Coming soon: AMC 20-152A soon to be approved by FAA

What is AMC 20-152A? Examining the Scope of its Application

AMC 20-152A has recently been approved by the European Union Aviation Safety Agency (EASA) for use within Europe and it is scheduled to be approved in the U.S. soon via the Federal Aviation Administration (FAA).

It holds the most updated versions of the previous DO-254, which is compulsory for all Ok aircraft hardware. The update requirements stem from the fact that hardware technology within the aviation industry has significantly improved since DO-254 was originally developed over twenty years ago, and consequently DO-254 fails to currently consider a couple of the most vital considerations in today’s market- including hardware complexity, COTS procurement, and FPGAs.

DO-254: A Historic Overview

Design Assurance Guidance for Airborne Electronic Hardware (DO-254) was developed as an ad-hoc response following two closely concurrent events.

The first and perhaps most obvious is the increasing role that fireware has undertaken within the sphere of avionics in recent years (which includes a significantly higher degree of silicon-based complexity).

The second reason was meant to tackle any avionics firmware development processes that were unregulated.

Despite the prolific development that was seen in embedded avionics software engineering back in the 1980s and 90s, at the time firmware development was merely an ‘informally adjunct art form’ according to AFuzion– an eminent aviation company that encapsulates a plethora of former pilots and safety engineers so as to supply the aviation industry with unrivalled insights and critical field-analysis.

In fact, firmware seldom had the essential and highly varied role that it has today; roughly two decades ago, firmware was merely relegated to specific, specialised functions and operations within avionics. This was because:

1. At the time, firmware development tools had very limited flexibility in comparison to software
2. Firmware was extremely difficult and inconvenient to change or optimize after being installed within silicon devices, and 
3. Firmware additionally held a reputation for a quite rigorous and difficult update and debugging process- in comparison to software. 

Despite the undeniable truthful nature of the above claims, there were a plethora of expert aviation engineers at the time that were assured the evolutionary adaptation of increased firmware in the avionics industry was an essential step in the coming years. 

This meant that, in time,  Field-Programmable Gate Arrays (FPGAs) significantly reduced the aforementioned restrictions of firmware and consequently proliferated its use- illustrating modern developmental tools, increased execution speed and flexibility, and hasty updates.

Consequently, the evolutionary changes in this area quickly meant that an increasingly larger trend emerged whereby aviation engineers and developers chose to exercise reasonable ‘’logic via silicon’’, in comparison to merely relying on software. 

The Creation of D0-254

So what was the problem with DO-178?

Simply put, as DO-178 failed to solely apply to silicon-based logic (or have a relative regulatory counterpart), the possibility remained where silicon-based logic could ‘by-pass’ the rigorous procedural rigmarole that is involved with the certification of aviation software. 

This is where DO-254 comes in, it details- and consequently ensures, that all firmware developed for avionics is subject to an equally rigorous and strict developmental process with the one seen with software. 

DO-254 is applicable to all avionics hardware- albeit with most interpretations primarily focused on Complicated electronic hardware. This is because Simple hardware is much more easily definable via the relative black-box pre-requisites- which can already be tested at a black-box system level as mandated by ARP4754A.

Therefore, not much additional utility is derived from the significantly increased cost that is prescribed by the activities within DO-254 (a more detailed design, planning method, and verification process) for Simple hardware. 

Final Take

Ultimately, the world of aviation indubitably has its own unique language, a plethora of eminent companies- including AFuzion led by CEO Vance Hilderman, have already been involved in the development process of the new AMC 20-152A, as well with its likely scope of application in the field of Avionics.

Consequently, there are already in a position to provide adequate guidance to aircraft companies looking to understand the ways in which they can: a) always strictly comply with the new AC 20-152A regulations, b) perform a relevant gap analysis on their existing processes if and when required, and c) understand the aforementioned objectives of AMC 20-152A.