Aspen: Driving a Stake Through Iron Gyros

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In writing about things to do with airplanes, I find myself using the word "progress" advisedly, especially when discussing anything to do with regulation. Unfortunately, that includes about everything. One area where progress has been glacially slow is convincing the FAA to give up on the idea of requiring steam gauges to backup glass panel suites in certified airplanes. Most piston airplanes flying with glass—new or used—have as many as three steam gauges still in the panel—an airspeed indicator, an altimeter and an attitude indicator.

This really did make sense when glass first appeared in volume five years ago. Although the manufacturers had some fancy predictive algorithms on reliability of glass systems, they were just that, predictions. Five years hence, we're now in sight of ridding the panel entirely of vacuum or even electrically driven gyros. I flew in one such airplane on Thursday, a Mooney 231 that I used to own but sold to Peter Lyons in 2007. Lyons is one of the founders of Aspen Avionics so no surprise that the Mooney now has a lavish three-display Aspen system—two EFD1000 PFDs and an EFD500 for chart, map, weather and other functions.

The last time I saw this airplane three years ago, it had a not-that-shabby Century HSI, a Garmin 530 and an MX20 multi-function display. When I slid behind the new glass Thursday morning, the overwhelming sensation was a little disorienting. Actually, it was closer to vertigo. To fit everything into the panel, most of the basic elements were moved around, except for the center radio stack. To stuff all those boxes into the old panel, we had to stick the JPI engine monitor down on the lower pedestal, an unhappy compromise. Now the monitor is where it ought to be: left of the main displays and right in the pilot's direct view. And here's the interesting part: The new panel has vastly more capability in a much smaller space, with a largish unoccupied space on the co-pilot side. The weight and payload of all of this was a wash. The workmanship and detail--done by Santa Fe Aero Services--superb.

In current installations, with dual ADAHRS, which this is, the only required backup is an AI, which the Mooney has. Going forward, perhaps by next year, Aspen sees a path to eliminate even that backup, ushering in the era of full glass for legacy airplanes. The technical hurdle to be overcome is the single-point failure of compromised pitot-static data. Lyons told me Aspen has a solution for this, but it isn't ready to talk about the details.

Electrically, the Aspens come standard with an onboard lithium backup battery sufficient for 30 to 40 minutes of operation. As an option, you can add an additional lithium backup which will run a PFD for two hours—more than enough to resolve the typical electrical failure scenario. Although the Aspens rely on external navigators for detailed nav data, they also have their own internal GPS sensors which are suitable for limp-home navigation.

Looking forward, if I were redoing that panel again, I would take the full-glass option, lose the backup AI and the vacuum pump. I might consider a second alternator in its place, if feasible, but maybe not even that. Not so long ago in that Mooney, I flew a lot of low IFR, some of it at night. I'm less interested in that now. Age does that to you. It's not a Part 25 transport category airplane, has definite limitations and I'd be willing to live with them, so why spend the money on impractical redundancy that you're unlikely to need. After all, there's still only one engine.

Later in the day Thursday, I toured Aspen's factory in Albuquerque and learned how the company tests each of these unit before they're shipped. It's interesting stuff. I'll post a video on that and my flight with Peter in a few days.

Comments (36)

It's pretty exciting to read about and see all of the opportunities to retrofit legacy airplanes with glass. Our flying took a quantum leap forward in terms of awareness and safety a few years ago when we bought the 496. However, the glass panels will remain only a dream since the cost of equipping our 1975 172M exceeds the value of the airplane! Maybe some years from now production volume and competition will bring the price down. Until then we'll soldier on with the steam gauges aided by a healthy dose of "496 situational awareness."

Thanks for the post - still enjoy reading about what is available.

Posted by: Ron Horton | November 5, 2010 2:51 PM    Report this comment

Ron, have you priced out a basic Aspen PFD lately? The ratio of dreamlike avionics cost to airplane value is surprisingly low. Come to AOPA next week see for yourself. Cheers.

Posted by: RONALD TARRSON | November 5, 2010 6:06 PM    Report this comment

Paul, you are right on the mark. We have an Aspen PFD in our Aerostar and rapidly see the day when the "backup" steam gauges are relegated to history. Even today, if the Aspen were to die, I'd be more likely to use the 530W/430W to keep the airplane right side up, rather than the old horizon. Hopefully, the FAA rulemakers will catch up soon!

Posted by: LARRY BAUM | November 5, 2010 9:09 PM    Report this comment

So here we clearly see the beauty of the Aspen modular concept compared to the others one piece glass. Aspen are also the most responsive and user friendly company today. If they now only came out with their own GPS/NAV/COM.... with airways!

Posted by: ROBERT ZIEGLER | November 8, 2010 4:33 AM    Report this comment

I strongly think we need to support break-out companies that compete against the monopolistic ones; I am sure you will find more gratefulness with much better service, even though they are young and getting started (maybe making a few more mistakes). Aspen would have appeared to make something more economically feasible for retrofits and its new attitude based AP connection is a superb addition.

Posted by: Horace Ferguson | November 8, 2010 5:33 AM    Report this comment

Being a Commercial/Multiengine/Instrument/A&P and vendor at EAA for 22 years, we are the manufacturers of Scratch-Off Window/windshield restoration system, we have seen many changes. Lately the AOPA has posed the question " Why are 70%-80% of student pilot start-ups not finishing?" Price, price... price. Have a failure in one of these glass panels? Big bucks - have a failure with a gyro - 200 bucks. Light Sport? Biggest mistake - not including the worlds most popular trainer the C-150 to which there are licensed examples for sale for around 13 grand. Light Sport Craft - 80 grand. GA will not survive if prices are not kept in check. I am very excited about ASPEN and am myself will be installing their displays in our T-28 and Piper Geronimo - however we cannot forget our roots and the people with stars in their eyes only realizing the price to play is prohibitive.

Posted by: MML INC. MC LAIN | November 8, 2010 6:20 AM    Report this comment

I couldnt agree with Scott more, but it's not only price. I started out in a steam gauge 172 with KAP140 AP and garmin 430. Eventually I tried a 172 G1000 with the above AP. What I REALLY needed to REALLY learn how to fly was a basic steam gauge 172 with NO AP and maybe a hand-held GPS to learn another system of navigation. Eventually I found out that when I could hand fly the plane (particularly in IMC)I THEN knew how to fly. All that other stuff is great, but AFTER you learn to fly. And by no way will you get me to rely solely on GPS unless I am forced to...and then I would probably quit flying.

Posted by: Horace Ferguson | November 8, 2010 8:18 AM    Report this comment

I rejected the Aspen because of cost, both to procure and to install. All I need is a reliable AI and a DG that has a course heading output for my GTS800. The only way to get heading output from the Aspen was to go with the $10k "pro" unit. Then it takes $3000 to $4000 to install it. You're breaking apart all the pitot-static lines, installing the extra chassis for the "pro" and diving into the radio wiring harnesses when you add the extra ARINC 429 lines. Blech.

And, whoopee, I get an HSI. Who needs an HSI when there's a thing called the 'Magenta line' on my MX-20?

I don't have $14k for the Aspen. The airpseed, altimeter, and VSI have been working fine for me for the last 29 years. My brain is a better analog processor than a digital processor, so I'll stay with the analog format for those gauges, thanks.

So what's the solution in my case? To solve the heading output problem, I found a OH'd vacuum boostrap vacuum gyro (Sigma-Tek 4000H) that gets the bootsrap heading to the GTS800. It works. Cost to trade-in the old DG plus installation was about $3k.

Next, the vacuum AI gets moved to a spare hole in the panel and the primary AI now becomes the RC Allen LCD RCA 2600-3. I can probably install it myself with AI supervision. $2500. Done.

Voila. It's all I need for less than half the price of the Aspen equivalent.

I think Aspen is missing the boat on the Legacy market and really don't have true "round hole" replacement products.

My 2 cents.

Posted by: David Rosing | November 8, 2010 8:55 AM    Report this comment

Based on the photo, the setup in the Mooney was NOT two PFD-1000s and one MFD-500. It was one PFD-1000, one MFD-1000 and one MFD-500. The MFD-1000 has the reversionary mode to take over the PFD function in case of a failure of the PFD, but has the MFD functions visible at the bottom of the right hand display.

Posted by: ROBERT LEVITTAN | November 8, 2010 8:58 AM    Report this comment

On my experimental aircraft I decided early on to bag the vacuum system entirely. Since it is a 2 place tandem plane, panel space is at a premium. I elected to go with all glass and no steam gauge back ups. I do have the redundant battery back up
for the critical instruments to get me
down safely should the need ever arise.

Posted by: Ric Lee | November 8, 2010 9:38 AM    Report this comment

>>>I think Aspen is missing the boat on the Legacy market and really don't have true "round hole" replacement products

Posted by: LARRY ANGLISANO | November 8, 2010 12:26 PM    Report this comment

>>>There's limited if any cutting of the panel, the system easily taps into existing pitot and static lines, and plays generously with existing radios in the avionics stack.

Posted by: David Rosing | November 8, 2010 3:13 PM    Report this comment

I've just had the Aspen Pro 2000 units (PFD & MFD) installed in my experimental aircraft while it was in the shop for some other work. I hope to pick it up soon, so I haven't flown with it yet. However, I also fly a Citation 551 with GNS 530/430, GMX 200, Sandel 4500 series EADI and EHSI. I have about 600 hr in the Citation, and about 500 of that with the new avionics. I flew 2,000 hr in Cessna 210, P210, and Beechcraft Duke all across the U.S. with no GPS or moving map capability.

I can tell you that although I do my annual simulator recurrency checks entirely on steam gages, I would no longer fly single pilot hard IFR without a state-of-the-art moving map display and a good autopilot. If all you're doing is flying around the local area or VFR cross country on nice days, then the new technology may not be warranted from a cost standpoint. But if I'm carrying kids and grandkids in serious IFR, I want everything going for me, and a reasonable investment is cheap insurance.

Posted by: Walt Woltosz | November 8, 2010 4:31 PM    Report this comment

I wonder what the impact on steam gauge availability will be when GA does go all glass in new airplanes as seems completely inevitable. I can't see the price of glass stuff getting any cheaper, it's not like there is a really large market for anything built for GA. Have transponders come down in cost? The glass stuff makes so much sense although, at times, it makes me feel like the pilot is a redundant peripheral prone to erratic error states.

Posted by: robert miller | November 8, 2010 4:51 PM    Report this comment

>>How many 172 owners are ponying up to the Aspens when they cost about half the price of the airframe?

Posted by: Paul Bertorelli | November 8, 2010 5:08 PM    Report this comment


I didn't meant to imply that Larry didn't know about the install, merely that the installation issues drive the COST of the installation (which a lot of folks don't know) and that the Aspen interface choices made during the design drive costs higher for Legacy users.

And at ~$13k for a PFD installation, I haven't seen a lot of installations in 172's where I live. (YMMV)

The other thing not addressed by Aspen (to my satisfaction) is the gracefulness of failures that steam gauges offer, i.e., as electronic components get old and are baked in the heat from sitting outside all summer they can fail in very odd ways, osmetimes catastrophically. So how does Aspen address redundancy? Are they fully block redundant? (What aobut display and power supply?) Cross-strapped? (But you have to be careful with cross-strapping because a failure in the A-side system can cascade over to the redundant B-side and fail the entire unit if one is not careful)

In my mind the only thing bad with iron gyros is the vacuum pump. In all other aspects they fail in a known, predictable manner, are easy (and cheap) to repair and offer graceful degradation (you can hear an abnormal gyro whine? It's going south!)

So fix the pump problem and all the arguing is moot.

Posted by: David Rosing | November 8, 2010 5:27 PM    Report this comment

I recall the same rhetoric when we went from vinyl albums to CD's. I strongly agree with the above comment: if your'e putzing around VFR in a 172, you sure do not need a bunch of expensive avionics, but the minute you hit hard IMC, there is no comparison on the ease of the "scan". It really doesnt even exist in glass.

Posted by: Horace Ferguson | November 8, 2010 6:29 PM    Report this comment

So how does Aspen address redundancy? Are they fully block redundant? (What aobut display and power supply?) Cross-strapped? (But you have to be careful with cross-strapping because a failure in the A-side system can cascade over to the redundant B-side and fail the entire unit if one is not careful)

Posted by: Paul Bertorelli | November 8, 2010 6:36 PM    Report this comment

Aspen appears to have a great product I've watched for some time. The problem for those of us with $35K airplanes; it's hard to spend $10K, then have to spend more than that to install a Brand G GPS receiver to drive the unit. I'll jump on Aspen the SECOND they include a GPS database so I can keep my navcoms (and $8,000+). Like a large segment of pilot/owners, I don't need LPV approaches as long as my GS receiver works.

Posted by: STEVEN JONES | November 8, 2010 8:26 PM    Report this comment

I fly a C172SP with G1000 and in 1200 hours the only things that have failed on this airplane are the vac pump the backup AI and the backup ALT. And for IMC I'll take a good glass panel and an auto-pilot over steam gauges any day.

Posted by: Brent Dalrymple | November 9, 2010 7:57 AM    Report this comment

I basically fly the mountain West in my C-210D where Aspen is actually located. Fancy pants IFR instrumentation is of little value here because IFR = ICE. When you can solve my ICE problem then maybe. But I can by a lot of Southwest tickets for the cost.

Posted by: ARTHUR THOMPSON | November 9, 2010 8:38 AM    Report this comment


I wasn't thinking of Part 25 or 23 airplanes, I merely wanted to maintain the same block redundant reliability that exists with the 'old' steam gauges, namely, completely independently powered with completely separate attitude references. E.G. "needle-ball-airspeed" with its electric TC is completely independent of vacuum AI. For it's clunkiness, it's very elegant in failure-scenarios.

That's great that the Aspen has a 30 minute battery, but one has to ask with their proposed redundancy setup if a failure in one system could "take out" the other by nature of the cross-strapping between the boxes (e.g., if a battery fire in one Aspen diaplay could cause an internal short that then causes the other dislay to fail because of the nature of the cross-strapping between the two. In IMC that would be a death sentence.

I'm just asking. This stuff requires more thought as things get more complicated. . . .

Posted by: David Rosing | November 9, 2010 9:18 AM    Report this comment

>>>I'm just asking. This stuff requires more thought as things get more complicated. . . .

Posted by: LARRY ANGLISANO | November 9, 2010 9:33 AM    Report this comment

Interesting dialoge, and a lot of good thought, but a couple of observations as I wait one more week to pick up my Bonanza with it's new G500 and electronic standby AI. I learned to fly in Navy jet trainers and then flew fleet aircraft navigating off the tail of the number 2 needle driven by a very sporadic TACAN. We did it, but with a very intense training process not easily duplicated in a GA setting. After many years with the airlines, I had the joy of transitioning to Boeing PFD/MFD and EFIS MAP systems. As an instructor/check airman I've heard all the arguments at the start of the training process. but at the end it is a universal "Sum bear" that sure beats the old way. The increase in situational awareness and ability optimize your flight progress is so great as to be hard to quantify. Living in the Texas gulf coastal I've been caught with unforecast fog several times and it's nice to know my plane and systems won't let me down. BTW, my wife will be better able to "remain in the loop" and monitor what's going on.

Posted by: Burns Moore | November 9, 2010 6:53 PM    Report this comment

Avionics have come a long way. It seems like it was just a few years ago we were debugging approaches on one of the first Garmin GNS 430. >> I flew a lot of low IFR, some of it at night. I'm less interested in that now. Age does that to you.>> Paul, I thought I would never hear you say this. An article on the reasons why might be instructive...

Posted by: DANA NICKERSON | November 9, 2010 8:28 PM    Report this comment

larry anglisano installed my aspen and i am totally thrilled by it. he put in the pro model and my ifr scan is measurably improved.

Posted by: Unknown | November 10, 2010 7:04 AM    Report this comment

I was a steam gauge guy for over 30 years. Even when flying for a commuter in the 90s.

That all changed when I decided to install a Pro in my "old" Piper Charger nearly a year ago. The Pro coupled to the autopilot and Garmin 430W is a combination that can't be beat for single engine, single pilot IFR flying.

It took me about 5 hours of flying the new Pro and radios to get used to them. I'm not looking back! Sure it was not cheap (What is in aviation now days?), but it was time for an avionics update so why not at least step into the 21st century and gain the use of a "glass" display.

I can say that I did have a problem with the Pro display going out. Aspen took care of that within 24 hours. No complaints about customer service and product support.

My bigggest complaint is finding an affordable replacement for my vacuum back up AI. If I get that out of the panel I can lose the vacuum pump which I consider a very good thing.

The Pro is not for everyone, but it works at a reasonable cost even when fitting into older aircraft.

Posted by: Michael Trenholm | November 10, 2010 7:52 AM    Report this comment

Maybe if we could get rid of or modify the third class medical more pilots would stay in GA and spend their money on such things helping to bring down the cost. Or those that do stay in GA and spend lots money trying to keep their third class medicals could invest it in avionics instead.

Posted by: Unknown | November 10, 2010 10:19 AM    Report this comment

I'd love to have an Aspen! But since I don't, here's a $4.99 iPhone app that uses the iPhone's gyro sensors combined with GPS to get you a nice EFIS-like attitude display with speed, altitude, heading and position information. Nice for backup.

Check it out at

Posted by: Bram Bout | November 11, 2010 2:48 PM    Report this comment

Nice one Aspen. Maybe their PFDs are the backup unit for Garmins etc? But IMO it ain't progress if any previous capability or redundancy or security layer is lost. How often does lightning or an alternator failure take out a steam gauge?

Posted by: John Hogan | November 13, 2010 4:17 AM    Report this comment

Posted by Paul Bertorelli on November 8, 2010>>>>Not a lot of technical development going on in steam gauges, tho>>>>>

Not so. And you can make a difference, Paul. For example, the FAA is apparently dead-set against the use of silicone hoses for legacy vacuum systems and insist we use degradeable rubber hoses in certified. How about you write a piece on silicone hoses and how they could help save lives (I mean, why should I die for the FAA's laziness to approve a silicone vacuum system hose?)

Posted by: David Rosing | November 15, 2010 8:36 AM    Report this comment

That's because, David, I was referring to developmental work, not sustaining legacy systems. It's silly to call to silicone hoses R&D on the same level as what Aspen is doing. I'll concede the FAA should just rubber stamp improved materials applications after reviewing the manufacturer data.

Posted by: Paul Bertorelli | November 15, 2010 9:33 AM    Report this comment

Ah, but what is Aspen actually doing--other than mimicing functionality of steam gyros?

Let's think about this a minute. What MUST we have? Let's go on a hypothetical IFR flight.

We MUST: control aircraft about all 3 rotational axes (yaw, pitch, roll) This is accomplished via Attitude Indicator, compass, (and as backup devices, turn coordinator & airspeed)

We MUST: control position of the aircraft in 3-dimensional space (LAT, LONG, altitude) For this we have any combination of GPS, VOR, ADF, DME, ILS, and our buddy the altimeter, and to a lesser extent the VSI.

We MUST: keep the aircraft from falling below minimum safe speed for flight, nor exceed maximum aerodynamic loads. Hence, we have our prime instrument, the airspeed.

Then we MUST keep the engine running, hence we need tach, MP, fuel quantity, oil press/temp & cylinder temp.

So what is Aspen really doing other than (hopefully) making the above more reliable with the use of hundreds of thousands of transistors? All the other stuff they offer on the display is on the 'nice-to-have' category, but it's not absolutely NEEDED.

But I'm just having a pleasant discussion.

Posted by: David Rosing | November 15, 2010 10:07 AM    Report this comment

Oh, and I forgot to mention, not only does the Aspen have the hundreds of thousands of transistors, it also has a common power supply to perform all those functions as well as use a backup power supply technology (LiIon) which (albeit rarely) has been known to catch on fire and, theortetically, could destroy the entire unit, thereby reducing system functionality a bit. Not that that could EVER happen.

Posted by: David Rosing | November 15, 2010 10:26 AM    Report this comment

Glass panels are not economically feasable for a large segment of the pilot population. The six pack has worked well for years and will continue to work well at a fraction of the cost. My students learn to use a very sophisticated computer for situational awareness. Their brains. GPS is a wonderfull tool and has increased safety but in insist that my students be able to have it go black and motor on with confidence.

Brian Thompson Washington State

Posted by: Brian Thompson | November 15, 2010 12:11 PM    Report this comment

I'll try and get this in before the Indian Hackers flood this blog. I've just received my airplane back after install of the G500 w/ chartview and JPI930. With 15 years experienceon Boeing glass displays, I feel comfortable making these observations: Using Jeppesen chartview and GNC530 requires more recent currency and familiarity than the traditional 6 pack. There is so much interplay between the auto pilot, GPS, GPSS, approach selection, activation and integration with all the above items, it could become very easy to be overwhelmed, get way behind and loose the all important SA. I'm still learning, but I'm continually amazed by all the capabilities. Good luck and stay current for you making the jump.

Posted by: Burns Moore | December 20, 2010 10:24 AM    Report this comment

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