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bakerocb
Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA
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 Posted: Tue Jun 10, 2014 10:25 am Post subject: Direction Indicator Needs |
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6/10/2014
Hello Aeroelectric and Avionics Listers, I know that there are many technically smart people on these lists and I would like to enlist your assistance.
Picture this situation: There are hundreds (maybe thousands) of EAB (Experimental Amateur Built) IFR capable aircraft flying around with vacuum driven mechanical spinning mass gyroscopic attitude and directional indicators. A large percentage of these builders and pilots would like to (or need to) replace those indicators with something electronic (other than expensive electrical motor driven mechanical spinning mass gyroscopic) in nature and remove the entire vacuum system from their EAB.
Replacing the attitude indicator does not appear to be a big problem in meeting the requirement of 14 CFR 91.205 (d) ( “Gyroscopic pitch and bank indicator (artificial horizon)” since there are several offerings available. Here are some:
http://www.dynonavionics.com/docs/D6_intro.html
http://trutrakap.com/product/gemini-pfd/
http://www.grtavionics.com/mini.html
http://www.sandia.aero/?q=node/80
But there does not appear to be available an electronic directional indicator that would meet the 14 CFR 91.205 (d) (9) criteria for a “Gyroscopic directional indicator (directional gyro or equivalent)” if one believes that the Regulatory intended direction to be indicated must indeed be the current aircraft magnetic heading and not the current aircraft magnetic course (provided by GPS) over the surface.
I feel that somewhere in the electronic magic that MEMS
<< https://www.memsnet.org/mems/what_is.html >>
and AHARS
<< http://www.microstrain.com/inertial/3DM-GX3-25?gclid=CjgKEAjw2dqcBRC2q-LXjpfxjnQSJAAeYF5LUC4gvWycBVg6DDW_mzzSdTyyF3q0yoQHrT6ij9VbvvD_BwE >>
represents there must be a practical, relatively inexpensive means of creating a direction indicator that will meet the intended requirements of 14 CFR 91.205 (d) (9). If so, I (and probably many others) would like to buy one for my EAB airplane.
How about it experts (and entrepreneurs) are my desires hopeless and unrealistic?
OC
'O C' Baker says "The best investment you can make is the effort to gather and understand information."
[quote][b]
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deej(at)deej.net
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| Posted: Tue Jun 10, 2014 11:36 am Post subject: Direction Indicator Needs |
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On 06/10/2014 02:24 PM, Owen Baker wrote:
| Quote: | But there does not appear to be available an electronic directional
indicator that would meet the 14 CFR 91.205 (d) (9) criteria for a
“Gyroscopic directional indicator (directional gyro or equivalent)” if
one believes that the Regulatory intended direction to be indicated must
indeed be the current aircraft magnetic heading and not the current
aircraft magnetic course (provided by GPS) over the surface.
|
I am not familiar with the other brands, but the GRT EFIS units come
with an external magnetometer box which gives magnetic heading
information to the EFIS.
Is that what you are asking about?
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
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bakerocb
Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA
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| Posted: Tue Jun 10, 2014 2:14 pm Post subject: Direction Indicator Needs |
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6/10/2014
Hello Dj Merrill, Thanks for your quick response. You wrote: ".... an
external magnetometer box which gives magnetic heading
information to the EFIS."
1) See here for information on what constitutes a magnetometer:
http://science.howstuffworks.com/magnetometer-info.htm
If the heading that appears on the display, see here:
http://www.grtavionics.com/mini.html#Features
is simply the indication of a remotely located magnetometer (which is
available for the Mini-X and Mini-AP, but not the Mini-B) then I don't think
that will meet the intended requirement of 14 CFR 91.205 (d) (9) criteria
for a “Gyroscopic directional indicator (directional gyro or equivalent)”.
2) One other big downside of the Mini displays from GRT was GRT's failure to
package the units such that they could be readily installed in a standard
round nominally 3 inch instrument cut out hole where the old attitude
indicator resides. See here:
http://www.grtavionics.com/Mini%20Drawing%202.pdf
Needing to cut panel metal to install a Mini unit from GRT in an existing
panel raises the difficulty of a swap over significantly. Note that Sandia
recognized the significance of this issue and packaged the SAI 340 - Quattro
accordingly. See here:
http://www.sandia.aero/?q=system/files/SAI340BroR2Web.pdf
I am still searching.
OC
====================================================================
From: Dj Merrill
Sent: Tuesday, June 10, 2014 3:34 PM
To: aeroelectric-list(at)matronics.com ; bakerocb(at)cox.net
Subject: Re: AeroElectric-List: Direction Indicator Needs
I am not familiar with the other brands, but the GRT EFIS units come
with an external magnetometer box which gives magnetic heading
information to the EFIS.
Is that what you are asking about?
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
=================================================
On 06/10/2014 02:24 PM, Owen Baker wrote:
| Quote: | But there does not appear to be available an electronic directional
indicator that would meet the 14 CFR 91.205 (d) (9) criteria for a
“Gyroscopic directional indicator (directional gyro or equivalent)” if
one believes that the Regulatory intended direction to be indicated must
indeed be the current aircraft magnetic heading and not the current
aircraft magnetic course (provided by GPS) over the surface.
|
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http://www.matronics.com/Navigator?AeroElectric-List |
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ribrdb(at)gmail.com
Guest
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| Posted: Tue Jun 10, 2014 3:02 pm Post subject: Direction Indicator Needs |
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The dynon d6 pilot guide says "Like a conventional gyro-stabilized magnetic compass, magnetic heading reacts immediately to turn rate so that heading changes are reflected immediately. It then uses magnetometer data over the long term to ensure that it remains correct. Additionally, heading is corrected for attitude so that it is accurate as you pitch and roll. " Sounds equivalent to a dg to me.
The gemini feature list also includes "Track DG"
On Tue, Jun 10, 2014 at 11:24 AM, Owen Baker <bakerocb(at)cox.net (bakerocb(at)cox.net)> wrote:
[quote] 6/10/2014
Hello Aeroelectric and Avionics Listers, I know that there are many technically smart people on these lists and I would like to enlist your assistance.
Picture this situation: There are hundreds (maybe thousands) of EAB (Experimental Amateur Built) IFR capable aircraft flying around with vacuum driven mechanical spinning mass gyroscopic attitude and directional indicators. A large percentage of these builders and pilots would like to (or need to) replace those indicators with something electronic (other than expensive electrical motor driven mechanical spinning mass gyroscopic) in nature and remove the entire vacuum system from their EAB.
Replacing the attitude indicator does not appear to be a big problem in meeting the requirement of 14 CFR 91.205 (d) ( “Gyroscopic pitch and bank indicator (artificial horizon)” since there are several offerings available. Here are some:
http://www.dynonavionics.com/docs/D6_intro.html
http://trutrakap.com/product/gemini-pfd/
http://www.grtavionics.com/mini.html
http://www.sandia.aero/?q=node/80
But there does not appear to be available an electronic directional indicator that would meet the 14 CFR 91.205 (d) (9) criteria for a “Gyroscopic directional indicator (directional gyro or equivalent)” if one believes that the Regulatory intended direction to be indicated must indeed be the current aircraft magnetic heading and not the current aircraft magnetic course (provided by GPS) over the surface.
I feel that somewhere in the electronic magic that MEMS
<< https://www.memsnet.org/mems/what_is.html >>
and AHARS
<< http://www.microstrain.com/inertial/3DM-GX3-25?gclid=CjgKEAjw2dqcBRC2q-LXjpfxjnQSJAAeYF5LUC4gvWycBVg6DDW_mzzSdTyyF3q0yoQHrT6ij9VbvvD_BwE >>
represents there must be a practical, relatively inexpensive means of creating a direction indicator that will meet the intended requirements of 14 CFR 91.205 (d) (9). If so, I (and probably many others) would like to buy one for my EAB airplane.
How about it experts (and entrepreneurs) are my desires hopeless and unrealistic?
OC
'O C' Baker says "The best investment you can make is the effort to gather and understand information."
| Quote: |
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
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[b]
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fly4grins(at)gmail.com
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| Posted: Wed Jun 11, 2014 12:25 am Post subject: Direction Indicator Needs |
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| Quote: | http://www.grtavionics.com/mini.html#Features
is simply the indication of a remotely located magnetometer (which is
available for the Mini-X and Mini-AP, but not the Mini-B) then I don't think
that will meet the intended requirement of 14 CFR 91.205 (d) (9) criteria
for a Gyroscopic directional indicator (directional gyro or equivalent).
|
I'm curious as to why you are concerned this hardware would be inadequate. It seems to me that it fits the bill and then some.
To reference what Ryan cited:
| Quote: |
The dynon d6 pilot guide says "Like a conventional gyro-stabilized magnetic
compass, magnetic heading reacts immediately to turn rate so that heading
changes are reflected immediately. It then uses magnetometer data over the
long term to ensure that it remains correct. Additionally, heading is
corrected for attitude so that it is accurate as you pitch and roll. "
Sounds equivalent to a dg to me.
|
This would be quite a bit better than a DG- It won't precess, doesn't need to be manually synced to a compass, and there are no bearings to wear out. If your concern relates to the display, there are many certified drum-type DG's still flying today. That's not my first choice for a display, but it does work.
Thoughts?
[quote][b]
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stuart(at)stuarthutchison
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| Posted: Wed Jun 11, 2014 1:17 am Post subject: Direction Indicator Needs |
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G’day OC,
We have the same issue in Australia, with policy anchored to antiquated analogue designs. CASA, our FAA, was slammed by most sectors of the Aviation community in submissions to the Federal Government review (still underway) over recent months.
In my mind the installation should be ‘no less safe’ than existing IFR instruments. There is a LOT left to be desired in many S/E Type Certified IFR aircraft that depend on a notoriously unreliable single vacuum pump to drive the two most important flight instruments on the panel, the attitude indicator and the DG, neither of which are required to have a built-in failure flag. These two instruments usually also drive the autopilot! The compass is fast becoming totally obsolete alongside a certified GPS, perhaps several, that measure point-to-point track. Among other things, magnetic heading from the magnetometer helps calculate wind, but if you know the track and groundspeed, who needs a wet compass?! Flying limited panel on the ‘backup’ electric turn and bank indicator (which actually indicates rate of change of heading, not roll and is gimbal limited to about rate 1 or 2) is extremely difficult in rough weather, which has resulted in numerous fatalities.
CASA has yet to agree that system safety can be achieved a variety of ways, not the least by full redundancy. The Garmin 1000 is not fully redundant, which is why there is a backup three-pack to complement the PFD/MFD. A second AHRS, ADC and magnetometer would be required to make the system fully redundant, but software is also vulnerable to latent bugs and multiple systems can be expected to behave the same way under the same preconditions, so alternative hardware or staggered software versions seems like a good idea to me. CASA is wedded to outdated TSO’s, arguing that if a piece of equipment is required by the Regs, then it must be approved in one of the recognised ways. In the absence of a specific approval, in most cases, that means a TSO. CASA don’t seem to care that the most recent TSO for attitude indicators was published via typewriter in 1959. We do not want Dynon, AFS, GRT etc etc to required TSO’s, nor is it necessary in order to achieve the equivalent form, fit, function and quality intended by the TSO.
Like the US, Australia will slowly adopt ‘performance-based’ testing for equivalent functionality of non-TSO flight instruments, but the authorities are moving at a glacial pace. I think it is statistically significant that there are thousands of Dynon, AFS, GRT etc etc systems being operated VFR in the AB(E) community without systemic issues that would preclude them being used for IFR. Heated pitots becoming overcome with trapped moisture/ice are unhelpful for the IFR cause, but these are known issues that can and will be overcome in due course. All this is in relation to flight instruments of course. Communication/Navigation/Surveillance (CNS) systems are a different matter and should be TSO’d if we expect to fly IFR in/around airspace with airliners and paying passengers.
Cheers, Stu
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Owen Baker
Sent: 11 June 2014 04:24
To: aeroelectric-list(at)matronics.com; avionics-list(at)matronics.com
Subject: Direction Indicator Needs
6/10/2014
Hello Aeroelectric and Avionics Listers, I know that there are many technically smart people on these lists and I would like to enlist your assistance.
Picture this situation: There are hundreds (maybe thousands) of EAB (Experimental Amateur Built) IFR capable aircraft flying around with vacuum driven mechanical spinning mass gyroscopic attitude and directional indicators. A large percentage of these builders and pilots would like to (or need to) replace those indicators with something electronic (other than expensive electrical motor driven mechanical spinning mass gyroscopic) in nature and remove the entire vacuum system from their EAB.
Replacing the attitude indicator does not appear to be a big problem in meeting the requirement of 14 CFR 91.205 (d) ( “Gyroscopic pitch and bank indicator (artificial horizon)” since there are several offerings available. Here are some:
http://www.dynonavionics.com/docs/D6_intro.html
http://trutrakap.com/product/gemini-pfd/
http://www.grtavionics.com/mini.html
http://www.sandia.aero/?q=node/80
But there does not appear to be available an electronic directional indicator that would meet the 14 CFR 91.205 (d) (9) criteria for a “Gyroscopic directional indicator (directional gyro or equivalent)” if one believes that the Regulatory intended direction to be indicated must indeed be the current aircraft magnetic heading and not the current aircraft magnetic course (provided by GPS) over the surface.
I feel that somewhere in the electronic magic that MEMS
<< https://www.memsnet.org/mems/what_is.html >>
and AHARS
<< http://www.microstrain.com/inertial/3DM-GX3-25?gclid=CjgKEAjw2dqcBRC2q-LXjpfxjnQSJAAeYF5LUC4gvWycBVg6DDW_mzzSdTyyF3q0yoQHrT6ij9VbvvD_BwE >>
represents there must be a practical, relatively inexpensive means of creating a direction indicator that will meet the intended requirements of 14 CFR 91.205 (d) (9). If so, I (and probably many others) would like to buy one for my EAB airplane.
How about it experts (and entrepreneurs) are my desires hopeless and unrealistic?
OC
'O C' Baker says "The best investment you can make is the effort to gather and understand information."
[quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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