EPN ATSEP Workshop 2019

Sten Winther

October 2019

2

Human Factors

Or

Human Performance

Welcome

Case Boeing Model 299

October 30, 1935, Wright Air Field, Ohio

Flight competition – next generation long-range bomber.

Case Boeing Model 299

Investigation:

Determined that the cause of the crash was a very simple thing —the control lock (gust lock) had been left in place.

https://www.thisdayinaviation.com/tag/boeing-model-299/

Opinion:

Modern planes were simply too complex to operate safely, even by two of the best test pilots in the world.

Boeing Model 299,

Human factors

Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the (engineering and) design of products, processes, and systems. The goal of human factors is to reduce human error, increase productivity, and enhance safety and comfort with a specific focus on the interaction between the human and the thing of interest.[Wikipedia]

Ergonomics (or Human Factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory. principles, data and methods to design in order to optimize human well-being and overall performance. [International Ergonomic Association, 2016]

Cognitive Bias

Human in the system

System to perform a function

f (x)

f (x) = Model of the system

Safety I (Erik Hollnagel) Safety II

Linear

Risks emerge in a system that is considered fundamentally safe

Technichal failure or Human mistakes

Complex interaction

Risk and safety come from the same sources

Variation

The Machine metaphore The Ecosystems metaphore

Operational performance

Erik Hollnagel

Performance

Time

Limit of uacceptableperformance

System design and human error

10% Equipment failure

90%HumanError

70%SystemInducedError

30%IndividualError

Human Errors

Operation Upsets

Todd Conklin

Principles of Human Performance (Todd Conklin)

1. People are fallible2. Error-likely situations are predictable3. Individual behaviors are influenced4. Operational upset can be avoided5. Management’s response to failures matters

Safe – Safety ManagementDomain for dilemmas

Failuredomain

Dilemmadomain

Safe domain

RoutinePracticeKnown conditionsHigh Situation AwarenessComfort zone

Change StabilityTechnical OperationVFR BusinessRegulation FreedomStaffing FlexibilityCulture ProceduresDegradation MitigationMilitary Civil

FailuresFaultsMishapsSlipsLapsesMistakesError

SafetyManagement

Work as done and work as imagnied

Human Error

Human error 2

Human error 3

20

Safety DifferentlySafety II, Human ErrorFour approaches post TMI

• James Reason: Slips, Lapses and Errors;• The Swiss Cheese Model

• David Woods: Human Error is contested – but does it matter anyway

• Erik Hollnagel: There is not such thing as Human Error –it does not exist!

• Sidney Dekker: Drift into failure.

All four were significantly influenced by Jens Rasmussen

The Causality Credo is challenged

..all the foundations of a system that is maintaining a fragile balance on a global scale: producing more, using more complex tools, in more difficult places, inevitably resulting in greater risks.

The art of successful intervention in safety involves controlling the compromise and the trade-offs between the benefits of controlled safety and the resulting looses in terms of managed safety.

Amalberti

Reality

Total safety = controlled safety + managed safety

• The level of safety is high, but the adaptive expertise of operators are consequently reduced as they are no longer exposed to exceptional situations and are no longer trained to work outside their procedural framework.

• Currently no known solution which can preserve both the expertise of the operators in exceptional situations and the benefit of achieving maximum system safety by procedural means.

(Amalberti, 2013)

Total safety in ultra safe systems like ATM

Production vs. safety vs. economic efficiency

Jens Rasmussen

1997

Major socio-technical system

Complex systems

1. Complex systems are intrinsically hazardous systems.2. Complex systems are heavily and successfully defended against failure.3. Catastrophe requires multiple failures – single point failures are not enough..4. Complex systems contain changing mixtures of failures latent within them.5. Complex systems run in degraded mode.6. Catastrophe is always just around the corner.7. Post-accident attribution accident to a ‘root cause’ is fundamentally wrong.8. Hindsight biases post-accident assessments of human performance.9. Human operators have dual roles: as producers & as defenders against failure.10. All practitioner actions are gambles.11. Actions at the sharp end resolve all ambiguity.12. Human practitioners are the adaptable element of complex systems.13. Human expertise in complex systems is constantly changing14. Change introduces new forms of failure.15. Views of ‘cause’ limit the effectiveness of defenses against future events.

• Historical perspective

The human in the system

• Future perspective

The user interface or human–machine interface is the part of the machine that handles the human–machine interaction. Membrane switches, rubber keypads and touchscreens are examples of the physical part of the Human Machine Interface which we can see and touch.

Human machine interface HMI

Example of HMI

• Visibility: By looking, the user can tell the state of the system and the alternatives for action

• Constraints: The system enforces critical interactions.

• Good Mapping: It is possible to determine the relationship between the action and their results, between the controls and their effects, and between the system state and what is visible.

• Feedback: The user recieve full and continuous feedback about the results of their actions.

Criteria for good HMI

Good examples HMI

Good design, is not just a question of good HMI.

• First Principle: Trade offs and work arounds

• Second Principle: The minimal Action Rule

• Third Principle: Form should match function and vice versa

• Fourth Principle: What you look for is what you see

• Fifth Principle: Show what is going on

(Steven Shorrock; Erik Hollnagel ”The Nitty-Gritty of Human Factors”)

The Nitty-Gritty of Human Factors- a practical approach

Automation

Level of automation

• Tasks that are too difficult to automate are left to humans• For the most of the time, humans are there to monitor the system• Operators get de-skilled because of lack of practice• Whenever something goes wrong, humans are given back control

• Humans are removed fromthe system because theyare not reliable, but theyare asked to intervene in the most difficultsituations.

Bainbridge, 1987

Ironies of automation

“Manual control is a highly skilled activity, and skills need to be practiced continuously in order to maintain them. Yet an automatic control system that fails only rarely denies operators the opportunity for practicing these basic control skills … when manual takeover is necessary something has usually gone wrong; this means that operators need to be more rather than less skilled in order to cope with these atypical conditions.”

Automation paradox

• Demand for quick response

• Conditions Complexity and distribution of technology

Team Work

“Purpose affirms trust, trust affirms purpose, and together they forge individuals into a working team.” ― Stanley McChrystal, Team of Teams: New Rules of Engagement for a Complex World

• https://www.youtube.com/watch?v=biNebig1gUI

Video ThyssenKrupp

• Human beings, viewed as behaving systems, are quite simple. The apparent complexity of our behavior over time is largely a reflection of the complexity of the environment in which we find ourselves.

(Simon 1996)

Systems thinking

• Early focus on users, activities and context.

• Active involvement of users.

• Appropriate allocation of function between user and system.

• Incorporate of user-derived feedback into system design.

• Iterative design.

User-centered design principles

• MIL-STD-1472G

• FAA System Safety Handbook, Chapter 17: Human Factors Principles & Practices December 30, 2000

• ICAO Human Factor Digest No. 11 — Human Factors in CNS/ATM Systems (Circular 249)

• ISO 9241-210:2010

• ISO 6385:2004

• CANSO Human Performance Standard of Excellence

• CAA CAP 1377 (Automation)

Standards

Accident and incidentsAlthough the additional flight crew were a valuable resource, had they not been available the primary flight crew would have likely responded to the situation in a similar manner. However, the gathering of information to assist in decision making would have required the use of alternative resources and methods.

Accident and incidents

Accident and incidents

When multiple failures or out-of-limits conditions were detected by ECAM they were prioritisedaccording to the programmed ECAM logic.106 In that event, the highest priority procedure relating to the sensed condition was displayed first.

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