Aviation SMS Considerations related to establishing As Low as Reasonably Practical (ALARP) & Acceptable Level of Safety Performance (ALOSP)

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Review by Sofema Online (SOL) www.sofemaonline.com

Introduction – What do we mean by ALARP?

We typically accept within aviation that it is not possible for all risks to be eliminated which is why we use the term ALARP (As low as reasonably practicable).

The principle of the ALARP approach which includes a Cost-Benefit Analysis (CBA):

»  Essentially all efforts should be made to reduce safety risks to the lowest level possible.

» Once we reach the point whereby the cost of enabling any further safety measures significantly outweighs the safety benefit it is better to accept the risk and to ensure that we fully mitigate the exposure within the ALARP / CBA framework.

Note - A risk should be tolerated only if it can be demonstrated that there is a clear benefit in doing so.

The ALARP principle identifies three categories of risk:

» Unacceptable risks are classified as unacceptable regardless of the benefits associated with the activity.

o An unacceptable risk must be eliminated or reduced so that it falls into one of the other two categories

» Tolerable risks that people are generally prepared to tolerate to secure their benefits.

o Must be properly assessed and controlled to keep the residual risk ALARP.
o Must be reviewed periodically.

» Acceptable risks are considered sufficiently low and well-controlled.

o Further risk reduction is required only if reasonably practicable measures are available.

Steps to determine whether a risk is a tolerable include:

» Compliance with Legal requirements;

» Expert judgment (Safety Expert Group);

» Cost-benefit analysis (Establishes that the cost of a control measure is grossly disproportionate to its safety benefit);

» Industry Best Practice (rules/standards).

ALoSP - Acceptable Level of Safety Performance

An Acceptable level of safety performance (ALoSP) is the combination of several performance targets, that are measured using safety indicators, and the action plans needed to achieve the set targets. An ALoSP is part of both an SSP and a service provider’s Safety Management System (SMS):

» The acceptable level of safety is generally defined in terms of the probability of an aircraft accident occurring.

» It is typically defined individually for each operator/service provider on the basis of the target level of safety required to demonstrate acceptance within the framework of the State Safety Program (SSP) Factors to be considered include:

o Complexity of operations
o Past safety performance
o Existing safety regulatory framework
o Applicable safety standards

Summary - Each agreed established level of safety should be commensurate with the complexity of individual operator/service providers’ operational contexts, and the level to which safety deficiencies can be tolerated and realistically addressed.

Next Steps

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