AeroElectric-List Digest Archive

Thu 09/18/14


Total Messages Posted: 14



Today's Message Index:
----------------------
 
     1. 05:06 AM - Re: alternator knocked off line when strobes turned on (Bubblehead)
     2. 07:30 AM - Garmin AHRS drifting (Werner Schneider)
     3. 10:18 AM - Re: Re: alternator knocked off line when strobes turned on (Steve Sundquist)
     4. 10:32 AM - Re: alternator knocked off line when strobes turned on (Steve Sundquist)
     5. 12:00 PM - Re: Garmin AHRS drifting (Peter Pengilly)
     6. 12:49 PM - Dual electric system in glasair (James Robinson)
     7. 01:04 PM - Re: Garmin AHRS drifting (Robert L. Nuckolls, III)
     8. 01:57 PM - Re: Garmin AHRS drifting (Peter Pengilly)
     9. 02:33 PM - Re: Garmin AHRS drifting (Jeff Luckey)
    10. 02:43 PM - Re: Garmin AHRS drifting (Kelly McMullen)
    11. 03:04 PM - Re: Garmin AHRS drifting (Peter Pengilly)
    12. 03:11 PM - Re: Garmin AHRS drifting (Peter Pengilly)
    13. 03:29 PM - Re: Garmin AHRS drifting (mmayfield)
    14. 05:40 PM - Re: alternator knocked off line when strobes turned on (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 05:06:58 AM PST US
    Subject: Re: alternator knocked off line when strobes turned
    on
    From: "Bubblehead" <jdalmansr@gmail.com>
    Perhaps disconnect each strobe power supply one at a time and see if the system still trips. You might find out one of the power supplies is bad. This assumes you have a separate power supply for each strobe. -------- John Keller, TX RV-8 N247TD Read this topic online here: http://forums.matronics.com/viewtopic.php?p=430709#430709


    Message 2


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    Time: 07:30:00 AM PST US
    From: Werner Schneider <glastar@gmx.net>
    Subject: Garmin AHRS drifting
    Interesting read I've got today, seems to have an impact on Garmin G1000, G1000H, G950, G900X, G500, G500H, G600 when after power up the aircraft is moved the first 10 seconds. Was not aware of this http://ad.easa.europa.eu/ad/SAFO14004 So does the G3X then have a different platform? Cheers Werner


    Message 3


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    Time: 10:18:37 AM PST US
    From: Steve Sundquist <sttwig@gmail.com>
    Subject: Re: alternator knocked off line when strobes turned
    on Thanks, I will look into that. On 9/18/2014 5:05 AM, Bubblehead wrote: > > Perhaps disconnect each strobe power supply one at a time and see if the system still trips. You might find out one of the power supplies is bad. This assumes you have a separate power supply for each strobe. > > -------- > John > Keller, TX > RV-8 N247TD > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=430709#430709 > > --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com


    Message 4


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    Time: 10:32:31 AM PST US
    From: Steve Sundquist <sttwig@gmail.com>
    Subject: Re: alternator knocked off line when strobes turned
    on Joe, Thank you for your input. About all I know about the strobes is that they are old Whelans. The alternator kicks out immediately, within 2 or 3 SECONDS upon switching on the strobes. I have seen no failure in the strobes as they continue to operate normally, on battery power, after the alternator is kicked off line. Per another suggestion, I am going to look for power supplies for the strobe system in the wings in addition to the one next to the battery which may be just for the tail. Steve On 9/17/2014 8:42 PM, Joe Motis wrote: > Hi Steve, I am assuming that your strobes are capacitive discharge, > what if some of the capacitance is going to ground after it warms up 2 > to 3 minutes as per your data. > > Is a partial or intermittent failure in the strobe power supply > capable of sending high voltage pulses back into the 12 volt side of > the system? > Bob? > > On Wed, Sep 17, 2014 at 2:53 PM, Steve Sundquist <sttwig@gmail.com > <mailto:sttwig@gmail.com>> wrote: > > <sttwig@gmail.com <mailto:sttwig@gmail.com>> > > I have done the suggested testing. The bus voltage at 1000 rpm > settles in around 14.24 volts although I did see it as high as > 14.4 volts at one point. The bus voltage is virtually the same at > 2000 rpm. When I load up the system to 45 plus amps at 2000 rpm, > the bus voltage drops to about 13.1 volts. When I dump the load > all at once the system does not trip. The battery is an Odyssey > PC680 about three years old. The voltage regulator is not > adjustable, but it appears that is not the problem. > > Thank you > > Steve > > > Sent from my iPad > > > On Sep 17, 2014, at 5:52 AM, "Robert L. Nuckolls, III" > <nuckolls.bob@aeroelectric.com > <mailto:nuckolls.bob@aeroelectric.com>> wrote: > > > III" <nuckolls.bob@aeroelectric.com > <mailto:nuckolls.bob@aeroelectric.com>> > > > > At 22:54 2014-09-16, you wrote: > <sttwig@gmail.com <mailto:sttwig@gmail.com>> > >> > >> Thank you for your response. > >> This is a new condition. The OV protection relay is part of > the InterAv system, part no. 635-62448. There is no voltmeter in > the system so I don't know what the normal buss voltage is. The > only instrumentation in the system is the ammeter on the > alternator output. I will load up the system and turn it all off > at once after I reinstall the alternator. I removed it for > testing at a local shop. > > > > Sorry you went to the trouble before troubleshooting > > to find out what device needed to be repaired/replaced. > > > > It's unlikely to be the alternator. > > > > You need to KNOW the regulation set-point for the > > system. Get a digital voltmeter and check voltage at > > the bus at 1000 rpm and minimal electrical load, 2000 > > rpm and min load, then 2000 rpm with max load. While > > at 2000 rpm, see if you can cause the system to trip > > with the load-dump experiment I suggested earlier. > > > > The symptoms you've described thus far strongly suggest > > a skitterish ov protection system being irritated by > > either an elevated bus voltage -or- internal cauese. > > The most likely is elevated bus voltage. If your > > regulator is adjustable, set the bus to 14.2 volts. > > > > What kind of battery and how old? > > > > This is a good discussion to be sharing with the rest > > of the List membership. Getting the tools out to remove > > a piece of hardware is best reserved until you KNOW which > > piece needs to be removed. Fortunately, there are relatively > > easy techniques for deducing which piece that is. > > > > > > > > Bob . . . > > > > > > > > > > > == > - > Electric-List" > target="_blank">http://www.matronics.com/Navigator?AeroElectric-List > ========== > FORUMS - > _blank">http://forums.matronics.com > ========== > b Site - > -Matt Dralle, List Admin. > target="_blank">http://www.matronics.com/contribution > ========== > > > * > > > * --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com


    Message 5


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    Time: 12:00:43 PM PST US
    From: Peter Pengilly <peter@sportingaero.com>
    Subject: Re: Garmin AHRS drifting
    > So does the G3X then have a different platform? Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that is the subject of the AD. However the G3X is not certified so cannot be the subject of an AD. It seems unlikely that the GSU 73 or 25 use fundamentally different algorithms than the GRS77, so will probably exhibit similar performance if abused. Peter _ _ On 18/09/2014 15:28, Werner Schneider wrote: > <glastar@gmx.net> > > Interesting read I've got today, seems to have an impact on Garmin > G1000, G1000H, G950, G900X, G500, G500H, G600 when after power up the > aircraft is moved the first 10 seconds. > > Was not aware of this http://ad.easa.europa.eu/ad/SAFO14004 > > So does the G3X then have a different platform? > > Cheers Werner > >


    Message 6


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    Time: 12:49:48 PM PST US
    From: James Robinson <jbr79r@yahoo.com>
    Subject: Dual electric system in glasair
    Hi Bob<br/>I have your dual alt , dual batteries, with x connect. One circ uit is fine " B". The " A" circuit is dead. I can hear the solenoid click b ut no power any where on that circuit. X connect doesn't seem to do anythin g. Any trouble shooting advice appreciated. Jim Robinson. 530 409-1021<a hr ef="https://overview.mail.yahoo.com?.src=iOS"><br/><br/>Sent from Yahoo Mail for iPhone</a>


    Message 7


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    Time: 01:04:31 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Garmin AHRS drifting
    At 13:59 2014-09-18, you wrote: > > So does the G3X then have a different platform? > >Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that >is the subject of the AD. However the G3X is not certified so cannot >be the subject of an AD. It seems unlikely that the GSU 73 or 25 use >fundamentally different algorithms than the GRS77, so will probably >exhibit similar performance if abused. > >Peter All modern AHRS systems have shed their 'iron' gyros representing horizontal and heading references in favor of rotational rate sensors. When I was working the GP180 program at Lear wayyyy back when, a supplier (I think it was King Radio) came in to pitch their latest and greatest offering to the new airplane. One of the presenters made kind of a show of opening a briefcase-like container on the table and turning on a switch. A light came on. He then proceeded to the next phase of his presentation. After a time, the 'briefcase' began to emit a 'ticking' sound . . . about one tick per second. We were all looking at the thing with some concern but the guy at the view graph projector seemed oblivious to attention being paid to the ticking box on the table. At some point he smiled and said, "Oh yeah, that briefcase contains one of our new laser-ring gyros. It outputs a stream of pulses proportional to rotation . . . that ticking you hear is a measure of its present rotational speed." "But sir . . . it's not moving!!" "Ahhh . . . but it is . . . those ticks are marking rotation of the earth."' This was my first introduction into some of the engineering and physics upon which the modern gyro-less systems are based. Assuming that you can measure rotation rate or position about any axis with precision, you can use that to replace a spinning gyro assuming further that you KNOW from what orientation from which you began making measurements. This means that from the time you power up the system there will be an interval of time for the software to stand up and say, "yeah . . . I know where the horizon is and I've got a lock on present yaw orientation in space . . . but until you give me some GPS course data or some magnetometer data corrected for deviation, I'm not going to know what our heading orientation is . . . " That laser ring gyro took several minutes to stand up. It was a positional sensor with drift that was essentially zero. Modern MEMS sensors are rate sensors. You have to integrate rate over time to deduce the difference in angle. Drifts and offsets are low but not zero. Hence the necessity to stand still while the byte thrashers decide when they're ready to go flying . . . or even taxiing. They'll first wash out offset by assuming that you're standing still. Once you move, data coming from other sources will wash out calibration issues . . . and it always takes some amount of time. 10 seconds is pretty quick and I'm having a little trouble putting my arms around the impatience for getting under way or perhaps already being under way when the system gets powered up. One more example of a check-list forsaken . . . Bob . . .


    Message 8


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    Time: 01:57:24 PM PST US
    From: Peter Pengilly <peter@sportingaero.com>
    Subject: Re: Garmin AHRS drifting
    The first aircraft I worked on had a 'iron' gyro platform that had to be spun up to speed and then 'torqued' until the gyro axes were perpendicular to the earth by aligning the vertical axis with gravity. A good align, taking at least 5 minutes (something longer) resulted in a gyro drift of 1nm per hour ... and it cost tens of thousands of $$$! The equipment available today is remarkable - no discernible drift after a 10 second align, amazing! I'm using an AFS EFIS that takes around a minute to align - I though that was rather good. Peter On 18/09/2014 21:02, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 13:59 2014-09-18, you wrote: >> > So does the G3X then have a different platform? >> >> Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that >> is the subject of the AD. However the G3X is not certified so cannot >> be the subject of an AD. It seems unlikely that the GSU 73 or 25 use >> fundamentally different algorithms than the GRS77, so will probably >> exhibit similar performance if abused. >> >> Peter > > All modern AHRS systems have shed their 'iron' gyros > representing horizontal and heading references in favor > of rotational rate sensors. > > When I was working the GP180 program at Lear wayyyy back when, > a supplier (I think it was King Radio) came in to pitch their > latest and greatest offering to the new airplane. > > One of the presenters made kind of a show of opening a > briefcase-like container on the table and turning on > a switch. A light came on. He then proceeded to the next > phase of his presentation. After a time, the 'briefcase' > began to emit a 'ticking' sound . . . about one tick per > second. We were all looking at the thing with some concern > but the guy at the view graph projector seemed oblivious > to attention being paid to the ticking box on the table. > > At some point he smiled and said, "Oh yeah, that briefcase > contains one of our new laser-ring gyros. It outputs a stream > of pulses proportional to rotation . . . that ticking you > hear is a measure of its present rotational speed." > > "But sir . . . it's not moving!!" > > "Ahhh . . . but it is . . . those ticks are marking rotation > of the earth."' > > This was my first introduction into some of the engineering > and physics upon which the modern gyro-less systems are > based. Assuming that you can measure rotation rate or position > about any axis with precision, you can use that to replace > a spinning gyro assuming further that you KNOW from what orientation > from which you began making measurements. This means that from the > time you power up the system there will be an interval > of time for the software to stand up and say, "yeah . . . > I know where the horizon is and I've got a lock on present > yaw orientation in space . . . but until you give > me some GPS course data or some magnetometer data corrected > for deviation, I'm not going to know what our heading > orientation is . . . " > > That laser ring gyro took several minutes to stand up. > It was a positional sensor with drift that was essentially > zero. Modern MEMS sensors are rate sensors. You have to > integrate rate over time to deduce the difference in > angle. Drifts and offsets are low but not zero. Hence > the necessity to stand still while the byte thrashers > decide when they're ready to go flying . . . or even > taxiing. They'll first wash out offset by assuming that > you're standing still. Once you move, data coming from > other sources will wash out calibration issues . . . and > it always takes some amount of time. 10 seconds is pretty > quick and I'm having a little trouble putting my arms around > the impatience for getting under way or perhaps already > being under way when the system gets powered up. > > One more example of a check-list forsaken . . . > > > Bob . . . > >


    Message 9


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    Time: 02:33:00 PM PST US
    From: Jeff Luckey <jluckey@pacbell.net>
    Subject: Re: Garmin AHRS drifting
    So how does a modern AHRS re-initialize after an airborne re-boot? (perhaps due to some electrical failure) Magnetometer? -Jeff On Thursday, September 18, 2014 2:09 PM, Peter Pengilly <peter@sportingaero.com> wrote: The first aircraft I worked on had a 'iron' gyro platform that had to be spun up to speed and then 'torqued' until the gyro axes were perpendicular to the earth by aligning the vertical axis with gravity. A good align, taking at least 5 minutes (something longer) resulted in a gyro drift of 1nm per hour ... and it cost tens of thousands of $$$! The equipment available today is remarkable - no discernible drift after a 10 second align, amazing! I'm using an AFS EFIS that takes around a minute to align - I though that was rather good. Peter On 18/09/2014 21:02, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 13:59 2014-09-18, you wrote: >> > So does the G3X then have a different platform? >> >> Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that >> is the subject of the AD. However the G3X is not certified so cannot >> be the subject of an AD. It seems unlikely that the GSU 73 or 25 use >> fundamentally different algorithms than the GRS77, so will probably >> exhibit similar performance if abused. >> >> Peter > > All modern AHRS systems have shed their 'iron' gyros > representing horizontal and heading references in favor > of rotational rate sensors. > > When I was working the GP180 program at Lear wayyyy back when, > a supplier (I think it was King Radio) came in to pitch their > latest and greatest offering to the new airplane. > > One of the presenters made kind of a show of opening a > briefcase-like container on the table and turning on > a switch. A light came on. He then proceeded to the next > phase of his presentation. After a time, the 'briefcase' > began to emit a 'ticking' sound . . . about one tick per > second. We were all looking at the thing with some concern > but the guy at the view graph projector seemed oblivious > to attention being paid to the ticking box on the table. > > At some point he smiled and said, "Oh yeah, that briefcase > contains one of our new laser-ring gyros. It outputs a stream > of pulses proportional to rotation . . . that ticking you > hear is a measure of its present rotational speed." > > "But sir . . . it's not moving!!" > > "Ahhh . . . but it is . . . those ticks are marking rotation > of the earth."' > > This was my first introduction into some of the engineering > and physics upon which the modern gyro-less systems are > based. Assuming that you can measure rotation rate or position > about any axis with precision, you can use that to replace > a spinning gyro assuming further that you KNOW from what orientation > from which you began making measurements. This means that from the > time you power up the system there will be an interval > of time for the software to stand up and say, "yeah . . . > I know where the horizon is and I've got a lock on present > yaw orientation in space . . . but until you give > me some GPS course data or some magnetometer data corrected > for deviation, I'm not going to know what our heading > orientation is . . . " > > That laser ring gyro took several minutes to stand up. > It was a positional sensor with drift that was essentially > zero. Modern MEMS sensors are rate sensors. You have to > integrate rate over time to deduce the difference in > angle. Drifts and offsets are low but not zero. Hence > the necessity to stand still while the byte thrashers > decide when they're ready to go flying . . . or even > taxiing. They'll first wash out offset by assuming that > you're standing still. Once you move, data coming from > other sources will wash out calibration issues . . . and > it always takes some amount of time. 10 seconds is pretty > quick and I'm having a little trouble putting my arms around > the impatience for getting under way or perhaps already > being under way when the system gets powered up. > > One more example of a check-list forsaken . . . > > > Bob . . . > >


    Message 10


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    Time: 02:43:28 PM PST US
    From: Kelly McMullen <kellym@aviating.com>
    Subject: Re: Garmin AHRS drifting
    Just to clarify a misconception....ADs most certainly can be issued on non-certificated equipment. Not common, and up to aircraft owner/operator to determine if it applies to their situation. Part 39 applies to ALL aircraft, not just type certificated aircraft. While it is rare to issue one on an experimental airframe, the FAA does have the authority, and often issues ADs on components used on both certificated and experimental aircraft. No different than if you have a Lycoming O-360-A1A engine on your Puffmaster 1000, and an AD is issued on that engine. No different than a King KX-170B...it was non-TSO, only met FCC requirements, not any particular FAA standard, but it certainly could have an AD issued for whatever. You can ignore the AD if you choose, but if you have an accident where someone/something gets injured, do you want to be sitting at the plaintiff's deposition explaining why you ignored the AD? On 9/18/2014 1:02 PM, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 13:59 2014-09-18, you wrote: >> > So does the G3X then have a different platform? >> >> Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that >> is the subject of the AD. However the G3X is not certified so cannot >> be the subject of an AD. It seems unlikely that the GSU 73 or 25 use >> fundamentally different algorithms than the GRS77, so will probably >> exhibit similar performance if abused. >>


    Message 11


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    Time: 03:04:55 PM PST US
    From: Peter Pengilly <peter@sportingaero.com>
    Subject: Re: Garmin AHRS drifting
    Yes, there have always been airborne re-alignment techniques. Once the platform has toppled a rough alignment can be done quickly (a few seconds as the pilot will be needing some information soonest) using combinations of (hopefully) reliable data, such as gravity, mag heading, GPS, airspeed (with OAT input), a stored position/velocity from a state model. Some of these are more reliable than others, hence the need for the pilot to fly level and unaccelerated for a while where possible, and also depends on the sophistication of the software algorithms (perhaps $$$ behind the developer). I have never seen inside these algorithms, but I would hope they would compare the available data. Such as if heading is changing don't believe gravity, how does heading compare with GPS track (hopefully constant offset), how does GPS speed compare to airspeed/TAS (again constant offset?), and so on, to figure out what can be believed, and so get the best available alignment. Its never going to be quite as accurate as a ground align, but should be sufficient to get you on the ground without too much additional workload. On 18/09/2014 22:32, Jeff Luckey wrote: > So how does a modern AHRS re-initialize after an airborne re-boot? > (perhaps due to some electrical failure) > > Magnetometer? > > -Jeff > > > On Thursday, September 18, 2014 2:09 PM, Peter Pengilly > <peter@sportingaero.com> wrote: > > > <peter@sportingaero.com <mailto:peter@sportingaero.com>> > > The first aircraft I worked on had a 'iron' gyro platform that had to be > spun up to speed and then 'torqued' until the gyro axes were > perpendicular to the earth by aligning the vertical axis with gravity. A > good align, taking at least 5 minutes (something longer) resulted in a > gyro drift of 1nm per hour ... and it cost tens of thousands of $$$! The > equipment available today is remarkable - no discernible drift after a > 10 second align, amazing! I'm using an AFS EFIS that takes around a > minute to align - I though that was rather good. > > Peter > > On 18/09/2014 21:02, Robert L. Nuckolls, III wrote: > > <nuckolls.bob@aeroelectric.com <mailto:nuckolls.bob@aeroelectric.com>> > > > > At 13:59 2014-09-18, you wrote: > >> > So does the G3X then have a different platform? > >> > >> Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that > >> is the subject of the AD. However the G3X is not certified so cannot > >> be the subject of an AD. It seems unlikely that the GSU 73 or 25 use > >> fundamentally different algorithms than the GRS77, so will probably > >> exhibit similar performance if abused. > >> > >> Peter > > > > All modern AHRS systems have shed their 'iron' gyros > > representing horizontal and heading references in favor > > of rotational rate sensors. > > > > When I was working the GP180 program at Lear wayyyy back when, > > a supplier (I think it was King Radio) came in to pitch their > > latest and greatest offering to the new airplane. > > > > One of the presenters made kind of a show of opening a > > briefcase-like container on the table and turning on > > a switch. A light came on. He then proceeded to the next > > phase of his presentation. After a time, the 'briefcase' > > began to emit a 'ticking' sound . . . about one tick per > > second. We were all looking at the thing with some concern > > but the guy at the view graph projector seemed oblivious > > to attention being paid to the ticking box on the table. > > > > At some point he smiled and said, "Oh yeah, that briefcase > > contains one of our new laser-ring gyros. It outputs a stream > > of pulses proportional to rotation . . . that ticking you > > hear is a measure of its present rotational speed." > > > > "But sir . . . it's not moving!!" > > > > "Ahhh . . . but it is . . . those ticks are marking rotation > > of the earth."' > > > > This was my first introduction into some of the engineering > > and physics upon which the modern gyro-less systems are > > based. Assuming that you can measure rotation rate or position > > about any axis with precision, you can use that to replace > > a spinning gyro assuming further that you KNOW from what orientation > > from which you began making measurements. This means that from the > > time you power up the system there will be an interval > > of time for the software to stand up and say, "yeah . . . > > I know where the horizon is and I've got a lock on present > > yaw orientation in space . . . but until you give > > me some GPS course data or some magnetometer data corrected > > for deviation, I'm not going to know what our heading > > orientation is . . . " > > > > That laser ring gyro took several minutes to stand up. > > It was a positional sensor with drift that was essentially > > zero. Modern MEMS sensors are rate sensors. You have to > > integrate rate over time to deduce the difference in > > angle. Drifts and offsets are low but not zero. Hence > > the necessity to stand still while the byte thrashers > > decide when they're ready to go flying . . . or even > > taxiing. They'll first wash out offset by assuming that > > you're standing still. Once you move, data coming from > > other sources will wash out calibration issues . . . and > > it always takes some amount of time. 10 > * > > > *


    Message 12


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    Time: 03:11:12 PM PST US
    From: Peter Pengilly <peter@sportingaero.com>
    Subject: Re: Garmin AHRS drifting
    The situation in the US may be different to other countries. As I understand it the CofA of an aircraft will not be valid if an AD is not complied with. In the UK amateur built aircraft don't have a CofA, they have a permit to fly. Therefore the CAA has to raise a Mandatory Permit Directive to make ADs effective on permit aircraft. On 18/09/2014 22:42, Kelly McMullen wrote: > <kellym@aviating.com> > > Just to clarify a misconception....ADs most certainly can be issued on > non-certificated equipment. Not common, and up to aircraft > owner/operator to determine if it applies to their situation. Part 39 > applies to ALL aircraft, not just type certificated aircraft. While it > is rare to issue one on an experimental airframe, the FAA does have > the authority, and often issues ADs on components used on both > certificated and experimental aircraft. > No different than if you have a Lycoming O-360-A1A engine on your > Puffmaster 1000, and an AD is issued on that engine. No different than > a King KX-170B...it was non-TSO, only met FCC requirements, not any > particular FAA standard, but it certainly could have an AD issued for > whatever. You can ignore the AD if you choose, but if you have an > accident where someone/something gets injured, do you want to be > sitting at the plaintiff's deposition explaining why you ignored the AD? > > On 9/18/2014 1:02 PM, Robert L. Nuckolls, III wrote: >> <nuckolls.bob@aeroelectric.com> >> >> At 13:59 2014-09-18, you wrote: >>> > So does the G3X then have a different platform? >>> >>> Yes, the G3X uses a GSU 73 or GSU 25 ADAHRS, not the GRS 77/77H that >>> is the subject of the AD. However the G3X is not certified so cannot >>> be the subject of an AD. It seems unlikely that the GSU 73 or 25 use >>> fundamentally different algorithms than the GRS77, so will probably >>> exhibit similar performance if abused. >>> > >


    Message 13


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    Time: 03:29:27 PM PST US
    Subject: Re: Garmin AHRS drifting
    From: "mmayfield" <mmayfield@ozemail.com.au>
    Totally concur with the comment about ADs. An Airworthiness Directive can be issued on pretty much anything pertaining to safety of flight, whether it's "certified" equipment or not. Owner/builders of experimental aircraft are of course responsible for their own maintenance. But if you don't bother keeping up to date with ADs or decline to carry out an AD on an item in your plane, you could well be hung out to dry legally if anything goes wrong with that piece of equipment. Plus there's the obvious point that it simply makes good safety sense to just do it. On the topic of IRS/AHRS alignment, 10 seconds is nothing! We used to have to wait at least 15 minutes for IRS alignment before even starting our engines on some early systems when I was in the military. Anyone complaining about having to be stationary without the engine running for a 10 second or even a 60 second alignment gets no sympathy from me! [Wink] -------- Mike Read this topic online here: http://forums.matronics.com/viewtopic.php?p=430758#430758


    Message 14


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    Time: 05:40:19 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: alternator knocked off line when strobes turned
    on At 12:31 2014-09-18, you wrote: >Joe, > >Thank you for your input. > >About all I know about the strobes is that they >are old Whelans.=C2 The alternator kicks out >immediately, within 2 or 3 SECONDS upon >switching on the strobes.=C2 I have seen no >failure in the strobes as they continue to >operate normally, on battery power, after the >alternator is kicked off line.=C2 Per another >suggestion, I am going to look for power >supplies for the strobe system in the wings in >addition to the one next to the battery which may be just for the tail. What we're witnessing is one or more incursions on the design limits for an aircraft device to either emit or succumb to noise. Ostensibly, both the strobes and ov protection system in the regulator were qualified to their intended purposes . . . both have a long service history. The ov protection system is supposed to be pretty robust. You have to ELEVATE the bus voltage above trip limits for a pretty good interval of time . . . hundreds of millisecond. Even if the strobe were to suffer it's worst possible failure . . . what mechanism would pump energy BACK into the system with sufficient magnitude to irritate a normally functioning ov protection system? On the other hand, one or more components within the ov protection system could have aged sufficiently to decrease voltage excursion or duration necessary to trip it. This scenario seems more likely than an 'energy dump' from the strobe back into the system. Bob . . .




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