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The Startle Response


‘We’re going to crash! This can’t be true! But what’s happening?’ were the last words from pilot David Robert on board Air France flight 447 as it crashed into the Atlantic ocean, in June 2009 killing all 228 on board.

During some recent flight training, I was reminded of the parallels between aviation training and self-defense training:  In December of 2016, I attended a three day Upset Recovery Training (URT) course by Prevailance Aerospace Safety Academy, located in Chesapeake, VA.  URT is designed to teach pilots how to prevent and recover from loss of control in flight, which is the single biggest killer in commercial aviation today.

The first day of training consisted of a comprehensive analysis of aviation accident information, flight physiology and specific upset recovery techniques. Upon reviewing various high-profile accident cases, it became clear that all the pilots involved shared the same common denominator; a physiological reaction known as the startle response. The startle response (also known as limbic hijack) is the physical and mental response to a sudden unexpected stimulus. More commonly known as ‘fight or flight’, this physiological reaction occurs in response to what you may perceive as a harmful event, attack, threat to your survival or simply fear. The fight or flight response enables us to react with appropriate actions: to run away, to fight, or sometimes freeze to be a less visible target.  The body responds with increased activity such as:

  • Circulation increasing blood supply to brain, muscles and to limbs (more O2). Brain activity changes: we think less and react more instinctively.
  • Heart beats quicker and harder—coronary arteries dilate.
  • Blood pressure rises.
  • Lungs take in more oxygen and release more CO2.
  • Liver releases extra sugar for energy.
  • Muscles tense for action.
  • Sweating increases to speed heat loss.
  • Adrenal glands release adrenalin to fuel response.

In aviation, startle often occurs when the autopilot disengages and hands control to the pilot in a highly dynamic, time-critical condition. According to Human Factors SA psychologist Jo-Anne Hamilton, two systems in the brain—the reflexive fast system and the slow system—play different roles in our reaction to danger.

The reflexive fast system acts immediately—in one twelfth of a second—by sending information directly to the sense organs through the thalamus to the amygdala. The slow system sends sensory information to the hippocampus and cortex for further evaluation. It’s slower because it requires conscious processing.

Hamilton says that pilots in these non-routine, emergency and abnormal situations will have difficulties in recognizing that a problem has occurred and difficulties in getting out of the normal mode of operations.

‘It may be a series of startle responses or more like one “big one” where the brain is kind of hijacked,’ Hamilton says. ‘Then we make a decision and once we make the next decision and our frontal cortex shuts down so our thinking capacity is not working so well—that leads us to the next decision etc. and we go down into a tunnel.

"And it’s extremely difficult once someone is in that tunnel—and you can see from the Air France example—to stop, step back and say, “wait, we are doing something really dumb here".

We’ve evolved to confirm our decisions not to disconfirm them—it’s our natural human inclination. 

What does this have to do with self-defense training? The startle response is a powerful mental force that is a critical component to self-defense training. An unexpected assault often results in disorientation compounded by the psychological challenges of startle and surprise. Additionally, the techniques necessary to defend yourself from a determined attacker can be counter-intuitive, requiring unique skill, awareness and discipline.

Lt. Col. Dave Grossman said it best, “You do not rise to the occasion in combat, you sink to the level of your training.”

So whether you are attacked in the street or lose control of your airplane, you get one chance to get it right.  The good news is your startle response can be lessened by developing correct muscle memory thru recurrent and specific training.  This is accomplished by focusing on the skills and techniques necessary to survive real-world, worst-case scenarios.



  • Prevailance Aerospace Safety Academy,
  • Martin, W., Murray, P. and Bates, P. (2012). The Effects of Startle on Pilots During Critical Events: A Case Study Analysis.
  • Flight Safety (2015). Without warning: the startle factor