Mishap, defined

As an example, a NASA Procedures and Guidelines document (NPG 8621 Draft 1) defines a root cause as Along a chain of events leading to an mishap, the first causal action or failure to act that could have been controlled systematically either by policy/practice/procedure or individual adherence to policy/ practice/procedure. ... 

Hartel, Smith Prince, Defining aircrew coordination Searching mishaps for meaning. Paper presented at the Sixth International Symposium on Aviation Psychology, Columns, OH, ... 

Adverse events occurred in 3.7% of hospitalizations and 27.6% were due to negligence (defined as care that fell below the standard expected of physicians in that community, and which might therefore lead to legal action). Almost half of adverse (47.7%) events were associated with an operation. The most common non-operative adverse events were adverse drug events, followed by diagnostic mishaps, therapeutic mishaps, procedure related events and others. Permanent disability resulted from 6.5% of adverse events and 13.6% involved the death of a patient. Extrapolations from this data suggested that approximately 100 000 deaths each year were associated with adverse events. Later analyses indicated that 69.6% of adverse events were potentially preventable. 

Safety in other domains is assessed by the incidence of accidents and injuries aviation accidents, road accidents, lost time injuries at work and other types of mishap are counted and tabulated by various means. Defining these accidents is... 

By using a matrix to quantify and prioritize the risks the intrinsic subjective nature of risk assessment is not reduced, but a consistent framework for evaluating risk is provided. Although different matrices may be used for various applications, any risk assessment tool should include the elements of hazard severity and mishap probability. The risk level defined in the matrix represents the degree of risk associated with a hazard by considering these two elements. 

The MIL-STD-882D standard practice describes a system safety approach that is useful in the management of Environmental, Health of Safety mishap risks encountered in the life cycle of Department of Defense (DOD) systems, subsystems, equipment, and facilities. To paraphrase the standard, mishap risk must be identified, evaluated, and mitigated to a level acceptable (as defined by the system user or customer) to the appropriate authority, and compliant with federal laws and related rules. Further, residual mishap risk associated with an individual system must be reported to and accepted by the appropriate authority. These basic requirements are fundamental to system safety. 

Risk Mathematically, expected loss the probability of an accident multiplied by the quantified consequence of the accident (SSDC) an expression of the possibility of a mishap in terms of hazard severity and hazard probability (MIL-STD-882) note Hazard exposure is sometimes included (AFR 800-16) as defined in NHB 5300.4(10-2), The chance (qualitative) of loss of personnel capability, loss of system, or damage to or loss of equipment or property (NSTS 22254) a measure of both the probability and the consequence of all hazards of an activity or condition. A subjective evaluation of relative failure potential. In insurance, a person or thing insured (ASSE). 

Establishment of Well-Defined Controls and Limits Important to the determination of appropriate controls and limits is a thorough and complete understanding of the processes, procedures, and credible mishaps. Every operation must bq analyzed in detail to determine that the entire process will be subcritlcal under both normal and credible abnormal conditions. 

Debate over use of the term accidents versus incidents has been a long and continuing one. Although these terms are used as virtually interchangeable in the context of this book, you should be aware of the distinction between the two. Accidents are usually defined as unexpected, unplanned, and uncontrollable events or mishaps. These undesired events result in personal injury, or property damage, or equipment failure, or some combination thereof An incident is aU of the previous as weU as adverse production effects. Accidents are a subset of incidents (see Figure 1.1). 

This definition of an accident undermines the basic philosophy of this book, that we can control these types of events or mishaps. This is why we spend time identifying hazards and determining risks with the probability that a hazard will result in an accident with definable consequences. Thus, striving for a safe workplace, where the associated risks are judged to be acceptable, is a goal of safety. This will result in freedom from circumstances that can cause injury or death to workers, and damage to or loss of equipment or property. This is essentially a definition of safety. 

Several authors of this book question whether NASA has learned from experience. Integral to such discussion is defining relevant experience - a topic that is subject to dispute. Some focus on similarities between the Challenger and Columbia disasters to suggest that history has repeated and NASA has not learned (chapters 3, 8). Others say that similarity between the two disasters is overdrawn and one needs to appreciate nuanced differences (chapters 4, 6). Also salient are parallels with other failures - such as the JPL robotic failures of 1999, the Apollo 1 disaster, and the Columbia 1999 mishaps. In his Preface, Sean O Keefe suggests that some factors that contributed to NASA s failures also contributed to NASA s notable successes, so what should have been learned may only be clear in retrospect, if then. 

It is also a good idea (but not required in the regulations) to indicate whether the accident was considered preventable or non-preventable. A preventable accident is defined as one in which a driver, who exercises normal judgment and foresight, could have foreseen the possibility of the accident that in fact occurred, and could have avoided it by taking steps within his/her control which would not have risked causing another kind of mishap. 

An early definition was propounded by Lord MacNaughton in the case of Fenton v. Thorley Co. Ltd (1903) AC 443 where he defined an accident as some concrete happening which intervenes or obtrudes itself upon the normal course of employment. It has the ordinary everyday meaning of an unlooked-for mishap or an xmtoward event, which is not expected or designed by the victim. ... 

On the other hand, voluntary incident reports are shown as not very useful in their current form for evidence-based modeling. They may only be useful in the way that they are currently used, as the alerts for possible hazards in the daily operation of shipping. In order to make the incident reports useful for accident modeling, first they need to be prepared in a more systematic way that can address the causality of the mishaps, and second a more consistent definition of near-miss situation needs to be defined to reliably assign occurred mishaps to a specific type of accident. 

Stating that mishap risk for a particular hazard is acceptable can be misleading if not thoroughly defined. If a high-ranking authority accepts a high-risk hazard because a lower-ranking person cannot, does that really make the system suitably safe, or does it discount the risk It may be more ethical and cost-effective to state that the potential mishap risk presented by a particular... 

Accidents (mishaps) are classified into three categories as delineated by the Department of Defense Instruction (DoDINST) 6055.7. These categories are Class A, Class B, and Class C, which are defined as follows ... 

A CSI is essentially the same as an SCI except that systems required to identify CSIs have additional statutory and regulatory requirements that the contractor must meet in supplying those CSIs to the government. For systems required to have a CSI list, HA and mishap risk assessment is used to develop that list. The determining factor in CSIs is the consequence of failure, not the probability that the failure or consequence would occur. CSIs include items determined to be life-limited, fracture critical, fatigue-sensitive, and so on. Unsafe conditions relate to hazard severity categories I and II of MIL-STD-882. A CSI is also identified as a part, subassembly, assembly, subsystem, installation equipment, or support equipment for a system that contains a characteristic, failure mode, malfunction, or absence of which could result in a Class A or Class B accident as defined by DoDINST 6055.7. 

Fault injection is the process of deliberately inserting faults into a system (by manual or automatic methods) to test the ability of the system to safely handle the fault or to fail to a safe state. Usually, fault injection criteria is defined by system safety and is implemented by the software test engineering group to measure the system s ability to mitigate potential mishaps to an acceptable level of risk. 

For technical purposes, a hazard can be defined as the existence of a specific set of system conditions that form a unique potential mishap event. In other words, a hazard is an existing system state that is dormant, but which has the potential to result in a mishap when the inactive hazard state components are actualized. A hazard is a potential mishap, and a mishap is an UE that has occurred as a result of an actualized hazard. This more technical definition is necessary because in order to mitigate the risk presented by a hazard, all of the components and parameters comprising the hazard must be identified and understood. 

If a hazard is a potential mishap, then the hazard introduces a risk of loss that is presented by the mishap and its potential outcome. Hazard-mishap risk can be changed (mitigated) but only when the hazard components are known and understood. Therefore, it is necessary to identify and understand the composition of all hazards within a system in order to understand and mitigate the risk before a mishap actually occurs. A hazard is an entity that contains only the specific elements necessary and sufficient to result in a mishap. The components of a hazard define the necessary conditions for a mishap and the end outcome or effect of the mishap. A mishap is the result of an actuated hazard, and a hazard is a unique system entity. This entity is a set of prearranged or predesigned hazardous conditions that are inadvertently built into a system through human design. In the safety sense, mishaps are formulated events in... 

Another way to technically define a hazard is A hazard is a set of inactive conditions, which consist of a Hazardous Source, an Initiating Mechanism and a Target-Threat Outcome, which leads to a mishap when the Initiating Mechanism is actualized. A hazard is a physical entity that characterizes a potential mishap. A hazard is a condition that is prerequisite to a mishap that is, it is a blueprint for a mishap. When a hazard exists, a hazard triangle is created (see discussion below). 

If a mishap is an actual event that has occurred and resulted in death, injury, and/or loss, and a hazard is a potential condition that can potentially result in death, injury, and/or loss, then a hazard and a mishap must be linked by a transition mode. These definitions lead to the principle that a hazard is the precursor to a mishap a hazard defines a potential event (i.e., mishap), while a mishap is the occurred event. This means that there is a direct relationship between a hazard and a mishap, as depicted in Rgure 2.34. 

Hazard/mishap risk is a fairly straightforward concept, where risk is defined... 

---