AV-30 vs. Garmin 275 vs. Garmin G5 vs. ______

[McMooney]

On 10/20/2024 at 12:01 PM, Vance Harral said:

Not trying to justify the shop's quote, but if you're installing a G5 HSI, the G5 unit and its 4 connections (pitot, static, CANBUS, RS-232 or GPS antenna) is only a fraction of the work.

If you want the HSI to actually show heading you have to mount and wire a magnetometer, and if you want it to show nav information, you have to interface it to a navigator, which is a multi-wire thing that almost always has to be done through a GAD29 box that you have to mount somewhere.  There's an OAT probe option which gives you true airspeed data that may be in the shop quote.  If you want altitude data sent to the transponder for serial altitude encoding, that's another G5 -> GAD29 -> transponder connection.  Autopilot interface is another GAD29 connection.  All this stuff involves disassembling existing connectors and adding additional pins to them.

The mechanical mounting of the magnetometer and GAD is some of the work, and the addition of pins/crimps/solder joints to connect up the nav box and transponder and OAT probe is quite a lot of work.  And while we joke a little about the "Mooney tax", the tight space behind the panel in the average Mooney really does make the job worse.  You have to build a shelf behind the panel for the GAD29, or alternatively put it in the tail cone and remove the interior to run the wiring up to the panel.

That's what I thought too, but it took me a little over two weeks of working more-or less full time (not including weekends).  I'm slow, though, and of course it goes faster if you've done it before.  Again, not trying to justify the shop's quote, which I agree sounds exorbitant even at 80+ hours of labor.

But bottom line, there's a big difference between an ADI vs. an HSI installation for any of the G5/GI-275/AV-30.  Again, @Jake@BevanAviation hit the nail on the head when he pointed out that it's all about the connectivity you want, and that's mostly on the HSI side.  You can whittle down the cost by connecting less stuff, but only at the tradeoff of reduced capability.

connecting things isn't overly difficult, the g5 system is mostly connected with a number of 2 wire busses, can, arinc and serial.  

i had the whole thign wired up onmy bench in less than an hour.  now snaking all that wire thru the plane while making sure it's all white and indistinguishable, thats the money maker.

I really like the dynon setup, mostly a bunch off preconfigured 9 pin dsub connections between the dynon components,.

oh yeah and they have the mounting shelves so most of it can go in as a unit

 

 

Edited October 21, 2024 by McMooney

[laytonl]

On 10/17/2024 at 7:54 PM, Utah20Gflyer said:

I think the Uavionix products are acceptable with the addition of a magnetometer which I think is still in the approval process for certified planes.   So maybe not quite ready for prime time but getting close.  
 

I did two GI275s and they are great.  I like that two of them replaces the entire 6 pack.  The AV30 and G5 you only get to replace 2 instruments and have to keep the other 4 legacy instruments.   I like the idea of getting rid of things that have to be maintained.   I did keep my airspeed indicator but got rid of the others and created room for a panel mounted I phone max that I display foreflight on.  

Actually the magnetometer is certified.  I have one for my AV30C’s in the citabria.  It still has to be reset occasionally, but it’s not unusual for the DG to go several days without needing to reset to the compass.  The Av30 is a great device, and can be a good transitional unit.  If you are not comfortable with it as your primary DG, you can always repurpose it as a backup AI.  Lee

[Vance Harral]

1 hour ago, McMooney said:

i had the whole thign wired up onmy bench in less than an hour.  now snaking all that wire thru the plane while making sure it's all white and indistinguishable, thats the money maker

I think I'm agreeing with you when I say that wiring stuff up on the bench is a somewhat uninteresting experiment, and not indicative of the labor to actually install the system.  In addition to not having to worry about routing, you also don't have to secure anything in a way that will hold up to years of airframe vibration.

For us, feeding wire through nooks and crannies of the airframe was not really all that labor intensive either.  The real bear is that unless you're (re)building the entire system from scratch, you have to disassemble the D-shell connectors that are already plugged into existing components in-situ, to add new pins (and if you're doing the work cleanly, to remove old ones as well).  That's not something you're going to get a handle on with bench testing.  In our case, getting access to the D-shell connectors for the GTN-650 ARINC connections was extremely difficult, and we had to de-socket over a dozen of those micro-sized pins for the no-longer-needed GI-106 connection as well (a lot of shops simply don't do that sort of thing, they just cut the wires).  The transponder D-shells were a little more accessible but not much.  Again, there's sort of a Mooney tax here due to the limited space behind the panel.  Depending on how prior work was installed, it can be incredibly difficult to add new work without damaging anything -  especially since some of the newer Garmin gizmos have the configuration ROM embedded in the connector, with tiny, fragile wires.  If you damage any existing work you have to repair it, which is a lot harder than installing new stuff from scratch.  And the damage may not be apparent until you start trying to bring up the system after initial installation, in which case you have to debug, then go back and disassemble things again.  You can probably guess how I know all this.

None of the work strikes me as particularly difficult, just tedious and time consuming.  Again, pros make fewer mistakes, and I'm not trying to justify exorbitant shop rates that seem to be based on what the market will bear rather than dollars-per-hour labor.  I'm just scarred by the experience of thinking it would take X amount of time, being "smart" enough to plan for 2X, and then discovering once again that things often wind up taking about double your 2X estimate.   Like doing your own plumbing at home, the labor cost often seems more reasonable once you've actually tried doing the job yourself (successfully or not).

[Ragsf15e]

Nobody mentioned working inside the wing (or tailcone - which requires hiring a very light midget with small feet) to build a shelf for the magnometor or removing/replacing all the pilots side interior.  Those can take some time to do right depending on the airplane.

My 2 G5s connected to gns430w and autopilot were about $12k in 2020, so these estimates seem reasonable?

Edited October 22, 2024 by Ragsf15e