hotrod180 wrote:

hpux735 wrote:.... I recently read that there was a rule change that lets you (potentially) remove all the vacuum parts from your plane and go all-electric. This is cool to me because the vacuum pump MTBF is something like 500 hours, a vacuum-driven AI is around 1000 hours, and an electric gyro AI is a few 1000 hours. A solid-state gyro is more likely to be in the neighborhood of 10,000-100,000 hours. In addition, it'll weigh less, and won't have the parasitic load on the engine. Personally, I'm only interested in devices certified for primary instrumentation, because that's the only way to get rid of the vacuum system on a certified plane.....

I think the FAA policy statement allows for the replacement of a vacuum horizon with a solid-state one, but it like the vacuum unit it replaces it must be certified for IFR use. Probably something like this RC Allen 2600 series digital horizon.
http://www.aircraftspruce.com/catalog/i ... ca2600.php
But hang onto your hat- they list at $2600!

This is true... to fly IFR you have to have two AI indicators... with different power sources. Having two on electric, one needs to have a battery backup that is good for at least 30 minutes. I have never seen the FAA differentiate between solid state or gyro driven.... just the power source.

YMMV
gunny

Gunny wrote:
This is true... to fly IFR you have to have two AI indicators... with different power sources. Having two on electric, one needs to have a battery backup that is good for at least 30 minutes. I have never seen the FAA differentiate between solid state or gyro driven.... just the power source.

YMMV
gunny

Better check that again... Part 91.205. That may be true if you are operating under Part 135 or 121 though.

I don't think you need 2 AIs with different power sources to fly IFR. If that were true, most of our airplanes with steam gauges couldn't be certified to fly IFR. The T&B/turn coordinator is typically electric and the AI is typically vacuum (or pressure) operated, so that they have 2 different power sources. That way, if one source goes down, the pilot could continue to fly partial panel using the other.

What is required by this new FAA policy is that if both are going to be electric, then the AI must have an independent backup power supply. RC Allen offers a backup battery that will power a standard electric gyro for more than an hour, and one of their solid state versions for about 6 hours. Of course, they don't give that away, either--it's $650 at Spruce! So if an owner changed out the vacuum AI for an RC Allen solid state version and added the battery, that's a $3250 + installation mod. Pain! The other instrument manufacturers charge more for their equivalent gauges.

If the DG was pulled and replaced with an electric one, RC Allen has them priced at $2200 to $2300 at Spruce. These are gyros, not solid state.

Granted that all these electric instruments will likely outlast a vacuum pump, by the time you spend at least $5500 on them plus installation, you can buy several vacuum pumps!

Cary

It does feel like, at that point, an aspen efis more sense

A little pricey, but I just read that Sandia 340 was just certified as a primary instrument. $3500, but pretty capable and only a 1/2 pound.

http://www.aopa.org/News-and-Video/All-News/2015/October/23/Sandia-340-standby-attitude-indicator-also-certified-as-primary?WT.mc_id=151030epilot&WT.mc_sect=gear

It seems like we're talking about three different things:
1) replacement of the standard vacuum horizon, as required for IFR flight
2) backup for the standard horizon, for IFR flight
3) "just in case" backup for VFR flight
#3 is what I'm interested in, and the Dynon D2 looks like the best combination of low price & features I want. GRT Mini-GA would probably be second place, but more expensive at $1450 vs $1095 for the D2 (discounted to $1K at Spruce). Don't need or want the synthetic vision, if I did the GRT would probably be top dog. To tell the truth, I'm not too interested in some of the D2 features either, and if possible would probably disable some of them to de-clutter the screen.

http://www.dynonavionics.com/docs/PocketPanel.html

http://www.grtavionics.com/mini-ga.html

hotrod 180

I have flown a D1 for three years for your application #3. Excellent unit for application. I see no need for declutter IMHO. Can't disable functions.

I used the wrong terminology.... and words do mean things. You only need one AI, the other attitude indicator can be a Turn-and-Slip/Turn Coordinator. But it is true about two different power sources. The reg does not require vacuum over electric... just two different power sources. Two electric indicators of acceptable type, with at least one having a battery backup (of at least 30 minutes) satisfies the IFR requirement.

gunny

Flyboy_AK wrote: I have flown a D1 for three years for your application #3. Excellent unit for application. I see no need for declutter IMHO. Can't disable functions.

My bad. A friend of mine has a Dynon D6 (?) and I recall him telling me that he could disable some of the display features. I assumed that the D2 was the same way.