A Dozen Dirty Habits in Aircraft Maintenance: Part-1

Overview:

In this article, we will examine "A Dozen Dirty Habits in Aircraft Maintenance", a model within the scope of Human Factors in Maintenance (HFIM). It is a model created entirely within the aircraft maintenance culture, but I think it will be valid and useful for many sectors and especially for industrial sectors.

How was the Dirty Dozen of Human Factors Designed?

The Dirty Dozen refers to twelve of the most common human error preconditions, or conditions that can act as precursors to accidents or incidents. These twelve factors lead people to make mistakes. The Dirty Dozen in Aircraft Maintenance is a concept developed by Gordon Dupont, the first president of the Pacific Aircraft Maintenance Engineers Association, in 1993 and forms part of a core training program for Human Performance in Aircraft Maintenance. Since then, it has become the cornerstone of Human Factors in Aircraft Maintenance (HFIM) training worldwide.

The Dirty Dozen is not an exhaustive list of human error accident precursors; ICAO lists more than 300 human error precursors. The Dirty Dozen is a cross-cutting set of these 300 human errors. 

In addition to ICAO, the Canadian Armed Forces also kept records of all maintenance error accidents and provided a special committee with a databank filled with thousands of maintenance error records.

After reviewing each record, any accident that could be classified as "careless" was removed from the group and put into its own pile. The careless pile was then analyzed many times until these 12 prerequisites for human error, the twelve most common factors, emerged and became known today as the "Dirty Dozen".

Since 1993, all areas of the aviation industry, not only aircraft maintenance, have found the Dirty Dozen a useful introduction to open discussions on human error in their work, organization and workplace. So pilots, flight line workers, air traffic controllers and cabin crew have also found habits in the Dirty Dozen that they themselves have.

- HFIM deals with people networking and interacting in ever-changing ways. The SHELL Model and the Dirty Dozen explain this very well.

- Human factors affect safety, quality, cost, performance.

- A dozen dirty human factors need to be well examined and evaluated in the context of HFIM.

HFIM; safety, quality, cost, performance, etc. are important in all aircraft maintenance processes, but in large complex aircraft maintenance processes the network of interactions grows in non-linear ways. This non-linearity is evident in the following areas;

- Human factors related to Aircraft Maintenance management systems.

- The work process in use and the tasks performed with them.

- The equipment in use and the aircraft systems that operate them.

- A wide range of environmental factors.

HFIM is influenced by each of the above, but it also influences each of them, shaping them further.

This will show that in large complex projects the group of human factors to be considered is much broader, takes on increasing importance and requires even more attention due to project size and complexity.

Twelve Human Factors in Aircraft Maintenance or the "Dirty Dozen"

Aircraft Maintenance Management is about many things. At its core, it is about mobilizing resources to achieve output or results. Mobilized resources usually consist of labor, materials and equipment. As we tried to explain in our SHELL Model in Aircraft Maintenance article; People interact in a complex network of hardware, software, work environment, people as individuals and people as a group, and they interact with those in this network in ever-changing ways.

Gordon Dupont identified twelve factors that contribute to errors in judgment and ultimately performance errors in aircraft maintenance activities and called them the dozen dirty factors in aircraft maintenance. We can list these human factors as follows, the first six habits will be described in Sect: 1, and the remaining six habits in Part: 2:

1. Lack of communication 

2. Laxity caused by complacency, complacency

3. Lack of information

4. Distraction, distraction

5. Lack of Teamwork

6. Physical and mental fatigue, burnout

7. Inadequate or lack of resources

8. Pressure on the employee

9. Lack of self-confidence

10. Stress

11. Lack of awareness

12. Norms

1. Lack of communication

Poor communication is often one of the leading contributing and causative factors in accident reports and is therefore one of the most critical human factor elements. Communication refers to the transmitter and receiver as well as the method of transmission. The instructions transmitted may be unclear or inaccessible. The receiver may make assumptions about the meaning of these instructions and the transmitter may assume that the message has been received and understood. In verbal communication, it is common that only 30% of a message is received and understood.

Detailed information must be communicated before, during and after any task and especially at shift transitions. Therefore, messages should be written down when they are complex and organizations should use logbooks, worksheets and checklists etc. Assumptions and opportunities to ask questions, both given and received, should be avoided.

In the incident depicted in the First Picture below, the body technician says "I think the day shift can finish screwing the panel". Lack of communication is depicted as leaving an airplane panel unfinished without informing the next technician in any written or verbal form, assuming that the next technician knows which part of the airplane is unfinished. To eliminate doubt, it is necessary to use maintenance information systems and fault logbooks to communicate. At shift changes, the person taking over the shift is briefed on the work to be done and the work that has been completed. It should never be assumed that something has been done, it should always be checked, because "Trust does not preclude checking".

Communication is not only the exchange of data but also the exchange of information. Communication requires information to be communicated and must be free from bias. One of the biggest challenges to communication is the perception that communication already exists. Knowledge transfer must avoid creating questions that act in a way that limits its objective use, often by eliminating or discouraging critical information and reflection. "This result looks good, don't you agree?" is an example of a framing question.

2. Laxity caused by complacency, complacency 

Self-indulgence can be defined as a feeling of self-satisfaction with a loss of awareness of potential dangers. Such a feeling usually arises when carrying out routine activities that can be "thought of" by an individual (sometimes the whole organization) as easy and safe and that have become habitual. The consequences of the general relaxation in alertness and important signals will be overlooked and the person will see only what he or she expects to see. Complacency can also occur following a highly intense activity, such as recovering from a possible disaster, in which the relief felt at the time can lead to physical relaxation and reduced mental alertness and awareness. This particular psychological experience is called emptiness.

Too much pressure and demand results in excessive stress and reduced human performance, while too little results in insufficient stress, boredom, apathy and reduced human performance. It is therefore important to maintain an adequate or optimal level of stress with different stimulation, while performing simple, routine and habitual tasks and when tired. Following written instructions and adhering to procedures that increase alertness, such as inspection routines, can provide appropriate stimulation. Important to avoid: Working from memory; assuming something is OK when you have not checked it; and signing off on work you are not sure has been completed. Teamwork and mutual cross-checking will provide sufficient warning when you are tired.

The body expert shown in the picture above says, "I have checked that cable at least 1000 times until today, I have never found any error... There is no fault in that cable". Smugness is portrayed when a maintenance person, as he finishes signing an inspection form, says to himself that he has checked the airplane part a thousand times and never found anything wrong; this despite the fact that a control surface of the airplane has a faulty cable. Thus, doing a routine task over and over again can lead to overconfidence, complacency due to increased competence, and errors in judgment can arise. You must train yourself to expect to find a mistake and constantly look for these mistakes or dangers. Never sign for anything you have not done. Never assume anything, always check.

Complacency, complacency, complacency caused by complacency is another recipe for complacency, and the root cause is usually overconfidence. The "been there, done that" attitude is especially dangerous in complex situations. Our instinctive use of pattern recognition often oversimplifies what we see. We are looking at the situation through a window and not seeing the whole picture. Even if we have the bigger picture in mind, we must remember that a snapshot in time does not necessarily tell you the trajectory of the "overall aircraft maintenance movie".

The detailed use of technical documentation in the assessment of aircraft maintenance performance and progress provides us with an objective assessment that can then provide a basis for confidence in maintenance conditions.

A technician with a lot of experience in a particular aviation field is likely to perform the same task for many years in a row. The repetition of his work makes him overconfident in his abilities and he tends to underestimate the importance of the task he is performing, sometimes even superficially.

To avoid performing all tasks mechanically, the aircraft maintenance specialist must be aware of the importance of his actions and the possible consequences. Therefore, it is important to use checklists to the letter to reduce the possibility of errors.

3. Lack of knowledge 

In the picture above the airframe specialist is complaining "this is the third part to bend! what's going on?". Lack of knowledge is depicted in the way that a maintenance person cannot understand how an aircraft part can be bent for the third time even though he keeps working on it, indicating that there is a possibility that there is a lack of specific knowledge on how to do it. This could be due to the rapid development of technology and therefore the need for more knowledge when carrying out the task. Do not rely on memory and refer to relevant up-to-date technical books. If in doubt, always ask. Get retrained in Aircraft Type. Keep in mind that systems will constantly evolve, in this example we see that the airframe specialist was not able to keep up with some changes in the aircraft's braking system.

Regulatory requirements for training and qualification can be extensive and organizations have to strictly enforce these requirements. However, a lack of on-the-job experience and specialized knowledge can lead workers to misjudge situations and make unsafe decisions. Aircraft systems are so complex and integrated that it is almost impossible to perform many tasks without significant technical training, existing relevant experience and adequate reference documentation. Furthermore, systems and procedures can change dramatically and employees' knowledge can quickly become outdated.

It is important that employees undertake continuous professional development and that the most experienced employees share their knowledge with their colleagues. Part of this learning process should include the latest information on human error and performance. Asking someone for help or information should not be seen as a weakness; in fact it should be encouraged. Checklists and publications should always be referenced and followed and one should never make assumptions or work from memory.

Lack of knowledge can take many forms. From a clear lack of necessary technical knowledge; confronting a new type of problem; lack of clarity in maintenance processes; team-based role ambiguities (what is my job, what is yours); and the absolute absence of necessary data, etc.

When faced with any of these knowledge challenges, there may be a tendency not to ask for help or to avoid asking questions that might reveal ignorance.

Remember: We are all collectively smarter than any one of us. It is important to create synergies by bringing different maintenance teams together to gain the necessary knowledge and, most importantly, perspectives.

Lack of knowledge about aircraft maintenance systems can lead system specialists to misinterpret certain situations and make unsafe decisions. Maintenance checklists and technical documentation should always be followed to the letter.

4. Distraction, distraction

Distraction is a particularly important human factor in any task-based work, whether mental or physical. Distractions arise not only from how we work, but also from a wide range of work processes and environmental factors. We need to periodically stop and make sure that we and our teams are focused on the task at hand. If necessary, the task may need to be reframed.

Distraction, or perception drift, is caused by all possible external stimuli that distract the system expert from the task at hand.

It is recommended to use maintenance checklists to avoid distraction and refocus on the task, and if there is an interruption during the task, it is recommended to take three steps back from where the expert left off, refocusing without any forgetfulness.

Distraction can be anything that takes a person's attention away from the task they are working on. Some distractions in the workplace are unavoidable, such as loud noises, requests for help or advice, and daily safety issues that need to be resolved immediately. Other distractions can be avoided or postponed to more convenient times, such as messages from home, non-urgent work-related management decisions (e.g. shift patterns, leave entitlement, meeting dates, administrative tasks, etc.) and social conversations.

Psychologists say that distraction is the number one cause of forgetting things: hence the need to avoid being distracted and distracting others. Humans tend to think ahead. So when we return to a task after a distraction, we tend to think we are further ahead than we actually are.

It is best to complete a task before responding to reduce errors caused by distraction. If the task cannot be completed without rushing, we can prominently mark (or "lock") the unfinished work as a reminder to ourselves and anyone else who might complete it. When returning to work, after being distracted, it is a good idea to start at least three steps back to retrace some steps before starting the task again. If necessary, it can be appropriate and useful to have someone else double-check our work using a checklist.

Management has a role to play in reducing distractions for its employees. This can include good workspace design, environmental management and procedures that create "safety zones", "safety circles" or "undisturbed areas" around workers engaged in critical tasks.

5. Lack of Teamwork

Many tasks and operations in aviation are teamwork; no single person (or organization) can be responsible for the safe outcome of all tasks. However, if someone is not contributing to teamwork, this can lead to unsafe outcomes. This means that workers need to rely on and support their colleagues and other external organizations. Teamwork consists of many skills that each team member will need to prove their competence.

Some of the key teamwork skills include: leadership, followership, effective communication, building trust, motivating self and others, and giving praise.

To build an effective team, the following issues need to be discussed, clarified, agreed upon and understood by all team members as appropriate

A clearly defined and sustained purpose or goal(s)

Roles and responsibilities of each team member

Communication messages and methods

Limitations and boundaries

Emergency procedures

Individual expectations and concerns

What defines a successful outcome?

Disclosure arrangements

Team dismissal arrangements

Opportunities for questions and clarifications

The effectiveness of a team can also be improved by selecting team members to reflect a wide range of experience and skills, and also through practice and rehearsal.

Lack of Teamwork is one of the key Dirty Habits, some of the other eleven Dirty Habits are likely to be there. The presence of Lack of Teamwork makes it easier for the others to form.

"Lack of Teamwork" played a major role in the fatal DC-8 crash pictured above. The three-man maintenance team was not communicating with the flight crew, especially the flight engineer. During the transit maintenance of the aircraft, there was a serious lack of nitrogen pressure in the tires. The technician in charge did not report this to the captain, even though the captain was carrying money for just such emergencies and would most likely have obtained the necessary nitrogen for the deflated tires. 

What is the Lack of Teamwork, as shown in the First Picture below? Not seeking or considering the input of others is a failure. Simply put, it is not working together for the best possible outcome.

As numerous incidents have shown, teamwork is not an easy habit to get into. The team should be seen as your entire organization, not just your department or team.

Teamwork is like a three-legged stool. A three-legged stool is stable even when the ground is uneven, unlike a four-legged stool that wobbles. Large complex maintenance, troubleshooting or overhaul activities are performed by teams, not individuals. These teams are inherently multidisciplinary and dynamic. Lack of teamwork can also be affected by all kinds of interpersonal problems. Frequent and, if possible, informal contact with each member of the team can help to build commitment and a spirit of cooperative unity.

Aircraft maintenance requires specialized personnel with different tasks who share a common goal of keeping the aircraft airworthy. Each aircraft maintainer is therefore an integral part of a complex organism that acts together and requires teamwork.

This must be understood and accepted by everyone in the team by establishing a working relationship based on mutual trust.

6. Physical and mental fatigue, burnout