apparently earlier versions have had problems but they seem to have that sorted.
g500 is a alot more work to install but 40k seems outrages.
try Lambert aircraft in Kortrijk.
I have an Aspen and I am very satisfied with it. No problems whatsoever. There was a high infant mortality rate but one should not conclude that those were inherent design problems and that such problems cannot be fixed. One should realize that Aspen did something rather new and the form factor combined with the functionality far exceeded state of the art.
Aspen have done an excellent job partnering with others and making their unit interoperate. Newest example is the Avidyne DFC90 digital autopilot which uses the Aspen AHRS as its control input and is fully operated through the Aspen PFD (alt + speed preselect, annunciations, etc.). That is the most advanced retrofit autopilot available today, by far. Garmin's comparable G700 is only for new aircraft.
The G500 would have cost an order of magnitude more and required a totally new panel whereas the Aspen was a rather simple installation and the only steam gauge I had to give up is the VSI. The functionality of the Aspen is equivalent to the G500.
At the same time when I got the Aspen I also had a GNS430W with the Garmin GPS antenna installed. Both packed up within 6 months and had to be replaced. Garmin's support was less responsive than Aspen's. I learned from the dealer that there was a batch of bad GPS antennae and they replacing them by the dozen.
BTW: there is a 5 year warranty extension on the Aspen units for $1000. A very fair offer.
I have an Aspen PFD in an older (1987) TB10. There's no question this is by far the simplest and cheapest way to install an EHSI, air data computer and non-vacuum AI in a single package. Having live calculated wind and a ground track indicator on the HSI is a huge workload reduction in IMC, and the HSI itself is a massive improvement over the old CDIs (the same is of course true of any glass system).
So far (120 hours, about 1 year), the system works very well. I also had a dodgy remote sensor to start with, but once this was replaced I had no more issues. I'm now planing an upgrade of the ACU to display the ADF on the HSI and get rid of the RBI.
I'm now planing an upgrade of the ACU to display the ADF on the HSI and get rid of the RBI.
Interesting, is that possible certification wise? I also have the ACU2 and the ADF hooked up to it but kept the RBI. I never use the ADF for anything (and certainly wouldn't unless the GPS satellites fell from the sky) but keep it installed to be legal on NDB approaches. Freeing up some panel space would be useful.
I'm now planing an upgrade of the ACU to display the ADF on the HSI and get rid of the RBI.
Interesting, is that possible certification wise?
I talked to Avionik Straubing about this ca. a year ago and was told it would be ok to remove the separate indicator. Have not done it (yet) as I have the ACU1 (and would therefore need to upgrade to the ACU2) and currently do not need the additional panel space.
I am not aware of any law saying the ADF must have its own indicator.
That is not the same as saying there are no IR examiners anywhere in Europe who will insist on one 
In the past, even an RMI was not favoured, because it makes NDB approaches easy. Well, it would make them easy if the whole system worked with some useful accuracy 
I agree the Aspen gives you a lot of bang for your buck, but I am not at all sure they will ever make it reliable, due to the huge amount of heat generated and the resulting thermal cycling. But that's just my opinion...
I stuck with the GT factory fit, and later fitted the Sandel SN3500 EHSI and I am about to put another one on the RHS, to create a proper "pilot panel" there. A lot of people who installed the SN3500 put their old KI525 HSI on the RHS, but mine will go on Ebay. I am also installing the SG102 AHRS gyro, replacing the big heavy KG102A in the back, and that will give me the reversionary horizon mode on both the 3500s.
A nice future mod would to a second small alternator (the B&C one) on a spare vac pump mounting point, and a means to power some avionics (can't do it all, especially not pitot heat as well) from that. The TB20's main electrical weak point is the single alternator, and I don't think there is room under the cowlings to fit a 2nd full size one. This mod would either use a Beech STC as a "follow-on STC" for a 337 field approval, or be done as a minor mod (I have 2 x DER and 1 x DAR to get informal opinions from on stuff like that) but I have not researched that yet.
I am not aware of any law saying the ADF must have its own indicator.
There is (although I can't remember where, so maybe I'm imagining it) a requirement for a separate indicator for at least one approach aid. I have a CDI/ILS wired in to NAV2 as a backup to get me down. Quite apart from any certification requirements, this seems to be a pragmatically sensible thing.
That is not the same as saying there are no IR examiners anywhere in Europe who will insist on one
In the past, even an RMI was not favoured, because it makes NDB approaches easy. Well, it would make them easy if the whole system worked with some useful accuracy
Ha! That's why I want to wire the ADF into the Aspen ... the whole point is to make the tricky part of the test/learning easier. In real life I fly NDB approaches with a GPS OBS displaying both the HSI and pointer on the Aspen, and the ADF on the RBI. It can be amusing (and slightly terrifying) to compare the GPS derived pointer to the ADF pointer: I have seen 15 degrees difference in VMC - if I saw that in IMC I think I would go around and find somewhere else to land.
Very much agree re backup indicators. That's why I have two ways of displaying most things:
GPS map and track info etc
NAV1
NAV2
ILS
DME
ADF
WX500 Stormscope
TAS605 Traffic
Altitude
Pressure altitude
Voltage
OAT
Oil pressure
Oil temperature
Fuel
When the 2nd SN3500 EHSI goes in, the RMI will be removed and the EDM700 (3" version) will go there.
With glass avionics one tends to not get all of this backup functionality - if you assume that the LCD backlight packs up, which it can; it seems to be the primary failure mode of even the best quality laptops.
With glass avionics one tends to not get all of this backup functionality - if you assume that the LCD backlight packs up, which it can; it seems to be the primary failure mode of even the best quality laptops.
You can but in reality most don't. The beauty of the Aspen is that it actually allows you to have complete redundancy because it does not require a lot of panel space so you keep what you had before. If you install a G500, you have to remove most steam gauges and would have to pay for new integrated backup devices.
I get the same level of redundancy you listed with the exception that my GPS/NAV1 is only connected to the EFIS but that's why one has a NAV2 with a separate indicator.
I'm not a fan of those NAV1/NAV2 switchable displays, it can be a killer. I have already more than once made the mistake of having the GNS430 in the wrong mode (GPS vs VLOC).
Another failure mode which most are not prepared for is loss of electrical power. It is not that unlikely at all. Imagine you're in solid IMC and go through your avionics. For me this was a major concern for all equipment decisions. The Sandel setup doesn't have its own battery backup, does it?
I did find the a Flying review of the TB20 here Review from 1999by Robert Goyer from 1999 but couldn't find anything negative in it. Anyway my point is that Flying archives are on the web. No reason to keep them stacked in the attic.
