AHRS tried to kill me

[Andy95W]

2 hours ago, RobertGary1 said:

Turning from the north the compass will initially Indicate a turn in the opposite direction. It’s really the reason we have gyro dg’s. 
 

-Robert  

In 2020, it's really the reason we have GPS heading.

[Cruiser]

using any AHRS data in a non-certified manner seems very risky to me. 

[RobertGary1]

1 hour ago, mooniac15u said:

Didn't you learn to work with your magnetic compass (including accounting for that) as part of your partial panel training?  There will be a lag and then it will indicate which direction you are turning.  If the point is trying to decide which gyro is providing you the correct information then you will have your answer fairly quickly and you can switch back to using the gyro with the mag compass as confirmation.

You can also get some indication of which way you are turning from any moving map display in the cockpit including on a tablet.  Any of these things should point you towards the gyro with the correct information.

For compass turns for sure, I’ve taught them.  But for the determination of attitude I’m afraid it’s hopeless. Perhaps a few more seconds than without at best. 
 

-Robert 

[RobertGary1]

1 hour ago, Andy95W said:

In 2020, it's really the reason we have GPS heading.

I suspect someday atc will switch from providing magnetic headings to providing courses headings and then we can rid ourselves of the compass and it’s lesser peers. 
 

-Robert 

[Ibra]

1 hour ago, Andy95W said:

In 2020, it's really the reason we have GPS heading.

Isn't that what pilots (and ATC) are supposed to be flying in the first place? 

10 minutes ago, RobertGary1 said:

I suspect someday atc will switch from providing headings to providing courses and then we can rid ourselves of the compass and it’s lesser peers. 

Yes that would cut lot of fat  (also less and less VORs are flashing vs compass north but we still have runway wind/orientation in magnetic...)

Just don't apply that innovation in navigation to flying ground vs indicated speed...

Edited February 28, 2020 by Ibra

[mooniac15u]

 

19 minutes ago, RobertGary1 said:

For compass turns for sure, I’ve taught them.  But for the determination of attitude I’m afraid it’s hopeless. Perhaps a few more seconds than without at best. 
 

-Robert 

Are you kidding?  You asked about one G5 showing a right turn and the other showing a left turn.  It's right here in case you forgot.

8 hours ago, RobertGary1 said:

Assuming the failure mode is a red X. But if it’s  like the OP shows here and one G5 shoes a turn to the right and the other a turn to the left what do you do??

 

 -Robert 

I suggested using your compass to tell you which way you were turning and give you a clue which G5 was indicating correctly.  Now you're talking about trying to determine attitude?  Nobody said anything about using a compass to determine attitude.

 

[RobertGary1]

49 minutes ago, Ibra said:

Isn't that what pilots (and ATC) are supposed to be flying in the first place? 

 

No, today we’re not suppose to fly gps course heading when assigned an atc heading. We’re supposed to fly magnetic which is the sole reason the compass and DG, etc are mandatory. If the FAA changed this the compass would be gone. 
 

-Robert

[RobertGary1]

58 minutes ago, mooniac15u said:

 

Are you kidding?  You asked about one G5 showing a right turn and the other showing a left turn.  It's right here in case you forgot.

I suggested using your compass to tell you which way you were turning and give you a clue which G5 was indicating correctly.  Now you're talking about trying to determine attitude?  Nobody said anything about using a compass to determine attitude.

 

Maybe I could see it if the turn was caught quickly and very shallow. But I can’t imagine the average pilot in a frightened steep turn in the clouds trying to decipher this.  
 

-Robert 

[Hector]

Backup AI if you fly IFR. I use ForeFlight connected to a permanently mounted Stratus and have used its AHRS in simulated conditions and it can definitely get you out of trouble. However, I almost never have the synthetic display turned on in ForeFlight and by the time I noticed something wrong it might be too late. My backup electric AI is part of my scan and will let me know right away if there is something wrong. It already has! I had a vacuum pump failure and my vacuum AI started going sideways and I caught it right away as it was displaying differently from the electric AI. For something that can truly save your bacon add a backup AI


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[201Steve]

I had an erroneous reading on my G5 a few months ago in VMC. It was a turbulent day, and it kinda cocked itself in a left bank even in straight/level. Apparently it was an “algorithm error” that was prone to error in turbulence. A software upgrade seems to have resolved it but I’m still skeptical. 

[skykrawler]

It pays to operate everything in the ways you might use and depend on from time to time.  So that was a smart move.

I still have the basic panel with a G5 for backup.   For me the turn indicator is primary until I reach my heading. Then its HSI.  Attitude is the cross check.

Sometimes I use the G5 for primary, but my habits are ingrained.   And its not because its EFI......I work at simulation facility and fly transport category EFI a lot.

 

 

[Jerry 5TJ]

One reason I selected the L-3 ESI500 as backup to the Garmin G500 is that it uses different hardware and different software.  

[EricJ]

14 minutes ago, Jerry 5TJ said:

One reason I selected the L-3 ESI500 as backup to the Garmin G500 is that it uses different hardware and different software.  

I call that "implementation diversity", and it's why I keep FltPln Go loaded on one of my tablets even though I primarily use Avare.   Redundancy won't help you if whatever killed your primary system also kills the backup.    The ESI500 does not have the GPS dependency that most of these things do, but apparently falls to a degraded attitude mode if it is in a turn for more than three minutes.   I'd be interested in how they do alignment corrections in that one.

 

[wishboneash]

The Dynon D3 is a decent solution for me. It's always available and very sensitive (maybe too sensitive). It would be nice to be able to dial down its sensitivity.

[Boilermonkey]

While having something fail is somewhat inevitable, my big concern with the problem that PT20J saw was the lack of system integrity.  The system didn't know that it had failed.  That's a big deal.  Modern avionics, even simple GPS receivers have some level of integrity checks.   Of course certified electronics must have a way to measure integrity and display it, but there is a glaring gap with some of these systems that we use in an advisory manner.

[M20F-1968]

When I did my rebuild, I redesigned my panel 2X and then when the G600 came out, redesigned it again.  

The end result is that I have three attitude indicators.  One in the G600 driven by AHRS.  A second 3" vacuum and a third 2" electric.

I kept the vacuum system due to the retractable step.  Thus, I always have 2 back-up attitude  indicators in the panel and running.

The delays in response time using an Ipad touch screen just to pull up approach plates and airport data is annoying and distracting to me.  

I would not want to be using an Ipad as a component of what I am using as a primary flight instrument.  The back-up instrument needs to be as reliable 

as what it replaces.

John Breda

[RobertGary1]

It’s one of the reasons I’m keeping my vacuum attitude indicator along with dual gi-275’s. I don’t understand folks who are so anxious to get rid of the vacuum system when it represents a free additional source of attitude. 

 

-Robert 

[kpaul]

21 minutes ago, RobertGary1 said:

it represents a free additional source of attitude. 

How is it Free?  Vac pumps seem to fail every 500 hours or so...not free, overhauling the ADI...not free.  Also, there is a weight penalty...not free.

I'm not disagreeing with you that an independent source of attitude is important.  In fact my plane has a vac system and a backup vac system and the only thing hooked up to it is the ADI.

[StevenL757]

19 hours ago, Cruiser said:

using any AHRS data in a non-certified manner seems very risky to me. 

Exactly.  And just to save money in many cases.

What I also find amazing is that I rarely find anyone talking in the same manner about the far-greater number of Aspen-related component failures that I’m hearing here about Garmin stuff.

[EricJ]

3 hours ago, Boilermonkey said:

While having something fail is somewhat inevitable, my big concern with the problem that PT20J saw was the lack of system integrity.  The system didn't know that it had failed.  That's a big deal.  Modern avionics, even simple GPS receivers have some level of integrity checks.   Of course certified electronics must have a way to measure integrity and display it, but there is a glaring gap with some of these systems that we use in an advisory manner.

Most GA gyro or electric attitude indicators have no integrity checking, you just have to keep an eye on them and cross-check everything constantly.   So from that perspective I don't see the new ones as any worse, and better in many aspects.   The G5 (and even the Stratux AI display) will provide a warning if the GPS reference is lost.   The G5 gives warnings for all kinds of things, so it's way ahead of the game compared to a typical vacuum AI.

[RobertGary1]

2 hours ago, kpaul said:

How is it Free?  Vac pumps seem to fail every 500 hours or so...not free, overhauling the ADI...not free.  Also, there is a weight penalty...not free.

 

It’s free because it’s already there before you take it out. People are so excited to pull it out; I don’t understand it. 
 

-Robert 

[EricJ]

10 minutes ago, RobertGary1 said:

It’s free because it’s already there before you take it out. People are so excited to pull it out; I don’t understand it. 
 

-Robert 

I haven't gotten rid of mine yet, but I'm eager to.   Compared to more modern technology they're failure prone and expensive to maintain, and getting rid of it will free up a bunch of space under the panel as well as make maintenance access a lot easier around the accessory case and the firewall.   Can't think of a reason to keep it.

 

[Ragsf15e]

17 minutes ago, EricJ said:

I haven't gotten rid of mine yet, but I'm eager to.   Compared to more modern technology they're failure prone and expensive to maintain, and getting rid of it will free up a bunch of space under the panel as well as make maintenance access a lot easier around the accessory case and the firewall.   Can't think of a reason to keep it.

 

Traditional vacuum ADIs also fail in a way that makes it much easier to get spatial disorientation.  They don’t generally alert.

At least the G5s, Aspen, etc have some error checking and a big red x for their known failure modes.  There are also the requirements to keep your traditional backups and many people have installed 2xG5s for their built in redundancy.

I for one, think that my ifr safety has been increased by installing 2xG5s in place of my vac/standby vac and single ADI.  I have the 2xG5s and an electric TC/autopilot (stec still works without the ADIs) and worst case I have the FF attitude from the GTX.  If I’m really on that, lots of other bad stuff has happened.

So, sure, if you install 12 different ADIs that use 12 different power and attitude sources, you could say you have more redundancy than I do and are thus safer, but I just don’t see a reason to do that.  If people with 2xG5s and backup instruments start falling out of the sky, I’ll change my tune.

[RobertGary1]

47 minutes ago, Ragsf15e said:

 

I for one, think that my ifr safety has been increased by installing 2xG5s in place of my vac/standby vac and single ADI.  I have the 2xG5s and an electric TC/autopilot (stec still works without the ADIs) and worst case I have the FF attitude from the GTX.  If I’m really on that, lots of other bad stuff has happened.

So, sure, if you install 12 different ADIs that use 12 different power and attitude sources, you could say you have more redundancy than I do and are thus safer, but I just don’t see a reason to do that.  If people with 2xG5s and backup instruments start falling out of the sky, I’ll change my tune.

For me 3 is the magic number. If one failed it’s easy to tell which one it is. I have also found that when the g1000 ahrs fails I’ve gotten a red X but I don’t 100 trust software detection. I feel better with 3. And the 275’s save so much space in my panel vs the 3-4 instruments it replaces it was an easy choice. 
-Robert