Who Stole Our Cheese? A “Reason–able” Explanation for Eroding Safety Margins

Many years ago, the human error demigod James Reason introduced the world to his iconic Swiss Cheese model of safety. In it, he described how we are all protected by several layers of Swiss Cheese, from the highest regulatory requirements all the way down through OEM and organizational procedures, automation, and various other training and protective systems.

Along the way he postulated that no part of the system was perfect, and each layer had holes – or gaps – in the protection and when they lined up, the protection was gone. A single threat could cause a mishap. Recent events lead me to believe these holes are getting bigger and our safety margins are eroding right in front of our eyes. Here are just a few examples from the last year.

·???????A potentially catastrophic runway incursion at JFK where the FO was implementing new pre-takeoff procedures for the first time

·???????A major cargo airline crew landing on the wrong runway in Tulsa

·???????An ATR first officer inadvertently feathers the props instead of lowering the flaps on final approach in Nepal, resulting in 72 fatalities

·???????A software breakdown at a major airline that stranded thousands of holiday passengers and flight crews

·???????Total failure of the nationwide NOTAM system due to a software installation violation

·???????A near miss in Austin between a FedEx and SWA airliner

·???????An airline ground worker killed by getting sucked into a running jet engine

·???????A pipeline patrol helicopter encountering a 500-foot tower that was not on the VFR charts, then discovering several others. When he reported it to his FSDO, was told “I’ll send it to DC, but I’m not sure what they will do with it or when.”

·???????A major airline crew descending to less than 800 feet over the ocean with hundreds of passengers on board

·???????A major airline proposing a drastic reduction in flight hour requirements due to the pilot shortage

·???????Multiple reports of short-staffed maintenance facilities resulting in mandatory overtime and extended shifts

I could go on, but you catch my drift.

These things happen in aviation, but the frequency and severity of these events are exceedingly troubling. It is becoming clearer every day that we may have more holes than cheese. So, what is going on, and more importantly, what can we do about it?

What is going on?

Experience and turnover in all areas – Air Traffic Control, air crew, and maintenance – are all placing strain on those who remain. Secondary effects include rapid advancement to the Captain’s seat, younger, less experienced first line supervisors in maintenance facilities, and a turnover of personnel unlike anything we have ever seen before. All of this compounded by the general mental health decline we are all experiencing due to post-COVID, economic, political, and societal factors. Inexperience + distraction = trouble.

Aging systems are failing faster under the strain. Aviation is not the only part of our transportation system experiencing this. Railroad derailments and other indicators make it clear that we are operating with outdated systems we rely on for our safety.

What can we do?

While there are many threats that must be dealt with by senior executives, there are a few things we ought to be doing every day.

·???????Assume less. Maintain a healthy skepticism of things you normally accept at face value. For example, on final approach expect that aircraft cleared for takeoff in front of you be delayed or experience trouble. Mentally prepare for the go-around.

·???????Verify more. Did your automation input actually take in the system? Did you hear the radio or intercom instructions clearly? Expect things to be wrong until you prove to yourself they are right.

·???????Communicate more. Ask questions, check for comprehension with directives, double check the paperwork.

·???????Show up a few minutes early to think through and brief contingencies. Mental preparation for the routine should become SOP in the today’s world. Things that have never happened before are happing every day.

These are strange times. We need to get ready and stay ready.