Anyone who has ever driven on a curvy mountain road hasdeveloped an appreciation for guardrails. We realize that misjudging the maximum speed to enter the next curve or the distraction of an incoming phone call could potentially cause us to hit a guardrail, causing expensive damage to our vehicle, but we would not careen over the cliff. Driving that road places a substantial load on our cognitive abilities but the guardrails are there just
in case our cognitive workload at any time exceeds our cognitive ability.
We do not have physical guardrails when we fly airplanes,but we can erect mental guardrails to catch us before we execute bad decisions resulting from the common error causal factors or cognitive biases.
These mental guardrails have already been constructed. Wejust need to use them. Probably the first to come to mind are the Personal Minimums Checklist (PMC) and the Flight Risk Assessment Tool (FRAT). These
tools, when used properly and as intended, put up guardrails against several common error causal factors such as the “Bias Bundle Bomb” of illusory superiority, confirmation bias, and continuation bias. They also help guard
against the very strong influence of pressure from external factors and the dangers imposed by fatigue, stress, and medications. They even, when properly created, put up guardrails against flying when our recent experience in the given conditions is insufficient.
Though relying on less reliable subject evaluations, the IMSAFE Checklist also serves as a set of guardrails by evaluating our health, any medications we are using, our stress level, recent alcohol use, possible fatigue, and our emotional wellbeing. Another useful, but again subjective tool, is the Risk Matrix. It asks us for an estimation of the severity of a given situation and the likelihood that the situation will arise. The matrix then reveals the level of risk involved. The problem with the tools requiring a subjective decision is that our cognitive biases and external factors can weigh in on our inputs, skewing the results.
The variety of checklists we use also serve as guardrails. Theymust be well constructed and followed explicitly to be effective. Collectively, they can help avoid the hazards associated with distractions, normal lapses in working memory, weak planning skills, normative social influence, and more.
One set of guardrails is critical and applies to everyapproach we fly regardless of the kind of airplane, the flight conditions, or the airport environment. The concept is simple, but the effect on safety is dramatic. A stabilization altitude is established. There are eight conditions to be met for an approach to be considered stabilized. If, at any time, the airplane is below the stabilization altitude and all conditions are not met, the approach
is abandoned.
I once did a presentation titled "Help! My Brain isTrying to Kill Me?” That is of course overly dramatic, but our unconscious mind can sometimes override our training and good sense. Regardless of our certification level or how fat our logbook has become, as humans we are subject to these strong influences. Erecting these mental guardrails can help protect us from our humanness.

Use the following links to learn more about the mental guardrails.

Personal Minimums Checklist and FRAT

IM SAFE Checklist and Risk Assessment Matrix

Checklist Basics

Stabilized Approach