Aviation Maintenance: Human Errors and Causes

An Overview of Aviation Maintenance

Aviation Maintenance operations are the backbone of all successful aviation activities. A good maintenance of the aircraft assures safe and reliable air travel to the public. Without a proper maintenance environment the aviation industry would be adversely affected. In the earlier days the aircraft's used were smaller in size, but still they needed regular maintenance checks for their efficient operation.The present aviation industry has developed to a great extent from where it started, the number of aircraft's in use at present have increased to an unimaginable extent.As the aviation industry is growing with the ultra modern long haul aircraft's and wide bodied super jumbo's like A380, B777's etc, there has been an increase in demand for efficient maintenance and overhaul operations.

The aircraft's which are built with state of the art technology and computing required highly sophisticated maintenance systems. As the technology involved in maintenance of the aircraft's advanced the cost of maintenance also increased to a considerable extent. But still the maintenance operations has to be carried out on a periodic basis to ensure safe and reliable operation of the industry.

Human Errors in Aviation Maintenance

The aviation maintenance personnel work in highly sophisticated aircraft's with complex inbuilt systems. Hence they need to be trained on upgraded technologies and new systems in order to provide an error free maintenance. The maintenance personnel should be trained in a way they must be able to repair, analyze and certify the systems in accordance to the standards of the Aircraft manufacturers and the Aviation authorities.

However, these rapid improvements in technology and complexity of the systems have been helpful in maintenance operations but they also present new possibilities of human errors. The major human errors occurring in maintenance are due to

  • The dis-assembly of the components and the failure to re-assemble them attracts more errors.
  • The re-assembly and installation are the areas where errors occur irrespective of who does the job.

These are the major error prone activities of aviation maintenance.

Causes of Errors in Aviation maintenance

The major causes for the occurrence of human errors in maintenance can be given as follows.

According to Pratt & Whitney in their survey in 1992, the major causes for the 120 inflight engine shutdowns on Boeing 747 aircraft's were mainly due to

  • Incomplete installation (33%)
  • Damaged on installation (14.5%)
  • Improper installation (11%)
  • Equipment not installed or missing (11%)
  • Foreign object damage (6.5%)
  • Improper fault isolation, inspection (6%)
  • Equipment not activated or deactivated (4%)

Some of the other related causes are

  • Complex maintenance related tasks
  • Time pressure for delivering the aircraft
  • Fatigue of the maintenance personnel
  • Maintenance procedures not followed accordingly
  • Usage of outdated maintenance manuals

Analysis of past aircraft accidents due to maintenance errors

The accidents from the past reveal that most of them have been maintenance related accidents. During the 10 year period from 1988 to 1997 there were 1474 such accidents involving aircraft's which were due to maintenance errors. On an average 18% of the aviation accidents were mainly due to maintenance errors. Out of the reported accidents around 20% of them were due to incomplete installation of parts and the next most frequently errors were due to improper maintenance inspection, annual inspection etc.

Some of the major accidents caused due to human errors in aviation maintenance.

  1. In 1979, there were 272 casualties due to the crash of a DC-10 aircraft which was due to the improper maintenance adopted by the maintenance personnel.
  2. In 1991, an Embrarer 120 carrying 13 persons crashed due to a structural damage. The cause of the accident was due to failure in replacing the attachment screws during the periodic maintenance operations.

Mohd Noor Hj Said , Nooh Abu Bakar, Ahmad Zahir Hj Mokhtar, Neoh Siang Gee (January 2011). Assessing Significant Human Factors Impacting Human Error in
Aviation Maintenance.

William T. Shepherd. Human Error In Aviation

B.S.Dhillon (2007). Human Reliability and Error in Transportation Systems. http://www.springerlink.com/content/978-1-84628-811-1/#section=285815&page=1&locus=2.

Contributors to this page

Authors / Editors

Gokul KrishnanGokul Krishnan

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License