Accident Common Themes

Accident summaries organized relative to the common themes across groups of accidents.

Accident Common Themes
Flawed Assumptions
Photo: Swissair flt #111
Photo: Swissair flt #111
McDonnell Douglas MD-11
September 2, 1998
Peggy's Cove, Nova Scotia

Assumptions are essential elements of safety determinations for every aspect of the design, operation, and maintenance of the airplane.  These are expected results that, if all goes as intended, a safe outcome is produced. However, if the part, human, or feature does not perform as it was assumed it would under the specific situation, a completely different, and in come cases, catastrophic outcome can result.

View Related Accidents

Human Error
Photo: KLM flt #1736
Photo: KLM flt #1736
B747-200/B747-100
March 27, 1977
Tenerife, Spain

This is the most common of all accident themes and exists in one form or another on nearly all accidents. It involves humans that, in the course of doing their work, make errors that are later shown to have caused, or substantially contributed to the accident. These are human actions that, if done correctly, results in a safe outcome, but if done incorrectly, can result in an accident. It also represents one of the greatest opportunities for advancing safety by the application of targeted interventions which are intended to reduce the risks for human error.

View Related Accidents

Organizational Lapses
Photo: Air Florida flt #90
Air Florida flt #90
B737-200
January 13, 1982
Washington, DC

This is where an institutionalized process, procedure, or requirement that allows vital tasks or information to be handled in such a way so as to prevent an accident precursor from being recognized or safety intervention from being initiated. This breakdown could be in the form of a fleet-wide activity that is later found to be deficient, gaps in safety information flowing from one person or organization to another, or key personnel being unaware of an issue because of organizational impediments to the information.

View Related Accidents

Pre-existing Failures
Photo: Lockheed Electra L-188 wind tunnel testing
Photo: Lockheed Electra L-188 wing failures
Wind Tunnel Testing

This is a failure condition on a single airplane or possibly a fleet of airplanes that exist, either as a latent condition or an active fault. The failure condition itself may not represent a hazard, but in combination with one or more additional failures or malfunctions, an accident can result. The failure can also be a known condition such as a component that is listed on the airplane’s Minimum Equipment List (MEL).

View Related Accidents

Unintended Effects
Photo: American Airlines flt #191
Photo: American Airlines flt #191
DC10-10
May 25, 1979
Chicago, IL

This is a situation where an initiative, change, new process, or other activity intended to improve something actually produces, in addition to the improvement, an undesirable outcome. The undesirable outcome may not manifest itself for many years and may not be related to the condition being improved, but an undesirable outcome occurs that would not have otherwise happened.  It also underscores the complex interdependence that all actions have the potential for when assessing issues concerning the safety of the commercial fleet.

View Related Accidents