On July 29, 2020, EASA released a long-awaited and very important document. Finally on October 7. 2022, the FAA followed suit. AMC/AC 20-152Awhich we’ve posted on our website here  so you can easily find them) had been in development for many years and represents – AT LAST – harmonization between the FAA and EASA regarding compliance of airborne electronic hardware. In addition to harmonization of the US agencies and industry groups, AMC/AC 20-152A also provides state-of-the-art policy regarding electronic hardware embedded in airborne systems and equipment.


On April 19, 2000, the RTCA released the document DO-254, governing the development of airborne electronic hardware. On June 30, 2005, the FAA released Advisory Circular AC 20-152, recognizing RTCA/DO-254 as a means of approval by showing the equipment design of airborne electronic hardware is appropriate for its intended function. This established the use of DO-254 for airborne electronic hardware development for aircraft developers applying for certification through the Federal Aviation Administration (FAA).

The problem was that European Aviation Safety Agency (EASA) never took similar steps to formally recognize RTCA/DO-254.

This inevitably led to some differences and discrepancies in compliance expectations for those trying to gain aircraft certification across both the FAA and EASA. These differences have now been harmonized under AC/AMC20-152A.

Significant Aspects of AC/AMC 20-152A

This AC/AMC is significant in four distinct ways:

  • Formally Recognizing and Clarifying the use of DO-254
    AMC 20-152A finally recognizes the use of the development assurance standard EUROCAE ED-80/RTCA DO-254. It also clarifies its use on digital and mixed-signal custom devices, simple vs. complex devices, DAL D compliance objectives, and circuit board assemblies (CBAs or PCBs).
  • Addressing Modern Aspects of Hardware
    It also provides guidance for development assurance when electronics use COTS (Commercial-Off-The-Shelf) and Intellectual Property (IP) components.
  • Objective Focused
    AC/AMC 20-152A focuses on providing new compliance objectives, offering development teams flexibility to determine the activities to meet these objectives. The format of this AC/AMC provides objectives for each area of concern and leaves it to the applicant to determine the activities they will perform to meet these objectives.
  • Harmonization
    This document was fully developed with the FAA. Together EASA and the FAA reviewed and processed all comments and additionally performed a joint legal review. (Note: My contact at the FAA has reaffirmed that the FAA equivalent document, AC/AMC 20-152A, will be released soon.)

What Will this Mean for YOUR Project?

If you have been working on an FAA certification project under the AC 20-152 you will notice scope of work impact under the new AC 20-152A.  The scope change affects the following:

  • Compliance to DO-254 will include the circuit board assembly (CBA) when the CBA contains a complex custom device or complex COTS devices.
  • Compliance to DO-254 will include use and categorization of COTS devices (complex or simple). The reasoning for including this now as needing to be addressed under DO-254 is due to the increased complexity of embedded functions in a single COTS device.
  • Validation is clarified to be for all requirements, not just derived.
  • Simple device definition is different than previous guidance in FAA Order 8110.105
  • DAL C will need to comply with design standards. Currently DO-254 does not require design standards for DAL C.
  • For DAL A and B, the elemental analysis code coverage for HDL will need to consider more than just statement coverage.
  • Errata clarifications for Table A-1 for DO-254 revises some of the HC1 and HC2 data control categories.
  • More extensive section and objectives for COTS IP. This is much like what was in CAST 32.
  • Planning and compliance have added new objectives for the following areas:

A unique identifier for each objective is defined with a prefix and an index number (i) as follows:

— for the development of custom devices, the identifier is ‘CD-i’; (CD-1 to CD 12 objectives)

— for the use of COTS IP in custom devices, the identifier is ‘IP-i’; (IP-1 to IP-7 objectives)

— for the use of COTS devices, the identifier is ‘COTS-i’; (COTS-1 to COTS-8 objectives)

— for the development of CBAs, the identifier is ‘CBA-i’. (CBA-1 objective)

The good news is that my consulting company, Patmos Engineering Services, has already been involved in the early work on this new guidance.  Templates and checklists  available from ACS now include these new compliance items and are tailorable by design assurance level.   I understand and can provide guidance on how best to comply and perform a gap analysis on your existing processes if needed, to help your company better understand the new objectives of AC/AMC 20-152A and how to comply.