DO-254, Design Assurance Guidance for Electronic Hardware

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RTCA DO-254 / EUROCAE ED-80, Design Assurance Guidance for Airborne Electronic Hardware is a document providing guidance for the development of airborne electronic hardware, published by RTCA, Incorporated and EUROCAE. The DO-254/ED-80 standard was formally recognized by the FAA in 2005 via AC 20-152 as a means of compliance for the design assurance of electronic hardware in airborne systems. 

The guidance in this document is applicable, but not limited, to such electronic hardware items as

• Line Replaceable Units (quickly replaceable components)
• Circuit board assemblies (CBA)
• Custom micro-coded components such as field programmable gate arrays (FPGA), programmable logic devices (PLD), and application-specific integrated circuits (ASIC), including any associated macro functions
• Integrated technology components such as hybrid integrated circuits and multi-chip modules
• Commercial off-the-shelf (COTS) components

The document classifies electronic hardware items into simple or complex categories. An item is simple "if a comprehensive combination of deterministic tests and analyses appropriate to the design assurance level can ensure correct functional performance under all foreseeable operating conditions with no anomalous behavior."  

Conversely, a complex item is one that cannot have correct functional performance ensured by tests and analyses alone; so, assurance must be accomplished by additional means. 

The body of DO-254/ED-80 establishes objectives and activities for the systematic design assurance of complex electronic hardware, generally presumed to be complex custom micro-coded components, as listed above. However, simple electronic hardware is within the scope of DO-254/ED-80 and applicants propose and use the guidance in this standard to obtain certification approval of simple custom micro-coded components, especially devices that support higher level (A/B) aircraft functions.

The DO-254/ED-80 standard is the counterpart to the well-established software standard RTCA DO-178C/EUROCAE ED-12C. With DO-254/ED-80, the certification authorities have indicated that avionics equipment contains both hardware and software, and each is critical to safe operation of aircraft. There are five levels of compliance, A through E, which depend on the effect a failure of the hardware will have on the operation of the aircraft. Level A is the most stringent, defined as "catastrophic" effect (e.g., loss of the aircraft), while a failure of Level E hardware will not affect the safety of the aircraft. Meeting Level A compliance for complex electronic hardware requires a much higher level of verification and validation than Level E compliance.

- Plan for Hardware Aspects of Certification (PHAC)

•  A Plan for Hardware Aspects of Certification (PHAC) is a document that outlines the processes and procedures for certifying an avionics hardware system. It's a key part of the DO-254 certification process.  

- Hardware Development/Design  Plan (HDP)

•  A Hardware Development/Design Plan (HDP) is a detailed document outlining the entire process of designing and developing a hardware product, from the initial concept stage to the final production phase, including specifications, design methodologies, testing procedures, timelines, and responsibilities of the development team, ensuring the product meets all required standards and functionalities.  

- Hardware Computer Installation & Assembly

•  DO-254 is a set of guidelines for designing and verifying airborne electronic hardware. It applies to the installation and assembly of hardware.  

- Hardware Validation and Verification Plan (HVVP)

•  A Hardware Validation and Verification Plan (HVVP) is a document that outlines the detailed strategies, methods, and procedures for testing and verifying hardware components to ensure they meet specified requirements, typically used in safety-critical systems where compliance with standards like DO-254 is necessary, particularly in the aerospace industry; essentially, it describes how the hardware will be validated (checking if it meets real-world needs) and verified (confirming it functions as designed) throughout the development process.  

- Hardware Process Assurance Plan (HPAP)

•  A Hardware Process Assurance Plan (HPAP) is a document outlining the processes and procedures a company will use to ensure the quality and reliability of hardware components during the design and development lifecycle, particularly in safety-critical applications like avionics, where compliance with standards like DO-254 is required; essentially, it details how the hardware development process will be managed to meet specific safety and quality objectives.  

- Hardware Configuration Management Plan (HCMP)

•  A Hardware Configuration Management Plan (HCMP) is a document that outlines the process for identifying, tracking, and controlling changes to all physical hardware components within a system, ensuring consistency, compatibility, and compliance with project requirements by documenting the current hardware configuration and managing any modifications made to it throughout the project lifecycle.  

- Hardware Configuration Index (HCI)

•  A Hardware Configuration Index (HCI) is a document used in the aerospace industry, particularly when adhering to standards like DO-254, that comprehensively details the configuration of a hardware system, including all its components, design parameters, development lifecycle data, and embedded logic, essentially acting as a complete record of the hardware design to ensure consistent replication and verification throughout the development process.  

- Hardware Requirements Standards (HRS)

•  A Hardware Configuration Management Plan (HCMP) is a document that outlines the process for identifying, tracking, and controlling changes to all physical hardware components within a system, ensuring consistency, compatibility, and compliance with project requirements by documenting the current hardware configuration and managing any modifications made to it throughout the project lifecycle.  

- Hardware  Requirements Document (HRD)

•  A Hardware Requirements Document (HRD) is a detailed document outlining the specific hardware specifications and components needed for a project or system to function properly, including details like processor type, memory capacity, storage space, peripherals, and environmental considerations, essentially serving as a blueprint for the hardware components required to meet the project's goals.  

- Hardware Design Standards/Specification (HDS)

•  Hardware Design Specifications (HDS) are documents that describe the hardware used in a system and how it will be connected to other systems. HDS documents are written by suppliers and are used to implement the goals of the Functional Design Specification (FDS).  

- Hardware Validation and Verification Standards (HVVS)

• "Hardware Validation and Verification Standards" (HVVS) refers to a set of guidelines and procedures used to ensure that hardware designs meet their intended functionality and performance requirements, typically including rigorous testing methods and documentation standards to verify that the hardware operates correctly under various conditions, often used in safety-critical industries like aerospace and medical devices; the most prominent standard in this area is usually the IEEE 1012 standard for System, Software, and Hardware Verification and Validation.

- Hardware Requirements Document (HRD)

•  A Hardware Requirements Document (HRD) is a detailed document outlining the specific hardware specifications and components needed for a project or system to function properly, including details like processor type, memory capacity, storage space, peripherals, and environmental considerations, essentially serving as a blueprint for the hardware components required to meet the project's goals.   Design Doc.

- Hardware  Interface Control Data (HICD)

•  An interface control document (ICD) in systems engineering and software engineering, provides a record of all interface information (such as drawings, diagrams, tables, and textual information) generated for a project. The underlying interface documents provide the details and describe the interface or interfaces between subsystems or to a system or subsystem. 

- Hardware  Implementation (HI)

•  Hardware implementation refers to the process of fabricating and constructing hardware components based on the design and specifications provided. 

- Hardware Test Cases & Procedures (HTCP)

•   Hardware Test Cases and Procedures (HTTP) refer to the structured methods and documented steps used to verify that hardware components and systems function as intended and meet specified requirements.  

• A test case typically includes a unique ID, a description of what's being tested, preconditions, test steps, input data, expected results, and post-conditions.  

- Hardware  Test Results (HTR)

•  Hardware test results are the outcomes of evaluations designed to verify that hardware components and systems function as intended, meet specified requirements, and are reliable. These results can indicate whether a device is operating correctly or if there are any issues that need to be addressed.  

- Hardware  Verification Analysis (HVA)

•  Hardware verification provides evidence that a production representative sample of your medical device meets the issued hardware requirements. Unlike software verification, which requires verification activities throughout the development, formal verification of hardware is performed entirely at the end of the design process, although much of the preparation must occur earlier in the project. 

- Hardware Traceability Matrix (HTM)

• Hardware Traceability Matrix establishes a correlation between the requirements, detailed design, implementation and verification data that facilitates configuration control, modification and verification of the hardware item. 

- Hardware Accomplishment Summary (HAS)

•  A "Hardware Accomplishment Summary" (HAS) is a document used in the aviation industry, particularly when adhering to the RTCA DO-254 standard, to detail all the steps taken during the design and verification process of an aircraft's electronic hardware, demonstrating compliance with safety critical requirements and providing a comprehensive record for certification purposes to aviation authorities like the FAA; essentially, it acts as a report outlining all completed hardware development activities and their verification results .

Requirements Management

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 The RTCA DO-154 and EUROCAE ED-80 Design Assurance Guidance for Airborne Electronic Hardware divide flight electronics hardware and components into two camps: simple and complex. Simple electronic hardware be tested to ensure that it works correctly under all operating conditions with no anomalies.

Complex hardware pertains to items considered to be so complex that it is impractical to ensure its correct functioning through standard tests and design processes.

DO-254 and EUROCAE ED-80 define five design assurance levels, commonly referred to as DAL, that describe how critical these components are for safe flight. The different DAL levels progressively describe components whose importance ranges from extremely important to trivial for safe flight.

DAL A describes flight electronics hardware whose failure or malfunction could cause a catastrophic, hazardous, or severe condition that would result in the deaths of everyone aboard the aircraft.

DAL B describes flight electronics hardware whose failure or malfunction could cause a severe or hazardous condition that could involve some loss of life. DAL C, meanwhile, describes hardware whose failure or malfunction would result in a major flight condition that likely will involve serious injuries.

DAL D describes hardware whose failure or malfunction would result in a condition that causes only a minor non-life-threatening flight condition. DAL E, finally, describes hardware whose failure or malfunction would have no effect on the aircraft's operational capability or pilot workload.

More information on the five Design Assurance Levels of DO-254 and EUROCAE ED-80 is available online from the FAA at www.faa.gov. Also contact the RTCA at www.rtca.org, or EUROCAE at www.eurocae.net.

• DO-254 Plan for Hardware Aspects of Certification
• DO-254 Hardware Process Assurance Plan
• DO-254 Hardware Configuration Management Plan
• DO-254 Hardware Development Plan
• DO-254 Hardware Verification & Validation Plan
• DO-254 Hardware Development Standards
• DO-254 Computer Installation & Assembly
• DO-254 Hardware Configuration Index
• DO-254 Hardware Requirements Document
• DO-254 Hardware Design Document
• DO-254 Hardware Interface Control Data
• DO-254 Hardware Implementation
• DO-254 Hardware Test Cases & Procedures
• DO-254 Hardware Test Results
• DO-254 Hardware Verification Analysis
• DO-254 Hardware Traceability
• DO-254 Hardware Accomplishment Summary

Project Development Documents 

• PHAC Plan for Hardware Aspects of Certification 
• HDP Hardware Development Plan 
• HVP Hardware Verification Plan 
• HCMP Hardware Configuration Management Plan 
• HPAP Hardware Process Assurance Plan 
• HRD Hardware Requirements Data 
• HDD Hardware Design Data 
• HVCP Hardware Verification Cases and Procedures 
• HVR Hardware Verification Results 
• HECI Hardware Environment Configuration Index 
• BCR Baseline Configuration Report 
• HCI Hardware Configuration Index 
• HTQ Hardware Tool Qualification Data 
• HAS Hardware Accomplishment Summary 

Project/Company Standards 

• HRS Hardware Requirements Standards 
• HDS Hardware Design Standards 
• VVS Validation and Verification Standards 
• HS Hardware Archive Standards 

Checklists are available for the following items: 

• Hardware Reviews (5 Lists) 
• Planning Documents (5 Lists) 
• Hardware Document (8 Lists) 
• Phase Transitions (12 Lists) 
• Traceability (1 List) 
• Baseline Reviews (1 List