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Human Factors Process for Reducing Maintenance Errors
As a result of the 1997 merger with McDonnell Douglas, the Maintenance Error Decision Aid (MEDA) process offered by Boeing is now available to operators of Douglas-designed commercial airplanes and their maintenance organizations. Since its introduction two years ago, a growing number of maintenance organizations for Boeing-designed airplanes have adopted MEDA, which is a tool for investigating the factors that contribute to maintenance errors. MEDA provides a comprehensive approach for conducting thorough and consistent investigations, determining the factors that lead to an error, and making suggested improvements to reduce the likelihood of future errors.
Maintenance errors cost operators of commercial airplanes millions of dollars each year in rework and lost revenue, and present potential safety concerns. For example, aviation industry studies indicate that as many as 20 percent of all in-flight engine shut downs and up to 50 percent of all engine-related flight delays and cancellations can be traced to maintenance error. In response, Boeing developed the MEDA process to help maintenance organizations identify why these errors occur and how to prevent them in the future. Successful implementation of MEDA requires an understanding of the following:
1. The MEDA philosophy.
2. The MEDA process.
3. Management resolve.
4. Implementing MEDA.
5. The benefits of MEDA.
The MEDA Philosophy
Traditional efforts to investigate errors are often aimed at identifying the employee who made the error. The usual result is that the employee is defensive and is subjected to a combination of disciplinary action and recurrent training (which is actually retraining). Because retraining often adds little or no value to what the employee already knows, it may be ineffective in preventing future errors. In addition, by the time the employee is identified, information about the factors that contributed to the error has been lost. Because the factors that contributed to the error remain unchanged, the error is likely to recur, setting what is called the "blame and train" cycle in motion again.
To break this cycle, the maintenance organization's MEDA investigators learn to look for the factors that contributed to the error, rather than the employee who made the error. The MEDA philosophy is based on these principles:
Positive employee intent (maintenance technicians want to do the best job possible and do not make errors intentionally).
Contribution of multiple factors (a series of factors contributes to an error).
Manageability of errors (most of the factors that contribute to an error can be managed).
POSITIVE EMPLOYEE INTENT.
This principle is key to a successful investigation. Traditional "blame and train" investigations assume that errors result from individual carelessness or incompetence. Starting instead from the assumption that even careful employees can make errors, MEDA interviewers can gain the active participation of the technicians closest to the error. When technicians feel that their competence is not in question and that their contributions will not be used in disciplinary actions against them or their fellow employees, they willingly team with investigators to identify the factors that contribute to error and suggest solutions. By following this principle, operators can replace a negative "blame and train" pattern with a positive "blame the process, not the person" practice.
CONTRIBUTION OF MULTIPLE FACTORS.
Technicians who perform maintenance tasks on a daily basis are often aware of factors that can contribute to error. These include information that is difficult to understand, such as work cards or maintenance manuals; inadequate lighting; poor communication between work shifts; and airplane design. Technicians may even have their own strategies for addressing these factors. One of the objectives of a MEDA investigation is to discover these successful strategies and share them with the entire maintenance operation.
MANAGEABILITY OF ERRORS.
Active involvement of the technicians closest to the error reflects the MEDA principle that most of the factors that contribute to an error can be managed. Processes can be changed, procedures improved or corrected, facilities enhanced, and best practices shared. Because error most often results from a series of contributing factors, correcting or removing just one or two of these factors can prevent the error from recurring.
The MEDA Process
To help maintenance organizations achieve the dual goals of identifying factors that contribute to existing errors and avoiding future errors, Boeing initially worked with British Airways, Continental Airlines, United Airlines, a maintenance workers' labor union, and the U.S. Federal Aviation Administration. The result was a basic five-step process for operators to follow (see figure 1 for process flow):
Event.
Decision.
Investigation.
Prevention strategies.
Feedback.
EVENT.
An event occurs, such as a gate return or air turn back. It is the responsibility of the maintenance organization to select the error-caused events that will be investigated.
DECISION.
After fixing the problem and returning the airplane to service, the operator makes a decision: Was the event maintenance-related? If yes, the operator performs a MEDA investigation.
INVESTIGATION.
Using the MEDA results form, the operator carries out an investigation. The trained investigator uses the form to record general information about the airplane, when the maintenance and the event occurred, the event that began the investigation, the error that caused the event (see "Maintenance Errors" for common examples), the factors contributing to the error, and a list of possible prevention strategies.
PREVENTION STRATEGIES.
The operator reviews, prioritizes, implements, and then tracks prevention strategies (process improvements) in order to avoid or reduce the likelihood of similar errors in the future.
FEEDBACK.
The operator provides feedback to the maintenance workforce so technicians know that changes have been made to the maintenance system as a result of the MEDA process. The operator is responsible for affirming the effectiveness of employees' participation and validating their contribution to the MEDA process by sharing investigation results with them.
Management Resolve
The resolve of management at the maintenance operation is key to successful MEDA implementation. Specifically, after completing a program of MEDA support from Boeing, managers must assume responsibility for the following activities before starting investigations:
1. Appoint a manager in charge of MEDA and assign a focal organization.
2. Decide which events will initiate investigations.
3. Establish a plan for conducting and tracking investigations.
4. Assemble a team to decide which prevention strategies to implement.
5. Inform the maintenance and engineering workforce about MEDA before implementation.
MEDA is a long-term commitment, rather than a quick fix. Operators new to the process are susceptible to "normal workload syndrome." This occurs once the enthusiasm generated by initial training of investigation teams has diminished and the first few investigations have been completed. In addition to the expectation that they will continue to use MEDA, newly trained investigators are expected to maintain their normal responsibilities and workloads. Management at all levels can maintain the ongoing commitment required by providing systematic tracking of MEDA findings and visibility of error and improvement trends.
Implementing MEDA
Many operators have decided to use MEDA initially for investigations of serious, high-visibility events, such as in-flight shut downs and air turn backs. It is easy to track the results of such investigations, and the potential "payback" is very noticeable.
In contrast, according to David Hall, deputy regional manager in the British Civil Aviation Authority (CAA) Safety Regulation Group, a high-visibility event may not present the best opportunity to investigate error. The attention of operators' upper management and regulatory authorities could be intimidating to those involved in the process. In addition, the intensity of a high-level investigation may generate too many possible contributing factors to allow a clear-cut investigation of the event.
Hall has recommended that operators look at the broader potential for improvement by using MEDA to track the cumulative effects of less-visible errors. Providing management visibility of the most frequently occurring errors can, in the long run, produce profound improvements by interrupting the series of contributing factors. According to Dr. Jim Reason, professor of psychology at the University of Manchester, MEDA is "a good example of a measuring tool capable of identifying accident-producing factors before they combine to cause a bad event."
Benefits
About 60 operators have already implemented some or all of the MEDA process. Participating airlines have reported several benefits, including the following improvements:
A 16 percent reduction in mechanical delays.
Revised and improved maintenance procedures and airline work processes.
A reduction in airplane damage through improved towing and headset procedures.
Changes in the disciplinary culture of operations.
Elimination of an engine servicing error by purchasing a filter-removal tool that had not previously been available where the service was being performed.
Improvements in line maintenance workload planning.
A program to reduce on-the-job accidents and injuries based on the MEDA results form and investigation methods
As this is public access information - I'm sure you can use it for teaching the troops!
Rigga
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