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07-11-2016, 05:58 AM
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Join Date: Mar 2006
Location: Newport, TN
Posts: 7,496
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Quote:
Originally Posted by vic syracuse
I am still not fond of integrated autopilots due to the potential to not have it when you might need it the most.
Vic
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I would love to see the statistical odds of this happening with a properly installed and configured dual screen, dual ADAHRS G3X System that includes a G5 and GMC30?.
While I also fully understand the benefits of having a working AP in IMC, I also don't personally consider it mission critical equipment in a plane that has proper redundancy built into the panel. One ponders how many hours have been flown in real IMC in planes that have no AP?
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07-11-2016, 06:18 AM
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Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 4,196
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Quote:
Originally Posted by Brantel
I would love to see the statistical odds of this happening with a properly installed and configured dual screen, dual ADAHRS G3X System that includes a G5 and GMC30?.
While I also fully understand the benefits of having a working AP in IMC, I also don't personally consider it mission critical equipment in a plane that has proper redundancy built into the panel. One ponders how many hours have been flown in real IMC in planes that have no AP?
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I agree with Vic. If the PFD goes dark for whatever reason, I find it reassuring that I can reach over to the AP head and quickly ensure that the wings are level and I'm maintaining altitude.
I will also admit that the amount of risk is small. I have see about a half a dozen times various vendor's PFDs reboot in flight. Fortunately for me, they've all been during VFR conditions.
I admit that I'm not familiar with the G3X, since my screens from another vendor were installed before the G3X was available. If the PFD the servos are attached fails, is there a mechanism that allows the MFD to take over control?
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07-11-2016, 07:01 AM
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Join Date: Jan 2005
Location: Twin Cities, MN
Posts: 1,565
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Nice panel.
In addition to a backup to the glass, I also choose to not use potentially debilitating substances when I fly, especially IFR. Being aware of what effects medication might have on your ability to fly is perhaps more fundamental to safe flight (VMC or IMC) than what's in the panel.
From the NTSB:
Quote:
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However, it is likely that diphenhydramine, which impairs cognitive and psychomotor performance, diminished the pilot's ability to recognize and manage the erroneous PFD indications.
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NTSB Link
__________________
Brad Benson, Maplewood MN.
RV-6A N164BL, Flying since Nov 2012!
If you're not making mistakes, you're probably not making anything
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07-11-2016, 07:04 AM
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Join Date: Mar 2006
Location: Newport, TN
Posts: 7,496
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Quote:
Originally Posted by rleffler
I admit that I'm not familiar with the G3X, since my screens from another vendor were installed before the G3X was available. If the PFD the servos are attached fails, is there a mechanism that allows the MFD to take over control?
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Yes if the PFD fails, the MFD automatically turns itself into the PFD and takes over. This is called the reversionary mode in Garmin terms.
As well...if a system also includes a G5 and the PFD and the MFD both fail, it will take over control of the AP automatically as long as there is a GMC 30? installed with the system.
The G5 is a game changer for the G3X system since it has the ability to basically act as a stand alone AP when paired with a GMC 30? when the primary G3X AP controlling systems fail (it can also be installed as a totally stand alone AP)... It serves triple duty as a backup PFD/ ADAHRS and GPS as well.
Last edited by Brantel : 07-11-2016 at 07:08 AM.
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07-11-2016, 07:13 AM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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re "So between the G3X, G5 and Sandia I think I got my attitude covered"
Sound conclusion based on knowledge of 3 sound systems.
However when the chips are down in hard IFR, there has to be a way of a particular system ALERTING the pilot when it is at fault. There is no time to determine which system is at fault, the failure has to be ID'ed immediately. Any use of a failed data to control the flight will not end well.
When I worked for a living, this was of concern as it is today. Systems were simpler and vey reliable but if a failure occurred, out would pop a fail flag. There was no ambiguity and there was a means of switching to a good system.
Do the G3X, G5 and Sandia systems have internal failure monitoring? Will the pilot know without question a failure has occurred?
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07-11-2016, 07:24 AM
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Join Date: Mar 2006
Location: Newport, TN
Posts: 7,496
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Quote:
Originally Posted by David-aviator
Do the G3X, G5 and Sandia systems have internal failure monitoring? Will the pilot know without question a failure has occurred?
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While it is impossible for a system's watchdogs to catch everything, the G3X and the G5 will flag invalid indications with a big red X if it detects issues with the source of the information.

Last edited by Brantel : 07-11-2016 at 07:28 AM.
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07-11-2016, 08:02 AM
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Join Date: Jan 2010
Location: Destin
Posts: 1,543
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first time i've ever seen it, but yesterday in flight my PFD showed the attitude fail x for a brief moment, the AP disconnected- very strange because in the past when AHRS anomalies were detected, AHRS2 would simply be used- seamlessly, i need to contact g3xpert and figure out why it caused a panic mode of sorts this time
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07-11-2016, 10:33 AM
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Join Date: Mar 2010
Location: KSGJ / TJBQ
Posts: 2,039
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Quote:
Originally Posted by BobTurner
Re-read the whole sentence. If GPS is available then air data is not used to compute attitude.
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OK, but that wasn't my question.
Quote:
Originally Posted by g3xpert
If the G5 is installed with pitot/static connections, the airspeed, baro altitude, and vertical speed is all air data derived, not GPS
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THANKS! That is what I wanted to know. When connected to a pitot/static system it displays air data derived airspeed, baro altitude and VS. THAT is what I want in a backup system. I was concerned it used GPS derived speed/altitude, only using air data to improve GPS data and during GPS failures. The G5 is an actual full backup EFIS for any system, not just a Garmin. 
__________________
Galin
CP-ASEL-AMEL-IR
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2020 Donation made
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Last edited by GalinHdz : 07-11-2016 at 10:44 AM.
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07-11-2016, 10:43 AM
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Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,686
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Quote:
Originally Posted by David-aviator
re "So between the G3X, G5 and Sandia I think I got my attitude covered"
Sound conclusion based on knowledge of 3 sound systems.
However when the chips are down in hard IFR, there has to be a way of a particular system ALERTING the pilot when it is at fault. There is no time to determine which system is at fault, the failure has to be ID'ed immediately. Any use of a failed data to control the flight will not end well.
When I worked for a living, this was of concern as it is today. Systems were simpler and vey reliable but if a failure occurred, out would pop a fail flag. There was no ambiguity and there was a means of switching to a good system.
Do the G3X, G5 and Sandia systems have internal failure monitoring? Will the pilot know without question a failure has occurred?
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Yes they all have there own system failure monitoring, but... it's not the hard failure that worries me as those are generally easy to flag (red X) it's the soft incipient failure that can bite you (like the accident aircraft).
Being that we don't have a triple redunant system available that uses comparitors for monitoring them we have to use our brains. So for me having 3 seperate attitiude/air data displays directly in front of me makes it relatively easy to spot a system that does not agree with the other two.
I think if we had a triple ADAHRS system that actually "voted" we would have a more fault tolerant system, but right now to the best of my knowledge, I don't believe that's available for us. The pilot has to sort out which system(s) are or are not working.
__________________
Walt Aronow, DFW, TX (52F)
EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
Last edited by Walt : 07-11-2016 at 10:46 AM.
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07-11-2016, 10:43 AM
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Join Date: Mar 2006
Location: Newport, TN
Posts: 7,496
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Quote:
Originally Posted by GalinHdz
The G5 is an actual full backup EFIS for any system, not just a Garmin. 
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Yep, and if you couple it with servo(s) and a GMC 30? , one can also have a stand alone AP that has a bonus PFD built in as well...
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