Exploring the Most Common Avionics Mistakes that Engineers Make, as well as How to Best Avoid Them
During his time as a pilot trainee, Vance Hilderman- the founder and current CEO of AFuzion (a prominent boutique aviation company), would often hear the phrase ‘’There are old and bold pilots; but there are no old and bold pilots.’’
This is meant to highlight the critical importance of avionics developments in aircraft safety, which clearly is primarily concerned with execution and preparation, not luck or ad hoc improvisation.
Afuzion shares a great deal of DO-254 information and research. However, to ensure pilots consistently avoid the most common DO-254 mistakes, their preparation should almost always begin by reading the relevant requirements and specified objectives of DO-254, according to Vance- who authored a whitepaper that critically analyzed the most common mistakes that even the greatest engineers tend to make, and the best ways to avoid them to promote the ‘’best possible luck’’ in the sphere of avionics.
DO-254: An Overview
DO-254 is often referred to as ‘’DO-178C’s Little Brother’’. Despite this, it, unfortunately, is quite dissimilar to the prominent software. This common fallacy has been labeled one of the most common factors that lead to experienced pilots making significant mistakes. They tend to presume that hardware development is virtually identical to its software counterpart.
DO-254 is relatively vague and subjective, whereas avionics certification normally mandates conformance in conjunction with a very high degree of quality and reliability. As a result, its success is rather elusive, and this has meant that it has been the recipient of significant complaints from both sides of the avionics spectrum.
This suggests a very tightly monitored depth control during the procurement process- especially when procuring commercial off-the-shelf avionics.
In fact, DO-254 is seldom cost-efficient during its very first usage- but this is rather unsurprising considering the industry at hand.
‘’The entire landscape of competitive avionics- both in a commercial and military context, is primarily focused on long-term: cost-effectiveness, equipment lifetime and safety’’- explains Vance.
Consequently, the ideal goal should always be to achieve DO-254 legal compliance whilst retaining the aforementioned competition.
Always remember, avionics-related mistakes are very rarely- if ever, a result of ‘’bad luck’’. Contrarily, they are the direct result of a lack of planning and understanding of the relative DO-254 objectives and regulations.
Top 3 Engineering Mistakes: A List
So we have established the importance of regularly taking the prescribed precautions to comply with the avionic sector’s safety. Let’s take a look at some of the most common- yet severe, engineering mistakes that can be very dangerous, according to AFuzion.
Failing to Understand and Apply CAST-27 then AMC 20-152A
DO-254 mandates an application to circuit cards, DAD D systems, and LRU’s. Having said that, its earlier informal ‘’revision’’ by the cross-Atlantic North American/European coordination group known as Certification Authorities Software Team (CAST) led to the authorization of an official memo (CAST-27), which further delineated a variety of aspects of DO-254.
In August 2020, this effort was further extended by EASA/FAA- who informally issued AMC 20-152A. The FAA successfully adopted this in mid-2021.
Avionics engineers currently working with DO-254 have an absolute obligation to review and apply AMC 20-152A adequately to save a prolific amount of capital and time (as it significantly cuts down on DO-254 certification-related work).
Poor Management Visibility & Manual Reviews
Working with DO-254 means adhering to over 50 major objectives and complying with reviews of dozens of process steps, artifacts, and documents.
However, management seldom actually has access or visibility into the actual review status, which means this prerequisite can easily not be followed.
‘’A simple solution would be to automate the review process via the already approved FAA-compliant DO-254 checklists, and automate the project management process with a DO-254 specific project tracking tool’’- Vance Hilderman.
This would effectively ensure that all recorded metrics are based on audits and reviews- which can go a long way in improving engineer’s performance and holistic skill sets in the long term.
Suggested Video for you by Afuzion:
Inadequate and Non-Automated DO-254 Traceability
Traceability is a crucial element of avionics safety, with both top-to-bottom and bottom-to-top options being duly required for DO-254 certification.
Top-to-bottom traceability can ensure that all: hardware requirements, hardware logic, system-level requirements, and hardware tests are adequately complete, whereas bottom-to-top traceability is focused on the logical reasons behind each prescribed, mandated step of DO-254 certification.
Neglecting Independence
DO-254 does require a prolific degree of ‘’independence’’- particularly as the criticality level increases.
‘’The term independence refers to the dissimilarity between the originator of a DO-254
required life-cycle step or…and the verifier of that same step or artifact’’ explains Vance.
If the mandated degree of independence (for each specified criticality level) is not satisfied, then the entire certification is unilaterally subjected- meaning that each step (or possibly the entire product) will likely have to be repeated or be entirely re-engineered.
Consequently, engineers are heavily encouraged to pay significant heed to the potential ‘’highest level’’ of criticality that their product may require someday in the future as if the criticality level of the product rises in the future. The degree of independence no longer satisfies it. A very high amount of rework and re-designing will be required- increasing total costs significantly.
Conclusion
Whilst it would be very convenient to conclude that the three aforementioned mistakes are the only ones in the entire sphere of avionics that could be made when working with DO-254, this is obviously not the case.
The aforementioned whitepaper itself acknowledged a plethora of other factors, including a) Insufficient PHAC, b) No Unwarranted Changes, c) Excessive Logic Iterations, and d) Lack of Automated Testing- to name a few.
Regardless, by spending an adequate amount of time learning from preceding mistakes, you are much more likely to be ‘’armed’’ with the necessary information and field expertise to take your own individualistic approach and explore how to avoid best making common mistakes in the future.
