Accident Common Themes

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

Accident Common Themes
Flawed Assumptions
Flawed Assumptions
Photo: Wright Flyer III
September 17, 1908
Ft. Myer, Virginia

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 some cases, catastrophic outcome can result.

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Human Error
Human Error
Photo: Air Tractor
August 5, 2013
Balcko, Oklahoma

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, result 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.

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Organizational Lapses
Organizational Lapses
Photo: Cessna 208B
September 2, 2011
Bethel, Alaska

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.

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Pre-existing Failures
Pre-existing Failures
Photo: Cessna 185
May 31, 2010
Tofino, B.C

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.

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Unintended Effects
Unintended Effects
Photo: Beechcraft Model 35 Bonanza
February 3, 1959
Near Clear Lake, Iowa

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 safety.

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