Avionics system Standard
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The document discusses avionics system standards crucial for ensuring safety and reliability in aviation, distinguishing between hardware and software standards. It details the DO-254 hardware standard for critical avionics components and the DO-178 software standard for embedded avionics software, both of which define levels of criticality based on failure consequences. The importance of compliance with these standards is emphasized for the development and operation of safe aircraft systems.
Avionics system Standard
- 1. AVIONICS SYSTEM STANDARDS INTRODUCTION Avionics is the Electronic System used in Aviation. As the advancement in Avionics had grossing demand inducing the incompatibility and conflict in Avionics application which soon realized the usual approach to seek the safety and reliability will not work for safety critical system, there was great need for the solution of design error, thus which prompted the Avionics System Standards. PRESENTED BY: Maria Vannesa Belenario Waad Jamal Almuqalbi Jeran Rai
- 2. GENERAL CATEGORY OFAVIONICS STANDARDS In General, Avionics system standards are mainly classified in following categories; ● ● Avionics Hardware Standards. Avionics Software Standards.
- 3. AVIONICS HARDWARE STANDARDS The importance of Avionics hardware is often overlooked because of the small size of most items. However, the safe and efficient operation of any Aircraft depends on correct selection and use of Avionics Hardware which is also to be determined by the certain standard. As result, The DO-254 specification was created by Radio Technical Communication For Aeronautics (RTCA) committee back in the 1990s, and was written to apply to all levels of hardware, including circuit boards, resistors, and capacitors-as well as chips.
- 4. DO-254 Simply stated, Design Assurance Guidance For Airborne Electronic Hardware ( DO-254 ) is a requirements-driven process-oriented safety standard used on commercial electronics that go into aircraft. (Conceptually speaking, this standard applies to all electronics in anything that flies or could crash and pose a hazard to the public.) DO-254 was specified in 1990s, however when the Federal Aviation Administration ( FAA ) enacted the DO- 254 specification as policy in 2005, it chose to limit the scope to “complex custom micro-coded components” like PLDs, FPGAs, and ASICs.
- 5. DO-254 The DO-254 standard is the counterpart to the well- established software standard RTCA DO-178B/EUROCAE. There are levels of compliance defined by the five Criticality Levels, A through E, which depend on the effect a failure of the hardware will have on the operation of the aircraft, where DO-254 Level A Being Most Critical and DO-254 Level E Being Least Critical and is must be determined by FAA system safety assessment process and must be verified by FAA.
- 6. DO-254 CRITICALITY LEVELS ➔ ➔ DO-254 Level A : DO-254 Level A hardware is hardware whose anomalous behavior, as shown by the system safety assessment process, would cause or contribute to a failure of system function resulting in a catastrophic failure condition for the aircraft. Failure of DO-254 Level A hardware could be typified by total loss of life. Approximately 20-30% of avionics systems and 40% of avionics hardware implementation must meet DO-254 Level A criteria. DO-254 Level B : DO-254 Level B hardware is hardware whose anomalous behavior, as shown by the system safety assessment process, would cause or contribute to a failure of system function resulting in a hazardous/severe-major failure condition for the aircraft. Failure of DO-254 Level B hardware could be typified by some loss of life. Approximately 20% of avionics systems and 30% of avionics hardware implementation must meet DO-254 Level B criteria.
- 7. DO-254 CRITICALITY LEVEL ➔ ➔ DO-254 Level C : DO-254 Level C hardware is hardware whose anomalous behavior, as shown by the system safety assessment process, would cause or contribute to a failure of system function resulting in a major failure condition for the aircraft. Failure of DO-254 Level C hardware could be typified by serious injuries. Approximately 25% of avionics systems and 20% of avionics hardware implementation must meet DO-254 Level C criteria. DO-254 Level D : DO-254 Level D hardware is hardware whose anomalous behavior, as shown by the system safety assessment process, would cause or contribute to a failure of system function resulting in a minor failure condition for the aircraft. Failure of DO-254 Level D hardware could be typified by minor injuries. Approximately 20% of avionics systems and 10% of avionics hardware implementation must meet DO-254 Level D criteria.
- 8. DO-254 CRITICALITY LEVEL ➔ DO-254 Level E : DO-254 Level E hardware is hardware whose anomalous behavior, as shown by the system safety assessment process, would cause or contribute to a failure of system function with no effect on aircraft operational capability or pilot workload. Failure of DO-254 Level E hardware would have no impact on passenger or aircraft safety. Approximately 10% of avionics systems and 5% of avionics hardware implementation must meet DO-254 Level E criteria (note however that the amount of DO- 254 Level E implementation is increasing due to passenger entertainment and internet communications subsystems that are currently designated Level E; it is deemed likely by us that the criticality levels of these systems will increase due to integration with other, more critical, avionics systems).
- 9. DO-254 COSTS AND BENEFITS ➔ ➔ DO-254 is often thought to add 50-200% to avionics hardware development. In reality, actual additional DO-254 cost should be on the order of 30%-50%, presuming basic high-reliability hardware engineering principles are used from the onset. In addition to being necessary for flight products, DO-254 benefits include: verifiable hardware quality, higher reliability, consistency, greater re-usability, lower lifecycle costs, decreased maintenance cost, faster hardware integration, and greater portability.
- 10. AVIONICS SOFTWARE STANDARDS Avionics Software is embedded software with legally mandated safety and reliability con-cerns used in Avionics. In early 80s, the cost of Computers went down due to the introduction of personal computer and the Aviation industry started Replacing Or Enhancing The Conventional Airbrone System With Software Functionality. Thus, increased use of Software and Computer Systems for Safety Critical application MOTIVATED to develop First Version DO-178 ( Software Considerations in Airborne Systems and Equipment Certification ) jointly by RTCA And EUROCAE.
- 11. DO-178 ➔ ➔ ➔ ➔ Since it was the First Of Its Kind, so it was initially written at a Conceptual Level. The rules to be standardized were developed by Trial And Error over time. Since the Airbrone system were being replaced/enhanced with software functionality which lead to introduce the first concept of Software Verification. The software application were divided into three level of categories: Critical, Essential And Non-essential.
- 12. DO-178A ➔ ➔ ✔ ✔ ➔ ➔ Published in 1985. The feature introduced: Systematic and Structured detail, Software Development Verification Processes. Concept of Software application Level 1, 2 And 3 corresponding to Criticality Safety Level. There was total Lack Of Understanding Of The Purpose. Misinterpretation led to Disqualification Software Development Cycle.
- 13. DO-178B ➔ Evolved From DO-178A, cira 1985. ➔ DO-178B is guidance document only and focuses on software processes and objectives to comply with these processes. ➔ Recommended certification to obtain Approval OfAirborne Softwares. ➔ DO-178B is Not Prescriptive. ✔ Vendors are allowed how objectives are satisfied. ➔ DO-178B objectives varies, How To Software Failure Can Effect System Safety.
- 14. DO-178B CRITICALITY LEVELS DO-178B defines five safety levels : ➔ ✔ ➔ ✔ Level A : Catastrophic; Failure results in preventing the flight from continuing Safely and/or Landing. An example of such system is an engine controller software. Level B : Hazardous; Failure results to serious or fatal injuries to the aircraft occupants. Examples are Primary Flight Displays (PFDs) and failures of pressurization system software.
- 15. DO-178B CRITICALITY LEVELS ➔ ✔ ➔ ✔ ➔ ✔ Level C : Major; Failure results in causing discomfort or injuries to the occupants. Examples are Flight Management System (FMS), autopilot and auto landing systems. Level D : Minor; Failure results in causing some inconvenience to the occupants. Examples are such systems include transponders and communication equipment. Level E : No Effect; Failure of in-flight entertainment functions and satellite phone and internet access.
- 16. DO-178C ➔ ➔ ➔ It was Completed In November 2011, Approved By RTCA In December 2011, Available For Sale And Use In January 2012 and FAA Approved In 19, July 2013. Includes Formal Methods - Mathematical Based Techniques used for specification, development and Verification Of Avionics Software. Formal methods can be used to "prove That Software Is An Accurate Representation Of The Mathematical Expressions”.
- 17. DO-178C ➔ ➔ Object Oriented Programming Languages like C++ And Ada are highly standardized because they are at a higher level of abstraction than other languages which lead to promote re-use and promise more efficient development. Model-Based development which model systems at veryhigh-level, domain-specific languages, are often used to Automatically Generate Source Code Directly From The Model.
- 18. DO-178C CRITICALITY LEVELS ➔ ✔ ➔ ✔ Level A : Catastrophic; Failure may cause deaths, usually with loss of the airplane. Level B : Hazardous; Failure has a large negative impact on safety or performance, or reduces the ability of the crew to operate the aircraft due to physical distress or a higher workload, or causes serious or fatal injuries among the passengers.
- 19. DO-178C CRITICALITY LEVELS ➔ ✔ ➔ ✔ ➔ ✔ Level C : Major; Failure significantly reduces the safety margin or significantly increases crew workload. May result in passenger discomfort (or even minor injuries). Level D : Minor; Failure slightly reduces the safety margin or slightly increases crew workload. Examples might include causing passenger inconvenience or a routine flight plan change. Level E : No Effect; Failure has no impact on safety, aircraft operation, or crew workload.
- 20. CONCLUSION ON DO-178( ) ● ● Note : The DO-178( ) solely focuses on Design Assurance where the Required Assurance Is Defined On The Basis Of The Respective Criticality Levels. The major concern with DO-178( ) is that it is often Misunderstood As Software Development Standard Rather Than The Assurance Standard. DO-178C is the best assurance standard because its source codes are traceable, provide clearer language and terminology, provide more consistency, clearify the hidden objectives and so on. So, DO-178C is the Currently Applied Means for the software aspects of Airborne Avionics Systems And Equipment Certification.
- 21. THANK YOU ! “FLIGHT SAFETY IS SIMPLE, THE NUMBER OF SUCCESSFUL LANDING SHOULD EQUAL THE NUMBER OF TAKE-OFFS”