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FAA Order 8110.105

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Airborne Electronic Hardware Approval Guidelines
FAA Publication
AbbreviationFAA Order 8110.105
Year started2008[1]
Latest versionB
2024 (2024)
OrganizationFederal Aviation Administration
DomainAvionics, type certification
Websitefaa.gov

FAA Order 8110.105B, Airborne Electronic Hardware Approval Guidelines is an explanation of how Federal Aviation Administration (FAA) personnel can use and apply the publication

  • DO-254, Design Assurance Guidance for Airborne Electronic Hardware, RTCA,

and the additional guidance and clarifications in advisory circular

  • AC 20-152A, Development Assurance for Airborne Electronic Hardware, FAA.

The order additionally identifies

  • AC 00-72, Best Practices for Airborne Electronic Hardware Design Assurance Using EUROCAE ED80() and RTCA DO 254(), FAA.

FAA Order 8110.105B defines a consistent process for certification authorities to follow when reviewing airborne electronic hardware (AEH). This order includes worksheets that may be used to assess standardized certification authority Level of Involvement (LOI) in hardware projects.[2]

Applicants developing under AC 20-152()/DO-254 may reference Order 8110.105B to be more informed of the number of certification liaison reviews to support and how much data is expected from them, determined by the level of involvement assessed by the certification authority.[2]

Revision History

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Revision Year Title
Basic 2008 Simple And Complex Electronic Hardware Approval Guidance
A 2017 Simple and Complex Electronic Hardware Approval Guidance
B 2024 Airborne Electronic Hardware Approval Guidelines

Revision B canceled 8110.105A and 8110.105, Simple and Complex Electronic Hardware Approval Guidance, which had different intent and content. These cancelled revisions supplemented RTCA DO-254() by explaining to private users of that standard how FAA aircraft certification staff could use that document "when working on type certification projects".[1] They covered "specific topics of interest to the FAA that may go above and beyond content specific to DO-254."[1] As such, these revisions were recommended for reference by developers applying under DO-254() for certification of electronic hardware designs,[3] including those implemented in "custom micro-coded components" (ie., ASICs, PLDs, or FPGAs).

The order now only gives limited instructions on the Airborne Electronic Hardware Review Process to FAA staff and designees. The previous content was removed "to eliminate duplication or conflict with AC 20-152A or AC 00-72," which were released in 2022.[4]

Clarification of application of DO-254 to simple electronic hardware

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Custom micro-coded devices are typically presumed to be complex components that cannot be verified through testing alone and must be assured through formal design assurance processes such as those defined in DO-254. However, some applicants have proposed their specific applications as simple components, that is, those that can be verified through testing alone, thereby requiring much less effort to certify.[5] DO-254 had been considered too ambiguous on its application to simple hardware. This concern was the topic of the Certification Authorities Software Team's 2007 CAST-30 position paper, Simple Electronic Hardware and DO-254 and ED-80.

In particular, Order 8110.105 originally provided clarification of DO-254 guidance for "simple" electronic hardware. Such simple hardware does not require as rigorous design assurance as complex functions installed in custom micro-coded components, for example. This definition and related recommendations were removed by Revision B, as this is now covered by the greatly expanded Revision A of AC 20-152 and the new AC 00-72, both released in 2022.

General clarification of application of DO-254

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Additionally, Order 8110.105 originally addressed some of the omissions and clarification needs identified by the Certification Authorities Software Team in their position paper, CAST-31, and as such informs electronic hardware developers of interests beyond those presently expressed in DO-254.[1] This content was removed in Revision B. The order is now only instructions for FAA Aircraft Certification Service personnel to use and apply on the Airborne Electronic Hardware Review Process.

Background

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Functioning electronic hardware systems and products certified through DO-254() processes range from replaceable electronic boxes, circuit boards within such enclosures, and any ASICs, PLDs, or FPGAs placed on such boards. These sorts of electronic hardware can be classified as simple or complex.[6] With respect to DO-254(), a device is classified as simple if comprehensive inspection or testing alone can demonstrate that it is reasonably free of design defects or errors and has deterministic behavior. A complex device, then, is one that cannot be assessed by comprehensive inspection or testing alone.[7][8][9]

For the purposes of aircraft type certification efforts, aircraft system components are designated as software or hardware. Software components are computer programs installed and operating on computers or microcontrollers and are usually subjected to the design assurance processes of RTCA DO-178() when installed in aircraft. DO-254() is applied to the certification of both simple and complex hardware components, particularly inclusive of both simple and complex custom micro-coded components. "A hardware item is considered simple if a comprehensive combination of deterministic tests and analyses can ensure correct functional performance under all foreseeable operating conditions with no anomalous behavior." All other hardware items are considered complex and, since complex hardware items cannot be completely validated by inspection and testing alone, design assurance methodology is required.[10] Advisory Circular 20-152 recognizes the guidance in DO-254 as a suitable means for demonstrating compliance for the use of complex custom micro-coded components within aircraft systems.[11] However, application of DO-254 to simple micro-coded components was not explicitly addressed by that circular.[12]

Initially, applicants and developers were concerned with the apparent ambiguity of DO-254's guidance on simple electronic hardware. That document is largely concerned with the objectives and activities of developing complex electronic hardware. However, it provides only one short paragraph suggesting that a simple hardware item should be configuration controlled and verified, but "extensive documentation is not needed". In response to the concern, CAST-30 Simple Electronic Hardware and RTCA Document DO-254 and EUROCAE Document ED-80 was completed in 2007 to provide clarification to the guidance in DO-254/ED-80 specifically for simple electronic hardware.[13][14] Following this, FAA Order 8110.105 was released in 2008 to supplement the guidance for both simple and complex electronic hardware,[1] and updated to Revision A in 2017. Three primary chapters are clarification of

  • topics applicable to both simple and complex electronic hardware,
  • topics applicable to complex electronic hardware alone, and
  • topics applicable to simple electronic hardware alone.[15][16]

The particular interest in topics applicable to simple electronic hardware alone was the reduction of documentation submitted to support certification. Applicants for simple hardware were advised to submit the following:

  • A plan for hardware aspects of certification
  • A hardware verification plan
  • A hardware configuration index
  • A hardware accomplishment summary

This selection reflects that only testing, rather than rigorous design assurance, is needed to verify simple hardware.

This advice was removed in Revision B. Rather than providing any list of expected submissions, AC 00-72 now only advises simple hardware applicants that "Due to the simplicity of the device, the life cycle data is reduced.", and provides only the broadest suggestions on how the limited documentation may be covered (Section 3.1.3).

References

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  1. ^ a b c d e Cary Spitzer; Uma Ferrell; Thomas Ferrell, eds. (2015). Digital Avionics Handbook, Avionics, Development and Implementation (3rd ed.). Boca Raton, FL: CRC Press. p. 14-17 to 14-18. ISBN 978-1138076983. The FAA published Order 8110.105 originally in 2008. ... The Order explains FAA interpretation and application of DO-254 to simple and complex electronic approval. [emphasis added]
  2. ^ a b Tammy Reeve (May 14, 2024). "Order 8110.105B (and the Evolution of Guidance Surrounding DO-254)". Airworthiness Certification Services. Retrieved 2024-10-23. Order 8110.105B now primarily focuses on how many reviews and how much data the auditors expect to see, which is determined by something called the level of involvement (LOI). The LOI calculation is influenced by both the Design Assurance Level (DAL) and other project criteria. Appendix C of Order 8110.105A included worksheets that helped calculate the LOI. Appendix B of Order 8110.105B covers the same content but adds the use of COTS and COTS IP as factors in these calculations. For teams who want to understand what external reviews you'll be subject to and why, Order 8110.105B is a great document to review.
  3. ^ Spitzer, Ferrell, and Ferrell, p. 14-17 " ... it behooves applicants and PLD developers to be familiar with the content and intent of the Order ...."
  4. ^ Tammy Reeve (May 14, 2024). "Order 8110.105B (and the Evolution of Guidance Surrounding DO-254)". Airworthiness Certification Services. Retrieved 2024-10-23. Order 8110.105A added a number of topics that needed some urgent clarifications. Order 8110.105B replaces Order 8110.105A, which had some conflicts with the newer documents AC 20-152A and AC 00-72, that covered and expanded upon much of the content of 8110.105A with more informed and thorough approaches.
  5. ^ Spitzer, Ferrell, and Ferrell, p. 14-2 "Classifying hardware as simple allows for a reduction in the hardware design assurance activities and documentation described within DO-254."
  6. ^ Digital Avionics Handbook, Avionics. p. 14-1. The hardware items encompass line-replaceable units (LRUs), circuit card assemblies, and custom microcoded devices such as fieldprogrammable gate arrays (FPGAs) and ...
  7. ^ Digital Avionics Handbook, p. 14-2, Hardware that is fully testable, through comprehensive and deterministic verification tests that address all foreseeable operating conditions, is classified as simple. The verification of simple hardware needs to demonstrate that the hardware has deterministic behavior and is free of anomalies.
  8. ^ Acquisition Management : A Guide for Program Management. Systems Command, United States. 1976. Retrieved 2022-06-16. Complex equipments and subsystems cannot be evaluated by inspection and testing alone. [emphasis added]
  9. ^ Challenges and Approaches for Selecting, Assessing and Qualifying Commercial Industrial Digital Instrumentation and Control Equipment for Use in Nuclear Power Plant Applications. IAEA. 2020. ISBN 9789201100207. Retrieved 2022-06-16. This is particularly important for ... complex hardware (such as FPGAs), where inspection or testing alone cannot confirm the behavior of the device. [emphasis added]
  10. ^ RTCA/DO-254 "Design Assurance Guidance For Airborne Electronic Hardware", Appendix C
  11. ^ AC 20-152, FAA, Office AIR-100, 2005. "This AC recognizes the guidance in RTCA/DO-254 applies specifically to complex custom micro-coded components with hardware design assurance levels of A, B, and C, such as ASICs, PLDs, and FPGAs", Page 1.
  12. ^ "8110.105 Simple And Complex Electronic Hardware Approval Guidance" (PDF). FAA Order. FAA: 1–2. 2008-07-13. Retrieved 2019-09-04. "[AC 20-152] doesn't recognize RTCA/DO-254 as a way to demonstrate compliance to regulations for simple micro-coded components.
  13. ^ "CAST-30 Simple Electronic Hardware and RTCA Document DO-254 and EUROCAE Document ED-80, Design Assurance Guidance for Airborne Electronic Hardware" (PDF). Position Paper. FAA: 1. Retrieved 2019-09-04. This CAST paper provides clarification to the guidance in RTCA document DO-254 and EUROCAE document ED-80 for simple electronic hardware, ...
  14. ^ Digital Avionics Handbook, pp. 14–18 CAST-30 is listed as relevant to 8110.105
  15. ^ "8110.105 Simple And Complex Electronic Hardware Approval Guidance" (PDF). FAA Order. FAA. 2008-07-13. Retrieved 2019-09-04.
  16. ^ Digital Avionics Handbook, pp. 14–18 The table list these three subjects.
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