# Simple six-pack replacement. Is there such a thing?

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#### ToddK

##### Well-Known Member
HBA Supporter
For day VFR you don’t need a six pack. ASI/ALT, skid/slip ball, and a magnetic compass are all you need.

#### ScaleBirdsScott

##### Well-Known Member
The Talos stuff looks pretty good too if one wants a hard-wired solution direct to a tablet screen; the GUI is maybe a bit plain, but it seems functional.

#### pfarber

##### Well-Known Member
HBA Supporter
GPS altitude is very inaccurate.
No, its just not giving you barometric height.

Again OP is VFR Day, low and slow. GPS is fine for the cost. If you want an altimeter then you need to calibrate the pitot system, calibrate the altimiter, remember to set the barometric pressure etc etc etc. So yeah, you altimeter can also be wrong.

#### Dana

##### Super Moderator
Staff member
For day VFR you don’t need a six pack. ASI/ALT, skid/slip ball, and a magnetic compass are all you need.
You don't even need a skid ball.
No, its just not giving you barometric height.

Again OP is VFR Day, low and slow. GPS is fine for the cost. If you want an altimeter then you need to calibrate the pitot system, calibrate the altimiter, remember to set the barometric pressure etc etc etc. So yeah, you altimeter can also be wrong.
GPS altitude can jump around by hundreds of feet from one fix to the next. Not what you want when, say, trying to fly at the correct traffic pattern altitude.

#### BJC

##### Well-Known Member
HBA Supporter
GPS altitude can jump around by hundreds of feet from one fix to the next. Not what you want when, say, trying to fly at the correct traffic pattern altitude.
I don’t spend much time looking at GPS altitude when flying, but I never have noticed it jumping around, much less by hundreds of feet. I have watched GPS altitude in my truck when driving in mountainous areas, and never saw anything resembling jumping around there either.

Not saying that it doesn’t, just that I haven’t noticed it.

BJC

#### PagoBay

##### Well-Known Member
I'm wondering if there is a device out there that does nothing but replace the six-pack.
I know a few aircraft owners that have the Levil Aviation iLevel3-AW and one pilot who has the Levil Aviation BOM. They have other models that are less expensive as well. Definitely worth a look.

#### cluttonfred

##### Well-Known Member
HBA Supporter
For true day VFR only use, I think the UMA 3-1/8" ASI and ALT (oddly cheaper than the 2-1/4" ones), a slip/skid ball, and a compass are about the simplest way to go. Engine instruments benefit more from combination into a single electronic package that can work out to be cheaper than individual gauges, but there again it depends what you want. If a tach, oil pressure, and temperature are enough (plus a voltmeter or at least a low voltage idiot light if not using magnetos) then auto instruments will do just fine.

##### Well-Known Member
Here is the panel for my Eindecker. Slip/skid ball, ASI, Grand Rapids EIS with altimeter, cheap auto compass, and Icom radio. Everything needed for VFR day flight. I found the compass so inaccurate that I removed it and haven't gotten around to a replacement. I never fly more than 30 miles or so and Kansas comes equipped with N/S/E/W grid lines.

#### Kurt Ayres

##### Member
Thank you for all the help, everybody, and for defining the issue for me. I will look into all the options you suggested. To be more clear, I'm just in early stages of planning build #2, and just want to have a pretty good idea of what I want to do right from the beginning with regard to instruments, instead of playing catch-up at the end.

#### Kurt Ayres

##### Member
Thing is, if you’re replacing your six-pack (I asssume by that you still want some kind of attitude info) then pretty much almost anything out there is going to give you at least some kind of nav/map capability “free”.

I think your simplest bet is going to be something like an AV-30 or GRT Mini, but we really need more info to help you out. I’m willing to help you dig through options but I’d need to know what exactly you’re really trying to do—what you have now, what you’re trying to gain, what you’re replacing, etc. A picture of your current panel would be helpful.
Thank you for your guidance. I should have been more clear in my original post: I'm planning build #2, and want to already have an idea of what I want to do with regard to instruments before I begin. I suppose my goals would be lighter weight and less panel clutter without a large increase in cost. I looked at the AV-30, and really like it; it seems to be what I have in mind.

#### TFF

##### Well-Known Member
It’s going to depend on airspace. If I was flying near or under a mode C veil, I would want a pitot system as primary as that is how the system is set up.

VFR with no reasonable way to fly into towered airspace, the only reason to have any altitude is getting pattern altitude right at the airport and to give a decent check of being 500ft away from people or property. I’m assuming no reason to fly above a couple of thousand AGL.

GPS is dependent on quality of equipment. I have dealt with Lidar ,where the sampling is thousands of times a second, to some cheap toy, where it’s close in a horseshoe kind of way. Do serious aerobics, and ADSB can loose GPS signal. Upside down doesn’t get much signal. Also had a canopy build up enough static electricity that it blocked both a handheld Garmin and IPad, at night, 200 miles from any recognizable landmarks that I would have visually known, if I could see. We added an external antenna right away.

#### Dana

##### Super Moderator
Staff member
I don’t spend much time looking at GPS altitude when flying, but I never have noticed it jumping around, much less by hundreds of feet. I have watched GPS altitude in my truck when driving in mountainous areas, and never saw anything resembling jumping around there either.

Not saying that it doesn’t, just that I haven’t noticed it.
Here's two GPS tracks from the same flight. I was measuring climb performance in the smooth air out over the ocean to evaluate my propeller modifications. The first is from a Garmin 60Csx which gets its altitude information from a built in pressure sensor:

This next one is from a Pixel 3 phone with no pressure information:

Note that the ground track is pretty smooth for both, but the altitude... well, you can see.

Staff member

#### ScaleBirdsScott

##### Well-Known Member
We're looking at an AV-30 install for our project, and one thing that I diddn't catch until only in the last few days when getting ready to pull the trigger through our dealer, is that the GPS moving-map function they advertise only works as a slave to another GPS moving map unit. So it doesn't have the means to take, say, just a signal from an antenna or little black box and figure out what to display to you for a map. It requires some kind of larger more expensive dedicated GPS instrument that is calculating that data and already displaying it, then will feed it over a wire. I guess if you have some unit and are running synthetic vision having the AV30 put out a minimap is a cool trick. But other than that, for someone looking for minimal instrumentation it's not the complete done-in-one package I had assumed.

So it seems like for cross-country planning we'll need a way to mount an Adventure Pilot or an Tablet running apps for a navigation map. And once you have that, there's really little point for the AV-30 to be used for a map at all.

So beware of that.

All that said, in even a year from now I expect there to be some notable changes in what is out there and what can be done. I fully expect that in 2021 something like an AV-30 would be able to do it's own navigation as long as you have the right antenna.

#### Heliano

##### Well-Known Member
Let me poke my nose briefly into this discussion about GPS altitude. GPS altitude is geometric altitude, which is different from barometric altitude. Barometric altitude (adjusted to the local QNH) and geometric altitude are the same ONLY IN STANDARD ATMOSPHERE. When the air is colder than standard the geometric altitude shows higher than berometric; the contrary happens when air is hotter than standard. As everything in air navigation is still based on barometric altitude, one must exercise caution. Another point is: if waas is not available for any reason, GPS geometric altitude is NOT reliable, because RAIM (Redundant Autonomous Integrity Monitoring) only checks latitude and longitude. It does NOT verify integrity of geometric altitude. That is the main reason why LPV approaches (which use GPS geometric altitude on final) require WAAS.

#### koyama

##### Active Member
I am surprised that nobody mentioned the Dynon D10A. This is a complete, and self contained 6 pack replacement that is time proven to work. It can be setup as simple as 2 wires, power and ground, and 2 hoses, pitot and static, and you are done!
It even has an internal backup battery to keep it going when the simple connections go south. I have one in almost every plane I own, and they just work with no fiddling.
They have many advanced features that you don't even see on the really high end units. My favorite is auto altimeter.
When you shutdown, it remembers the altitude. When you later start up, it sets the baro from the stored altitude.
It is one of those things that "just works" and it is well cheaper than buying the instruments for a 6 pack.

In the photo above, this D10A is linked to the EMS, so warnings from the EMS are available on screen as well.
As you can see, it has everything a 6 pack would have and more, including a very well behaved AOA.

#### cluttonfred

##### Well-Known Member
HBA Supporter
At $2,330, the D10A is not going to be the solution for everyone. In addition to the tablet-based solutions, there are dedicated units like the GRT Mini, MGL Xtreme, and AvMap Ultra that will give you the basics (pitot-static and GPS-derived indicators) for about$900-1500, so a lot less than a D10A.

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#### koyama

##### Active Member
At $2,330, the D10A is not going to be the solution for everyone. In addition to the tablet-based solutions, there are dedicated units like the GRT Mini, MGL Xtreme, and AvMap Ultra that will give you the basics (pitot-static and GPS-derived indicators) for about$900-1500, so a lot less than a D10A.
The reason I mentioned the D10A is that there is no shortage of them on the used market for ~$1200. That puts them in the zone where it is extremely difficult to home make anything cheaper, and if you consider your time, likely impossible. (I have about 12 of them, and I have never paid more than$1300 for one. I sometimes get them broken in the $100 range usually the display gets broken from a crash, and spend ~$50 to get them working. Water damage is common as well, you have to keep them dry.)
Also, you have to consider reliability. There is no tablet that can match the reliability and track record of the D10A.
I have used many of the GRT, and MGL units, as well as AvMap. They all have some issue that falls short somewhere, so even if you have to spend a few dollars more, it is well worth it. The D10A is the only one I have seen to date that "just works" with no fiddling about or hassle, that has some value as well.
Just my 2 cents worth.

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#### dog

##### Well-Known Member
The reason I mentioned the D10A is that there is no shortage of them on the used market for ~$1200. That puts them in the zone where it is extremely difficult to home make anything cheaper, and if you consider your time, likely impossible. (I have about 12 of them, and I have never paid more than$1300 for one. I sometimes get them broken in the $100 range usually the display gets broken from a crash, and spend ~$50 to get them working.)
Also, you have to consider reliability. There is no tablet that can match the reliability and track record of the D10A.
I have used many of the GRT, and MGL units, as well as AvMap. They all have some issue that falls short somewhere, so even if you have to spend a few dollars more, it is well worth it. The D10A is the only one I have seen to date that "just works" with no fiddling about or hassle, that has some value as well.
Just my 2 cents worth.
Dynon D10a on barnstormers for \$750 in Fl

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