Understanding Error and Violations within the Aviation Maintenance Environment

Posted by on in Regulatory
  • Font size: Larger Smaller
  • Hits: 333


It is considered that errors and violations together form the unreliable part of our human performance. Moreover, that 70-90 percent of current aviation incidents & accidents are due to in some part to “human factors”.

Errors and violations contribute to accidents both directly and by making the consequences of other problems more serious. An accident typically involves several contributing factors, some usually being quite visible and others possibly latent in nature.

Note - The consequences of an error is typically independent to the magnitude of any pre-cursor (small errors in combination may in fact lead to a big accident!).

What is the difference between an Error and a Violation?

The fundamental difference between errors and violations is that violations are deliberate, whereas errors are not. In other words, committing a violation is a conscious decision, whereas an error can be made while a person is consciously trying to perform in an error-free manner.

Therefore, we can say the following:

Human error is an unintentional action or decision.

Violations are intentional failures – deliberately doing the wrong thing.

Error Types

There are three types of human error:

a) Slips (typically occur at the task execution stage)

- Slips can be thought of as actions not carried out as intended or planned.

- Slips are usually easy to detect quickly and do not have immediate serious consequences due to built-in system protections. 

b) Lapses (memory)

- Lapses are missed actions and omissions, i.e. when somebody has failed to do something due to lapses of memory and/or attention or because they have forgotten something, e.g. forgetting to lower the undercarriage on landing. 

- Lapses may be more difficult to detect and therefore may also be more likely to have consequences.

c) Mistakes (typically occur at the planning stage)

- Mistakes are a specific type of error brought about by a faulty plan/intention, i.e. somebody did something believing it to be correct when it was, in fact, wrong, e.g. switching off the wrong engine.

- Mistakes are even more dangerous, because the person committing the mistake believes that he or she is doing the correct thing and thus carries on with the action often despite a growing number of signs that things are not going right.

Human error can happen to even the most experienced and well-trained person.


Violations involve deliberately (and consciously) departing from known and established rules or procedures:

a) Personally, optimizing violations

b) Organizationally optimizing violations

Violations may become routine when a violation becomes what is normally done (the norm) within your workplace.

Routine violations may be shortcuts which are taken to help you get the job done more quickly, more easily, or perhaps more efficiently.

Note - Unless you monitor and control this (willingness to Violate) behaviour, it can lead to a culture that tolerates violations.

Sofema Aviation Services (SAS) and our Sister Company SofemaOnline (SOL) offer EASA compliant regulatory training including Human Factors and Maintenance Error Management System in company and online training - for details please see www.sassofia.comwww.sofemaonline.com or email office@sassofia.com and online@sassofia.com

Last modified on