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managing activity (MA) and incorporated in the Request for Proposal (RFP) and subsequent contract and
prime item specification. The vehicle used by the MA is a Preliminary Hazard List (PHL). Following
contract award, the first technical task of a contractor's system safety staff is the flowdown of safety
criteria to subsystem specifications and the translation of such criteria into a simplified form easily usable
by the detailed design staff. The detailed criteria is generated from a Requirements Hazard Analysis
using the PHL and Preliminary Hazard Analysis (PHA) as inputs along with requirements from standards,
regulations, or other appropriate sources. Safety design criteria to control safety critical software
commands and responses (e.g., inadvertent command, failure to command, untimely command or
responses, or MA designated undesired events) must be included so that appropriate action can be taken
to incorporate them in the software and hardware specifications. This analysis, in some cases, is
performed before contract award.
Figure 8-1: A Proactive System Safety Plan
An approach of expecting each member of the design staff to research and establish a list of safety
features is not only inefficient but high risk. The detailed designer has many "first" priorities and is
unlikely to give focused attention to safety. An efficient and effective approach is for the system safety
staff to compile comprehensive safety design criteria. These criteria should be in a simple to use format,
requiring little research or interpretation. A checklist is a good format that the design engineer can
frequently reference during the design process. The contractor's system safety staff and the MA can
subsequently use the same checklist for design safety auditing purposes.
Sources for detailed safety design criteria include Occupational Safety and Health Administration
(OSHA) standards, MIL-STD-454, Requirement 1, and MIL-STD-882. Design review is typically a
continual process using hazard analyses. Active participation at internal and customer design reviews is
also necessary to capture critical hazards and their characteristics. All major milestone design reviews
(reference FAA Order 1810.1F, paragraph 2-8) provide a formal opportunity for obtaining safety
Mission Needs
Analysis
Design
Contract
Requirements
Safety Design
Criteria
System Safety
Analysis
Additional
Safety
Requirements
Design
Reviews
Prototype
Test
Design
Approval
Production
& Test
FAA System Safety Handbook, Chapter 8: Safety Analysis/Hazard Analysis Tasks
December 30, 2000
8- 3
information and precipitating active dialogue between the MA safety staff and the contractor's safety and
design engineering staff. All resulting action items should be documented with personnel responsibility
assignments and an action item closing date. No formal design review should be considered complete
until safety critical action items are closed out satisfactorily in the view of both the MA and the
contractor. That is, both must sign that the action has been satisfactorily closed out.
All critical hazards identified by either hazard analyses or other design review activities must be formally
documented. Notification of each should be provided to the appropriate contractor staff for corrective
action or control. The Hazard Tracking/Risk Resolution system in Chapter 4 of this handbook should be
used to track the status of each critical hazard.
8.2 Analysis
8.2.1 What is the Role of the Hazard Analysis?
Hazard analyses are performed to identify and define hazardous conditions/risks for the purpose of their
elimination or control. Analyses examine the system, subsystems, components, and interrelationships.
They also examine and provide inputs to the following National Airspace Integrated Logistics Support
(NAILS) elements:
· Training
· Maintenance
· Operational and maintenance environments
· System/component disposal
Steps in performing a hazard analysis:
1. Describe and bound the system in accordance with system description instructions in Chapter 3.
2. Perform functional analysis if appropriate to the system under study.
3. Develop a preliminary hazard list.
4. Identify contributory hazards, initiators, or any other causes.
5. Establish hazard control baseline by identifying existing controls when appropriate.
6. Determine potential outcomes, effects, or harm.
7. Perform a risk assessment of the severity of consequence and likelihood of occurrence.
8. Rank hazards according to risk.
9. Develop a set of recommendations and requirements to eliminate or control risks
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