Page 8 - TN811 issue 2

The Swiss Cheese Model
Being new to the utility industry and damage prevention, there is one word I hear more than any other, no matter where I am, who I am talking to, or what we are talking about: “Safety”.
In my prior career in law enforcement, I had the opportunity to work in
an Air Operations Unit as a “flight officer”. Obtaining the position just
a few months after the terror attacks
of September 11, 2001, my job was to assist an officer/pilot in a small, single- engine fixed-wing Cessna 206 airplane. Prior to 9/11, the position involved assisting with navigation to various calls for service, working multiple radio systems, enforcing traffic violations and performing suspect and missing person searches. The mission had immediately changed to patrolling the state’s
power utility grid and sub-stations for suspicious activity, bridge and highway structure checks and flying over miles of open aqueducts, dams, and other public water sources.
At the time, I was not and had never been a pilot. I knew nothing about aircraft or aviation. One of the most interesting parts of my training revolved around preventing aviation accidents and disasters and issues surrounding “human error”.
In 1998, Galaxy Scientific Corporation Advanced Information Technology Division out of Atlanta, Georgia, prepared a paper for the Federal Aviation Commission titled, “Human Factors Guide for Aviation Maintenance” and under a chapter discussing “Human Error”, stated the following:
“Another basic principle of error management is that the best people can sometimes make the worst mistakes. Being trained for the job, being skilled and experienced reduces the absolute rate of errors, but it does not eliminate
them entirely... Errors are consequences rather than causes. They are the product of many interacting factors: personal, task-related, situational and systemic.”
“The Swiss Cheese Model of Accident Causation” is a risk analysis and risk management model used in multiple industries, including aviation. It relates that accidents don’t occur because of a single cause, but a chain of errors with some readily apparent causes and some not so easily identifiable. The model considers a host of factors that could include company culture, industry practices, support services, rules, regulations, physical health, personal life, etc. The premise is that if each defense protecting you from a disaster were stacked on top of each other like pieces of Swiss Cheese, while each layer has imperfections (holes) the support of the structure should lower the risk of severity of each threat.
Why do I remember The Swiss Cheese Model after all these years?
I had been flying with a particular pilot for several months (let’s call him Bryce). Bryce and I primarily worked during daylight hours, and we worked very well together.
Bryce was a Marine, a very experienced pilot, and a stickler for policy and procedure (he fell into that “best
people” category of the “Human Factors Guide”). Before every flight, he would meticulously go over every inch of the aircraft looking for defects or damage. He would check the weather conditions of our flight plan and research any regional flight restrictions or notices. He would check in with our airport control tower. He religiously followed his own pre-flight safety checklist as a pilot and then sat with me in the cockpit going over another written checklist of items using a verbal “challenge and response” system for pre-flight settings in the
aircraft before every take-off. I never felt safer cooped up in that tiny aircraft than when I was flying with Bryce.
A few months into flying with each other we had been moved from flying exclusively during daylight hours to flying at night. Switching to night flying had a whole host of new challenges and we anticipated some adjustment. As we prepped for our first night flight, Bryce checked the tower recording
for airport issues (being based out of
a small airport, the control tower was not staffed at night). We headed to our aircraft and went through our routine and checklists as usual and fired up the aircraft for take-off with nothing out of the ordinary. While pointing towards one of the two runways, Bryce activated the runway lighting remotely through a radio frequency. We both watched and acknowledged the runway lights come on, an indication the runways were active for use. Bryce rotated the aircraft towards the secondary runway that was located off to our left and taxied the plane for take-off. What we had missed, due to our pre-flight position, was the lights for THIS particular runway had not turned on.
As Bryce increased the aircraft speed on the runway for take-off, he noticed something on the ground just a few hundred feet in front of us... a blacked- out and disabled aircraft directly in our path! Having built up enough speed, and with a Herculean pull on the yoke, he was able to get our aircraft up in time to gain flight, fly over the downed plane, and narrowly avoid a collision.
When an analysis was done of our incident the chain of errors and “holes” in the system came out. The disabled and abandoned aircraft had attempted to land earlier in the evening and had a landing gear failure, leaving it stranded and blocking the runway. For reasons I do not recall, the owner of the plane did
CONTINUED ON PAGE 9
6 • Tennessee811 2023, Issue 2
Marcus Bartholomew
TN811 Damage Prevention Liaison