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.

[1] Initially, the DO-254 was commonly interpreted as applying only to complex custom micro-coded components within aircraft systems with Item Design Assurance Levels (IDAL) of A, B, or C.[2][3] DO-254 guidance on simple electronic hardware and other topics needed some clarification.

[4] Specifically excluding COTS microcontrollers[5] (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.

[3][5] 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.

[7] Cetain of the new objectives in AC 20-152A explicitly state DO-254's application to circuit board assemblies (CBA).