Humans are prone to errors; therefore, it is not a surprise that human errors have been a major cause of various occupational accidents. The number of accidents caused by mechanical failure has dramatically decreased over the past 40 years; however, those caused by human error have decreased at a slower rate. This implies that involvements aimed at curbing incidences of human error have not been effective as compared to mechanical failures. Therefore, there should be more focus on the human genesis of error in order to reduce the occurrence of the accidents (Wiegmann & Shappell, 2001).
Chapter Review of Factual Information
Various actions in Gulfstream are suspected to be behind the circumstances neighboring the accident involving G650. During the G650 program, gulfstream:
In estimating the takeoff speeds for G650; it used an inconsistent assumption leading to V2 speed that could not be attained since they were too low.
Ignored to exhaust investigation on what led to the two uncontrolled cases that happened previously during G650 field performance flight testing.
Instead of establishing the major cause for V2 overshoots; it shifted its focus on empowering pilots with techniques to resolve the V2 overshoot issues (NTSB, 2011).
HFACS attempts to analyze human errors basing on the reason’s model at each level of failures identified under the concept of active and latent errors. According to Wiegmann & Shappell (2000), there are four levels of failure; those are: preconditions for unsafe acts, unsafe supervision, unsafe acts, and organizational influence.
The unsafe act is the ultimate failure in a chain of shortfalls that starts with organizational influence. However, when investigating an accident, investigators always begin with analyzing an unsafe act committed by an operator. They then follow the four accident series of events through the four levels, after which indirect and direct influences of operator’s actions are established (Wiegmann & Shappell, 2000).
HFACS further modifies the reason’s model by establishing the susceptibility points at each stage in the system. For example, organizational influences are susceptible to errors connected with resource management which includes allocations of finances, equipment and facilities. The organizational climate that includes management policies, structures and procedures together with organizational processes, which comprise of operations, procedures and safety error that exist in the organization (Wiegmann & Shappell, 2000).
Under unsafe supervision, the susceptibility errors are caused by supervisors’ negligence; issuing clear guidance to the workforce, ensuring obedience of safety-related laws and regulations by personnel, can stil breed a dangerous working environment (Wiegmann & Shappell, 2001).
Precautions of unsafe acts are vulnerable to errors such as: the personal aspects which are caused by the operator and they include misappropriation of team resources and other aspects that affect personal readiness. Secondly, environmental aspects, which are a result of external forces surrounding, and influence an individual’s performance. Lastly, physiological, mental and physical conditions may arise due to fatigue and effects of over-the-counter medications. On the other hand, unsafe act includes actions contributed by an operator in breeding an error. The errors are categorized into: unintentional error, which can be either perceptual or skill-based errors, and willful violation which is normally a result of ignorance to rules and measures (Wiegmann & Shappell, 2000).
The HFACS is an all-inclusive and user-friendly tool in identifying and classifying human errors leading to accidents. It has taken in to account the organization failures and the status of operators, and generally, all aspects of human error have been accounted for.