Maintenance error decision aid

Definition

The Maintenance Error Decision Aid (MEDA) is a structured process used to investigate events caused by maintenance technician and/or inspector performance.

Description

Developed originally by the Boeing Company in the early 1990s with the active involvement of three major international airlines, a maintenance staff trade union and the U.S. Federal Aviation Administration (FAA), MEDA was the first structured attempt to enhance the value derived from investigation of maintenance error by providing a process in which human error was placed in its full procedural context. It has since been widely adopted — and adapted — as a basis achieving effective maintenance error investigations worldwide.

The MEDA method was developed as a more effective alternative to simply ‘retraining’ employees found to have made maintenance errors. It was realised that by the time a specific individual had been identified as responsible for an error, information about the factors that contributed to the error had often been lost. It was concluded that if the factors which contributed to an error remained, then similar errors would be likely to recur.

Boeing describes the MEDA philosophy as being based on three assumptions:

• That people want to do the best job possible and do not make errors intentionally

Investigators will get more help from employees who do not feel their competence is in question. The employees are more likely to be helpful in identifying the factors that might have contributed to an error and in suggesting possible solutions.

• That a series of factors is likely to contribute to an error

Findings on the context of a particular error investigation may have much wider significance for the occurrence of errors generally. Often, matters like difficulty in understanding of documentation (job cards, the aircraft maintenance manual, the illustrated parts catalogue or the applicable component maintenance manual), inadequate lighting, poor shift handover or aircraft design issues may be disclosed in an investigation. «Fixing» just some of the identified factors will probably be able to significantly reduce the likelihood of most types of error recurring.

• That most of the factors which contribute to an error can be managed

Involvement of employees close to an error in the investigation of it helps to establish how to manage the issues. Processes can be changed, procedures improved or corrected, facilities enhanced and best practices shared.

The MEDA process is described as having five key stages:

• Selection of the technical event to be investigated by the maintenance organisation involved

• Decision on whether the error identified was maintenance-related

• Investigation using the MEDA results form to record relevant information about the event which disclosed the error and the error that caused the event, the factors contributing to the error and a list of possible prevention strategies.

• Prevention Strategies review leads to prioritising, implementation and tracking of process improvements

• Feedback to the workforce advises what changes have been made, explains the value of employee participation and shares the results of the investigation.

Further Reading

• MEDA Investigation Process, Boeing AERO magazine

Historically incident and accident investigation where skewed in the direction of understanding the employee who made the error “The Culprit”.

Without a MEDA type process the organization typically lacks the management processes to deal with the employee in a “Just and Fair” way, often resulting in discipline which may be considered unfair and often results in the employee becoming defensive.

As a result little added value is obtained, also opportunities are missed including fundamental elements connected with organizational process which may have contributed to the error. This can even be exacerbated by the insistence of re-training which adds little to the process as the underlying issues were often connect more with culture than knowledge.

A previous Human Factors (HF) Study showed that only around 4% of Aviation Maintenance incidents where directly related to knowledge issues).

Even a process may be found within organisations known as “blame and train” where a cycle of such events can be seen to exist, discover a problem, blame an Individual, retrain and so on to repeat with the next employee.

What was required was a process to interrupt this ineffective process.

The Aviation Maintenance Error Decision Aid (MEDA) process was developed by Boeing and brought a new way of thinking to the investigation process.

Firstly that Maintenance Staff do not intentionally commit errors, in fact the opposite they take pride in their work.  Once we accept that even the best mechanic is capable of making a mistake and this fact may not directly have a bearing on the person’s competence, the cultural relationship is able to take on a different dimension. In such a relationship it becomes possible to fully explore all causal and contributing factors in a more effective way.

Secondly, that in any event there is typically a contribution of Multiple Factors some of which may in fact be considered latent which contribute to the event. Once the employer is able to step back from the immediate need to apportion blame a much more effective analysis and root cause determination process may be undertaken. Against this background co-operation from the employee is much more forthcoming and the “blame” focuses instead not on the employee but on the organisations process and procedures.

Thirdly is the understanding that most of these factors can in fact be managed. Once we understand a weakness then the process may be changed and associated procedures strengthened or omissions address. Issues concerning tooling equipment and facilities also addressed.

Aviation Maintenance Error Decision Aid Training supports the Knowledge that typically it is a chain of events which leads to an accident, removing one or more of the links is often enough to actually prevent the error. If we can encourage people to report also “nearly” accidents we can become proactive and avoid such in the first place.

Sofema Aviation Services offers 2 and 3 day MEDA Training programs as well as MEDA Training for Trainers.

For additional details please see: www.sassofia.com or email: office@sassofia.com.

Tags:

Aviation Maintenance Error Decision Aid,

Human Factors,

MEDA,

MEDA Training for Trainers,

Sofema Aviation Services