Maintenance Error

Maintenance Error


The unintended failure to carry out a maintenance task in accordance with the requirements of that task and/or not working in accordance with the principles of good maintenance practice.


Aviation industry studies have found that the origin of as many as 20% of all in-flight engine shutdowns can be traced to maintenance error.

Typical maintenance errors include:

  • Electrical wiring discrepancies.
  • Loose objects left in airplane.
  • Incorrect installation of components.
  • Fitting of wrong parts.
  • Inadequate lubrication.
  • Access panels, fairings, or cowlings not secured.
  • Fuel or oil caps and fuel panels not secured.

For installation errors on engines, one specific study found the following types of error:

  • Borescope plug not refitted.
  • Engine-driven pump (EDP) drive shaft seal not fitted.
  • Engine attachment bolts incorrectly fitted.
  • Anti-ice valves locked out.
  • Fire bottle squibs not fitted.
  • Fuel pipe not secured.
  • Magnetic chip detectors (MCDs) not fitted.
  • Prop spinner fitment not completed.
  • Fuel control unit (FCU) controls not fitted.

The circumstances in which maintenance error occurs are the focus of human factors methodology.

Analysis of maintenance error data collected by a group of UK Maintenance Organisations found that when the type of error was classified, four categories accounted for 78% of the errors. These were Installation error - 39%, Inattention (damage) - 16%, Poor inspection standards - 12% and Approved data not followed - 11%.

The presentation of this data was accompanied by some solutions for both "people" and "process" for all the main types of error found.

Further Reading


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