Human Factors: Identifying Errors

By Mike Broderick — February 01, 2013

Identifying Errors in the Workplace
and Getting to Know The Dirty Dozen


Say what? — OK, I know why you’re thinking. Where is this crazy guy taking us today? Well, the short answer is, today we are going to discuss the Concerns of Human Influences (aka Human Factors) on all of us AMTs. And specifically, today we are going to concentrate on the influence of the infamous “Dirty Dozen.” Never heard of ‘em?


Well sit tight, because by the time we are finished, we will all be real familiar with what they are and how they have a negative impact on our performance as aircraft maintenance technicians. But why, you ask, am I venturing out of the technical operation of the mechanical and into the technical operation of the mechanic? Because how the mechanic manages the challenges of the mechanical directly affects not only the lives of those who fly the product of our work but also the lives of those who are flown.

How do human factors affect us at work? Well, it is universally agreed that 80 percent of maintenance errors involve certain factors of human behavior. Post-accident investigations – where maintenance activities were determined to be the cause – have identified the 12 major human factors most directly responsible for maintenance errors. These particular human factors, if not detected and addressed, can cause, at the very least, wasted time and or wasted money, and at the worst, an injury to the AMT or cause an aircraft accident resulting in an injury or possibly death of the pilot, crew and passengers. These 12 negative dynamics of human behavior have been christened “The Dirty Dozen.” We will identify and discuss each one in some detail.

Now the study of human factors has become an industry within our industry and there are several individuals specializing in the education and implementation of systems to mitigate the effects of negative human behavior on aircraft maintenance. One of the best in this field is Richard Komarniski of Grey Owl Aviation Consultants. Trust me, I will not attempt to put myself on his level of expertise. However my intention for today’s class is to insert my perspective as an AMT into the science of human factors.

My research for today’s lesson involved information from the FAA website as well as the anecdotal information I have gleaned from not only from Richard’s presentations and articles, but from several other authorities within the discipline of human factors.
So without further preamble let’s open the discussion on:

The Concerns of Human Influences

In our session today we will:

•    review a definition of human factors
•    define human error and discuss the types and kinds
    of human error
•    identify, define, and discuss the “Dirty Dozen”

What are Human Factors?
The term “human factors” refers to the overall environment of the job, which includes the company’s organizational structure and the individual human characteristics that influence behavior at work in a way that can affect health and safety.

Say what? Don’t you just love psycho-babble? OK, in plain AMT speak, it’s the interaction of three elements: the job, the individual, and the organization, which have been consolidated and packaged under the term “human factors”. Breaking this down to its core, human factors is really the study of the individual’s behavioral response within the maintenance environment, created by a particular job’s responsibilities, combined with the individual’s state of mind while interacting with the objectives of the organization.

By applying this knowledge we are able to design, develop, and implement systems and services into the maintenance working environment, which will result in a safer maintenance product that is provided with greater efficiency. Hmm, that sounded less like AMT-speak and more like psychobabble didn’t it? Well, let’s keep going and see if we can’t put some plain English to this stuff.

Human Error
We have said that certain negative elements, either human behavior or the work environment, can lead us to make errors in the performance of our maintenance duties. So what exactly is an error? Well, according to my trusty dictionary an error is “a mistake; the state or condition of being wrong in conduct or judgment.” So then a human error can be defined as a human action (mistake), resulting in unintended consequences. And errors can be further categorized into types and kinds. The types are unintentional and intentional, and the kinds are active and latent. Let’s talk about the types first.

Types of Errors
Unintentional error: An unintentional error is an unintended wandering or deviation from accuracy. For example, because you are distracted, you don’t notice the expired calibration date on the torque wrench you are going to use. This mistake causes you to under-torque a set of split-line nuts and bolts.

Intentional error: An intentional error is knowingly deviating from safe practices, procedures, standards, or regulations. Let’s use the out-of-calibration torque wrench example again. Only this time you see the sticker, but ignore it for whatever reason, and under-torque the same set of split-line nuts and bolts. The result is the same as the first example, only this time you knew you shouldn’t have used this wrench.

Kinds of Errors
Active error: An active error is the specific individual activity that is an obvious event. In the previous examples above, it is obvious that the split-line bolts were under-torqued, whether it was intentional or unintentional.

Latent Error: A latent error can be less obvious to detect, as latent errors are company issues that can lead up to the event. Once again, using the same examples about the torque wrench, let’s propose the idea that the torque wrench, which was out of calibration, should not have been available for use and thus could be a company issue. Perhaps company policy may not be clear as to who is ultimately responsible for monitoring the tool calibration dates; therefore removing this torque wrench from the active group of precision measuring tools was overlooked, resulting in the tool’s availability for use. Make sense?

The Dirty Dozen
Having looked at types and kinds of errors, we now have the basic concept behind the dirty dozen. These are considered to be the 12 specific human factors which have been determined to degrade an AMT’s ability to perform effectively and safely. So let’s go over them, define each one, and then discuss ways to eliminate them from our daily maintenance activities.

1)    Lack of Communication: We must communicate with one another and explain what work has and has not been completed when passing the job on.

a)    Never assume the work has been completed.
b)    Ensure that you are discussing exactly what has been completed and what needs to be completed in order for the next AMT to work on the job.
c)    Complete all worksheets so the next AMT knows for sure what has been done.

2)    Complacency: We all have a tendency to become overconfident when we do the same job repeatedly:
“I know this system like the back of my hand; I don’t need no stink’n manual.”

a)    Always use the worksheets and the current edition of the maintenance manual when working.
b)    Always expect to find something wrong.
c)    Always double-check your work and have another AMT follow behind you
d)    Never sign off on something you did not fully check.

3)    Lack of Knowledge: The technology in our industry is constantly changing. We must remain current on new products and what new maintenance procedures are required.

a)    If you do not know how to fix something, ask for assistance from someone who does.
b)    Ensure that all your work documents and maintenance manuals are up to date.
c)    Do not let your ego exceed your ability.

4)    Distraction: A distraction is anything that takes your mind off the task at hand. Distractions can cause us to think we are further ahead in the process than we are.

a)    Keep off your cell phone when working. This means no talking, texting, tweeting, or liking your friends on Facebook. Cell phones should be kept from use while you are working. Make your calls on your break. Personal emergencies should come through the company system to your manager to you. Cell phone usage at work is my favorite thing to hate.
b)    Use a detailed checklist.
c)    If you leave a job or take over a job, review all the previous steps to ensure nothing has been overlooked to this point.

5)    Lack of Teamwork: Personality differences in the work place need to be left in the parking lot. It is imperative that you learn to play well with others while on the job. Lack of teamwork can and does affect the safety of maintenance.

a)    Ensure that lines of communication are open and free-flowing between members of your maintenance team.
b)    Be sure to discuss specific duties when jobs require more than one person. Make sure each person knows what their assigned task is. Encourage questions before the job starts.
c)    Watch your buddy’s back with respect to safety while you are working together.

6)    Fatigue: Sometimes our job calls for long hours and late nights. Fatigue can cause a decrease in your attention span and a decreased level of consciousness. Working while you are exhausted can be dangerous. Pretty obvious I know, but we have all been guilty of this at one time or another.

a)    Don’t do complex tasks if you know you are exhausted. It is far better to explain the cause of a late departure than to explain the cause of a final departure.
b)    Know your limits and those of your team. Don’t push the fatigue envelope.
c)    Keep yourself in good physical shape, exercise, eat right, and get plenty of sleep. This will help when the occasional late night comes along.

7)    Lack of Resources: Do not improvise when it comes to using the correct tool or part for the job.

a)    Maintain a sufficient supply of parts and anticipate the need for standard replacement parts.
b)    Do not substitute a part with one that is “close enough and should work.”
c)    Ensure that all the special tooling required for the job is in proper working order. If you break it, make sure you let management know so they can replace the tool or get the broken one fixed.

8)    Pressure: There is always a schedule to be met. As AMTs, you cannot let the pressure of time constraints get in the way of finishing the job safely.

a)    Make sure that the pressure applied is not caused by lack of planning or execution on your part.
b)    Ask for extra manpower if it will help get the job done.
c)    When asked how long a certain task will take, be truthful. Don’t over-promise and under-deliver.

9)    Lack of Assertiveness: Don’t be afraid to speak up if you see something wrong, either with a piece of equipment or with the way somebody is doing a job. If it doesn’t seem right, say something.

a)    Provide a clear explanation when you see something that is unsafe or incorrect.
b)    Never compromise your standards.
c)    Allow for others’ opinions of your work or actions. Accept constructive criticism; however, refer to “b” above, should you be asked to compromise your standards.

10) Stress: Can be self-induced or caused by an outside source. Stress is a subconscious distraction that can cause you to lose your place in the flow of the maintenance task.

a)    Take a short break, or if required, take time off if the stress is caused by a personal issue. Family problems, financial issues, or relationship problems all can cause stress and all need to be dealt with – only not while you are working on an aircraft. Try not to bring these difficulties to the job.
b)    Tell your manager or a team member that you might be under some stress and to watch your work.
c)    Keep yourself healthy and well rested, this will help mitigate stress.

11) Lack of Awareness: Lack of awareness and #2 (Complacency) go hand-in-hand here. Sometimes being so proficient at a certain task causes us to take no notice of a recently issued change notice issued or bulletin.

a)    Always refer to the maintenance manual and the latest publications, letters, and bulletins released by the manufacturer or AD notices.
b)    Always ask for other team members to check your work, including your paperwork.
c)    Don’t assume you are doing the job right – double check.

12) Norms: This is short for normal: the way things are normally done. These are the unwritten rules that are followed or tolerated by a good number of organizations even though these procedures are possibly unsafe. Because nothing has happened to change the norms they stay in place. Unfortunately, in a most cases, negative type norms are changed by accident, and not before.

a)    The correct way of doing something may not be the easiest way or the “normal” way. Make sure you are doing it the correct way.
b)    Challenge the norms and make sure that everyone follows the same and correct standard.
c)    Don’t accept “this is the way we have always done it….” if that way is unsafe.

So there it is: a short discussion of how we are influenced by our personal and professional environments, and how these influences can impact the way we perform our duties. We have a huge responsibility to ensure that every pilot who asks us if this aircraft is OK to fly, that when we say: “You bet; enjoy your flight. See you when you get back,” they are able to concentrate on their job, knowing we did ours right.

See you next time; now go enjoy a tall cool adult beverage on me, after you have finished for the day, of course.

About The Author

Mike Broderick

Mike Broderick is V.P. of Business Development at Helicopter Engine Repair Overhaul Services (HEROS). Over the past 35 years, he has served as a shop technician, engine shop supervisor, Engine Program Director, Director of Maintenance, Director of Operations, and owner of a Rolls-Royce engine overhaul and MD Helicopter component overhaul shop. He is a certified A&P, and holds a Bachelor of Science degree in Aviation Administration. As well, Mike has been appointed as an FAA representative for the FAA Safety Team (FAAST) and is a member of the HAI Tech Committee. Mike is a regular contributor to Air Maintenance Update.

View all articles by Mike Broderick.