AC 20-152

The Advisory Circular AC 20-152A, Development Assurance for Airborne Electronic Hardware, identifies the RTCA-published standard DO-254 as defining "an acceptable means, but not the only means" to secure FAA approval of electronic hardware for use within the airspace subject to FAA authority. Commonly, the DO-254 has been interpreted as applying to complex custom micro-coded components within aircraft systems with Item Design Assurance Levels (IDAL) of A, B, or C. However, Revision A of this AC clarifies that AC 20-152 and DO-254 applies to all type certification of all electronic hardware aspects of airborne systems, including all electronic hardware that is not complex, that is, "simple electronic devices". Revision A also defines objectives in addition to those identified in DO-254; applicants choosing to follow DO-254 under the authority of AC 20-152A must also accomplish these additional objectives.

Specifically excluding COTS microcontrollers (see AC 20-115/DO-178C), complex custom micro-coded components include field programmable gate arrays (FPGA), programmable logic devices (PLD), and application-specific integrated circuits (ASIC), particularly in cases where correctness and safety can not be verified through testing alone, necessitating methodical design assurance. Simple devices are those that are verifiable with testing alone, such that the FAA may agree that methodical design assurance is unnecessary.

For DAL D hardware, as long as the applicant follows DO-254, the applicant does not need to apply this advisory circular since the FAA does not expect to examine the life cycle data. However, if the applicant chooses to follow other design practices for DAL D hardware (as permitted by this AC) the FAA will review the data.