ASPEN VS G5's when coupled to 400b autopilot?

JOHN SEMERC

JOHN SEMERC

Filing Flight Plan
Joined
Mar 18, 2017
Messages
21
Display Name
Display name:
skytrails
Recently swapped out my 530W for a 540 and love it! My next attempt is at an autopilot and HSI, so gathering info and suggestions as to what my fellow pilots are equipping themselves with. All is info and knowledge is greatly appreciated.
 
I completely misread your question, I was thinking you were replacing your autopilot with a new one, but that doesn't appear to be the case now that I re-read the title, so ignore my original post. I'm currently debating the G5/Aspen myself. I like the G5 just because they're sort of the hot item these days. I'm a little concerned by the infrequent failure reports I've seen of the G5 losing AHRS and not returning until landing. The video I've seen of the pitot icing over and failing the Aspen completely was also concerning as well, but I guess these are outliers and maybe not anything to get overly worked up about.
 
Last edited:
Challenged said:
I completely misread your question, I was thinking you were replacing your autopilot with a new one, but that doesn't appear to be the case now that I re-read the title, so ignore my original post. I'm currently debating the G5/Aspen myself. I like the G5 just because they're sort of the hot item these days. I'm a little concerned by the infrequent failure reports I've seen of the G5 losing AHRS and not returning until landing. The video I've seen of the pitot icing over and failing the Aspen completely was also concerning as well, but I guess these are outliers and maybe not anything to get overly worked up about.
Click to expand...

How many AHRS failures have occurred with the G5? I’ve had mine for about 6 months and the only problem I’ve had is losing GPS signal during a roll. Outside of that, the thing is flawless. Much better than the Blue Mountain I replaced it with.
 
Yes, you're probably right, I'm sure the vast majority of either units work just fine. My initial instinct was to go with the Aspen, just because it is capable of so much more, but at what cost and do I really need all that. Then again, will the G5 complete the panel and will I be coming up with a short list of options when I do install a new auto pilot, being that Garmin is so proprietary over their products.
 
I think it comes down to which autopilot you want. GFC500 = G5. Other than that, Aspen is an option. But I think I’d still do two G5’s for the redundancy.
 
Yes, if you believe your future panel includes a GFC500 you will need the G5. That would end the decision process right there. And it will be quite AP/ADI/HSI combo indeed... fully integrated, all vertical modes, intercepts, procedure turns, holds, you name it. Unprecedented for the price.

If not, there's a bit more personal preference involved. Is money no object? There are some schools of thought that the Aspen should be the PFD/MFD of choice but I'd go straight to Garmin for the TXi at that price point. Total no-brainer in my opinion.

The Aspen has a glaring weakness with its failure mode. If you lose air data inputs the unit goes red-X. That's a really big deal. Lots of nice features, but those features don't count for a hill of beans when your PFD goes down. The Garmins work independently. Each unit has its own backup battery (4 hours... wow) and you can revert the HSI to an ADI if it goes down. That alone pretty much cinches it for me, but I'm a serious IFR traveler in my light twin. If I was day VFR or vanilla IFR maybe the Aspen would be a better fit.
 
For anyone else interested, here's the list of currently supported aircraft that you can install a GFC500 in, according to the Garmin site:

Beechcraft Bonanza
Models: S35, V35, V35A, V35B
Cessna 172
Models: F, G, H, I, K, L, M, N, P, Q, R, S, F172F, F172G, F172H, F172K, F172L, F172M, F172N, F172P
Cessna 182
Models: E, F, G, H, J, K, L, M, N, P, Q, R, S, T, T182, T182T, F182P, F182Q
Piper PA-28
Models: 150, 151, 160, 161, 180, 181
 
Velocity173 said:
How many AHRS failures have occurred with the G5? I’ve had mine for about 6 months and the only problem I’ve had is losing GPS signal during a roll. Outside of that, the thing is flawless. Much better than the Blue Mountain I replaced it with.
Click to expand...
I've had mine close to 1 year and zero issues.
 
I was one of the early adopters who was affected by a problem with GPS position on the G5. The problem was a "lean" to one direction of approximately 8-10 degrees of roll.

I wasn't the onIy one. There were others, but not many. I was a member of a group which seemed to include about seven or eight aircraft owners. There was a software revision in late '16 which fixed it for most of us and another revision in early '17 which fixed it for all of us. We "problem users" maintained a little email thread for a while and we still communicate occasionally. No one has had a recurrence since that last revision fixed it about a year and a half ago. The units have been 100% reliable since then.

Since then there have been multiple other firmware updates which have improved functionality, but no one has experienced a recurrence of the "lean" problem. Garmin got right on it and fixed it.

I love the G5. What a piece of gear. Wow.
 
Ryan F. said:
The Aspen has a glaring weakness with its failure mode. If you lose air data inputs the unit goes red-X. That's a really big deal. Lots of nice features, but those features don't count for a hill of beans when your PFD goes down. The Garmins work independently. Each unit has its own backup battery (4 hours... wow) and you can revert the HSI to an ADI if it goes down. That alone pretty much cinches it for me, but I'm a serious IFR traveler in my light twin. If I was day VFR or vanilla IFR maybe the Aspen would be a better fit.
Click to expand...

Unfortunately, most pilots don't have a solid understanding of AHRS technology and the failure modes. And the "red-X" is one of those areas. All AHRS driven units (G500, Aspen, etc.) use a combination of inputs (pitot static, GPS, etc.) to create the AHRS depiction. And it is the reason they need to have a supplemental AI instrument in case of AHRS failure. A unit like the L-3 ESI 500 is TSOd to function at a lower level equivalent to a mechanical AI if the pitot static input is invalid -- it is also the reason the unit costs $6k and can legally function as a backup to an Aspen or G500.

Matt G's video showing the Aspen red X on a flight to Europe was a good example of how the red X was misdiagnosed. On that flight the red X showed up because of the pitot icing that occurred. The Aspen failure mode showed "check pitot tube", yet the belief was the Aspen had failed. It hadn't, it was indicating that one of the inputs was not working. The situation is no different than if you flew on steam gauges and had your pitot tube freeze up and had your ASI act as an altimeter. The big difference is these pitot static inputs are part of the sensor group for AHRS units.

The Aspen, G500 (as does the G1000) all require a backup AI. Here is an excerpt from the G500 manual that talks about failures modes and their red X:
G500 AHRS Failure.JPG

The original G500 had no failover mode of the PFD (and required an optional battery). You lost the PFD portion, you were on steam. The Aspen 2000 (not the single 1000 unit) has a failover mode that allows the PFD information to be moved over to the MFD in reversion mode. The new G500 TXi also has this reversion mode. Both have battery backup modes.

To the original poster, whichever way you go, these new electronic boxes have a lot more to offer than the steam most of us flew with. If you go this route, I would VERY carefully check the requirements and capabilities of what you are considering. Integrating new with old may require additional hardware to make it work (GAD-43e, ACU2, etc.).
 
Last edited:
Marauder, on the contrary, I understand perfectly, and your reply confirms my understanding.

We both understand the failure mode the same way, but apparently the significance of that failure mode and why it occurs is different for us.

An iced up pitot tube (or loss of the pitot input) red-X's the Aspen's display. That is a grievous failure result for attitude information. What you've described in terms of losing pitot information for most integrated displays would result in invalidation of ADC (air data computer) data -- red X on the airspeed and/or altitude tapes, respectively -- not the ADI itself. In the case of the Aspen, lose one input, such as pitot, and you lose the entire PFD. Not only that, you can't revert to the MFD because... it, too, relies on the same pitot input.

Sure, the backup gyro is there for that reason. And that's why it's there. Still, you're talking about losing your entire panel, if it's an Aspen PFD/MFD combo, and going to the peanut, vs... well, nothing at all happening to the dual G5 setup.

The Garmin G5 does not rely on pitot information for attitude OR heading. An iced up pitot tube won't affect operation of the G5 whether it's in ADI or HSI mode. A loss of pitot input won't affect it, either. That's a very nice feature for reliability and safety. That was the point being made and it still stands.
 
Ryan F. said:
Marauder, on the contrary, I understand perfectly, and your reply confirms my understanding.

We both understand the failure mode the same way, but apparently the significance of that failure mode and why it occurs is different for us.

An iced up pitot tube (or loss of the pitot input) red-X's the Aspen's display. That is a grievous failure result for attitude information. What you've described in terms of losing pitot information for most integrated displays would result in invalidation of ADC (air data computer) data -- red X on the airspeed and/or altitude tapes, respectively -- not the ADI itself. In the case of the Aspen, lose one input, such as pitot, and you lose the entire PFD. Not only that, you can't revert to the MFD because... it, too, relies on the same pitot input.

Sure, the backup gyro is there for that reason. And that's why it's there. Still, you're talking about losing your entire panel, if it's an Aspen PFD/MFD combo, and going to the peanut, vs... well, nothing at all happening to the dual G5 setup.

The Garmin G5 does not rely on pitot information for attitude OR heading. An iced up pitot tube won't affect operation of the G5 whether it's in ADI or HSI mode. A loss of pitot input won't affect it, either. That's a very nice feature for reliability and safety. That was the point being made and it still stands.
Click to expand...

Ryan, I never inferred you didn't understand how these AHRS unit worked. You made that inference. The point of my post is that a iced over pitot failure is not an Aspen or Garmin failure, it is a airframe failure mode that if dealt with corrects the AHRS issue. The difference between my flying 30 years ago and today is I have a box capable of screaming at me to turn on the pitot heat. A lot of pilots believe it is an instrumentation failure. It's not.

And for your reference, a G5 does use both airspeed and GPS. Perhaps it doesn't red X if the pitot tube freezes over (I certainly would be interested in the failure mode displayed if anyone ever attempted to takeoff with their pitot tube covered). I do know Trek from Garmin indicated it can't be used as a backup to a G500 or Aspen (although I have seen pictures posted with claims of field approvals as a backup instrument) since it doesn't meet the TSO requirements to operate in a degraded state. I interpreted that to mean they didn't go after the backup AI certification because of either cost, market size or both.

G5 AHRS.JPG
 
Challenged said:
For anyone else interested, here's the list of currently supported aircraft that you can install a GFC500 in, according to the Garmin site:

Beechcraft Bonanza
Models: S35, V35, V35A, V35B
Cessna 172
Models: F, G, H, I, K, L, M, N, P, Q, R, S, F172F, F172G, F172H, F172K, F172L, F172M, F172N, F172P
Cessna 182
Models: E, F, G, H, J, K, L, M, N, P, Q, R, S, T, T182, T182T, F182P, F182Q
Piper PA-28
Models: 150, 151, 160, 161, 180, 181
Click to expand...

They are actively exploring certification or certifying on Mooneys and other submodels of the above. I saw a recent video on a Mooney prebuy that said Garmin is almost certain to certify them for the M20.
 
And for your reference, a G5 does use both airspeed and GPS.​

The G5 operates normally without GPS or airspeed data. It uses those inputs to improve its resolution, but the loss of the inputs does not cause the pilot to lose his/her attitude information; that is not true for the Aspen.

We are saying the same things, but coming to different conclusions on the practicality of the difference between how these units operate. You're pointing out that this failure mode exhibited by the Aspen unit is due to its simplified AHRS design which does not separate the air data functions out to an ADC. That is normal for avionics in this price range, but the advantage goes to the G5 for its simplicity. That simplicity translates into a robustness the Aspen simply doesn't have.

I'm not suggesting that makes the Aspen a terrible choice, but it's a worthwhile consideration when comparing the units.
 
Ok Gents, Thank you all, I decided to go and purchased an EFD1000 with synthetic vision. Now the quest continues...Auto Pilot??? Considering an Avidyne DFC90 when it gets an STC for the 210's, hopefully not too far in the future.

In poking around came around to the Dynon Skyview, it is quite impressive with all it has to offer... everything under the sky and already STC'd for the 172's!
 
I'm not sure what the current state of the DFC90 and servos are, used to be you had to install an STEC then throw it away and use those servos for the DFC90. Since STEC now has a modern digital autopilot I think I'd go with them directly instead(and it says Cessna 210K through R are currently approved, so not sure where yours falls.). Of course my personal preference would be a GFC 600 since I've found the 700 to be the best I've flown with, but approval there is probably further out.
 
I've looked at the stec3100 with a price tag of about 17K where as dfc90 rings out at about 10K and is STC'd to work with Aspen. Price point is definitely a consideration. It'll be going into a P210N.
 
JOHN SEMERC said:
I've looked at the stec3100 with a price tag of about 17K where as dfc90 rings out at about 10K and is STC'd to work with Aspen. Price point is definitely a consideration. It'll be going into a P210N.
Click to expand...
Prolly wanna check on an STC for the DFC90 in the 210. The only Cessna listed on Avidynne’s website is the 182.
 
JOHN SEMERC said:
I've looked at the stec3100 with a price tag of about 17K where as dfc90 rings out at about 10K and is STC'd to work with Aspen. Price point is definitely a consideration. It'll be going into a P210N.
Click to expand...

The important thing is the DFC90 at $10k doesn't include servos, which makes it a very expensive box that does nothing really. From what I can tell they don't support the 400b servos(or the 210). If you already had an STEC the upgrade to the 3100 is the same $10000 as the DFC90 would be, and a 'free' warranty on your existing servos.

The DFC90 basically a dead product in everything but name.
 
yes chartbundle you are entirely correct, the dfc90 is only STC'd for a direct replacement to the STEC-55 and is not a stand alone suystem. All it does is replace the computer, all the hardware and servo's remain STEC.
 
JOHN SEMERC said:
I've looked at the stec3100 with a price tag of about 17K where as dfc90 rings out at about 10K and is STC'd to work with Aspen. Price point is definitely a consideration. It'll be going into a P210N.
Click to expand...
I have a Cessna C182R I have 2 x gtn 650s I just installed a Aspen PFD 1000 Pro and have installed a Trio Pro pilot Autopilot the Trio has just completed the STC and they work well except don't automatically fly the hold. I chose the Aspen as you seemed to get more for your money. They had a special on in July or August that reduced the Pro to $3000 more than the VFR so I upgraded my installation. I think they are ridding themselves of current stock before the release on the E5
 
You must log in or register to reply here.
Back
Top