The HFACS Framework
Where it all began...
The HFACS framework was developed by Dr. Douglas Wiegmann and Dr. Scott Shappell in the United States Navy. The early ‘90’s were a turbulent time for the Navy Department as they suffered an exceedingly high rate of aviation accidents. Drs. Wiegmann and Shappell were tasked with identifying why these accidents were continuing to happen and how to reduce the accident rate.
Drawing upon the work of James Reason, Wiegmann and Shappell developed the Human Factors Analysis and Classification System. This new framework utilized the four tiers, or barriers, that Reason identified in his Swiss-cheese model of accident causation. In addition to these tiers, causal categories were created to identify and classify latent and active failures within an organization. With this framework in hand, they set out to analyze the Navy's aviation accidents. What they found was shocking.
The Navy's extremely high aviation accident rate was due to violations. In fact, the U.S. Navy and Marine Corps lead both the Army and the Air Force in percentage of accidents associated with violations. Using the HFACS framework, the Navy conducted a fine grained analysis of many of the aviation accidents that occurred throughout that decade. The investigation revealed that these violations were not isolated events, but were actually reoccurring patterns inherent to the Navy’s unique mission and culture.
Indeed, violations contributed to a large number of accidents, but why was this so? The HFACS analysis indicated that violations in the Navy/Marine Corps were due to a few key failures in the safety system. First, this branch of the U.S. Armed Forces embraced a unique culture which essentially encouraged servicemen to “do whatever it takes to get the job done, and ask forgiveness later.” To this end, violations were often tolerated by upper management in the spirit of “getting the job done” and offenders routinely received reprimands with only minor consequences. To make matters worse, in some cases management not only condoned these routine violations, but actually participated in the violations themselves.
Another key contributor to the violations was the practice of under-supervising new or juvenile enlistees during practice missions with large-scale equipment. Such poor supervisory practices often produced reckless and irresponsible behavior from the team resulting in a number of fatalities. Following the analysis of these groundbreaking results, the Navy instituted a number of interventions directly targeted at reducing these errors. Specifically, they placed increased emphasis on individual professionalism, sustainable practices for ensuring individual and group accountability, a no-tolerance policy for routine violations and general enforcement of the rules, as well as increased detachment supervision. As a result, a remarkable decrease in violations ensued bringing the Navy and Marine Corps violation rate in line with that of the Air Force.
Surprisingly, the reduction in human error mishaps associated with violations was only half of the story. The HFACS framework allowed researchers to track and reduce other types of errors. The same work found that mishaps associated with skill-based errors were dangerously on the rise. Recall that skill-based behavior is generally automatic in nature, requiring little cognitive effort (e.g. walking, typing, etc.). Apparently, recent reductions in federal funding forced pilots to practice flight skills in flight simulators, rather than actual flight training sessions, which were costly. While pilots were able to focus their training on critical tactical decision-making, they consequently lost the basic skills needed to automatically maneuver the aircraft during flight. Among a series of interventions geared toward addressing this error, the Navy refined basic flight skills (e.g. stick and rudder techniques). The result was a sharp decrease in human error mishaps associated with skill-based errors.
Decision errors, too, were on the rise. Again, these types of errors involve conscious thought resulting from failures caused when making rule-based, choice or ill-structured decisions. In the cockpit, these types of errors focused on tactical decision making, poor procedures, and an underdeveloped awareness of the criticality of poor decisions while flying. Interventions aimed to address these root causes and the Navy quickly saw a marked reduction in errors due to decision making.
Through the use of the HFACS framework to analyze aviation accidents, Wiegmann and Shappell were able to identify areas for improvement and develop interventions to address those specific problems. This same process has now been implemented across a variety of industries with equal success.
