A large number of maintenance-related aviation accidents and incidents occurred in the late 1980s and early 1990s. Then, Transport of Canada identified twelve human factors that degrade a person’s ability to perform tasks effectively and safely, which could lead to errors during aircraft maintenance.
These twelve factors are known as the “dirty dozen“. It was eventually adopted by the aviation industry as a simple means to discuss human error in maintenance. It is important to know the dirty dozen, how to recognize their symptoms, and most importantly how to avoid or learn from the errors caused by the dirty dozen. There are 12 common causes of human factor errors. Let’s understand one by one:
- Lack of Communication
- Lack of Knowledge
- Lack of Teamwork
- Lack of Resources
- Lack of Assertiveness
- Lack of Awareness
The above are all factors that can affect an individual’s performance. Lets study each of these in more details.
Lack of Communication:
It is important to be aware that in general only 30% of verbal communication is received and understood by either side in a conversation. People normally remember what was said first and last in an exchange; consequently it is important to put the most important part of your message first and then repeat it at the end. Depending on the complexity of the message it might be more effective to provide some form of written instruction such as a checklist.
Defined as: “Self-satisfaction accompanied by a loss of awareness of the danger.” If an activity has become routine and your feeling “fat dumb and happy”, you may be missing important signals. There is a tendency to see what you expect to see.
Lack of Knowledge:
Air operators have a regulatory responsibility to ensure that their personnel have the required training.
This is anything that draws your attention away from the task at hand. Psychologists say distraction is the number one cause of forgetting things. We are always thinking ahead. Thus, we have a natural tendency, when we are distracted before returning to a job, to think we are further ahead than we actually are.
Lack of Teamwork:
An effective team will:
- Maintain a clear mission
- Maintain team expectations
- Communicate to all team members
- Maintain trust
- Pitch in
Studies have shown that, similar to being under the influence of alcohol, we tend to underestimate the problem and overestimate our ability to cope with it. These studies have proven that after 17 hours of wakefulness, you are functioning as if you had an equivalent blood alcohol level of 0.05%. After 24 hours the level increases to 0.1%; a very sobering thought. The more fatigued you are, the lower your IQ. It is also noteworthy that the more fatigued you are, the more easily you are distracted.
Lack of Resources:
A lack of resources can interfere with one’s ability to complete a task because there is a lack of supply and support. Low quality products also affect one’s ability to complete a task.
Urgent demands, which influence our performance, include:
Interestingly, people put the most pressure on themselves. Self-induced pressures are those occasions where one takes ownership of a situation, which was not of their doing. The “monkey on your back” is yours because you accepted it. Being assertive and not accepting the “monkey” will help.
Lack of Assertiveness:
Assertiveness is the ability to express your feelings, opinions, beliefs and needs in a positive, productive manner. It is not the same as being aggressive.
The following are examples of how a lack of assertiveness can be offset:
- Get the persons attention and state the problem:
John, I have a concern with…
- Give consequences:
If we continue… this will be the result…
- Give solutions:
We could… you may want to try… I’d like to…
- Solicit feedback:
What do you think?
Remember to deal with one issue at a time (not multiples), do not embellish or exaggerate, stick to the facts, and stay calm.
There are two types of stress: acute and chronic. Acute stress relates to the demands placed on the body because of current issues; for example, time constraints for converting the aircraft from passenger to cargo configuration. Chronic stress results from long term demands placed on the body by both negative and positive major life events, such as divorce, or winning the lottery. Chronic stress can exaggerate the effects of acute stress. To handle acute stress, try to take a five-minute break and relax by deep breathing. Dealing with chronic stress is more difficult and usually involves a lifestyle change.
Lack of Awareness:
Defined as, “a failure to recognize all the consequences of an action, or lack of foresight”. To combat this, try asking yourself, “What if…, Do I see the complete picture? What have we forgotten?”.
Norms are unwritten rules or behaviours, dictated and followed by the majority of a group. Norms can be positive and negative. A positive norm would be scanning the area inside the aircraft you have been working on prior to closing up. A negative norm would be pushing an aircraft into the hangar by yourself.