There’s been a lot of new policy documents in the last few years that modify and modernize how DO-254 and DO-178C are applied. Its usually for good reason. Not only has technology evolved but so has our learning. One key learning is the understanding that a DO-178C or DO-254 Accomplishment Summary becomes a “un” accomplishment summary when too many Open Problem Reports (OPRs) remain unresolved at the end of a certification or TSO project. This was the motivation behind AC/AMC 20-189 (and FAA AC 00-71).

How Can the New AC/AMC 20-189 Help Manage Problem Reports in DO-178C and DO-254 Projects?

Both DO-178C (airborne software) or DO-254 (airborne electronic hardware, AEH) standards allow for a listing of OPRs in the accomplishment summary document.  However, many applicants have abused this and rather than address the problems prior to final compliance, they create long lists of unresolved and uncategorized PRs in the Software/Hardware Accomplishment Summary documents. This makes it difficult for applicants to show compliance and regulators to find compliance. The result, as one would guess, is equipment- and aircraft-level functional issues and airworthiness directives.

The New AC/AMC 20-189 provides guidance on a means of compliance when applicants have unresolved (i.e., open) PRs at the end of a TC, STC or TSO project.  The reason for this is to provide a consistent expectation related to the communication, review, and assessment of OPRs by all possible stakeholders who are integrating the software or AEH into their aircraft programs.

AMC 20-189 was released on July 29, 2020 by EASA (the FAA released harmonized policy AC 20-189 on Sept. 16, 2022). These documents provide guidance on management and classification of OPRs for airborne electronic hardware, software, and system development, at the time of product approval or ETSO authorization.


The compliance of system, software, and electronic hardware domains relies on managing PRs throughout the program to ensure the product is safe at the time of approval. The problem is the existing guidance was inconsistent and unclear, especially across and between each of these domains, in terms of what was required. The new documents provide consistent guidance on managing OPRs that works alongside existing guidance for each domain, and they are harmonized between EASA and the FAA.

What AC/AMC 20-189 Covers

This AC/AMC provides consistent terminology to use to define Problem Report “states,” type classifications for PRs, and guidance on how to manage them to enable the consistent and timely management of PRs across domains to ensure visibility of critical issues remaining at the time of approval.

What Will this Mean for YOUR Project?

First and foremost, if you are starting or working on any airborne systems, software, or hardware programs, you will need to review your configuration management procedures to see what gaps exist between those procedures and this AC/AMC.   You will then need to update your Configuration Management Plan document to ensure it aligns with this new guidance. (Don’t forget to have your certification liaison sign off on any significant changes).

The key things to keep in mind are:

  1. Stakeholders at each level should manage OPRs (TSO, System and final product — aircraft, engine propeller) according to this guidance.
  2. PR management plans and processes should span systems, software and hardware domains and be used throughout development and for continued airworthiness aspects.
  3. PRs that occur after a certification or authorization approval should be reported in a manner that is understandable to all affected stakeholders. For example, an equipment level PR after certification authority approval (via TC, STC or TSO) may affect aircraft level functions and create a hazard if not reported and addressed.
  4. Companies with distributed geographical organizations, especially across countries, should ensure that the tools and procedures for problem reporting are accessible (including viewing and resolution) by all affected stakeholders.
  5. Companies should strive to actively work to close problem reports throughout the development process to reduce the number of OPRs presented at the time of certification (or authorization in the case of a TSO/ETSO piece of equipment).
  6. The PR process and configuration management plan should describe classification systems and ensure the OPR content aligns with AC/AMC20-189. This will ensure that all affected parties understand the types and seriousness of the OPRs.
  7. The PR process should review documentation of the assessment of each OPR to ensure it clearly captures functional limitations and/or operational restrictions at the equipment level or product level.

Read the new AC/AMC 20-189 policy document on our site by clicking here.