Why Certified?

[Hawk-57]

I can’t find a good discussion as to why I should care if avionics are certified in any airplane (excluding the obvious commercial use of the plane or taking passengers for hire). Any help is appreciated.

 

[Rhino]

Certified aircraft aren't allowed to use non-certified avionics.

 

[airguy]

Certified aircraft aren't allowed to use non-certified avionics.

While accurate, that answer is not helpful for the question because it is incomplete.

Certified aircraft are not allowed to use non-certified avionics, but experimental aircraft are. Exceptions apply such as IFR navigators, ELT's ,and transponders.

 

[Hawk-57]

I got that, but why? The equipment works and is widely used in all airspace and a huge variety of aircraft. Is it for passenger safety or airliners? - it sure is NOT for military aircraft (I flew for 20 years and never had a civilian pilot license) I had to get one when I retired. How do they know if I buy a non certified? What do they do about it? Just trying to understand why I should pay much more for the same equipment.
Thanks for the discussions.

 

[Marc_J._Zeitlin]

I got that, but why? The equipment works and is widely used in all airspace and a huge variety of aircraft. Is it for passenger safety or airliners? - it sure is NOT for military aircraft (I flew for 20 years and never had a civilian pilot license) I had to get one when I retired. How do they know if I buy a non certified? What do they do about it? Just trying to understand why I should pay much more for the same equipment.

Because if you have a certificated aircraft with a TC, then each year, when you bring your plane to an IA for an annual inspection, they will determine if your plane meets the TC, any STCs, any 337's, and has appropriately legal equipment in it by examining the equipment. If it does not have certified equipment per the regulations, they will not approve the annual and may ground the plane. Not only that, but when you go to an avionics (or A&P/IA shop) to have the equipment installed in your plane, they will not do it unless it's legal equipment. Assuming they're honest, at any rate. Some are not, but I don't think you want to count on that, either for the install or the inspection.

And since, with TC'd aircraft, you are not allowed to do any and all work, as you are on E-AB aircraft, you must go to an approved avionics station and/or A&P and/or IA to have the work done.

So whether or not there's a good, logical or safety reason for having certified equipment in certified aircraft, there's a good, legal reason to do so - so that you can continue to fly the plane, rather than just stare at it on the ground.

 

[Rhino]

While accurate, that answer is not helpful for the question because it is incomplete.

True, but the question wasn’t exactly complete, so Iwas hoping it would prompt him to elaborate.

 

[JohnAJohnson]

I can’t find a good discussion as to why I should care if avionics are certified in any airplane (excluding the obvious commercial use of the plane or taking passengers for hire). Any help is appreciated.

It's a legitimate question Hawk, but unfortunately, in my opinion, the only true answer is a cynical one.

When it comes down to it, if drivers and their land vehicles had been licensed and regulated by the federal government instead of states, and the controlling bureaucracy eventually ran amok and development stopped and costs were prohibitive, there would have been a revolt. Part 121 can pass the cost to passengers. The military doesn't need to make a profit, plus, they're spending other people's money. So the answer for GA is, we replace required (by the Type Certificate) stuff, including flight instruments and other avionics, with stuff that is approved with a Supplementary Type Certificate, because we are an insignificant voting block.

 

[MikeD]

I can’t find a good discussion as to why I should care if avionics are certified in any airplane (excluding the obvious commercial use of the plane or taking passengers for hire). Any help is appreciated.

For the same reason why you should care if your engine, propeller, wheels, brakes, instruments, hoses, lights, bolts, nuts, screws, ...... are certified. If they are not then it is your responsibility to ensure whatever is installed is fit for purpose and doesn't impede safe operations. Not all owner/operators are capable of making that determination.

If you are flying an experimental aircraft, you can use any type of avionics, hardware, electronics, instrument, engine, propeller etc you desire. Just because you can, doesn't mean you should.

 

[Scott Campbell]

You can install non-certified avionics in your plane, you just need to change your plane to experimental and you can install whatever you want. This is how avionics get certified in the first place. We installed a hyperspectral seeker head in the wing tip of a Cherokee Six for testing by making it experimental. After we concluded the testing we put the old wing tip back on and got the type certificate back. I forget what all the required paperwork was, it was over 20 years ago (337 maybe?). If you don't restor it back to the original condition you might find it difficult to find a buyer for the plane when you go to sell it.

 

[Albee]

I can’t find a good discussion as to why I should care if avionics are certified in any airplane (excluding the obvious commercial use of the plane or taking passengers for hire). Any help is appreciated.

So you've gotten the lawyer answer, if you're not experimental you should care because otherwise you're not legal and ... eventually ... you'll be found out and penalized.

And you've gotten the cynical answer that it's another Big Brother overreach.

There's significant truth in both of those. Now I'll attempt to describe the good reason behind the first, which unfortunately enables the second.

First a short, mechanial anecdote. Somebody I knew was building a kit helicopter. I was interested and considering going in with them. But I'm an engineer so I started poking around the design a bit. Almost immediately, I found safety-critical bearings which were off-the-shelf from a reputable manufacturer, but they weren't "aviation" parts. Digging a bit more, I discovered these bearings were operating, under normal non-emergency design cruise conditions, ABOVE the manufacturer's published maximum load. Suddenly I understood why these helicopters required roughly $100/hour in replacement of time-limited parts, and STILL had a mean time between catastrophic mechanical failures of only a few hundred hours. But, perfectly legal in an E-AB 51% kit.

There is a a high probability you are not an electrical engineer qualified to evaluate a design for performance or for a myriad of failure modes, be they performance degradation, failure to function, or actively hazardous (e.g. catching fire) under all the operating scenarios, temperature, shock, vibration, g-load, age etc. your avionics may face. An avionics technician, no matter how brilliant, won't catch all of those. Most degree-carrying electrical engineers don't have the full skill set: companies hire several with overlapping skills to get all the jobs done. If by chance you ARE qualified, you know that it's actually a LOT of work to do all those evaluations. And surprise surprise, even a pretty forthcoming outfit like Dynon isn't going to let you download their source code, download their schematics, board designs and parts lists, their manufacturing instructions etc.

I don't have all that knowledge myself, but in a former life I worked in teams of engineers where between us all we DID have the knowledge and skills and we used them to bring things like the F-35 from idea to reality. So I know that the process looks like even though I can only do a few of the steps personally.

Here's Joe Pilot. He's nailed the private pilot certificate, 100% on the written and his examiner asked for pointers in airplane handling and weather intelligence. Joe also doesn't have the skills and knowledge to fully vet his avionics. Or his engine, aerodynamics, structure etc. How is Joe protected from a company, let's say FlyByNight Avionics, trying to make a quick buck by cutting corners? Enter Uncle Sam, who decides the general public has a right to expect that Joe and his airplane won't be crashing into their house. So Sam comes up with a lengthy list of standards FBN Avionics must meet, to reduce the chances of something going bad in a dangerous way. And Uncle says Joe can't fly an airplane with equipment that doesn't meet those standards. Meeting those standards means Uncle hires some qualified engineers and FlyByNight Avionics must provide all that design information to those engineers so they can see that everything has been done right. And once they agree, FBN can sell their equipment as "certified" for aircraft use. And Joe doesn't have to worry (as much) that the box will catch fire, or stop working because it's 105F in the cockpit or the antenna got wet.

Now, once upon a time, those standards made perfect sense. They were what anyone who knew what they were doing would agree should provide a reliable, safe product. This was probably about 1948. But part of the government, the people writing and enforcing those standards have almost ZERO motivation to update them, doing so only when it can be proven the new standards are even safer. But electronics has advanced, and now there are new technologies available, like the transistor. So that government army forms a study committee, or more likely a group of committees, to figure out how transistors could cause problems and write new standards. Until they're done, nobody can use a transister becuase Uncle Sam doesn't know how to certify it. So the standards still make sense if you ignore technology that's less than a decade or two "new". And probably always will.

I don't mean to imply that non-certified avionics are lacking in quality; not at all. But what quality is there, is present because the manufacturer wants to make a quality product, for all the good reasons to do so, and also because E-AB owners talk to one another and a bad product will quickly become widely known and unprofitable. Certification is an attempt by the government to mandate quality even for those who don't want to get that involved. The helicopter in my anecdote would never get certified with that bearing, but I'm pretty certain many of the kit builders had no idea how overstressed it was.

Buying Dynon non-certified was an act of faith in the beginning. Faith that Dynon wanted to grow and be well-respected and would do all the engineering work to make the products reliable and safe. And they did! But for a long time, only us wild and crazy people with passenger warnings on our aircraft could "take the chance" on a company like Dynon. It turned out to be a good bet; I'm sure other promising companies fell by the wayside during those years. Eventually, with a large installed experimental base and careful attention to detail, Dynon was able to go through what I'm sure was an expensive and frustrating process to get their hardware certified so Joe Pilot can use it. Autopilots in particular seem to be victims of the 1948 thinking. From what I've read, even though the next airplane to get a Dynon autopilot certification will use the exact same servos and control laws as the one before (different parameters and brackets of course), Sam's minons still demand those parts get vetted again as if they were new designs.

 

[Bill Putney]

Something I don't think has been touched on is that, presuming you are paying for insurance, if the aircraft isn't "Airworthy" in the legal sense (specifically "...meets it type design or as properly altered...") most insurance is void. My guess is that the airplanes you've been flying for the last 20 years were self-insured.

Making "experimental" modifications to your airplane takes it down a path that is hard to get back from. It makes the airplane all but un-sellable. It would cost a lot to have an A&P/IA re-conform the airplane to its type design and/or get all the approvals to keep unapproved modifications done. So, your airplane is going to have less resale value than what you paid for it despite it's really nice looking new panel.

For 14 CFR Part 91 operations, the FAA is really more concerned about the people on the ground that your airplane my fall on than the people inside. I think their feeling is that the people flying in a private airplane have made and informed decision. People on the ground, less so. A certified aircraft can fly anywhere in any conditions within the limitations set by the manufacturer and approved by "The Administrator".

Experimental is a different game. You can do about anything that pleases you. As a tinkerer it's very liberating, But the catch is the Limitations. An FAA inspector sets the Limitations for your airplane. I've never built an experimental, but an FAA Maintenance Inspector friend describes the process as making and inspection and determining where and how it can be flown and setting that all out in the Limitations. If you're building an RV and you do everything just right, the limitations are going to be just about how Vans outlined them. But suppose you started making structural changes, built your own engine, made all your own primary flight instruments and maybe your craftsmanship isn't up to standards. The Inspector thinks "Well... if this guy wants to fly this thing, I can't stop him, but I can keep the flaming pieces falling on someone else." and proceeds to write Limitations that say things like no flight over populated areas, no flights further than 5 miles from the home airport. Again, not going to try to regulate who's inside, but looking out for the innocent bystanders on the ground.

I suspect that the Dynon "Experimental" stuff is built and tested in exactly the same way as the "Certified" stuff. There really isn't a big financial penalty to using Certified equipment in your Certified aircraft (unlike products from some other avionics manufacturers). You must pay them for the use of the STC which is a fraction of what it would cost you to get the experimental stuff legally approved. Dynon does take on a lot of extra paperwork and scrutiny with their Certified products, but I'm guessing they feel those obligations are part of the business they are in and care for their customer's health and wellbeing. I'm notoriously squeaky, but in my own enlightened self-interest, I don't want to make life harder for companies that seem to be doing the right things for the right reasons. I think Dynon earns every dime and I want them to continue.