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Step 6: Supervise and Review
Once controls are in place, the process must be periodically reevaluated to ensure their
effectiveness. Workers and managers at every level must fulfill their respective roles to assure
that the controls are maintained over time. The risk management process continues throughout the
life cycle of the system, mission or activity.
15.4 Implementing the ORM Process
To derive maximum benefit from this powerful tool, it must be used properly. The following
principles are essential.
Apply the steps in sequence
Each step is a building block for the next, and must be completed before proceeding to the next. If
a hazard identification step is interrupted to focus upon the control of a particular hazard, other,
more important hazards may be overlooked. Until all hazards are identified, the remainder of the
process is not effective.
Maintain a balance in the process
All six steps are important. Allocate the time and resources to perform them all.
Apply the process in a cycle
The “supervise and review” step should include a brand-new look at the operation being
analyzed, to see whether new hazards can be identified.
Involve people in the process
Be sure that the risk controls are mission supportive, and that the people who must do the work
see them as positive actions. The people who are actually exposed to risks usually know best
what works and what does not.
15.5 Risk versus Benefit
Risk management is the logical process of weighing the potential costs of risks against the
possible benefits of allowing those risks to stand uncontrolled.
15.5.1 Types of Risk Defined
Identified risk: That risk that has been determined to exist using analytical tools. The time and
costs of analysis efforts, the quality of the risk management program, and the state of the
technology involved affect the amount of risk that can be identified.
FAA System Safety Handbook, Chapter 15: Operational Risk Management
December 30, 2000
15 -
7
Unidentified risk: That risk that has not yet been identified. Some risk is not identifiable or
measurable, but is no less important for that. Mishap investigations may reveal some previously
unidentified risks.
Total risk: The sum of identified and unidentified risk. Ideally, identified risk will comprise the
larger proportion of the two.
Acceptable risk: The part of identified risk that is allowed to persist after controls are applied.
Risk can be determined acceptable when further efforts to reduce it would cause degradation of
the probability of success of the operation, or when a point of diminishing returns has been
reached.
Unacceptable risk: That portion of identified risk that cannot be tolerated, but must be either
eliminated or controlled.
Residual risk: The portion of total risk that remains after management efforts have been
employed. Residual risk comprises acceptable risk and unidentified risk.
Figure 15-3: Types of Risk
15.5.2 Benefits Defined
Benefits are not limited to reduced mishap rates or decreased injuries, but may also be realized as
increases in efficiency or mission effectiveness. Benefits are realized through prudent risk-taking.
Risk management provides a reasoned and repeatable process that reduces the reliance on
intuition.
15.6 Acceptability of Risk
Risk management requires a clear understanding of what constitutes unnecessary risk, i.e., when
benefits actually outweigh costs. Accepting risk is a function of both risk assessment and risk
management, and is not as simple a matter as it may first appear. Several principles apply:
Unacceptable/Eliminate
Unacceptable/Control
Residual
Unidentified
Acceptable
Total Risk Residual Risk
FAA System Safety Handbook, Chapter 15: Operational Risk Management
December 30, 2000
15 -
8
· Some degree of risk is a fundamental reality
· Risk management is a process of tradeoffs
· Quantifying risk does not in itself ensure safety
· Risk is often a matter of perspective
· Realistically, some risk must be accepted. How much is accepted, or not accepted, is
the prerogative of the defined decision authority. That decision is affected by many
inputs. As tradeoffs are considered and operation planning progresses, it may become
evident that some of the safety parameters are forcing higher risk to successful
operation completion. When a manager decides to accept risk, the decision should be
coordinated whenever practical with the affected personnel and organizations, and
then documented so that in the future everyone will know and understand the
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System Safety Handbook系统安全手册上(57)
