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characteristics are well known or have been identified in previous hazard analyses. The MA
should identify these unsatisfactory characteristics or provide the analyses, if available, to the
contractor. The contractor will then compensate for these characteristics in the interface
design. In some cases, such characteristics may not be known or analyses and/or history is
not available. Then either the contractor or the MA must perform the analyses necessary for
interface design.
5.7.3 Commercial Off The Shelf/Non-developmental Items (COTS/NDI)
COTS/NDI are commercially developed hardware or software that are currently being marketed publicly.
A computer modem, LAN card (or system), radio, and desktop computers are some examples.
Procurement of these items saves development costs but is difficult for the system safety activity to
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December 30, 2000
5 - 30
assess, and even more difficult to influence. Simple items, such as the examples above, are usually
developed without an SSP. The amount of safety attention required should vary depending on the
criticality of the application and the available characterization history. Ideally, experience with the device
or more likely a similar model is available to provide the MA with guidance on the safety attention
required.
More complex and critical items require a MA decision process to ensure that the risk of accident is
acceptable. Commercial subsystem development for items such as a radio or system development for
aircraft are likely to include some form of failure-related analysis such as a FMECA or fault tree analysis.
A review of this contractor-formatted analysis may provide the necessary assurance. A poorly or nondocumented
analysis provides the opposite effect.
The COTS/NDI concept provides significant up-front cost and schedule benefits but raises safety and
supportability issues. For the NAS to benefit fully from COTS/NDI acquisitions, the SSP must be able to
ensure the operational safety of the final system without unnecessarily adding significantly to its
acquisition cost. The retrofitting of extensive safety analyses or system modifications may negate any
advantage of choosing COTS/NDI
For COTS/NDI acquisitions, a safety assessment for the intended use should be performed and
documented before purchase. Such analyses should contribute to source and/or product selection. This
should be contained in the buyer’s SSPP. COTS/NDI will be evaluated for operational use by
considering all aspects of the item's suitability for the intended purpose. Suitability criteria should
include technical performance, safety, reliability, maintainability, inter-operability, logistics support,
expected operational and maintenance environment, survivability, and intended life cycle. To assure risk
acceptability, appropriate hazard analysis must be conducted to evaluate the risks associated with initial
field testing of COTS/NDI.
Many developers of COTS/NDI may not have SSPs or staff to assess the suitability of COTS/NDI
proposed for NAS applications. Therefore, the MA must do the following.
·  Establish minimum analysis requirements for each procurement. These vary due to the
nature of the item being procured and the criticality of its mission. Examples include mission
and usage analysis and specific hazard analyses to determine the potential system impact on
the remainder of the system or the NAS itself.
·  Include in each procurement document the system safety analyses required for accurate and
standardized bidding
·  Restrict the application of the procured COTS/NDI to the missions analyzed, or reinitiate the
analysis process for new missions.
·  Apply skillful, creative tailoring when limiting the SSP scope to accommodate program size
and procurement schedules.
·  Marketing investigation, hazard analysis, and System Safety Working Groups are additional
considerations and are explained below.
5.7.4 Marketing Investigation
The MA could conduct a market investigation to identify the safety or other appropriate standards used to
design the system. The MA must determine the extent to which the system was certified or otherwise
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December 30, 2000
5 - 31
evaluated by government and non-government agencies such as the FAA, Department of Defense (DOD),
and Underwriter Labs. It must then determine what this information provides when compared to mission
requirements. The following basic questions form the basis of a COTS/NDI procurement checklist, such
as:
·  Has the system been designed and built to meet applicable or any safety standards? Which
　
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