Counter-Errorism in Diving: Applying Human Factors to Diving

Gareth Lock at The Human Diver

Human factors is a critical topic within the world of SCUBA diving, scientific diving, military diving, and commercial diving. This podcast is a mixture of interviews and 'shorts' which are audio versions of the weekly blog from The Human Diver. Each month we will look to have at least one interview and one case study discussion where we look at an event in detail and how human factors and non-technical skills contributed (or prevented) it from happening in the manner it did.

  1. SH291: What the Data Told Us: Fear, Trust, and the Stories That Never Get Told. Part 2 of 3.

    2d ago

    SH291: What the Data Told Us: Fear, Trust, and the Stories That Never Get Told. Part 2 of 3.

    This blog explains how a mixed-methods study explored why divers struggle to share honest, learning-focused stories about incidents. Using a large international survey, focus groups, and expert interviews, the research found that storytelling is strongly shaped by organisational culture, fear, and trust. Many divers—especially instructors—fear legal consequences, criticism, or damage to their reputation, which stops them from speaking openly, particularly in public settings. At the same time, there is confusion about key ideas like what counts as an “incident,” what “risk” really means, and what a “just culture” looks like, with very few divers linking incidents to learning. The study also showed that when stories include more context, people are less likely to judge and more likely to learn, but most divers are not taught how to do this. Overall, the findings suggest the diving community knows that sharing near-misses and building a just culture would improve safety, but lacks the trust, understanding, and organisational support needed to make that happen. Original blog: https://www.thehumandiver.com/post/msc-part-2-the-data-and-results Links and references: British Diving Safety Groiup: https://bdsg.org.uk/ Chan, W. T.-K., & Li, W.-C. (2023). Development of effective human factors interventions for aviation safety management. Frontiers in Public Health, 11, 1144921. https://doi.org/10.3389/fpubh.2023.1144921 EC. (2014). Regulation (EU) No 376/2014 of the European Parliament and of the Council of 3 April 2014. European Commission. Reason, J. (2016). Managing the risks of organizational accidents. Routledge. https://doi.org/10.4324/9781315543543 Tags: THD-English| THD-Learning, Incidents & Just Culture

    13 min
  2. SH290: What Happens Underwater, Stays Underwater — And That's a Problem. Part 1 of 3

    5d ago

    SH290: What Happens Underwater, Stays Underwater — And That's a Problem. Part 1 of 3

    This episode introduces the problem behind learning in diving safety, using the 2020 death of Linnea Mills to highlight how incidents are often caused by deeper system issues, not just individual mistakes. While near-misses and accidents happen regularly in diving, most are never shared or analysed, meaning valuable lessons are lost. Unlike industries such as aviation or healthcare, diving lacks strong reporting systems, regulation, and reliable data, so decisions are often based on uncertainty rather than evidence. Existing reports tend to focus on immediate causes like equipment failure or diver error, but miss the wider social, organisational, and environmental factors that shape outcomes. The episode argues that meaningful learning comes from “context-rich” stories that explain not just what happened, but why it made sense at the time. Drawing on safety research from other industries, it highlights the need for a stronger reporting culture, psychological safety, and system-level thinking to improve learning and prevent future incidents. Original blog: https://www.thehumandiver.com/post/msc-part-1-the-problem-space References: Dekker, S. (2017). Just culture: Restoring trust and accountability in your organization (3rd ed.). CRC Press, Taylor & Francis Group. Drupsteen, L., & Guldenmund, F. (2014). What is learning: A review of the safety literature to define learning from incidents, accidents and disasters. Journal of Contingencies and Crisis Management, 22(2), 81–96. https://doi.org/10.1111/1468-5973.12039 EC. (2014). Regulation (EU) No 376/2014 of the European Parliament and of the Council of 3 April 2014. European Commission. Gigerenzer, G. (2014). Risk savvy. Viking. https://www.amazon.co.uk/Risk-Savvy-Make-Good-Decisions/dp/1846144744 Lock, G. (2011). The application of the Human Factors Analysis and Classification System (HFACS) to improve diving safety. https://drive.google.com/file/d/1Iz3qRRyo2NjdiBGbPcRhj14NoCTuuM4/view?usp=share_link Mills v Gull Dive Center PADI (2022). https://www.scribd.com/document/555406095/Mills-v-Gull-Dive-Center-PADI-2nd-Amended-Complaint Orlady, H. W., & Orlady, L. M. (2017). Human factors in multi-crew flight operations (1st ed.). Routledge. Reason, J. (2016). Managing the risks of organizational accidents. Routledge. https://doi.org/10.4324/9781315543543 Snowden, D. (2002). Complex acts of knowing: Paradox and descriptive self-awareness. Journal of Knowledge Management, 6(2), 100–111. https://doi.org/10.1108/13673270210424639 Waring, J. J. (2005). Beyond blame: Cultural barriers to medical incident reporting. Social Science & Medicine, 60(9), 1927–1935. https://doi.org/10.1016/j.socscimed.2004.08.055 Tags: English| Learning, Incidents & Just Culture

    13 min
  3. SH289: Chac Mool - Diving Deeper into a Triple Fatality with Human Factors

    Jun 20

    SH289: Chac Mool - Diving Deeper into a Triple Fatality with Human Factors

    This episode examines a 2012 triple fatality at Cenote Chac Mool in Mexico using a Human Factors approach, showing how accidents are rarely caused by a single mistake but by a combination of small, interacting factors. A guide took two recreational divers beyond safe limits into an overhead cave environment without a continuous guideline, and all three ran out of gas and died. Instead of simply blaming the guide, the analysis explores how things made sense at the time, including authority gradients that stopped the divers from questioning decisions, fatigue from multiple dives, pressure to show something impressive, and increasing task load in a complex environment. Using the PETTEOT framework, the case highlights how people, environment, equipment, organisational culture, and time pressures combined to reduce safety margins until there was no capacity left to recover. The key lesson is that safety depends on understanding these system interactions, building psychological safety so people can speak up, and reinforcing clear rules and preparation to prevent small, “normal” deviations from turning into fatal outcomes. Original blog: https://www.thehumandiver.com/post/chac-mool-triple-diving-fatality Links: Full CREER manual: https://creer-mx.com/wp-content/uploads/2024/03/Manual-for-Cenote-Dive-Guides-vs010324.pdf The Thumb rule: https://www.thehumandiver.com/post/top-tips-for-diving-instructors-psychological-safety-and-the-thumb-rule Learning from Emergent Outcomes course waiting list: https://www.thehumandiver.com/lfeo Tags: English| Learning, Incidents & Just Culture

    24 min
  4. SH288: The 'Obvious Thing' Nobody Noticed

    Jun 17

    SH288: The 'Obvious Thing' Nobody Noticed

    This episode explores the fatal case of 18-year-old Linnea Mills to show how visible hazards can go unnoticed when an instructor lacks the mental capacity to recognise them. Linnea was overweighted, unable to inflate her drysuit, and using equipment that couldn’t provide enough lift—risks that seem obvious in hindsight but were missed due to a combination of inexperience, time pressure, unfamiliar gear, and commercial expectations. Using models like ECOM and COCOM, the episode explains how an instructor’s attention can be consumed by immediate tasks, leaving no capacity to monitor the bigger picture or reassess whether a dive should proceed. This isn’t about blaming an individual, but understanding how systems, workload, and limited experience can overwhelm decision-making. The key lesson is that effective instructors don’t just rely on skill, but on preparation—setting clear plans, checks, and limits before the dive—to protect their ability to recognise problems when it matters most. Original blog: https://www.thehumandiver.com/post/the-obvious-thing-nobody-noticed Links: Part 1: https://www.thehumandiver.com/post/the-picture-went-dark The Linnea Mills case: https://www.thehumandiver.com/post/linnea-mills-death-hf-systems-lens Tags: English| Sense-making, Decision-making, & Psychology

    15 min
  5. SH287: When the Picture Goes Dark

    Jun 13

    SH287: When the Picture Goes Dark

    This episode explores why divers don’t truly “lose” situation awareness, but instead run out of the mental capacity needed to maintain it. Through the story of James on a challenging wreck dive, it shows how increasing demands—like current, task focus, and effort—can quietly narrow attention until the bigger picture is lost, even when skills and training are sound. Using two human factors models, COCOM and ECOM, the discussion explains how control shifts from broad, strategic thinking to narrow, reactive behavior as workload rises, and how different layers of awareness—from basic task execution to overall planning—can break down under pressure. It highlights that mistakes are often not about poor decisions, but about limited cognitive resources in the moment. The episode also emphasizes the importance of good preparation, clear decision thresholds, teamwork, and deliberate pauses to manage workload, while showing how reflection after the dive helps improve future performance. Ultimately, it reframes the difference between novice and experienced divers as the ability to manage attention and maintain the bigger picture, not just technical skill. Original blog: https://www.thehumandiver.com/post/the-picture-went-dark Links: A 2026 study in Safety Science by Woltjer and colleagues: https://www.sciencedirect.com/science/article/pii/S0925753526000822 Part two: https://www.thehumandiver.com/post/the-obvious-thing-nobody-noticed Tags: English| Sense-making, Decision-making, & Psychology

    16 min
  6. SH286: The Shortcut That Gets You Home — and the One That Doesn't

    Jun 10

    SH286: The Shortcut That Gets You Home — and the One That Doesn't

    Divers make many decisions quickly, often without realising it, by using heuristics—mental shortcuts that help us act fast when time and information are limited. These shortcuts are essential and often effective, especially with experience, but they can also lead to predictable errors called biases when used in the wrong situation. Common examples include relying too much on recent experience, sticking to an original plan despite changing conditions, or only noticing information that supports what we already believe. In diving, where conditions vary and feedback is often limited, these biases can quietly increase risk. The key is not to avoid intuition, but to understand when it might be misleading and to slow down when needed. Tools like checklists, realistic training, and open team communication help balance fast thinking with more careful decision-making, improving safety and helping divers make better choices underwater. Original blog: https://www.thehumandiver.com/post/shortcuts-errors-and-the-gap Links: Gigerenzer’s push for people to be “risk savvy”: https://www.jasoncollins.blog/posts/nudging-citizens-to-be-risk-savvy Blog about the Scylla wreck tragedy: https://www.thehumandiver.com/post/scylla-wreck-penetration-leodsi Blog about the IJN Sata incident: https://wreckedinmyrevo.com/2023/11/16/close-call-on-the-ijn-sata-palau-120-fsw/ Tags: English| Sense-making, Decision-making, & Psychology

    10 min
  7. SH285: When Skill Alone Isn't Enough: The Resilient Performance Model

    Jun 6

    SH285: When Skill Alone Isn't Enough: The Resilient Performance Model

    Diving operations rarely fail because people lack skill; they fail when skilled individuals are not supported by the systems around them. The Resilient Performance Model from The Human Diver explains that performance comes from the interaction of three areas: technical skills, non-technical skills like communication and decision-making, and the wider context such as culture, workload, and resources. When one of these areas is weak or missing, problems appear—such as highly skilled divers working in silence, well-coordinated teams lacking critical skills, or strong systems where people feel unable to challenge decisions. True resilience happens when all three are aligned, allowing teams to adapt when things go wrong and still achieve safe outcomes. The key lesson is that improving safety isn’t just about better training or stricter procedures, but about creating an environment where people can speak up, make good decisions under pressure, and learn from both successes and failures to improve over time. Original blog: https://www.thehumandiver.com/post/resilient-performance-model Tags: Commercial Diving

    12 min
  8. SH284: LEODSI and PETTEOT: A Systems Approach for Understanding How Diving Really Works

    Jun 3

    SH284: LEODSI and PETTEOT: A Systems Approach for Understanding How Diving Really Works

    When something goes wrong in diving, people often ask “who made the mistake?”, but that question usually oversimplifies what really happened and stops us from learning. The Learning from Emergent Outcomes framework (LEODSI) takes a different approach by looking at diving as a system, where outcomes are shaped by many interacting factors rather than one person’s actions. It examines seven key elements—people, environment, tasks, equipment, external pressures, organisation, and time—to understand how decisions made sense in the moment and how conditions combined to produce the result. Instead of blaming individuals, LEODSI focuses on why events unfolded the way they did, recognising that both successes and failures come from the same system. By using this approach in everyday debriefs, not just after incidents, divers and teams can learn more effectively, improve safety, and make meaningful changes that reduce risk in the future. https://www.thehumandiver.com/post/what-is-leodsi-petteot Links: Learning from Emergent Outcomes course: https://www.thehumandiver.com/lfeo Tags: Learning, Incidents & Just Culture

    12 min
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About

Human factors is a critical topic within the world of SCUBA diving, scientific diving, military diving, and commercial diving. This podcast is a mixture of interviews and 'shorts' which are audio versions of the weekly blog from The Human Diver. Each month we will look to have at least one interview and one case study discussion where we look at an event in detail and how human factors and non-technical skills contributed (or prevented) it from happening in the manner it did.

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