectly

reassemble!

The Odds are Against Doing it Right!


A human action with

unintended consequences

Definition of Human Error


Types of Human Error


Active and Latent Errors


• 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


The Civil Aviation Authority’s List of Errors


• 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


Dirty Dozen — Lack of Communication


Dirty Dozen — Lack of Teamwork


Dirty Dozen — Norms


Dirty Dozen — Pressure


Dirty Dozen — Complacency


Dirty Dozen — Lack of Knowledge


Dirty Dozen — Lack of Awareness


Dirty Dozen — Lack of Resources


Dirty Dozen — Distraction


Dirty Dozen — Lack of Assertiveness


Dirty Dozen — Fatigue


Dirty Dozen — Stress


Iceberg Model


• Boeing’s event investigation

system

• Used by 500 airlines

worldwide

• Finds the contributing factors

Event Investigation — MEDA


Anything that can increase or decrease the likelihood of human error.

Performance Shaping Factors


MEDA Process


MEDA Corrective Actions


• 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


Maintenance Accidents6


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


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


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


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)


• 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


• Maintenance errors cause accidents

• Accident statistics

• Common maintenance errors

• Examples of maintenance-related accidents

• Specific accidents

Maintenance Accidents


Historic Maintenance-Related Accidents


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


• 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


Time for your “war stories”…

The rules:

No company names

No last names for the people

involved

Your Accident or Near-Miss Stories


7 Where to Get Information


www.hfskyway.com

Three Reference Manuals


• 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


www.hfskyway.com

For More Information — Publications


For More Information —www.hf.faa.gov


FAA Human Factors Resources: www.hfskyway.com


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


Summary8

human factor

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