Development and evaluation of the Maintenance Error Decision Aid (MEDA) process

Abstract The purpose of this study was to evaluate the development and implementation of an airline industry process for determining the factors that contribute to maintenance errors and making corrective actions to eliminate or reduce the probability of future, similar errors. A process like this is useful because maintenance errors have safety and economic consequences to the airline industry. The Maintenance Error Decision Aid (MEDA) process was developed based on the philosophy that maintenance technicians do not make errors on purpose, that errors result from a series of related contributing factors, and that these factors are largely under management control and, therefore, can be changed. The process was field tested by employees of eight airlines and one repair station. Five surveys, two meetings, and completed MEDA Results Forms were used to evaluate the process. Survey results indicated that: the MEDA process was easy to use, maintenance technicians did not feel intimidated by the process, and management and staff felt MEDA was useful and should be continued after the field test. Feedback from the meetings was that MEDA had been successfully used to correct contributing factors to error, and airline management commitment was the most important factor for successful MEDA implementation. Suggestions for improving the implementation process were also provided. The completed Results Forms were generally correctly filled out and indicated an average of 3.4 contributing factors per investigation. Seven of the nine organizations continued to use an error investigation process after the field test. Since the end of the field test, the authors have provided MEDA implementation consultation to over 60 airplane maintenance organizations around the world. Feedback suggests that approximately two-thirds of the organizations are using MEDA. Relevance to industry The safety consequences and economic losses to the airline industry due to maintenance errors are very costly. A process for determining the factors that contribute to errors so that they can be corrected should help eliminate future, similar errors. The philosophy that situational factors contribute to error could also be applied in factory settings to investigate fabrication, assembly, and operational errors.