Share this article: FacebooktwitterlinkedinFacebooktwitterlinkedin

ARTICLE  NASA’s New Book “Breaking the Mishap Chain” tells why Aerospace Accidents Happen


Aviation mishaps and, for that matter, accidents in general can be traced to causal factors or latent conditions that were precursors to the event. Dr. James Reason hypothesized that most accidents can be traced to one or more of four levels of failure: organizational influences, unsafe supervision, preconditions for unsafe acts, and the unsafe acts themselves.

NASA’s book examines nine accidents that took place at NASA and identifies underlying causes and lessons learned from past events to help prevent future mishaps. Analyzing past accidents to hopefully prevent a repeat occurrence is a valuable tool and process. However it typifies the reactive risk assessment methodology that has been the traditional approach to accident prevention for years. It focuses on accident outcomes or causes and most often the unsafe acts by personnel with the objective of trying to attach blame. Reactive Risk Assessment hones in exclusively on the safety concern and to identify What, Who and When. It often does not pinpoint “Why” and “How.”

In Dr. Reason’s model, an organization’s defense against failure is a series of barriers such as supervision, safety culture, procedures and checklists, etc. However, each individual part of a system has potential weaknesses or latent conditions that, when aligned, can result in a failure.

Identifying latent conditions or failures is particularly useful in the process of aircraft accident investigation, since such examinations encourage the study of contributory factors. This analytical perspective identifies elements that may have been dormant for a long time until they finally contributed to the accident. Latent failures span the first three failure levels in Reason’s model. Preconditions for unsafe acts can include a fatigued air crew or improper communications practices. Unsafe supervision encompasses such things as pairing two inexperienced pilots together and being sent on a flight into known adverse weather at night. Organizational influences encompass such things as reduction in expenditure on pilot training in times of financial austerity.

If we were able to identify and mitigate latent conditions, we could eliminate a lot of future accidents that are waiting to happen. The best way to do that is through adoption of a proactive risk assessment process and the best system for enabling that process is through implementation of a Safety Management System.

With SMS we’re trying to look deeper and identify all underlying latent conditions and take action to prevent them from popping up again. How many times after you read a mishap report that you thought about “if this airport or if this operator had done X or Y or they had X or Y in place that mishap would have been prevented.” SMS will provide the capability to identify those conditions and allow you to complete a risk assessment and make the right decision before moving forward.

NASA’s book provides valuable lessons and a good foundation on identifying underlying mishap causes. SMS provides the methodology for generating similar results as NASA. NASA has extensive resources with experts in fields not enjoyed by operators.

So the question is “How many latent conditions or potential underlying causes do you have in your system today?” You won’t know until you implement SMS!

Share this article: FacebooktwitterlinkedinFacebooktwitterlinkedin


  1. Recently someone told me that he was scared of turbulence because that was what caused the Air France Flight 447 accident. (Air France 447, an Airbus A330, disappeared on a flight from Rio de Janeiro to Paris in June of 2009. On April 3, 2011 the “black boxes”, including the cockpit voice recorder were recovered in 13,000 feet feet of water.) I told him that turbulence was only a minor cause, and only one piece in a long string of causes that started long before the accident happened. If turbulence was the only issue, I felt the plane would have landed safely in France.

Leave a comment

Your email address will not be published.