Aircraft Maintenance Training Programs

The “Dirty Dozen”

An important aspect of MRM is the “Dirty Dozen,” or the 12 most common negative factors that influence a mechanic's performance. Recognizing the Dirty Dozen will identify the chain of events leading to an error and provide ideas on how to develop safety nets to prevent accidents. They were created by Gordon DuPont of Transport Canada after a string of maintenance-related accidents in the late 1980s and early 1990s. The first six are “lack of” communication, resources, assertiveness, awareness, teamwork, and knowledge. The second six are “abundance of” pressure, stress, norms, fatigue, distraction, and complacency in the workplace.

First is lack of proper communication, which will result in poor work quality, important information being misinterpreted, and higher levels of stress. Barriers to good communication include passive listening, no/poor feedback, nonstandard terms (acronyms), inappropriate communication methods (verbal/nonverbal/written), vague or ambiguous information, and late information. These barriers exist between technicians, supervisor to technician, pilot to technician, and different maintenance departments. Safety nets that can be used to prevent problems are use of checklists and worksheets, proper “turn overs” to other technicians to complete the work, and an attitude of never assuming anything.

Second is the lack of resources, which includes technical manuals, parts and materials, tools, proper lighting, shelter from the elements, heat or cool temperatures, technical support (engineering), people, time, and ground support equipment. Resource safety nets involve ordering all necessary parts in advance and verifying they are on hand before starting a maintenance job, or arranging for a loan of parts and equipment when needed. Standards must always be maintained, and when in doubt, the aircraft must be declared unairworthy or be grounded.

Third is lack of assertiveness. Aircraft technicians need to be assertive when something is wrong to ensure a problem is not overlooked. A three-step assertiveness method is to be accurate, bold, and concise. Barriers to assertiveness may involve rank or position differences in authority, peer pressure, and a lack of confidence due to lack of knowledge or experience. Assertiveness safety nets involve recording all work in the aircraft log book and signing only for what is serviceable. When in doubt, it should be written up in the book, and technicians should refuse to compromise their standards.

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