When a “reliable” product fails in the field, it’s not just frustrating. It’s costly, embarrassing, and depending on the industry, dangerous—for an industrial robot to seize up on the factory floor, a military drone to go dark mid-flight, or a satellite subsystem to fail in orbit. These aren’t just technical issues. They’re the kinds of failures that damage trust, delay missions, and trigger expensive recalls or redesigns—problems the FIDES Methodology is specifically designed to address.
The thing is, these systems often pass reliability tests before launch. On paper, they look good. In real life, they break.
So what’s going on?
Let’s take a closer look at why so many products that seem “reliable” still fail in the field—and why the FIDES methodology is quietly becoming the go-to alternative for engineering teams who are done chasing phantom numbers.
The Hidden Problem Behind “Passing” QA
If you speak with engineers who have experienced several product lifecycles, you’ll hear the same story repeated over and over again. The team followed the process. They did HALT, ran the MIL-HDBK-217 calculations, maybe even used Telcordia standards. Everything passed. However, six months after the rollout, failure reports began to trickle in. A connector degrades faster than expected. A power board starts glitching under heat. A sensor fails due to vibration.
This disconnect between lab results and field performance is more common than most manufacturers would like to admit.
Here’s why: Traditional reliability standards like MIL-HDBK-217 were created decades ago. They were designed for the electronics of the time, which included bulky resistors, simple PCBs, and known failure mechanisms. Today’s components are smaller, more complex, and used in vastly different environments. A method built around 1980s tech can’t keep up with modern risks.
That’s where the cracks start to show.
Why Field Conditions Break “Reliable” Designs
In the lab, temperature and humidity controlled. Vibrations are predictable. Load cycles are repeatable. But out in the field? You can encounter sudden power surges, thermal cycling, rapid altitude changes, unexpected contaminants, or simply user abuse.
Most failure prediction models don’t account for that kind of chaos. They assume a “clean” use case. The result? A failure rate that looks great in Excel, but doesn’t match what happens on-site.
This is why products that should work often fail to do so. The assumptions baked into the model don’t reflect the reality on the ground. Many teams in aerospace have learned this the hard way. Field failures exposed the disconnect between paper reliability and real-world survival, leading to deeper scrutiny of aerospace MTBF numbers and how they’re calculated under actual operating stress.
And this is exactly the gap that the FIDES methodology was created to fill.
What Makes the FIDES Methodology Different
Unlike older reliability models, the FIDES methodology was designed from the outset to reflect real-world conditions, particularly in high-reliability sectors such as aerospace, defense, and automotive.
Developed by the French Ministry of Defense and a consortium of industry partners, FIDES was designed to address a specific challenge: accurately predicting the reliability of electronics used in harsh, unpredictable environments.
Instead of relying only on generic failure rates or historical component data, FIDES takes a different approach. It examines actual design practices, supplier maturity, and real-world use environments. It evaluates how your specific system is designed, how it will utilized, and what stresses it will encounter over time.
In other words, it doesn’t assume perfect conditions. It accounts for reality.
Beyond Components: FIDES Focuses on Process and Context
One of the biggest shifts FIDES introduces is moving beyond component-level math. Traditional models focus almost entirely on component stress and failure rates. FIDES still includes that, but it also examines the human and procedural aspects of engineering.
Are your suppliers consistent in quality? Do you have documented thermal analysis? How robust is your validation process? These are the factors that influence long-term reliability, even if they are not visible on a schematic.
This is a significant reason why the FIDES methodology has been gaining traction in industries where field failure is simply not an option. It pushes teams to think not just about parts, but also about design maturity, process control, and documentation—all the real-world aspects that impact whether your system survives a deployment or fails in the field.
Why More Teams Are Making the Switch
Engineering teams today are facing more pressure than ever. Tighter deadlines. Leaner budgets. More complex systems. At the same time, customers expect near-perfect reliability. No excuses.
When field failures happen, they often trigger full root-cause investigations, audit trails, and damage-control PR. For many teams, the cost of one major failure is enough to justify rethinking how they assess reliability in the first place.
That’s what’s been driving interest in the FIDES methodology.
It’s not a silver bullet, but it is a more honest framework. It doesn’t just give you a number—it walks you through how that number was derived, what assumptions are baked in, and where your risks lie. For teams weighing their options, it often starts with a standards comparison, evaluating legacy tools like MIL-HDBK-217 against more modern, process-aware frameworks like FIDES.
That kind of clarity is rare in traditional reliability tools.
FIDES Isn’t for Everyone—and That’s a Good Thing
It’s worth saying clearly: FIDES isn’t “easy.” It’s not plug-and-play. You don’t feed in part numbers and get a magic failure rate. There’s real work involved.
You have to document your design process. You need to understand your supply chain. You’ll have to make judgments about use environments, process controls, and maturity levels.
But for teams who are serious about preventing field failures—not just checking boxes—this is exactly what makes FIDES valuable.
It forces better questions. It helps uncover blind spots. And it provides engineering teams with a means to have more in-depth conversations about what “reliability” actually means in context.
The FIDES methodology isn’t for teams that want to go fast and check a box. It’s for teams that want to go deep and build something that lasts.
A Quick Reality Check: Is It Worth the Effort?
Let’s say you’re designing an industrial control board that will live inside a hot, dusty, vibrating enclosure for 10+ years. You can run MIL-HDBK-217 or Telcordia calculations, and you’ll probably get a result that looks okay on paper.
But if that board fails early—due to a capacitor cracking from thermal cycling, or a solder joint giving out from vibration—you’ll pay for it.
A new product recall. A disappointed client. Weeks of debugging and field reports.
Now, imagine you’d used the FIDES methodology upfront. Maybe it takes longer. Perhaps it’s a bit more work to document your assumptions, analyze supplier reliability, and simulate actual use conditions.
However, in exchange, you gain visibility into where the real risks lie. You spot that the enclosure cooling isn’t enough. Onece realize that the current supplier has inconsistent quality control measures. You adjust early, when it’s still cheap to fix.
That’s the tradeoff. FIDES costs more in the beginning, but it can save you from nightmare-level costs in the field.
Field failures don’t care about your spreadsheets. They don’t care if your lab tests passed or if your MTBF looks clean. What matters is whether the system can survive its actual environment over time without constant supervision.
This is the mindset shift that more engineering teams are now adopting. They’re moving away from traditional models that treat reliability like a checkbox—and toward frameworks like the FIDES methodology, which treat reliability like a living, evolving process.
If you’re designing systems that have to work the first time, every time—especially in harsh or mission-critical environments—it’s worth taking a hard look at how you’re evaluating reliability. Not just what the numbers say, but what they mean.
And if you’re tired of products that look good on paper but fail in the field, maybe it’s time to stop chasing better spreadsheets—and start building better systems.
The Bottom Line: A Clearer Picture of Reliability
The FIDES methodology won’t guarantee you’ll never have a field failure. But it will give you a clearer picture of what you’re building, where it’s strong, and where it’s still vulnerable.
And sometimes, that’s the difference between a product that fails quietly and one that just keeps working.
