The Human Safety System Series: STARTLE
- SRM Pilot
- Jul 26
- 5 min read
The First Test of the Human Safety System
Flight Deck Conversations
Episode 2 Blog Series
We've Been Looking at Startle the Wrong Way
If you've worked in aviation for any length of time, you've almost certainly experienced the startle effect.
Perhaps it was an unexpected engine problem after take-off.
A traffic conflict that appeared out of nowhere.
A sudden weather encounter.
Or maybe it wasn't aviation at all. Perhaps it was an unexpected phone call that changed your day, a medical emergency, or a critical equipment failure at work.
Whatever the event, the experience is remarkably similar.
Your heart rate increases.
Your breathing changes.
Your attention narrows.
For a brief moment, your thinking feels slower.
For years, we've recognised this response and labelled it the startle effect. We teach pilots about it during emergency training and discuss it during accident investigations. But I believe we've been asking the wrong question.
Instead of asking:
"How do we stop people becoming startled?"
Perhaps we should be asking:
"Why does the brain respond this way in the first place?"
Because once we understand the answer, everything about the conversation changes.
Startle Isn't a Training Problem
One of the first questions I ask pilots during human performance training is:
"Why can't we simply train the startle response out of people?"
It's a reasonable question.
After all, if we repeatedly expose pilots to emergencies during training, shouldn't they eventually stop becoming startled?
The answer is no.
Because startle isn't a training problem.
It's biology.
The startle response is an automatic survival mechanism that has evolved over hundreds of thousands of years. It occurs before we've consciously analysed the situation and before we've decided what to do next.
Understanding this isn't an excuse for poor performance. It's the foundation for improving performance.
Meet the Brain's Threat Detector
Hidden deep within the brain is a small almond-shaped structure called the amygdala.
Its job is surprisingly simple.
It continuously scans our environment for potential threats.
The amygdala doesn't care whether you've accumulated 20 flying hours or 20,000.
It doesn't know your experience level, your qualifications or your standard operating procedures.
Its priority is survival.
The moment it detects something unexpected that could represent danger, it responds almost immediately.
This response occurs before our conscious brain has fully processed what is happening.
That's why experienced pilots can still experience startle.
Experience doesn't remove biology.
When Survival Takes Priority
Once the amygdala detects a threat, it activates the sympathetic nervous system—our body's emergency response system.
This is the familiar "fight or flight" response.
Adrenaline is released.
Heart rate increases.
Breathing becomes faster.
Muscles prepare for action.
These changes are incredibly effective if you're escaping danger.
However, they also influence how the brain processes information.
This is where many operational errors begin, not because people suddenly become incompetent, but because their brain has temporarily changed priorities.
Your Mental Whiteboard Becomes Smaller
One of the first cognitive systems affected by acute stress is working memory.
Working memory is often described as the brain's mental whiteboard.
It's where we temporarily hold information while solving problems, recalling checklists, planning our next action and making decisions.
Under normal conditions, this system works remarkably well.
Under acute stress, its capacity decreases.
Suddenly, it becomes harder to remember information, process multiple tasks simultaneously or think several steps ahead.
This isn't a lack of intelligence.
It's a predictable neurological response.
The CEO of the Brain
Another important structure affected during acute stress is the prefrontal cortex.
If the amygdala is the brain's threat detector, the prefrontal cortex is its executive decision-maker.
This part of the brain helps us plan, prioritise, evaluate options and solve complex problems.
During a startle response, however, its influence can be reduced while the brain prioritises immediate survival.
This explains why experienced professionals sometimes describe feeling mentally "frozen" or unable to think as clearly as they normally would.
The brain hasn't stopped working.
It has simply shifted into a different operating mode.
Changing the Conversation
This understanding should change the way we think about performance.
Instead of asking:
"Why did the pilot make that mistake?"
Perhaps we should first ask:
"What was happening inside the pilot's brain at that moment?"
That question doesn't remove accountability.
It provides context.
And context helps us design better training, better procedures and better recovery strategies.
We Don't Train People Not to Become Startled
This is perhaps the most important message.
We don't train people not to become startled.
We train them to recognise the response, stabilise the situation, regain cognitive control and recover effectively.
The measure of performance isn't whether someone experiences startle.
Every healthy human will.
The real measure is:
How quickly can they recover?
That's the skill we should be developing.
Supporting the Human Safety System
This conversation extends well beyond aviation.
Surgeons.
Engineers.
Emergency service personnel.
Rail operators.
Healthcare professionals.
Anyone working in a high-consequence environment relies on the same human brain.
The technology changes.
The workplace changes.
The biology of the human brain doesn't.
Understanding how our brain responds under pressure isn't simply interesting neuroscience.
It's fundamental to building safer organisations.
Because every safety system ultimately depends on the human operating within it.
A Question for You
Tomorrow, before you begin work, take just thirty seconds and ask yourself:
How prepared is my Human Safety System today?
Not just physically.
Mentally.
Because understanding your own brain may be one of the most valuable safety skills you'll ever develop.
Continue Your Human Safety System Journey
Understanding the science behind the startle response is only the first step.
The real challenge is learning how to recognise these responses in yourself, manage cognitive workload under pressure, and recover effectively when the unexpected happens.
At SRM Pilot, we've developed practical, evidence-informed training that helps pilots build these skills through structured Single-Pilot Resource Management (SRM). Rather than simply learning what to do, our courses focus on understanding why the brain responds the way it does, and how to apply that knowledge in real-world flying.
Whether you're a student pilot, experienced GA pilot, IFR operator, or flight instructor, our programs are designed to help you build safer habits, better decision-making, and greater resilience under pressure.
Explore our SRM training programs:
Continue the Conversation
🎙️ Listen to this week's episode of Flight Deck Conversations, where we explore these ideas in more depth and discuss why this question has become central to my own research and professional practice.
💬 I'd love to hear your perspective. Have you ever experienced the startle effect in aviation, or another high-consequence environment?
How did it affect your thinking, and what helped you recover?
📱 Follow @srmpilot on Instagram and LinkedIn for more discussions on human performance, safety and decision-making.
Further Reading
References
Bürki-Cohen, J. (2010). Startle and surprise on the flight deck: Similarities, differences, and prevalence. Federal Aviation Administration.
Dismukes, R. K., Goldsmith, T. E., & Kochan, J. A. (2015). Effects of acute stress on aircrew performance: Literature review and analysis of operational aspects. National Aeronautics and Space Administration.
Endsley, M. R. (1995). Toward a theory of situation awareness in dynamic systems. Human Factors, 37(1), 32–64.
Federal Aviation Administration. (2021). Startle response. FAA Safety Briefing.
Federal Aviation Administration. (2022). Managing the unexpected. FAA Safety Briefing.
Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.
Klein, G. (1998). Sources of power: How people make decisions. MIT Press.
Landman, A., Groen, E. L., van Paassen, M. M., Bronkhorst, A. W., & Mulder, M. (2017). Dealing with unexpected events on the flight deck: A conceptual model of startle and surprise. Human Factors, 59(8), 1161–1172.
LeDoux, J. E. (1996). The emotional brain: The mysterious underpinnings of emotional life. Simon & Schuster.
Reason, J. (1990). Human error. Cambridge University Press.