The Biology of an Aircraft Upset Event and Loss of Control

As pilots, our exposure to biology is generally limited to human factors subjects like hypoxia, fatigue, and spatial disorientation. That is because these factors are more common to our routine flight operations. One of the problems with unexpected airplane upsets is that although they are very rare, the result is often catastrophic. That is why Loss of Control In-flight (LOC-I) from airplane upsets is the greatest cause of commercial and general aviation fatalities in the world.

It is easy to see how the physical forces involved in an airplane upset could escalate to a loss of control when the balance between them is lost. In fact, a good understanding of the underlying aerodynamic principles involved is a great way to increase pilot awareness that could help to avoid an upset and prevent a LOC-I in the first place. While less familiar to most pilots, the escalation of events at a neurophysiological level is equally enlightening with regards to how an upset event can lead to an LOC-I.

We can start by imagining that the brain operates on two separate and independent circuits, because essentially it does. We will call these two circuits the high road and the low road.

The high road involves cognitive thought that is centered in the prefrontal cortex, one of the more distinguishing anatomical features of the human species which allows us to be the only animals smart enough to fly airplanes, though birds have us beat when no equipment is allowed. While this area of the brain is good at higher order, “executive” function, it is also easily derailed. To quote a skydiving instructor: “I don’t care how smart you are on the ground, everyone turns stupid the first time they fall out of an airplane”; and so it often goes for the unwilling participant in an unexpected upset encounter.

This is when the low road circuitry kicks into gear. The driver for the low road is a region of the brain called the amygdala. The amygdala is sort of the gate-keeper for the fear response, and it is spring-loaded to the react position. If the amygdala senses something unfamiliar, it generally counts it as a threat and will respond first and ask questions later. Actually, it is the prefrontal cortex that asks the questions, the amygdala is a bit simplistic for that.

This relationship between the high and low road circuits of the brain works well in confronting many life-threatening situations. This innate fear response increases respiration, heart rate, and the release of stress hormones. Unfortunately, the same neurophysiological response that might prevent or repel an attack by a tiger can be unhelpful in confronting an airplane upset. In fact it could result in a hijacking. Not the kind where you squawk 7500, but an “amygdala hijack”.

The term “amygdala hijack”, coined by author Daniel Goleman in his 1996 book Emotional Intelligence, was used primarily to describe an inappropriate response to an emotional situation, but it can apply in physically threatening situations as well. As he put it, “…the architecture of the brain gives the amygdala a privileged position as the emotional sentinel, able to hijack the brain.” The amygdala receives sensory inputs before they ever get to the prefrontal cortex, it “cuts ‘em off at the pass” and provides reactions before the smarter parts of the brain even have a chance to evaluate the data.

This can lead pilots to exhibit unreliable and unpredictable behavior when confronted with an unexpected airplane upset event. The way to prevent this is through training. The mental modeling provided by Upset Prevention and Recovery Training (UPRT) establishes neural pathways and behavioral responses appropriate to upset situations. Instead of being overwhelmed by unfamiliar and threatening forces, instrument and warning annunciations, and visual scenes  the pilot calls upon structured responses learned through practice with APS. We look forward to flying with you.