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How to design avionics to last for life of airframe?

smash

Active Member
Recent discussions about EFIS hardware compatibility, software updates and feature requests, etc. now have me wondering about what is considered "best practice" for designing a glass panel. The RV-14 airframe could easily last over 30 years with proper maintenance (yes I've primed EVERYTHING in the airframe). iPhones and iPads don't last much beyond 4-5 years. How long will a Dynon or G3x system last? I would have to think any glass I put into a panel today would be lucky to last 5 years before replacement is required. Is there anyway to make that replacement less painful? Is there a wiring scheme that should be used that would be plug comparable with future replacements? Should I just go with steam gauges? What commitment do Dynon and Garmin have to future support? Are there standards that will be supported for the next 30 years like CAN bus or ARINC? Can any manufacturers speak to what their plans are for 30 year life span support?

Engines are life rated for some number of hours of operation and we all set aside funds for engine rebuild/replace as an ongoing expense. Maybe avionics should have a similar rating so we can at least understand the costs involved.
This stuff is a significant portion of the cost of the airplane and it would be nice to mitigate future expenses if possible. Any ideas?
 
The bigger issue is what your needs are. If your needs are technology-intensive, then you'll need to replace things relatively soon. If they aren't, the useful life will be increased. Barring outright failures and changes in FAA requirements, the avionics should last for quite a while.

I have an unprimed certified aircraft that's over 60 years old and is doing nicely. Its ancient nav-com is working well, as is its old transponder. But due to ADS-B rules, the transponder is due for a change. The plane is on its second engine.

So with a bit of luck your avionics will be fine for a long time. If you install analog instrumentation, that might last as long as the airframe.

Dave
 
I hope you are wrong on the five years. My Super Cub's D100 and D120 are on their eleventh year and I'm hoping for many more out of them. I hope my Skyviews in my RV-14A do the same.
 
I suspect many of them would last as long as your A/C but often we replace them to take advantage of the faster and newer technology. If you are OK with the older HW, then much concern unless the company goes out of business like Blue Mountain did years ago. As far as replacing them goes, there are two challenges to this, one is the physical aspect of the new equipment and how much work will it be to fit the new/bigger EIFS and then the wiring. For the wiring, I have chosen to go with the hub system (Approach fast stack) and frankly can not imagine any other way. It has been as cost effective as hard wire and has made any changes to the avionics a breeze when it comes to wiring. In the last 7 years since flying I have added two additions to my avionics and that has been just a plug and play. So when it comes to replacing my EIFS, I will be much more concern about the physical aspect of the new unit.
 
30 years

30 years??? My first homebuilt is still going strong at age 52. Spartan Executive's built around 1940 better than new if you want an all metal example. Twin Beech's, DC3's etc.
 
There are an awful lot of Garmin 430s going strong and still supported by the manufacturer, and it has been around a lot longer than 5 years. Hopefully, the current technology will continue to be supported for a long time, too. Choose your manufacturer wisely - if that is possible . . .
 
It helps to have a proper mindset. Don't build your airframe around your avionics. Build an airframe that can pretty much stand on it's own and add avionics ON TOP of everything. It's just a trick that leads you all the way through. Also, not a fan of hubs. These are simple airplanes that happen to have nice computers. But, like everything digital, it's out of date before you get it installed.
 
During times of changing regulations, changing technology and new products being introduced, not sure you want to design avionics to outlast or out live the airframe. I've also witnessed the avionics being outdated by the time you' re ready to install. I think the best method would be to build flexible and modular. The older you get the harder it is to work under the panel, take my word for it. Build it (panel) with future "change out" in mind. After all, that's what homebuilders like to do.
 
plan for change

Avionics technology is now on the "Moore's Law" price/performance/feature curve, which is of course excellent for us. This means that every 2 years or so something doubly amazing will be released.

This is why most manufacturers I have spoken to said to wait as long as possible before buying the avionics, and build the panel area for easy access and upgrades/replacement. There don't seem to be any real "standards" beyond the normal good wiring practices you see in various posts on this site and on aeroelectric.com.

What I was hoping to see is a very high brightness tablet, and a standard set of sensor aggregators. Then I could just put the latest tablet into the panel. This does not look like it's going to happen, as I guess the tablet manufacturers don't really care too much about screen brightness, and my ipads don't seem to want to stay lit on a hot day or when they are exposed to direct sunshine for a while.
 
Good topic to explore

I talk to a lot of builders about panels. Typically they walk up to the plane and ask "who built your panel?". After I tell them I did and get past the "I don't believe you" phase, we usually have a worthwhile conversation.

Now relating this the thread topic, I offer some foundation basics as a start:
- Assume you will modify your panel. The super wham-a-dyne carbon fiber, silk screened, does everything but makes your espresso panel that you labored with the avionics shop to get just right will scream to be modified once you start flying. My RV-8A went through five panel modifications, and one full panel rebuild to the SkyView system over a 13 year period. The RV-10 panel was replaced at the 18 month point. Only Comm #2 was changed, but much of the avionic placement was modified. I never use anything other than the stock Van's panel blank so panel redo was little more than a new blank, cutting holes and paint.
- To the earlier posts, I believe you can count on a decade or more of service from some key elements (e.g. the SkyView system, a GTN-650 and any steam gauges you may have). This means that the majority of you wiring (like the SkyView network) will support equipment upgrades.
- I offer that the dust has not yet settled on ADS-B compliance. I'd guess that some of the products from the plethora of options may not make it for the long haul. Here integrated EFIS solutions appear to have the advantage.

So what? Consider:
- Build your own panel. Have your avionics shop of choice build your harness for your certified GPS navigator buy you do the rest. Systems like the SkyView are so well documented anyone can do it.
- Stay with the stock Van's panel blank. If you must have the super wham-a-dyne carbon panel, buy two with one blank so you have it when you want to make a mod.
- There are so many options for labeling and such that you should assume the labels will be changed. Pick a process that supports this.
- Consider your first year of flying and build a panel to support. That way you have some time in the saddle to figure out what you really want, and another year to save up a few bucks to pay for it. If you do this, have some base concept in mind, so that what you buy for the first year will be used in the follow on panel. Example; one 10" SkyView with comm, transponder and autopilot and a steam gauge AirSpeed. The second SkyView and GTN-650 later.

Carl
 
I would have to think any glass I put into a panel today would be lucky to last 5 years before replacement is required.

This is only true if you have the mindset that you need the very newest features or hardware. But this was true 30 years ago too when a company came out with a newer com radio or transponder that was different than the one in your plane too. Did every 172 upgrade to digital display com radios to replace the old analog turn dials?

There's nothing that requires you to replace your avionics, even if they are no longer sold or software updates have stopped. The equipment still does what it did the day before, just like that old com radio does what it's supposed to.

As another analogy, do you consider all the RV-7 airframes to require replacement because the RV-14 came out? And the 6's all got crushed when the 7 came out? Nope, those are still great airframes that still do what they were designed to. It doesn't matter that there's something newer out there.

Dynon still sells and supports the Dynon D10A, first sold in 2004. SkyView was first sold in 2009 and while it now has three products in the line (classic, touch, HDX), they are all still supported, getting software updates, new features, and are all still sold. So there's a lot of history that software based EFIS products enjoy much more than a 5 year lifespan. These are not products that require a connection to the internet and some server to keep working.

Define your mission and needs, buy the equipment that meets those needs, and enjoy your plane. While it is any competitive company's job to keep coming out with new products which make you want the newest thing, we also believe it's our job to make sure we build quality products that are designed to last the life of an airplane so it's your choice to upgrade, not a requirement.
 
If the equipment you install today is still doing all you wanted it to do in 5 years, the tactic would be resist looking at the latest whiz-bang do-dad stuff in your buddies project, cancel your magazine subscriptions, walk thru OSH with blinders & think of the nice things you could buy your bride... & keep flying!

The more probable tactic would be plan now (build in easy access) for the unavoidable urge to update your panel in the future, arising more so from a do-dad issue rather than a unserviceable or obsolescence issue.
 
My dad, hopefully I won't go to purgatory for mentioning an alternate Home Built, installed a lord mounted sub panel in his Mustang ii, with 3 removable fascias for ease of access to the instrument bays behind it. Makes it a relatively simple task to reconfigure to allow for future upgrades.
 
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I bought my G3X right after the new GSU25 came out with AOA (4yrs ago?), the touch screens GDU's came out along with several software upgrades before I got my "outdated" G3X installed and flying. These new EFIS systems are all great and leaps and bounds beyond what most of us are used to flying with.

I spent most of today installing software and a couple more wires to take advantage of some new (free) functions offered, same ol' hardware just a couple new features that cost me a day of work cuz I'm slow.

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Spend the time to find the equipment that best fits your needs and install it and the wiring with "maintenance/upgrades" in mind and you'll likely be flying the same system longer than a paintjob....
 
I think there's two parts to this problem, the desire to have the latest wizardry and obsolescence of components. The first part is completely under your control, but the second is not. Seems like there's no reason you can't fly with the same equipment for 30 years so long as the manufacturer will repair it. But will they? I've got an Apollo/UPS/Garmin GX60 in my panel, a perfectly good radio that Garmin will no longer service. I'm on my second unit actually; the display failed on the first one which sent it to the junk pile. Good used replacements are becoming scarce. Meanwhile countless KX170s from the 1970s soldier on...

I've also got a Trutrak EFIS that has been out of production for years, but which I hope will continue to be serviceable (so far it hasn't needed anything). A really excellent unit which I think is superior in some ways to the best of the current crop. I would describe its simple design as relatively timeless.
 
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My first exposure to EFIS systems was flying the first production Diamond DA-40s equipped with the newly-certified G1000 in 2005. I thought, why would anyone want a computer in a plane? Computers are junk after 5 years. Surely these won't last as long as the round dials in that old 172 over there and when those fail you just pop out the bad instrument and replace it. And these screens are wired into all the systems in the plane, not just one. How could we ever replace it without spending as much as the plane is worth?

Well I had a lot to learn back then. Those G1000s are still going, with many new software updates I'm sure. We've built a lot of airplanes at our shop with both GRT and Garmin stuff since then and the only reason anyone that I know of has replaced a screen is to update it to the newest doo-dad like Synthetic Vision. Some updates are easier than others-- the new GRT screens have the same wiring as the old ones, so a screen update is not that big of a project. Other manufacturers are probably similar.

As others have said here, when you build your plane, keep the panel modular. Make sure the panel face is held in with screws so you can pull it all out if you need to. Design it so that you can remove items and replace as the airplane ages. Fly it and enjoy it! It will likely last many years longer than any piece of household electronics.
 
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