From Dirty Dozen to Filthy Fifteen: Evolving Human Factors in Aviation Maintenance

In aviation maintenance, the emphasis on safety has always been paramount. The “Dirty Dozen,” a list of 12 human factors that contribute to errors, has long served as a framework to help MRO (Maintenance, Repair, and Overhaul) professionals identify and mitigate these risks. However, as the industry evolves, so do the challenges, leading to an expansion of the list to the “Filthy Fifteen.” This updated framework captures modern stressors and influences in aviation maintenance, helping address risks from new technology, regulations, and workforce changes.

Here’s a look at the original “Dirty Dozen” factors and the three additions that make up the “Filthy Fifteen.” By understanding these factors, MRO teams can better prevent maintenance errors, enhance safety, and adapt to industry changes.

The Original Dirty Dozen

1. Lack of Communication
   Effective communication ensures tasks are completed accurately and avoids misunderstandings. Breakdowns in communication can lead to critical errors in maintenance.
2. Complacency
   Familiarity can breed oversight. When routine tasks are performed too frequently, complacency may prevent technicians from spotting potential issues.
3. Lack of Knowledge
   New technology and systems require ongoing training. When technicians lack knowledge about specific systems or tools, errors are likely.
4. Distractions
   Maintenance environments are filled with distractions, from loud noises to multi-tasking demands. Even a minor distraction can lead to significant errors.
5. Lack of Teamwork
   In a complex environment like an MRO, teamwork is essential. When teamwork is lacking, errors are more common as individuals may miss vital steps or misunderstand task priorities.
6. Fatigue
   Long hours and shift work can lead to physical and mental fatigue, impairing judgment and increasing the risk of mistakes.
7. Lack of Resources
   Insufficient tools, equipment, or materials can force technicians to make do, leading to improvised solutions that may compromise safety.
8. Pressure
   Tight deadlines and time constraints are common in aviation. When pressure builds, technicians might rush through tasks, increasing the chance of mistakes.
9. Lack of Assertiveness
   When technicians aren’t assertive, they may avoid questioning procedures or reporting safety concerns, even if they know something is wrong.
10. Stress
    Stress, whether from personal or work-related factors, can compromise focus and decision-making in maintenance work.
11. Lack of Awareness
    Technicians must maintain awareness of their surroundings to prevent accidents and errors. A lack of situational awareness can lead to critical mistakes.
12. Norms
    Established norms may conflict with safety practices. For example, “we’ve always done it this way” attitudes can prevent innovation or adherence to new safety protocols.

The Expanded Filthy Fifteen

The “Filthy Fifteen” adds three new factors to address emerging challenges in MRO work, reflecting the industry’s growing complexity and need for adaptability:

13. Technology Overload
    With advanced systems and digital tools increasingly used in MRO, technicians must navigate complex interfaces and data flows. Technology overload can lead to mistakes if technicians feel overwhelmed by the volume or complexity of information.
14. Information Overload
    The influx of information from multiple sources, such as manuals, digital dashboards, and communications, can overwhelm technicians. Information overload hampers the ability to filter relevant details, leading to missed steps or critical updates.
15. Procedural Drift
    As teams adapt processes on the fly, deviations from established procedures can become the norm. Known as procedural drift, this behavior is risky as shortcuts or modified routines may lack essential safety checks.

Addressing the Filthy Fifteen

1. Promoting Open Communication Channels

Developing an environment where technicians feel comfortable voicing concerns and sharing information ensures communication remains clear. Daily briefings and standardized reporting help keep all team members informed.

2. Continuous Training and Development

Training that covers both technical skills and soft skills—such as teamwork, stress management, and adaptability to new technologies—helps technicians remain prepared and engaged.

3. Encouraging Situational Awareness and Mindfulness

Techniques like mindfulness exercises can help technicians improve focus and maintain awareness, reducing errors related to distractions or complacency.

4. Leveraging Technology Mindfully

Ensuring that technology supports technicians rather than overwhelming them requires a balanced approach to tool implementation. This includes training on digital systems and ensuring interface designs are user-friendly.

5. Enforcing Adherence to Procedures with Regular Audits

Frequent checks and audits can identify procedural drift before it becomes problematic. Encouraging technicians to follow standard procedures, even when under pressure, is essential for safe operations.

The Future of Human Factors in MRO

The expansion from the Dirty Dozen to the Filthy Fifteen reflects the MRO industry’s evolving demands and the necessity of adapting to new challenges. By understanding and addressing these factors, MRO organizations can foster safer, more efficient maintenance environments. As the industry continues to grow, adapting human factors programs will remain essential for ensuring the ongoing safety and reliability of aircraft worldwide