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Single ADAHARS, Single big Screen and IFR

N804RV

Well Known Member
Seriously thinking about foregoing the double redundancy for PFD.

My thinking is, I'd have a single large screen (with a single ADAHARS and an EMS), a GTN650, and a small, inexpensive, self contained basic EFIS as a backup and maybe save a few dollars and some panel space.

Is anyone else doing this?
 
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If you have a second independent EFIS you DO have redundancy. Have you thought about how you will decide if they disagree?
There is an on-going discussion about what is better: a well integrated system with multiple attitude sources where the system decides what is broken; or a system with independent, isolated attitude sources where the pilot must decide what if anything is broken. I think the jury is still out.
 
That is exactly what I am installing in my aircraft. I have a Skyview Touch on the left side with the autopilot and control knob panels to the left. I have a D-6 mounted right above a Garmin 650 for a backup. Both the Skyview and D-6 have back-up batteries and are wired to the same VPX EFIS power circuit. This will allow me to download the EFIS systems to the backup batteries and save the battery for powering the Garmin 650 in the event of an alternator failure. I am mounting an IPAD on the right side of the panel, using all the functionality of Foreflight for the right seat.


Frank
building an RV-7A
dues paid for 2016
 
A different angle

I have a 7 inch Dynon planned centre stage of panel. Electric steam gauge turn and bank. Steam gauge airspeed altimeter. A AV8OR battery powered device on the right. Mission profile is Day/ Night VFR.

This should get me home with a failed electrical system.

Some thought given to Dynon SLE but still like the moving map display in panel even though Foreflight does it all as well.

Things changing so fast it is hard to keep up
 
There is an on-going discussion about what is better: a well integrated system with multiple attitude sources where the system decides what is broken; or a system with independent, isolated attitude sources where the pilot must decide what if anything is broken. I think the jury is still out.

Bob,
I'm not aware of any system (Experimental glass)where the 'system' has the ability to decide which specific ADAHRS source is broken no matter how many you have, is there one out there that actually does that?

I know they can show an error or mis-compare or in the case of a hard failed unit switch over to a backup source, but not actually throw out a unit that doesn't match the others (they don't agree), still up to the pilot to decide that one.
 
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do you have an auto pilot? that can keep you up right too. :)

I've learned (thankfully in VFR conditions) that as great as AP's are, they can misbehave or do the 'unexpected', you gotta keep a close eye on the automation.
 
I've learned (thankfully in VFR conditions) that as great as AP's are, they can misbehave or do the 'unexpected', you gotta keep a close eye on the automation.

On the flip side of this statement (and certainly NOT to disagree with Walt's thoughts on this point), more modern A/P's often contain a wonderful "gee whiz" feature called a "Straight and Level" button. If I had two attitude sources showing divergence, I would not hesitate to hit the big blue button and let the A/P act as a 3rd attitude reference. Wait and see which EFIS follows the airplane, then shut down the EFIS that shows the airplane is upside down! :D

I currently have two independent EFIS systems in our panel, plus an A/P with the big blue button. Even with all that, I'm still giving consideration to a true 3rd attitude source.
 
I'm planning for an IFR "capable" system. It seems like all the glass sales promotions are aimed at dual and triple redundancy. Yet, most IFR "capable" C-172s with vacuum systems do not have all this redundancy. And, they've trained how many thousands of instrument pilots?

I know this is an old debate. But, I'm really curios to know if there are any others out there flying IFR behind behind a big single display, instead of the airliner style full redundancy.

I know with the steam gauges, you've got some redundancy with the fact that each gauge is independent and discreet. Whereas, if the EFIS display fails, you lose everything. That's why I would put a small basic self-contained unit, maybe a used D6, as a back up.
 
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[ more modern A/P's often contain a wonderful "gee whiz" feature called a "Straight and Level" button. If I had two attitude sources showing divergence, I would not hesitate to hit the big blue button and let the A/P act as a 3rd attitude reference. Wait and see which EFIS follows the airplane, then shut down the EFIS that shows the airplane is upside down! ]

Where does the straight and level information comes from that will drive the AP? Does the AP have it's own independent AHARS?
Johan
 
But, I'm really curios to know if there are any others out there flying IFR behind behind a big single display, instead of the airliner style full redundancy.

There are thousands of military fighters with nothing more than this and a tiny "peanut" stby attitude indicator.
 
I'm planning for an IFR "capable" system. It seems like all the glass sales promotions are aimed at dual and triple redundancy. Yet, most IFR "capable" C-172s with vacuum systems do not have all this redundancy. And, they've trained how many thousands of instrument pilots?

.

Old IFR panels may look like dinosaur-poo but they do have a lot of redundancy because the 6-pack is broken into 3 different systems. If the vacuum system (attitude, heading) goes, you use your pitot/static instruments, electric turn/bank and compass to stay upright. If the pitot/static goes, you use your vacuum gyros and electric turn/bank. If electric goes use the other two. In the EFIS scenario, all your instrument systems are electric and they are all in one box, so a reliable, independent backup to keep the blue side up is important.
 
Modern redundancy

In a prior RV, we went with a similar approach (though I wasn't IFR trained at the time) & it worked nicely overall. One big 8.4in GRT Hx screen with dual AHRS, plus a Dynon D10a for back up provided dissimilar redundancy. You could select AHARS 1 or 2 for that single screen. Though if that one display failed, now you lost two sources at once.

Nowadays, I think a single big screen (even without dual AHRS), a different brand/software back-up (think G5, GRT mini, Dynon 10a), plus an iPad having a separate source of attitude info (Stratus 2/2S) gives you a tie-breaker and enough redundancy. Many fly with an iPad any ways for multiple reasons, so it's not an added equipment cost for them/me.

Even if some rare emergency destroys all electronics on board, this could provide basic attitude, altitude and ground speed to get down safely. Starting a flight fully charged, the battery life in the Stratus and iPad doesn't require keeping them connected to power except for the longest of XC days (more than 6-8 hours).

More commonly, if one brand/model of primary flight data acts up, it gives you sufficient independent options to compare and decide which to believe.

One downside -- I didn't like how I would lose the display of some desired information when displaying PFD, nav and engine information on the one screen. Specifically, if I remember correctly flap and trim indications come to mind. First world problem, I guess... I had to look over my shoulder to see flaps. Something to consider & assess with your specific model in mind for only one screen.

Just my thoughts with the modern tools readily available to us these days.
 
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mis-compare

The mis-compare function is the key.

I would assume it takes 2 AHRS talking to the same system to get the mis-compare function. Is this correct? A single AHRS would simply give the display (and autopilot I imagine) bad info until it died. Could be wrong as I'm new to these systems.

It seems to me 2 AHRS for a single screen and a independent stby would cover the tie-breaker problem. The question would be - is the backup AHRS being monitored when it isn't in use. I imagine so but not sure.
 
The mis-compare function is the key.

I would assume it takes 2 AHRS talking to the same system to get the mis-compare function. Is this correct? A single AHRS would simply give the display (and autopilot I imagine) bad info until it died. Could be wrong as I'm new to these systems.

It seems to me 2 AHRS for a single screen and a independent stby would cover the tie-breaker problem. The question would be - is the backup AHRS being monitored when it isn't in use. I imagine so but not sure.

Most of this was discussed in this thread I started some months ago...

http://www.vansairforce.com/community/showthread.php?t=139717
 
Just my opinion but honestly I don't think there's any real comparison between an inexpensive 'gyro' found is some AP's and a true ADAHRS such as the Garmin GSU25/73.

I respectfully disagree, sort of... If you have electric power my Trio Pro will fully control the airplane, with no reference to any other attitude source (like an EFIS), it will not allow the airplane to stall (if the pitot system is functional), and if your GPS is working it will fly an LPV right down until you hit the runway, and do it all better than 90% of the pilots who are hand-flying "real" ADAHRS systems.
OTOH, the digital altitude display and "bunch of dots" turn coordinator display make hand-flying using just the Trio display fairly difficult in all but calm weather. But if just used as a "tie breaker" between two EFIS boxes (one says wings level, one says turning), it easily tells you if you're turning, or not.
 
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Seriously thinking about foregoing the double redundancy for PFD.

My thinking is, I'd have a single large screen (with a single ADAHARS and an EMS), a GTN650, and a small, inexpensive, self contained basic EFIS as a backup and maybe save a few dollars and some panel space.

Is anyone else doing this?
IMHO if you are going to enter actual IMC (even if it is only "light" IMC) DON'T DO THIS! As a matter of fact you really need TRIPLE redundant so if two disagree you have something to refer to as a tie-breaker. Your life is worth more than "a few dollars and some panel space". As been noted in other posts, even the old airplanes you refer to have multiple redundant systems and sources. Even back then they didn't go with one single source.

Think of it as insurance. It is better to have it and not need it than need it and not have it. I can't stress enough; Your life is worth more than "a few dollars and some panel space"

:cool:
 
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It was easy for me.

I NEEDED a tie breaker. To me it's just another cost of safely flying IFR. 3 independent ADHRS was what I felt comfortable in the clouds with.

Sure it cost's a bit more, but me and my wife are worth every penny..

I'm sure there are any number of ways to do it.

Just always leave yourself an out when, not if, but when things go south.

15835847429_9e99f37849_c.jpg
 
Tie Breakers

Much discussion in this thread seems to imply that we need 3 fully independent AHRS/ADAHRS to have a "tie breaker'. However, just like a traditional 6 pack has adequate information to "tie break" in the event of instrument failure, so do glass panels with only 2 attitude systems. In my RV for example, I have a single AHRS dual display EFIS as well as analog airspeed, altimeter, artificial horizon, and vertical card compass for back up. I also have a Truetrak Vizion AP. In my case, a disagreement in bank between the iron gyro and efis can be resolved by observing GPS (GNS430W) track or the compass. Pitch information disagreement can be resolved by air speed and altitude trends. Heck, I learned to fly a Citabria "under the hood" including unusual attitude recoveries with only "needle, ball, and airspeed". And as others have stated, an independently functioning autopilot (Truetrak in my case) can also be used to stabilize the aircraft to determine which attitude source is correct. And yes, my plane has periodically been flown hard IFR, as well as many hours under the hood.

Skylor
RV-8
 
I'm Just Spit Ballin Here,

but it seems like most posters are talking about completing an Instrument flight after they lose a primary instrument. BAD CHOICE.
In the "old days", when we lost our sole vacuum source, we advised ATC (sometimes declaring an emergency) and looked for an exit out of IMC or a quick landing using our turn coordinator, compass and pitot static instruments. You don't need three or four or five independent ADAHARS sources to safely fly instruments, but you do need to know what to do if the dominos start falling, and from my experience, it's seldom to "carry on".
Terry, CFI
RV9A N323TP
 
Both absolutely correct

Both Skylor and Terry above are correct. It's a comfort level and what you are trained proficient too. In any emergncy or abnormal, fly the plane and work yourself out of it.

We had all rather be on the ground wishing we were up there than vice versa in a bad situation.
 
but it seems like most posters are talking about completing an Instrument flight after they lose a primary instrument. BAD CHOICE.
I personally was talking about figuring out which instrument to trust before using any of them to get you back on the ground ASAP. Without at least a third instrument you are taking a 50/50 chance of getting it right. Not odds I want to risk my life on. YMMV

:cool:
 
I'm planning for an IFR "capable" system. It seems like all the glass sales promotions are aimed at dual and triple redundancy. Yet, most IFR "capable" C-172s with vacuum systems do not have all this redundancy. And, they've trained how many thousands of instrument pilots?

I know this is an old debate. But, I'm really curios to know if there are any others out there flying IFR behind behind a big single display, instead of the airliner style full redundancy.

I know with the steam gauges, you've got some redundancy with the fact that each gauge is independent and discreet. Whereas, if the EFIS display fails, you lose everything. That's why I would put a small basic self-contained unit, maybe a used D6, as a back up.

This is what I have...a Dynon SV1000T (with its own ADAHRS and backup battery), and a Dynon D6 (again, with its own ADAHRS and backup battery).

Seems to me that we should look at the most likely failure mode of an electronic/MIMS/whatever ADAHRS, which I suspect is probably a complete failure (which would show as a failed component/red X/etc. on the corresponding display). Second most likely might be a complete failure of a sensor in one axis, which perhaps would be caught by the EFIS or the ADAHRS and flagged (I dunno...maybe not, but it seems if a sensor is out and not providing data, the Kalman filter can't operate properly and find a solution?). Third, and probably least likely, is an *incorrect* reading from a sensor...which is what all the "tie-breaker" discussion has really centered on.

So I'd be interested in real-world data on failure modes and likelihoods, and then one could do a proper FMEA to figure out how to mitigate those risks. Just saying "failure" is not specific enough.

In the case of an incorrect attitude, I should be able to first see the difference between the two systems, then resolve it by comparing it to GPS track, airspeed, altimeter, ROC indicator, etc. Just as an example...sort of like how it has always been done in the case of a failed mechanical gyro or vacuum pump for a "traditional" AI, right?
 
This is what I have...a Dynon SV1000T (with its own ADAHRS and backup battery), and a Dynon D6 (again, with its own ADAHRS and backup battery).

So I'd be interested in real-world data on failure modes and likelihoods, and then one could do a proper FMEA to figure out how to mitigate those risks. Just saying "failure" is not specific enough.

In the case of an incorrect attitude, I should be able to first see the difference between the two systems, then resolve it by comparing it to GPS track, airspeed, altimeter, ROC indicator, etc. Just as an example...sort of like how it has always been done in the case of a failed mechanical gyro or vacuum pump for a "traditional" AI, right?

Since you have an all-Dynon system, I'd be curious as to how it reacts to a partial pitot clog - bad enough to lose attitude reference, not bad enough to auto-switch to GPS (a failure like this has been reported here on VAF). Would both instruments look exactly the same (but both incorrect)?
 
Since you have an all-Dynon system, I'd be curious as to how it reacts to a partial pitot clog - bad enough to lose attitude reference, not bad enough to auto-switch to GPS (a failure like this has been reported here on VAF). Would both instruments look exactly the same (but both incorrect)?

That's probably a question for Dynon...a *partial* blockage? Dunno.

If airspeed is unavailable, the SV manual says that GPS groundspeed is used as an attitude aid ("GPS Assist" is displayed). But with a partial blockage, I suppose that both of them would show the same incorrect value.

Better install a 2nd pitot tube to avoid this SPF. :eek:
 
Two Engines?

I've been reading all of the posts regarding multiple ADAHARS and the worry of losing one or two and not being able to complete the IFR flight.

I've only got a single IFR G3X/GTN625 installation. I would be more concerned about losing the engine due to mechanical failure than losing the electronics. I've flown in actual IFR with only needle ball and airspeed in the past, before the days of ipads and Foreflights, and Garmin Pilots. If I had had these tools years ago I would have felt blessed. To anyone who has not flown actual IFR using only the needle ball and airspeed, I recommend it as a great confidence builder. You'll stop worrying about your backup ADAHRS agreeing.

Steve
 
Single screen ifr

Ken
Thanks for your question. I'm contemplating same scenario. My engine install is almost done then I'll be doing avionics. I fly IFR regularly in 6-pack Cherokee. I'm thinking for my RV7 I'll do Dynon Skyview plus a Dynon D2 pocket EFIS. But I'm also thinking and electrical Attutude Indicator-maybe. Plus I'll probably have Garmin 430 or equivalent. And I'll use VP-X but the AI would be wired outside of VP-X.

With my 6-pack if I loose vacuum pump I lose AI, DG and autopilot. Turn and bank is almost worthless backup gauge because it is too wiggly. But compass and Garmin 430 tells me if there is a direction change. Altimeter and GPS tells me if there is a pitch change. So I think there is a lot of backup in using the GPS, and the compass such that a third EFIS isn't necessary. And also plenty of info to decide if a gauge is wrong.

And iPAD with Garmin Pilot gives a lot of functionality that is working very reliably for me.

PS I'm in Anacortes.
 
I've been reading all of the posts regarding multiple ADAHARS and the worry of losing one or two and not being able to complete the IFR flight.

I've only got a single IFR G3X/GTN625 installation. I would be more concerned about losing the engine due to mechanical failure than losing the electronics. I've flown in actual IFR with only needle ball and airspeed in the past, before the days of ipads and Foreflights, and Garmin Pilots. If I had had these tools years ago I would have felt blessed. To anyone who has not flown actual IFR using only the needle ball and airspeed, I recommend it as a great confidence builder. You'll stop worrying about your backup ADAHRS agreeing.

Steve
FWIW Confidence is no good and can be deadly if you don't maintain proficiency. Most GA pilots I know maintain basic IFR currency, not proficiency. For those current but not proficient, the majority of GA pilots, having redundant systems to get them out of an IFR emergency is important. YMMV

Since you have an all-Dynon system, I'd be curious as to how it reacts to a partial pitot clog - bad enough to lose attitude reference, not bad enough to auto-switch to GPS (a failure like this has been reported here on VAF). Would both instruments look exactly the same (but both incorrect)?
Pitot indications are based solely on air pressure, air doesn't flow within the system. So a partial clog might affect how fast the indicator reacts to an airspeed change, but once the pressure builds up it will indicate correctly. That is why you can use different size lines (small line is the same as a "partial clog") with no major effect. No different than putting a flow restrictor (partial clog) on oil, fuel or manifold pressure gauge lines. They react slower, but still indicate correctly.

:cool:
 
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Pitot indications are based solely on air pressure, air doesn't flow within the system. So a partial clog might affect how fast the indicator reacts to an airspeed change, but once the pressure builds up it will indicate correctly. That is why you can use different size lines (small line is the same as a "partial clog") with no major effect. No different than putting a flow restrictor (partial clog) on oil, fuel or manifold pressure gauge lines. They react slower, but still indicate correctly.

:cool:

He's asking about the effect of a partial pitot blockage on the attitude computation, since Dynon (and presumably other EFISes) use air data in the computations for attitude. I assume the failure mode postulated here is something blocking it in such a way that, at least for a period of time, the airspeed (dynamic pressure) is jacked up somehow. Although you're right, it *should* stabilize at some value and then the airspeed AND attitude should recover.
 
He's asking about the effect of a partial pitot blockage on the attitude computation, since Dynon (and presumably other EFISes) use air data in the computations for attitude. I assume the failure mode postulated here is something blocking it in such a way that, at least for a period of time, the airspeed (dynamic pressure) is jacked up somehow. Although you're right, it *should* stabilize at some value and then the airspeed AND attitude should recover.

AFAIK for the attitude algorithms, Garmin units use GPS speed as primary with Pitot as backup but the GX guys can confirm. Dynon uses Pitot as primary with GPS as backup for the same. Either way it "shouldn't" cause a serious situation with a partial block since the indication will eventually be correct.

:cool:
 
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Can't comment on a blocked/partially blocked pitot but an intermittently blocked static port (rain/water) will cause an erratic pitch display on the Skyview.

Fin.
9A
 
Air does flow in the pitot tube - because of the drain hole. As the pitot opening gets reduced (bug, ice) down close to the size of the drain hole, the line pressure drops. And the airspeed reads low but not zero.
I know the GRT Horzon EFIS will show the horizon correctly without either airspeed or GPS data.
 
Air does flow in the pitot tube - because of the drain hole. As the pitot opening gets reduced (bug, ice) down close to the size of the drain hole, the line pressure drops. And the airspeed reads low but not zero.

As I remember it; as a partial pitot clog develops, changes in airspeed take longer and longer to change the pressure in the system making the display slow to react. As long as the partial clog size stays greater than the drain size, the system stays pressurized and the new airspeed eventually displays correctly. When the partial clog becomes equal or smaller than the drain, then there is no pressure in the system (excluding venturi effect) and for all practical purposes you have a complete clog. Drain holes are tiny!

IMHO this makes for great theoretical discussion(s), but not much for a practical application.

:cool:
 
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As I remember it; as a partial pitot clog develops, changes in airspeed take longer and longer to change the pressure in the system making the display slow to react. As long as the partial clog size stays greater than the drain size, the system stays pressurized and the new airspeed eventually displays correctly. When the partial clog becomes equal or smaller than the drain, then there is no pressure in the system (excluding venturi effect) and for all practical purposes you have a complete clog. Drain holes are tiny!

IMHO this makes for great theoretical discussion(s), but not much for a practical application.

:cool:

So we're back where we started :). A partial clog *may* have some temporary impact on the attitude display (and airspeed), but we don't really know what or how much of an effect it is (need manufacturers to weigh in here). But it should eventually clear. A complete clog...system goes to GPS assist, attitude shown is correct.

OK, that's *one* branch down the failure tree...still looking for inputs on likelihood of the failure modes for an ADAHRS itself.
 
I've had one experience with an airspeed malfunction while flying through rain. D10A with AoA in cruise flight the airpeed suddenly jumped to 500 knots and AoA display went nuts. Attitude remained stable throughout - until the display went black a few minutes later (unrelated failures).
 
You guys can rationalize all you want, but the actual experiment has been done, and reported here on VAF: light icing, airspeed fell off but did not go to zero, Dynon did not auto-switch, display showed false horizon. Since I bought my panel when there was no GPS backup, and loss of pitot data was a known problem with Dynon, it was an easy choice for me to buy GRT. The choice now is harder. But everyone should be aware of the compromises involved.
 
You guys can rationalize all you want, but the actual experiment has been done, and reported here on VAF: light icing, airspeed fell off but did not go to zero, Dynon did not auto-switch, display showed false horizon. Since I bought my panel when there was no GPS backup, and loss of pitot data was a known problem with Dynon, it was an easy choice for me to buy GRT. The choice now is harder. But everyone should be aware of the compromises involved.

I think we may be talking the same thing but from a different point. I had a similar issue back in 2012 with my D6 with no GPS connected. Rolling down the runway, airspeed accelerated slowly to 35Kts then stopped even though I knew we were still accelerating. I aborted the takeoff, taxied back and parked the airplane with the airspeed still indicating 35Kts. At the time I did not notice if the attitude was correct or not.

I disassembled the Pitot system and when I blew into the tube connected to the Pitot, a small dead ant flew out. Apparently the ant crawled in, partially clogged the pitot tube making the airspeed accelerate slowly. Once the ant was fully jammed in, the clog was complete and the airspeed stayed at 35Kts until I released the built up pressure by opening the system.

Needless to say I immediately connected the GPS to minimize this happening again. I was very lucky to be rolling down a 7,000ft runway which gave me time to realize something wasn't right and abort.

:cool:
 
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Seriously thinking about foregoing the double redundancy for PFD.

My thinking is, I'd have a single large screen (with a single ADAHARS and an EMS), a GTN650, and a small, inexpensive, self contained basic EFIS as a backup and maybe save a few dollars and some panel space.

Is anyone else doing this?

I'm new to the RV world nbut like your solution. How much are you budgeting for your avionics? Are you planning to be ADSB 2020 compliant and IFR? You thinking D6 for the Independant system?

Thanks in advance for your patience.
 
I'm new to the RV world nbut like your solution. How much are you budgeting for your avionics? Are you planning to be ADSB 2020 compliant and IFR? You thinking D6 for the Independant system?

Thanks in advance for your patience.

I've found that a good rule of thumb is 30% for the kit, 30% for the engine, and 30% for the panel seems to work. At least for the RV-10s.

Your mileage may vary depending on your mission, requirements, and if you buy used or get exceptional deals.

Yes on the ADSB and IFR. There are other options available today than just the D6, such as the Dynon D2, Garmin G5, and the Trutrak Gemini PFD. I'm sure that there are others.
 
I'm new to the RV world nbut like your solution. How much are you budgeting for your avionics? Are you planning to be ADSB 2020 compliant and IFR? You thinking D6 for the Independant system?
Thanks in advance for your patience.

Hey Steve.

I'm still thinking it over. But, like rleffler said, 1/3 airframe, 1/3 FWFWD, 1/3 Avionics/instrument is a good rule of thumb to start with, I think. And, that's probably only if you paint it yourself.

I'm planning on being ADSB 2020 compliant and IFR capable. So, I'm real close to just biting the bullet and getting a home equity loan in order to install all the bells & whistles.

Got a ways to go yet. So, still haven't decided on avionics yet. Maybe by this time next year.

If you really want a $ number, I'm thinking its gonna cost me at least $18K for avionics/instruments. But, that's not a hard number right now.
 
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If you really want a $ number, I'm thinking its gonna cost me at least $18K for avionics/instruments. But, that's not a hard number right now.

18K will get you a single screen G3X touch with autopilot servos and engine sensors. It will also get you a remote mounted Garmin com (GTR20), audio panel (GMA245), remote ADSB in/out/transponder unit (GTX45), an autopilot controller, and Garmin's WAAS GPS for the ADSB out. It'll also buy you the mounts and harnesses for all of that equipment. This is first cut (i.e. non-negotiated) pricing from the likes of Stein, Stark Avionics, etc.

To that, you need switches, annunciators, fuses, breakers, etc. plus any upgrades like backup batteries.

You won't be IFR at that price unless you find an IFR navigator on the cheap. And you won't have any backup capability. Figure another $5k (at least) to add that capability with a GTN625 and a G5X.

Don't forget an ELT.
 
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skyview failure mode

I thought this would be a good addition to this thread.

I have a Classic Skyview 7" display with a single ADAHRS. I have 300 hours on the installation and plane. Fly VFR only. Flying at 10500 over water last weekend, the AP dropped out and I got an overspeed warning for 511mph. The AI was erratic. GPS ground speed and navigation, as well as altitude remained functional and matched my G396 backup.

At the time, I did not want to reboot the system as I was stable and currently over water.

After landing, Dynon tech support felt it was the ADAHRS that went TU and overnighted a replacement. All is well.

I would have assumed the unit would have realized the failure and used GPS as a backup and flagged it as such. Instead, I listened to "overspeed" every 3 seconds for an hour until landing with airspeed showing around 511mph.
 
A Grand Rapids mini is low cost insurance. Or even TWO. That might be what I saw on Widgets panel.
And the self contained autopilots like Trio just keep on flying.... don't need no stinking gyro. (or ADAHRS as the case may be)
 
Back up attitude

I just bought a -10 that has a 3 screen G3X with one ADAHARS and fly IFR a lot. My choice was to add a G5 with backup battery. The G5 will back feed the G3 displays with data if the ADAHRS 1 fails and will provide over 3 hours of attitude even if the alternator fails and the ships battery has been depleted.

That?s enough to offer a 24,000 hour pro a comfortable redundancy, your mileage may vary.

Mark
 
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