Operating and Support Hazard Analysis (O&SHA)

Sofema Online (SOL) www.sofemaonline.com looks at the role of O&SHA as part of the Aircraft Certification Program

Introduction Evaluating an Operating and Support Hazard Analysis

The O&SHA identifies hazards/risks occurring during the use of the system. It encompasses operating the system (primarily procedural aspects) and the support functions (e.g., maintenance, servicing, overhaul, facilities, equipment, training) that go along with operating the system.

While other analyses might focus on specific aspects of the system (e.g., Preliminary Hazard Analysis, System Hazard Analysis, Subsystem Hazard Analysis), the O&SHA focuses on the broader operational and support tasks. It considers the system as a whole, throughout its life cycle, and in its operational and maintenance environments.

The purpose of the O&SHA is to evaluate the effectiveness of procedures in controlling those hazards which were identified as being controlled by procedures, instead of by design, and to ensure that procedures do not introduce new hazards.

>> Timing of the O&SHA is important. Generally, an Occupational Safety and Health Administration's (O&SHA) output (i.e., hazard control) is safety's blessing on "procedures."
>> In most cases, procedures aren't available for review until the system begins initial use or initial test and evaluation.
>> As a result, the O&SHA is typically the last formal analysis to be completed. Actually, the sooner the analysis begins, the better.

o Even before the system is designed, an O&SHA can be started to identify hazards with the anticipated operation of the system. Ideally, the O&SHA should begin with the formulation of the system and not be completed until sometime after the initial test of the system (which may identify additional hazards).

>> This is critical because design and construction of support facilities must begin far before the system is ready for fielding, and all special safety features (e.g., fire suppression systems) must be identified early or the costs to modify the facilities may force program managers and users to accept unnecessary risks.
>> When evaluating an O&SHA, it is important to ensure that the analysis considers:

o Normal operation of the system,
o Abnormal operation,
o Emergency operation,
o System installation,
o Maintenance,
o Servicing,
o Storage, and
o Other operations including misuse,
o Any other activity which influences the system in any way.

For each operation and support task, identify the potential hazards that could cause an accident or other undesirable event. This might include mechanical failures, human errors, design flaws, procedural gaps, environmental factors, and so on.

The evaluator should consider the following support aspects of an O&SHA:

>> Is there auxiliary equipment (e.g., loading handling, servicing, tools) that are planned to be used with the system?
>> Is there a training program? Who will do the training, when, and how? What training aids will be used? Mock-ups and simulators may be needed for complex systems.
>> Are there procedures and manuals? These must be reviewed and revised as needed to eliminate or control hazards.
>> This effort requires that the analyst have good working relationships with the organization developing the procedures. If procedures are revised for any reason, the safety analyst needs to be involved.
>> Are there procedures for the handling, use, storage, and disposal procedures for hazardous materials?

All findings from the O&SHA should be documented in a clear, concise manner. The documentation should include identified hazards, risk assessments, risk control strategies, and any outstanding issues that need further investigation.

Human Factor Considerations Related to O&SHA

Human factors are an important consideration for the O&SHA.

>> The O&SHA should be done in concert with the human factors organization since many accidents or accidents can be caused by operator error.
>> Equipment must be user-friendly and the O&SHA is an appropriate tool to ensure this takes place.
>> Ideally, the O&SHA should be performed by both by system safety and human factors personnel.
>> O&SHAs are normally completed and submitted as a single document, typically in a matrix format.

For a complex system, this analysis is composed of several separate analyses, such as one for operation and another for maintaining and servicing the system (sometimes called maintenance hazard analysis).

The latter might be performed for several different levels of maintenance. Maintenance analyses consider actions such as disconnecting and re-applying power, and use of access doors, panels, and hardstands.

The O&SHA should also include expanded operations, i.e., uses of the system for reasonable operations not explicitly specified in the equipment specification.

>> For example, an O&SHA should normally cover the risks associated with aircraft refuelling and engine maintenance.
>> There may be some unusual operational conditions (bad weather approaching) where an O&SHA may be necessary where refuelling needs to be performed simultaneously with the performance of maintenance.
>> Early test programs are a significant source of operating and support hazards not previously identified.

o An observant safety monitor might notice, for example, the proximity of an aircraft fuel vent outlet and hot engines. (Corrective action would be to relocate the vent to remove fuel vapours from the vicinity of the hot engines.)

To benefit from test programs, and identify these "expanded operations", O&SHAs can be required to include data from by contract to use test experience as an input to the analysis.

Benefits of Operating and Support Hazard Analysis

>> Enhances safety by identifying, assessing, and controlling hazards.
>> Reduces lifecycle costs by preventing accidents and incidents.
>> Facilitates regulatory compliance by providing documented evidence of the safety process.
>> Provides a structured way to assess and manage risks.

Challenges of Delivering Operating and Support Hazard Analysis

>> It can be a time-consuming and complex process, especially for large, complex systems.
>> It requires a multidisciplinary team with expertise in systems engineering, human factors, and safety science.
>> It depends on the quality of the available data, which may be limited or uncertain, especially for new or innovative systems.

Next Steps

Sofema Aviation Services (www.sassofia.com) offers training to cover CS 25 System Safety Assessments – please see here. For additional questions or comments, email team@sassofia.com