The Maintenance Error Decision Aid (MEDA) Process

Maintenance and inspection errors have been the primary cause of six percent of aircraft accidents and have contributed to an additional nine percent of the accidents from 1982 through 1993. What can maintenance organizations do to reduce these types of errors? This paper discusses the development and evaluation of a maintenance error investigation process-the Maintenance Error Decision Aid (MEDA). MEDA was developed based on the following philosophy: maintenance technicians do not make errors on purpose; errors result from a series of related contributing factors, and; these factors are largely under management control and, therefore, can be improved to prevent future, similar errors. The MEDA process was field tested at nine maintenance organizations. After a one-day training course, airline personnel were able to carry out a successful MEDA investigation to determine and correct contributing factors to error. An average of 3.4 contributing factors was found per error. Since the end of the field test, Boeing has provided MEDA implementation support to over 120 aircraft maintenance organizations around the world. Feedback suggests that all organizations using MEDA have found cost-effective solutions to maintenance error.