RTCA DO-254, Design Assurance Guidance for Airborne Electronic Hardware is a document that serves as a guidepost for the development of aeronautical electronic hardware. It categorizes electronic hardware items as part of the simple group or the complex group. it has performed faultlessly in every type of foreseen operating condition and shown no indications of unknown behavior. In contrast, a complex item is one whose flawless functional performance cannot be ensured merely by tests and analyses; therefore, assurance should be accomplished using additional methods.
The document begins with the premise that hardware design and hardware verification must be performed separately. A crucial role of the hardware designer is to ascertain that the design will fulfill all defined requirements. At the same time, the verification engineer will produce a verification plan that will enable the testing of the hardware to check if it satisfies each of its derived requirements.
The first step in the development process is planning, in which the design authority (the company behind the project) defines its approach towards the certification. After the plan is completed, it will be prepared for review by the authorities. This plan will mainly include the approach that the developer intends to take in keeping with the guidelines contained in DO-254.
Validation and Verification
The validation process for hardware development offers assurance of the correctness and completeness of the hardware item-based requirements based on the system requirements apportioned to the hardware item. Checking hardware requirements derived from system requirements is considered a system process instead of a hardware process. In other words, when hardware processes form the basis for hardware requirements, they should be correlated with system processes to see if they jive with the system requirements. Based on the document’s processes, a complete requirement is one where all defined attributes are important and all such important attributes have been listed and thoroughly explained; on the other hand, a correct requirement is one that is clearly defined and the defined attributes are totally error-free.
The verification process guarantees that the hardware item implementation satisfies derived requirements and all other hardware requirements. Verification is done in through a qualitative review, quantitative analysis, and functional testing.
Application to Basic Electronic Hardware
Fundamentally, for unsophisticated electronic hardware, the simple categorization should be warranted by defining, performing and recording the verification process. However, the hardware design assurance level will determine how rigorous and thorough this verification should be. When analyzing test coverage for Level A or B, it is important to show that all nodes and interconnections are exercised; for Level C, there is but one requirement and that is to establish correct operation for each condition combination and permutation implemented exclusively on the inputs of the device; and to analyze Level D, indirect system tests can be performed on the system that uses the Item. If the goal is to obtain simple electronic device certification, a minimum of documentation must still be presented.