Human Factors Considerations in Submersible Design

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• Human Factors Considerations in Submersible
  Design
• Doug Farrow
• SeaLordOne_at_aol.com
• August 16, 2003

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Human Factors

• What is human factors engineering?
• Why should I care about human factors?
• What are the basics?
• How do I apply this to the design of my PSUB?

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Defining Human Factors

• The technology developed to optimize the
  relationships/interfaces between people and
  engineered systems.
• Human Factors seeks to optimize the interfaces
  between humans and
• Other humans (e.g. crew, support, suppliers)
• Hardware (controls, indicators, view-ports)
• Software (display characteristics, processing
  times)
• The natural and operational environment (e.g.
  night)

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Good Human FactorsBuilding a User-Friendly World

• Good human factors are like the musical score
  behind a filmthe goal is that you dont notice
  them.
• Engineered products and processes should be
  matched to human capabilities and limitations.
• Why are phone numbers 10 digits long?
• Why are the grouped with ( ) and - ?

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Easy to Build or Easy to Use?

• Sometimes the mechanical and human factors
  engineering solutions are identical
• Simple mechanical devices may be simple to use as
  well (mousetrap)
• Sometimes there is a tradeoff
• Simple mechanical devices may be harder to use
  (manual vs. automatic transmissions)

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Safety Order of PrecedenceLast Choice Rely on
the Human

• Design the risk out of the system
• Provide safety devices
• Provide warning devices
• Provide procedures and training

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Typical Human Factors Subjects

• Sensory-perceptual factors
• Medical and physiological factors
• Knowledge and skill factors
• Information processing factors
• Judgement and decision-making factors
• Communication factors
• Personality and attitude factors

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Human Factors

• What is human factors engineering?
• Why should I care about human factors?
• What are the basics?
• How do I apply this to the design of my PSUB?

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The Prophet Speaks the Future

• In 2004 the number of aviation related fatalities
  in the United States will be
• 200 /- 200 (0-400)
• In 2004 the number of automotive related
  fatalities in the United States will be
• 43,000 /- 1,000 (42,000- 44,000)

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Hazard vs. Risk

• The automotive industry is a high hazard- high
  risk industry. Fatality statistics remain
  stable over time and are therefore very
  predictable.
• The aviation industry is a high hazard-low risk
  industry. Fatality statistics are unstable over
  time and are therefore difficult to predict.

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Good News-Bad News

• The good news for aviation is that the fatality
  rate is extremely low.
• The bad news is that it will be extremely
  difficult to lower it further.
• The other bad news is that the submersible
  community is in the same boat (no pun intended).

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High Hazard-Low Risk Industries

• Commercial Aviation
• Nuclear Power Plants
• Chemical Process Plants
• Marine and Rail Transport
• Petrochemical Industry
• Commercial Submersible Operations

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High Hazard-Low Risk Industries

• All obvious hazards have been addressed
• Greatest danger from less unpredictable events
• When accidents are so rare, other measures of
  safety are necessary
• Do you have safety processes in place?
• Are you applying them consistently?
• Are they working?

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Commercial Aircraft Accidents
70
35
60
30
25
50
20
40
Departures (million)/Rate per million
Accidents
15
30
10
20
10
5
0
0
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
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The Story in Commercial Aviation Today

• Human factors are significant contributors in
  approximately 70 of all accidents and
  incidents.
• Improving the Continued Airworthiness of Civil
  Aircraft, A Strategy for the FAAs Aircraft
  Certification Service, National Research Council,
  1988.

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Commercial Aircraft Accidents
70
35
60
30
25
50
20
40
Departures (million)/Rate per million
Accidents
15
30
10
20
10
5
0
0
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
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The Story in Commercial Aviation

• Human factor issues, specifically human errors,
  contribute to more aircraft incidents and
  accidents than any other single factor.
• As noted in chapter 2, lack of situational
  awareness is a key factor in CFIT (controlled
  flight into terrain) accidents, which are
  responsible for more fatalities than any other
  type of aircraft accident."

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ACCIDENTS BY PRIMARY CAUSEWORLDWIDE COMMERCIAL
JET - HULL LOSS
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Whos Error is it, Anyway

• The manufacturers and regulators and airlines
  other organizational entities often take the
  risks.

• The cockpit and cabin crew often then run the
  risks.

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If We Knew Then What We Know Now

• What we thought in 1970
• Accidents are caused by bad pilots who lack the
  right stuff.
• What we think in 2003
• Accidents happen to good pilots on a bad day

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Hold On, What Your Are Saying is...

• Submersible Operations is a high hazard- low risk
  enterprise.
• Most accidents in these enterprises are caused by
  human factors in general, and human error in
  particular, rather than mechanical malfunction.
• Some errors (upstream) will be made by others
  before you close your hatch, some you will make
  yourself (downstream) after you close your hatch.

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Pilot-Induced Aviation Accidents

• Pilots rarely crash because they cannot control
  their aircraft in flight
• Pilots usually crash because they fail to manage
  their flights
• Manage the Threats (complications)
• Manage the Errors (yours or others)

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Preventing Errors

• Human errors can be minimized, but they cannot be
  eliminated.
• Errors that are made must be detected and
  corrected (or at least managed).
• The aviation community is moving to a vision of
  the job of the pilot as one of threat and error
  management. (Assuming you have the technical
  skills to fly).

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Threats

• A threat is any event or condition that
  detracts from a perfect dive.
• Threats may include the weather, the sea state,
  visibility, equipment failures, delays, changes
  to plans, other boats, emergency situations,
  unexpected events, distractions, etc.
• Threats are additive Many small ones are as
  dangerous as one big one.

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Plan Continuation Errors

• An emerging trend in aviation safety data
  involves plan continuation errors, sometimes
  called get-home-it is.
• A pilot adopts an initial plan for the flight,
  but resists changing that plan in spite of
  increasing dangers and complexities.
• Merely a flesh wound

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Threat and Error Management

• First things first build a safe boat
• Design, construction, operation
• Then, build a safe operation
• Manage your threats
• Manage your errors

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Human Factors

• What is human factors engineering?
• Why should I care about human factors?
• What are the basics?
• How do I apply this to the design of my PSUB?

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Basic Human Factors Guidelines

• Allocation of Functions
• Consistency
• Standardization
• Safety
• User-Centered Perspective

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Allocation of Functions

• Allocate to machines the things they do well
  (monitor and execute), and to humans the things
  they do well (mission management).
• Which functions will be manual, which manual
  assist, which automatic?
• Consider the load on the human during a
  worst-case scenario.

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Allocation of Functions

• Do not automate because it is easy to do or
  because you canalways automate because you have
  a goal and a rationale for doing so.

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Consistency

• Strive for consistency in appearance, behavior
  response in
• Systems Equipment, Controls Indicators
• Examples
• Switch position up is always on, down is always
  off
• Labels have same typeface and font
• Indicators Left always low, right always high

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Standardization

• Identical fasteners, switches, breakers,
  connectors, etc.
• Not only to reduce tools and spares, but to
  simplify procedures and reduce the opportunity
  for error.
• Standardize controls, displays, markings, coding,
  labeling, etc.
• Standardize terminology across manual, checklist,
  equipment labels, etc.

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Safety

• Minimize opportunity for human error under
  normal, degraded emergency conditions.
• Equipment should fail to a safe mode
• life support to on, motors to off
• Systems Procedures should be
• Error resistant (hard to do it wrong)
• Error tolerant (errors have minor consequences)

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User-Centered Perspective

• Design to user abilities.
• Minimize user action, such as hand and eye
  movements.
• Design for subjective satisfaction

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Human Factors

• What is human factors engineering?
• Why should I care about human factors?
• What are the Basics?
• How do I apply this to the design of my PSUB?

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Think Through Every Stage in the Life-Cycle of
Your PSUB During the Design Phase

• 1.0 Analysis
• 2.0 Design
• 3.0 Construction
• 4.0 Testing
• 5.0 Operations
• 6.0 Maintenance
• 7.0 Upgrade
• 8.0 Disposition

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Think Through Every Stage in the Life-Cycle of
Your PSUB During the Design Phase

• 1.0 Analysis
• 1.1 Capabilities
• 1.2 Constraints
• 2.0 Design
• 2.1 Drawings
• 2.2 Computer Modeling
• 2.3 Scale Model
• 2.4 Full Size Mock-Up

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Think Through Every Stage in the Life-Cycle of
Your PSUB During the Design Phase

• 1.0 Analysis
• 1.1 Capabilities 200 ft., 5 kts., 2-man
• 1.2 Constraints 10K, fit on trailer
• 2.0 Design
• 2.1 Drawings Hull, equipment
• 2.2 Computer Modeling Calculations
• 2.3 Scale Model 3-Dimensions
• 2.4 Full Size Mock-Up Does it all fit?

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Make Three Columns
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The Same Three-Column Approach May Be Used For
Other Planning

• Example Worst Case Scenario Design
• You will want to think through everything that
  could go wrong, and prepare yourself and your
  PSUB to respond.
• Situation You suddenly loose all power at
  depth. Think Through
• What will my boat do if I loose all power?
• What will I do if I loose all power?

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In Summary

• The least reliable component of your PSUB is you.
• There are hard limits to the level of reliability
  you can attain.
• The primary risk to your safety is human error
  be prepared for it. Mange Threats Errors.
• Threats are cumulative.
• Lack of situational awareness and plan
  continuation errors may be your most dangerous
  errors.

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Questions?

• Easy Questions 1.00
• Hard Questions 2.00
• Honest Answers Priceless