Garmin 496 vs. Castleberry AI with T/C

Jalanci · #1 03-27-2007, 12:19 PM

As I'm building my RV7, I find this site extremely informative and there is a lot of expertise here that translates well to the spam cans. I'm a member of a flying club that had an electric AI go bad and looking to replace it. There are two schools of thought, replace it with the Castleberry AI/ TC and maybe with the autopilot option, versus getting a 496 with the GPS stabilized AI. I don't think the 396 will have a fast enough refresh rate to be a comfortable substitute.

Obviously, the 496 has a number of features added. The question we have is whether the 496, if IFR and the vac AI fails, would be a comfortable alternative to another electric AI. We're thinking of panel mounting the 496, but concerned about the FAA not being happy with this in a certified.

Opinions anyone? I'm still about 2 years from worrying about this, ok I'm optimistic, but I have to have goals.

Jalanci · #2 03-27-2007, 12:33 PM

I checked the 496 and thought it had an artificial AI. I didn't see it on the website.

kentb · #3 03-27-2007, 12:53 PM

Quote:

Originally Posted by Jalanci

As I'm building my RV7, I find this site extremely informative and there is a lot of expertise here that translates well to the spam cans. I'm a member of a flying club that had an electric AI go bad and looking to replace it. There are two schools of thought, replace it with the Castleberry AI/ TC and maybe with the autopilot option, versus getting a 496 with the GPS stabilized AI. I don't think the 396 will have a fast enough refresh rate to be a comfortable substitute.

Obviously, the 496 has a number of features added. The question we have is whether the 496, if IFR and the vac AI fails, would be a comfortable alternative to another electric AI. We're thinking of panel mounting the 496, but concerned about the FAA not being happy with this in a certified.

Opinions anyone? I'm still about 2 years from worrying about this, ok I'm optimistic, but I have to have goals.

The 496 can't be panel mounted in a certified plane.
The 496's GPS simulated 6 pack works great and I would use it for backup if I had to. But you need real instruments to fly IFR.
Don't know anything about the Castleberry.

Hope this helps, Kent

DBone · #4 03-27-2007, 01:29 PM

I had a 496 panel mounted (with AirGizmo) in my Cherokee in August last year with no problems. I thought the FAA was just TALKING about stopping this practice. I didn't think any rule change/addition had happened yet. Last I remember reading the FAA proposed it and AOPA was going to fight it.

That aside, I did some hood work with the 496 5-pack and it can do the job in the event of one system failing (vac or pit/static). I think you'd be hurting to ONLY use the 496 for IMC flight. If for nothing else, your scan will most likely not be as practiced and proficient enough. Even with only 1 system failed, I would not want to do extended flight with it, but it can get you down if it had to. I've also seen the 396 in action, and there's no way I would consider that the same level of backup. The upgraded processor makes a HUGE difference in the 496 from my experience.

hevansrv7a · #5 03-27-2007, 01:47 PM

First, the '496 does NOT have an AHI nor can it, being purely a GPS. Now that is not to take away from the (excellent) "panel" page, it's just a darn fact. It does not have airspeed, either for the same reason. It does have a rate of turn indicator but it's not a TC because there is no bubble. The importance of the bubble, it seems to me, would depend on the airplane. In an RV I would not think it very important.

OK, now is it a substitute for a backup AHI? I am a huge fan of the 296/396/496 as some have noted. But it is what it is and it is not what it is not. It is not an AHI. Can you use it to save your derriere? That's a big "it depends". If you have an independent autopilot that would help a lot to answer your questions. The combination of actual conditions and pilot skill would be big factors if it was not a practice run. Strong turbulence and high pilot anxiety could make this a very iffy proposition. I also agree that the 496 with its faster refresh rate would be better than its little brothers.

As to having a 496 "in" the panel, I agree with those who say you can do it as long as it's totally removable. However the FAA is considering making us prove our mounting devices are "airworthy" in order to keep us from doing this. My opinion does not count, but my opinion is that such a move would reduce safety signficantly and thus I would hope that AOPA and EAA would actively fight it. Clearly you cannot permenantly wire it to the certified aircraft.

Edit: - OK, maybe you can, but I'd be surprised. Inspectors are humans and human judgements vary. I use the 12v tap for power. I would have thought that permanently altering the aircraft wiring would need a 337, like my intercom did, for example. Heck, I'm not even as expert as I think I am, let alone a real one. Good luck to all.

DBone · #6 03-27-2007, 02:25 PM

Quote:

Originally Posted by hevansrv7a

Clearly you cannot permenantly wire it to the certified aircraft.

Does the FAA define "permenantly"?

I had my 496 mounted in the Cherokee with the AirGizmo mount. The wires went from the 496 behind the panel to hook into the 530 and the audio panel. The shop that did it is a very by-the-book shop, so I assumed that the install was okay because even though the wires went behind the panel and were plugged into the various components, the fact that the 496 itself was removable kept me legal.

Obviously it doesn't affect me any more since I sold the plane, but I'd like to give the new owner a heads up if his panel is considered against the regs.

hevansrv7a · #7 03-27-2007, 05:20 PM

Quote:

Originally Posted by DBone

Does the FAA define "permenantly"?

I had my 496 mounted in the Cherokee with the AirGizmo mount. The wires went from the 496 behind the panel to hook into the 530 and the audio panel. The shop that did it is a very by-the-book shop, so I assumed that the install was okay because even though the wires went behind the panel and were plugged into the various components, the fact that the 496 itself was removable kept me legal.

Obviously it doesn't affect me any more since I sold the plane, but I'd like to give the new owner a heads up if his panel is considered against the regs.

Please see my edit above. I'm not with the government and don't wish to speak for them. I thought it was clear, maybe it's not. Hmm.