iPhone and Garmin GTX 345 -AHRS

[LANCECASPER]

1 hour ago, Cruiser said:

"Feature rich" ? really? An AHRS that doesn't work and which Garmin even recommends not using...........  RIGHT .

Only one thing worse than not having a backup Attitude indicator . .  having a backup indicator that is giving you the wrong picture.  

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=124489&hilit=GTX345

[Vance Harral]

1 hour ago, Cruiser said:

An AHRS that doesn't work and which Garmin even recommends not using

This would certainly be an important piece of information.  @Cruiser, can you provide a link to this recommendation, or is it just something you heard in passing?

[Vance Harral]

5 hours ago, PTK said:

The few folks who talk about their Lynx, have you asked L3 why they didn’t give you AHRS? Or targettrend?

Can someone expand on TargetTrend?  Garmin isn't the only vendor which provides a traffic display that paints a track vector for threats, so I'd like to better understand the details.  For example, here's a screen grab from an AOPA article on the Lynx NGT-9000.  There is clearly a vector line for the yellow threat target, and the two non-threat targets have altitude trend arrows that indicate those aircraft are climbing:

My understanding is ADS-B/ADS-R message content includes latitude, longitude, altitude, heading, and horizontal and vertical velocity.  While the message itself doesn't contain any "trend" information, it's pretty trivial to compute a future position for a target, assuming it doesn't change its current flight path.  It seems like I've seen a lot of traffic displays with this sort of trend data.

This gets more complicated if the target is changing it's flight path.  I can imagine a "smart" box comparing several data points for a particular target, realizing it's turning, and heuristically painting a curved vector for the target on the display.  Does TargetTrend (or similar products from other vendors) do this?

 

[Vance Harral]

2 hours ago, jmoz said:

why not consider something like the Dynon D2 (http://www.dynonavionics.com/pocket-panel.php) for backup AI?

Well, for one thing, you apparently can't buy one any more.  That page you linked to says "Sorry, the requested product is not available", and I can't find one for sale anywhere but Ebay.

I think the relaxing of TSO rules, combined with the relatively small price difference between portable/backup AHRS units that display on an EFB and things like the Dynon D10 and Garmin G5, have essentially eliminated the market for things like the Dynon D2.

[PTK]

52 minutes ago, Vance Harral said:

Can someone expand on TargetTrend?  Garmin isn't the only vendor which provides a traffic display that paints a track vector for threats, so I'd like to better understand the details...

It's not a simple track vector. Targettrend gives you motion of traffic threats relative to own ship and it's instantaneous. Think of it as relative motion vs. absolute motion which is what other traffic sources give you. The big difference is that too much time is required to interpret absolute motion. With target trend it's instant and that's a huge advantage. Another advantage is that your traffic page is not flooded with irrelevant non-threats. Garmin is the only one that gives you targettrend.

[jmoz]

18 minutes ago, Vance Harral said:

Well, for one thing, you apparently can't buy one any more.  That page you linked to says "Sorry, the requested product is not available", and I can't find one for sale anywhere but Ebay.

I think the relaxing of TSO rules, combined with the relatively small price difference between portable/backup AHRS units that display on an EFB and things like the Dynon D10 and Garmin G5, have essentially eliminated the market for things like the Dynon D2.

Yeah, that seems like a pretty decent reason! I can't tell if it's discontinued or not (it's not listed on discontinued products), but if you can't buy it, that's more-or-less enough. At $1075 list with no installation costs, I'd have thought that would be a sufficient price difference for it to exist, but I guess that's not the case.

[LANCECASPER]

2 minutes ago, PTK said:

The GTX345 AHRS data is a good backup. 

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=124489&hilit=GTX345

These people that actually have them installed say differently.

"The performance of the AHRS data is very poor and my installer is finding it difficult to get calibration data and instructions from Garmin as it is nowhere to be found in the installation manual."

"There is no attitude calibration with the GTX 345, this calibration button simply calibrates the settings you have for the system . this is an emulated AHRS system just as used with the FlightStream and GDL 39. you calibrate or cage the system using the Garmin Pilot app." - Trek Lawler, Garmin International

"Okay, that makes sense if it actually worked. It will not calibrate from garmin pilot like my gdl39 did. Tried many times."

"To me it seems like it would cause potential problems than help. In fact it may be just plain dangerous. I would suggest those with these ahrs/gp setups to watch the attitude indicator for a period of time. These disconnects can happen and unless your really watching for them it could be missed easily. Of course if you were imc and saw this red x it would be catching your attention."

etc, etc, etc

[PTK]

I don't place much credence to those opinions. They don't phase me.

[LANCECASPER]

On 3/29/2018 at 11:04 AM, PTK said:

I don't place much credence to those opinions. They don't phase me.

True, what would Trek Lawler from Garmin know about the GTX345*?

I did an upgrade before the the GTX345 or Lynx came out. If I knew then what I know now, my first choice would be the Lynx, 2nd choice the GTX345.

 

*which by the way is a great ADS-B in/out transponder. The AHRS is just not meant to be a true backup, otherwise it would be certified as a backup.

[JKeeth]

59 minutes ago, PTK said:

It's not a simple track vector. Targettrend gives you motion of traffic threats relative to own ship and it's instantaneous. Think of it as relative motion vs. absolute motion which is what other traffic sources give you. The big difference is that too much time is required to interpret absolute motion. With target trend it's instant and that's a huge advantage. Another advantage is that your traffic page is not flooded with irrelevant non-threats. Garmin is the only one that gives you targettrend.

TargetTrend is exclusive to Garmin products because they designed, developed, and patented it.

The Lynx NGT-9000 is the only unit on the market that offers ATAS (https://www.faa.gov/nextgen/programs/adsb/pilot/atas/), plus a built-in color touchscreen display to see the traffic and weather, plus a built-in TAS/TCAS processor, plus diversity, plus terrain. I'd call that feature rich!

[PTK]

31 minutes ago, LANCECASPER said:

True, what Trek Lawler from Garmin know about the GTX345*?

I did an upgrade before the the GTX345 or Lynx came out. If I knew then what I know now, my first choice would be the Lynx, 2nd choice the GTX345.

 

*which by the way is a great ADS-B in/out transponder. The AHRS is just not meant to be a true backup, otherwise it would be certified as a backup.

I go by what the Garmin field engineers tell me.

It is not a back up for EFIS like the G500. And of course the G5 is not either. That's because it's not certified for lightning  strike survival. But my KI256 doesn't "need" a bu. The AHRS from the GTX345 provides the data and I see nothing wrong using it as a bu or reference.  

[LANCECASPER]

1 minute ago, PTK said:

I go by what the Garmin field engineers tell me.

Trek A. Lawler is Supervisor of Garmin Aviation Field Service Engineering
 

[MIm20c]

1 minute ago, PTK said:

I go by what the Garmin field engineers tell me.

Your sources appear to be very reliable. How’s the ki300 working out for you?

[PTK]

On 3/29/2018 at 12:38 PM, JKeeth said:

TargetTrend is exclusive to Garmin products because they designed, developed, and patented it.

The Lynx NGT-9000 is the only unit on the market that offers ATAS (https://www.faa.gov/nextgen/programs/adsb/pilot/atas/), plus a built-in color touchscreen display to see the traffic and weather, plus a built-in TAS/TCAS processor, plus diversity, plus terrain. I'd call that feature rich!

May I humbly suggest you fly with Garmin targettrend and experience the concept of relative motion of traffic? ATAS is not targettrend. Not even close.

[Marauder]

9 minutes ago, PTK said:

May I humbly suggest you fly with Garmin targettrend and experience the concept of relative motion of traffic? ATAS is not targettrend.

Do you know who JKeeth is? Everytime you post something you certainly just keep driving down whatever credibility you had.

[PTK]

Yes I’m aware. He is an L3 rep and of course biased. That’s why I made the very humble suggestion.

[MIm20c]

I have to agree with PTK the target trend looks really nice. Much better than traffic in map view that ForeFlight uses. 

[Vance Harral]

I'm still curious where the TargetTrend algorithms are implemented.  If they're in the 345 itself, then any display device - including Foreflight, FltPlan Go, etc - could theoretically display those trend vectors.  If they're part of the software in the display device instead (GTN-650 or Garmin Pilot or whatever), it's unlikely Garmin will ever give Foreflight or another EFB vendor the algorithm.  Also, if they're in the display device, then two different devices could potentially be running two different versions of the algorithms.   I can see this coming up with traffic display on a GTN vs. Garmin Pilot.  Garmin does a decent job rolling out GTN firmware updates, but it's a little annoying that we have to make a trip to our avionics shop and drop them a check for $100 every time we want the latest GTN firmware.  I'm aware some avionics dealers do this for free as a courtesy, but the shop that installed our 650 isn't one of them.  Consequently, we only upgrade the firmware every year or two, instead of every time an update is available.

[Bryan]

I have a GTN 750 and a GTX 345. The TrafficTrend is great displayed on the 750 and Garmin Pilot in my iPad. I think the 345 does this work but unsure. Both GP and the 750 display the EXACT data in real time. If each is doing the trending itself, they are perfectly in sync. This is why I think the 345 is doing it and not sharing the tech to FF. FF’s traffic display (and tending) is not as good, IMO.

As others have said, the AHRS in the 345 seems like a lesser AHRS just so they could check that box for the IPads of the world to market the 345. Everything else about it is GREAT! I wouldn’t trust the AHRS for hard IFR in a vacuum failure (Ki256) but don’t have much else currently. I don’t do a ton of hard IMC until I can get a proper backup AI. Invalid info, I think, it worse than no information.

At the point my engine driven backup fails, I will use my electric backup pump until I can get a KI300 or something else that can drive my A/P. I like the slide-in replacement for the Ki256 and removal of the only thing that is using my vacuum. If it ever comes to market.

[Marauder]

2 hours ago, Vance Harral said:

Can someone expand on TargetTrend?  Garmin isn't the only vendor which provides a traffic display that paints a track vector for threats, so I'd like to better understand the details.  For example, here's a screen grab from an AOPA article on the Lynx NGT-9000.  There is clearly a vector line for the yellow threat target, and the two non-threat targets have altitude trend arrows that indicate those aircraft are climbing:

My understanding is ADS-B/ADS-R message content includes latitude, longitude, altitude, heading, and horizontal and vertical velocity.  While the message itself doesn't contain any "trend" information, it's pretty trivial to compute a future position for a target, assuming it doesn't change its current flight path.  It seems like I've seen a lot of traffic displays with this sort of trend data.

This gets more complicated if the target is changing it's flight path.  I can imagine a "smart" box comparing several data points for a particular target, realizing it's turning, and heuristically painting a curved vector for the target on the display.  Does TargetTrend (or similar products from other vendors) do this?

 

 

1 hour ago, Vance Harral said:

I'm still curious where the TargetTrend algorithms are implemented.  If they're in the 345 itself, then any display device - including Foreflight, FltPlan Go, etc - could theoretically display those trend vectors.  If they're part of the software in the display device instead (GTN-650 or Garmin Pilot or whatever), it's unlikely Garmin will ever give Foreflight or another EFB vendor the algorithm.  Also, if they're in the display device, then two different devices could potentially be running two different versions of the algorithms.   I can see this coming up with traffic display on a GTN vs. Garmin Pilot.  Garmin does a decent job rolling out GTN firmware updates, but it's a little annoying that we have to make a trip to our avionics shop and drop them a check for $100 every time we want the latest GTN firmware.  I'm aware some avionics dealers do this for free as a courtesy, but the shop that installed our 650 isn't one of them.  Consequently, we only upgrade the firmware every year or two, instead of every time an update is available.

Garmin was part of the original Capstone project in Alaska, so they got involved early and were part of the development of what we know ADS-B is today. With that they developed proprietary firmware which included TargetTrend. It is unique and clearly limited to usage with Garmin products. When I was looking for ADS-B solutions, the 345 would not even work with my Aspens. Later, the firmware was opened up to work with Aspens but the TargetTrend capability would not display on my Aspens, only the industry standard traffic displays that you would find on TCAS type of systems.

The power of TargetTrend is a visual indication by using the trend arrow to point to the relative track of the target and to use that same target trend arrow to come out of the back of the target to show you are closing on a target. As you pointed out, all of this is done through the data associated with the target (direction of flight, speed, vertical climb/descent, etc). Garmin just has made it a feature that is limited to their hardware. Even with TargetTrend, Garmin includes a voice annunciation when that target becomes a threat. Exactly what the Lynx ATAS does. I have a lot of time flying with TargetTrend since it was my portable traffic solution until I installed the certified box. It is nice to see that you are gaining on a target but at the end of the day, I am only really interested when that target becomes a threat. And I certainly don't want to rely upon looking at a screen to determine that. Having a vocal warning of a conflict gets my attention.

Here is a flight between Philly and a Trump TFR. None of these ever became a verbal warning. 

But on this flight, the only plane anywhere near me did become one:

[Vance Harral]

Thanks Maurader, great explanation.

Question for you: when the NGT-9000 generates an audio warning, does the voice tell you where to look?  Something like "Traffic, 2 o'clock low!".  Or does it just say "Traffic!"?  And is it any different with the Garmin products?

[Cruiser]

Traffic alerts include a direction. "12 o'clock HIGH" etc.

As I understand the TargetTrend feature from Garmin includes the motion parameters of your airplane to show the resultant location of the target in relation to your airplane

In other words. when you are moving in your plane the relative location of the other plane changes. If you move forward and to the right and the other plane moves forward and to the left then the TargetTrends plots the closure of the two planes not just the motion of the target.

[Marauder]

24 minutes ago, Vance Harral said:

Thanks Maurader, great explanation.

Question for you: when the NGT-9000 generates an audio warning, does the voice tell you where to look?  Something like "Traffic, 2 o'clock low!".  Or does it just say "Traffic!"?  And is it any different with the Garmin products?

You can hear it for yourself on this page: http://l-3lynx.com/ (About half way down). I'm not selling 9000 boxes. I opted for it primarily because I want TAS (active traffic) and that required a separate box, at additional cost  and separate from the Garmin 345. There are a couple of other features that people tend to forget when think they are comparing apples to apples. The basic 345 comes with the AHRS, squitter transponder and the 978 UAT. The basic box requires you to connect it to a WAAS GPS for the position stuff. There is a version of the 345 with a built in WAAS GPS but it is at least $1000 more. The 9000 basic box includes a WAAS GPS, squitter transponder, 978 UAT and display screens. Another thing it includes is the TAS capability. It is built into the box but turned off. You need to purchase the software unlock and the traffic antenna to get active traffic.

Active traffic will become less important in the future. But right now I am picking up stuff all the time from planes who are below ADS-B coverage (typically in the traffic patterns of an airport). And in the case of ADS-B failure, TAS will always be there to do active interrogations of other plane's transponders.

If you are talking costs. I got quotes for the 345 without the WAAS GPS that ranged from $6500 to $8000 installed. The Lynx 9000+ (with active traffic turned on and the antenna) was quoted from $9,900 to $11,000. 

[Marauder]

22 minutes ago, Cruiser said:

Traffic alerts include a direction. "12 o'clock HIGH" etc.

As I understand the TargetTrend feature from Garmin includes the motion parameters of your airplane to show the resultant location of the target in relation to your airplane

In other words. when you are moving in your plane the relative location of the other plane changes. If you move forward and to the right and the other plane moves forward and to the left then the TargetTrends plots the closure of the two planes not just the motion of the target.

That is the old ATAS version. The new one also tells you distance.

Edited March 29, 2018 by Marauder

[Vance Harral]

Thanks for the info on traffic alerts, Maurader.  Based on your pointer and a little more research, looks like both the GTX-345 and the NGT-9000 call out azimuth, high/low, and distance.

The connection to a WAAS GPS isn't an issue for us because we already have a GTN-650.  So the flip-side of the argument is that with the NGT-9000, we're arguably paying for a WAAS GPS receiver we don't need.

We don't have any installation quotes yet, so time will tell on walk-away price.  But I can't imagine the installation costs on our particular airplane would vary much between the two boxes for just their respective basic feature sets.  That just leaves the price delta on the hardware itself.  The partnership is hoping to get out of the shop for $7500 or less.  Maybe way less, as various, much-less-capable options are also still on the table for us.  But we wont' really know until we start requesting quotes.  The only thing we know for sure is TAS is off the table - we'd rather spend those dollars elsewhere.  That makes the comparison between the GTX-345 and the NGT-9000 a close heat.

Edited March 29, 2018 by Vance Harral