Pilot Error: Getting to Know the ‘Dirty Dozen’ (Part 1)

Simon Newbold highlights the problem of human error in the aviation world, referencing the well-known ‘Dirty Dozen’ causal factors. What are these, and why are they important. We'll explore across this three-part article.

Guest Posts  |  Simon Newbold  |  27th February 2019
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Simon Newbold
Simon Newbold

Simon Newbold, an airfield operations consultant, began his career at then BAA Heathrow in September...

Pilot Error Crashed Airplane

Simon Newbold highlights the problem of human error in the aviation world, referencing the well-known ‘Dirty Dozen’ causal factors.
Picture the scene: It is early evening on a glorious summer’s day; the sun is still shining, and the sky is a deep blue without a single cloud in the sky. Heathrow Airport is a complete buzz of activity with aeroplanes everywhere as 1000s of travellers are moved in and out of the bustling hub.
I am on duty. My job is as an Airfield Operations officer is to patrol the vast wild expanse of the miles of concrete in my shiny yellow vehicle ensuring the safety of the Aerodrome.
I have a smile on my face as I love my job working at the real front line, diving on and off the capacity constrained runways carrying out vital surface checks, keeping that constant eye out for an opportunity to move birds away from danger and armed with my marshalling bats, ready to ensure the safe arrival of that aeroplane at the terminal building.
The shades are on, the arm gently resting – elbow pointing outwards of the window. The tan is coming along nicely as I cruise the manor, eyes scanning all around and the ear glued to the radio waiting to respond or react to anything that I can do to ensure all is well.
Suddenly I hear that call. What’s that? A plane needs help... a plane cannot park using the guidance system. I hear the message from the mighty control tower “Any Leader vehicles available?” I grab the microphone. “Heathrow Ground Leader 7, I’m on my way.”
I arrive at the aircraft parking stand to find a 747 with its mighty engines turning and burning, the heat haze causing a mirage of sea behind but sat patiently waiting in a stationary position. All around the docking spot is an army of vehicles filled with ready and eager workers.
I glance at the window of the terminal where there is a team of airline staff standing, twitching in anticipation. The dispatcher is perched in the mouth of the airbridge – the audience is set, this is now my stage.
I hastily drive onto the stand, a swift handbrake turn, the door swings open and out I step ready for the performance of my life. Help! Help! I hear the cry. I drop half of my sunglasses to one side and with I wink and a smile, I shout: “Do not worry, I am here…”
The shades get repositioned, ear protection is on and with my trusty bats the arms start to swing and flow and swing and flow like they’ve never swung before. Up and down, up and down, the rhythm is poetry. A little bit left, a little bit right and the mighty beast creeps onwards towards me following every single flick of my wrist.
I can hear the applause, I can hear the cheers, I feel 1,000 eyes following my every move just in complete awe of my show. I’m a hero!
My arms continue to wave almost sucking, beckoning the 400 tonnes of aircraft. It’s vital the wings do not hit anything, it’s crucial the plane is stopped in the correct position. 
The safety of the 500 people on board and the airlines pride is all down to me and my fingers. On we go, I’m not tired, I’m in my element, up and down, up and down on we go.
It’s all happening like a dream, not far to go now, come on, come on, left a little more, straight on, straight on, now right a touch, come on, up and down, up and down, that’s it – just right, up and down, up and down then all of sudden the cheers turn silent, as all of a sudden the show goes horribly wrong.
The show turns to a disaster. I hear a huge gasp all around as the performance of a lifetime becomes a disaster. As I stepped backwards beckoning the plane onto to its final position, I hadn’t seen the chocks. Those chocks that shouldn’t have been there. Those chocks that were in the wrong place. Those chocks that If I had only glanced behind me rather than showing off, those chocks, those silly bits of rubber, what happened?
As I swung, as I smiled, as I winked, as I walked backwards, suddenly bats and shades fly in all directions, legs in air, backside on ground as I collapse into a heap on the floor. Looking out of the corner of the bruised eye, what do I see? Palms clasped tightly over eyes, groans all around and I’m not sure but way up high in the cockpit – I’m sure I can see laughter.
Hastily I gather the bats, not the shades they are smashed to pieces. No longer is the full swing of the arms in motion. It’s a quick wave, a cross of the bats – job done and let’s get out of here. I limp back to the sanctuary of my yellow vehicle number 7 and disappear as quickly and as quietly as I could.
Awareness of Human Factors in Aviation

An understanding of human factors in aviation is crucial to the safe and efficient contribution of a human in the work place. There have been many studies, scientific theories, books and training material about the subject that are either directly scribed for aviation or as a general topic.
When writing these words, I thought that I would try to keep it very high level, light and simple. I could just leave this with the opening story as it is self-explanatory, but I’ll write on. The piece is not designed to try and educate, but just perhaps to stimulate some thought.
By thinking, maybe a situation that may have occurred due a failure can be averted. This perhaps is because of improved awareness, or maybe something as simple as a trigger that reflects to these words.
What are Human Factors in Safety?

To start with the high level, the subject of human factors is quite simply the study of behaviours and actions that make it easier to understand the ability to undertake a task. It applies everywhere where humans work or play. It has also been described as the study of all the factors that make it easier and safer to do the work in the right way.
Over the years some studies have also looked at the design and process implementation as a root cause that then has either led to a human behaviour, influenced it, or has directly created the end situation. In the perfect world the design and the human interaction along with interpretation should be in a place where everything is done in the right way and decreases the likelihood of an error occurring.
There is always opportunity to introduce design improvements in the work place and the equipment should be matched to fit all human capabilities. 
The study of this subject always has acknowledged the underlying fact of the universal nature of human fallibility and that errors will occur. The study of human factors is based on how we think and what actions we take.
These thoughts of course stem from that mass in our heads called the brain. How the brain is working, and processing is the sole reason for our actions. The brain is of course extremely powerful, it is very flexible, and it is particularly excellent at finding shortcuts quickly. 
It is very good at filtering all that information being fed into it and then great at making sense of things. Sometimes, however, our brain is just too clever for us, and mistakes will occur.
The Trickery of the Brain

Our brain unfortunately has a down side and often when errors occur it will be the brain’s fault, rather than being down to a design fault. Sometimes what you see is not obvious or maybe is totally different to what someone else sees. Sometimes the brain will play a trick on you to alter or change what you see. This can be a direct reason for an error, a mis-judgement, however severe the consequence is.
Introducing the Dirty Dozen

It must be assumed and recognised that mistakes will always happen and sometimes they are basic. Unfortunately, they will OFTEN also have severe outcomes.
We have already touched on the brain and it is therefore understood that very intelligent people who are very experienced, and fully motivated and being very careful, will still make a mistake. How many aircraft incidents have been attributed to pilot error? Why would a pilot make a mistake?
What is an error or a mistake? There are several ideas or the dictionary definition, but I prefer to think along the lines of the failure of a planned action to achieve its intended outcome. Or a deviation between what was done and what should have been done, doing the wrong thing when meaning to do the right thing.
Although I promised to avoid some of the scientific references one previous study that is high level enough and I believe is very valid is Gordon Dupont’s Dirty Dozen. 
Following several incidents in Canadian aviation, he published a list of 12 causal factors in 1993, which has come to be known as Dupont’s Dirty Dozen, outlined as follows:

  1. Lack of Communication
  2. Distraction
  3. Lack of Resources
  4. Stress
  5. Complacency
  6. Lack of Teamwork
  7. Pressure
  8. Lack of Awareness
  9. Lack of Knowledge
  10. Fatigue
  11. Laco of Assertiveness
  12. Norms
It is not a comprehensive list of human error accident precursors, for example, ICAO Circular 240-AN/144 lists over 300 human error precursors. However, since 1993 all areas of the aviation industry have found the Dirty Dozen a useful introduction to open discussions into human error in their businesses, organisations and workplaces.
While the list has increased awareness of how humans can contribute towards accidents and incidents, the aim of the concept was to focus attention and resources towards reducing and capturing human error. Therefore, over the next few months, we will offer examples of typical countermeasures designed to reduce the possibility of any pilot error, based on the Dirty Dozen. I’m sure you will find many recognisable elements.

Read the rest of Simon Newbold's excellent Pilot Error series here:

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Simon Newbold

Simon Newbold

Guest Post

Simon Newbold, an airfield operations consultant, began his career at then BAA Heathrow in September 1990.  He worked in a variety of front line operational and managerial roles before spending four years as an Airfield Planning Manager, before returning to the front-line operation as a supervisor. Simon’s passion and knowledge for all things in the operation and the airports’ history has seen him train over 100 staff. After 27 and a half years Simon left Heathrow in February 2018 to take on a new challenge working for the high-profile Airport Management Consultancy firm APMC.



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