Mailing List lml@lancaironline.net Message #34726
From: Clark Baker <bakercdb@gmail.com>
Sender: <marv@lancaironline.net>
Subject: Wow, scary EFIS stuff
Date: Tue, 28 Feb 2006 22:39:13 -0500
To: <lml@lancaironline.net>
On 2/27/06, Alan K. Adamson <aadamson@highrf.com> wrote:
>>These two message fragments are from a friend of mine that has the
GRT EFISin his RV8.  Scary stuff!  Glad he was VFR when it happened.  
Now if the other  guys would just get to a stable feature set and
spend some time (and money)  testing, instead of playing rev of the
week....<<

Since I have not seen a GRT user chiming in on this subject yet, I
wanted to relay my personal experience of dealing with the company
(GRT) over the past 15 years.  I feel the aforementioned statement
greatly discredits what I feel is one of the class acts in the
homebuilding industry.

I talked with Greg and Todd at GRT when they were first exploring the
idea of developing an EFIS to compliment their engine and fuel
monitoring equipment and gave them my input until they very quickly
surpassed my level of expertise (I am no Brent Regan, although I have
met Brent Regan).   About all Greg could think about was the quality
and reliability of the attitude data of the EFIS.  Once they were
comfortable with the quality of the attitude data and basic features,
they began production.  They then (and contine to add) additional
features based on testing, experience, and customer feedback and
suggestions.   Continued innovation, responding to their customers and
enivitable bug fixes, but far from a "rev of the week".

I have dealt with homebuilt vendors that over promised, under
delivered and were not there (or did not have the technical/etc)
ability to stand behind their product.  In my years of dealing with
GRT, they are the antithesis of this.  Two examples (other than the
usual continous solid customer support) come to mind: 1. I had a fuel
probe fail after several years (1 yr stated warranty).  I called Todd
up - he was surprised and unhappy it quit.  He said that the probes
should last a long time - sent another free of charge. 2. Called GRT
looking for a header tank fuel probe to drive my PPAvionics automatic
fuel transfer.  Todd asked what levels I would like to maintain in the
header, then said he would add two leads to a probe, code the
software, then ship me a probe that would both read fuel level and run
my auto fuel system.  From what I have read on other recent EFIS
posts, D2Avionics seems to be another example of taking a class act
approach with customers (in dealing with recent AHRS problems).

> Message 1 from yesterday
uploaded v28, installed terrain on flash. While shooting an ils approach
into ...  Thank goodness I was vfr. ...be careful out there.

A good reminder to never launch IFR after loading a software update,
regardless if certified or not.  Especially v28 of the GRT software,
which added a plethora of new features including a new VNAV system.
Even if everything works perfectly in your specific configuration, IFR
is not the time to be exploring the new features of your software
update.

If you uncover a problem, the first step should be to immediately
contact the manufacturer and see if it is a problem specific to your
installation or endemic to the equipment or software.  If it is not
specific to your installation, please disseminate the information in a
professional manner so other users (such as myself) can be alert to
the problem and hopefully provide useful input (and more importantly,
not die).


>
> Message 2 from today
> also noticed these multiple alarms on approach. Obstacles, terrain warning.
> Very
> annoying while driving down an ils. Just ran that exact approach tonight and
> it  went fine except for all the alarms. Those should be suppressed if your
> driving  down the approach.

Useful input, especially if provided to the manufacturer.  The terrain
feature was just added in this version and will likely be further
refined in later upgrades (maybe some type alarm inhibit when the ILS
is captured).  For now, the terrain and obstacle alarms can be turned
off (as described in the user's manual) from the Moving Map setup
page.


>>Not to be a commercial endorsement, but I do think that the money
and time that Chelton paid to test and certify their system has
dramatically helped the "sport" and "pro" versions that we in the
experimental market use.<<

The GRT system is not certified.  There are not 10 code checkers that
have tested every permutation (albeit in the STC'd applications and
not in an RV8, etc).  However, what you gain is lower cost, more
flexibility, more ability to respond to customer demands for
additional features.  Like most things in life, you must weigh the
cost versus the benefits.  I have only limited experience with the
Chelton EFIS, but it looks to be an exceptional product, and somewhat
of a rarity in the certified world with its value, innovation, and
features.  However, don't forget the origins of the certified (and
current experimental versions) Chelton product.

Regarding the "rev of the week" and complexity of modern software, I
have listed below the software revision history of the certified
Sandel SN3308 EHSI (electronic HSI) showing the magnitude of upgrades,
bug fixes, etc that a certified, relatively simple product (versus
current EFIS technology) can experience.  Food for thought.

Regards,
Clark Baker
N250JF
LNC2 360, 650hrs


SN3308 EHSI System Software History
The following table lists the released versions of SN3308 EHSI
software, and the key features of each. Missing version numbers were
internal test versions and were not released.

Each successive version includes all prior changes.

Version  Date  Key Features
2.10 4/25/02 Corrected issue with communication with ARINC-429 GPS
receivers upon power-on.
Updated operation during back course approach.  Bottom CDI needle will
not reverse sense when in ILS mode and course pointer is turned to
greater than 90 degrees from lubber line. This will be annunciated
with a 'BC' label above the bottom CDI needle.
Course lines will be drawn on moving map in OBS mode when connected to
Garmin GNS 430/530.
Moving map display enabled without activation of flight plan or
direct-to when connected to Garmin GNS 430/530.
400HZ Inverter Failed message delayed for 120 seconds after power-on.
Fast slave mode delay increased from 90 to 120 seconds.
ILS lockout setting in maintenance pages can not be enabled when
connected to dual Garmin GNS 430/530's.

2.09 12/1/00 Added support of heading information from the
Mid-Continent 4305 directional gyro.

2.08 9/25/00 Improved response when ARINC-429 GPS receiver experiences
signal loss.
Improved response from dimmer potentiometer input.

2.07 7/14/00 Added depiction of holding patterns, procedure turns and
DME arcs when interfaced with Garmin GNS 430/530.
Added support of OBS/LEG switching from King KLN-89B.
Added support for UPSAT (IIMorrow) GX series GPS to recognize serial
annunciator and deviation inputs.
Added support of expanded database which includes airports with
non-verified runways.
Corrected a scenario where SN3308 would occasionally not recognize
UPSAT (IIMorrow) GX series GPS units upon startup.
Corrected an issue with the CRS PTR feature where turning the heading
bug knob would cause the course pointer to be displayed on the moving
map even though it was hidden.
Corrected an issue where GPS flight plans were drawn without
adjustment for magnetic variation if there is no map database file in
memory.
Changed operation to continue to show vertical and horizontal
deviation bars when gyro and fluxgate are flagged.
Changed operation such that loss of external 400HZ inverter does not
affect compass card when a King KG-102 is used as the gyro source.
Minor changes to moving map drawing procedures to improve clarity.
Added new error message 'INVERTER CONFIG ERROR' to flag invalid system
configuration when external 400HZ inverter is required.
Added new message 'No Database Loaded' when there is no map database
file in memory.
Added presets for Century II, III and IV in FCS system maintenance page.
Added display of software version in system maintenance page.
Added support of heading information from ARINC 429 gyros.
Added BF Goodrich logo upon startup when WX-500 is installed.

2.05 3/02/00 Corrected a scenario where the flash memory could be
corrupted, resulting in the unit not powering up.
Corrected a scenario where the compass card could be erratic when used
with an RS-232 GPS.
Corrected a scenario where pressing certain key combinations at the
same time (pressing NAV and MAP simultaneously, for example) could
cause the unit to be unable to access the map setup function.
Corrected a scenario where the A-B function could have corrupted setup
parameters, resulting in the unit powering off when the A-B button was
pressed.
Added the following diagnostic fields to maintenance page 2: FG error
count, ADC re-sync count and 400HZ loss count.
Holding pattern, procedure turn and DME arc depictions from ARINC 429
data are temporarily removed.

2.03 1/21/00 Corrected an occasional instability in the compass card
which was observed on some installations using non KG-102 gyros.
Correctly flags invalid ARINC 429 GPS output.
Corrected an issue with keep alive power where SN3308 went through
complete startup procedure following a brief power interruption
instead of the quick startup procedure.

2.01 11/17/99 Changed moving map functions to support internal
Jeppesen database.  Displays airports, navaids, intersections and
airspace.  Also displays courselines between active waypoints
Added map auto-ranging functions through the up and down arrows
Waypoints and courselines drawn in standard colors
Added option to hide course pointer when moving map and courseline
from flight plan is shown
Corrected handling of direct-to flight plans from IIMorrow GPS units
Improved graphics processing to eliminate "barber pole" effect in
course pointer
Improved gyro smoothing
King FCS outputs now range to 12V
Added HOLD annunciation for Trimble GPS
Increased display time of software version on power-up
Fluxgate frequency error now changes compass rose to amber
Serial number now displayed in SYSTEM maintenance page
Increased speed of software upload

1.34 05/27/99 Fixed VOR/DME symbols sometimes missing from map
Course/Heading datum now independently settable for swapping H/C
Sperry SPZ500 added to FCS menu

1.33 05/19/99 "GPS Invalid" now draws an "X" over LNAV annunciator and
redlines MAP annunciator
Supports II Morrow enhanced protocol for the GX-series, allows map
data over RS-232
Supports Collins VIR-30A nav receiver
Supports ARINC 568 DME receivers
Removes spurious "Bulb Test Failed" messages
Maintenance page changes:
FCS entries added for Cessna 400B
FCS gradients now in Volts/Degree

1.32 03/28/99 Supports GARMIN GNS 430 via ARINC 429 interface
Allows selection of XYZ -180 as Gyro selection (Inadvertently removed
on prior software)
Maintenance Page 2 has additional diagnostics for fluxgate excitation
Analog DME_VALID threshold moved to 3VDC to support Collins DME 451
Supports MOD-1 hardware level

1.17 03/12/99 Now supports KN62/64 DMEs when tuned from their front panel.
Now supports 2x5 tuning configuration for KN62/64 DMEs.
Fluxgate status items now shown in maintenance page 2 for easier
troubleshooting.
Fluxgate excitation noise immunity improved.

1.13 01/28/99 Auto-slew function retains last known course if
communication with GPS receiver is lost.   This prevents an
inadvertent course change.
Fixed a very rare situation in which a map waypoint may be incorrectly
displayed when data source is an RS-232 GPS.
System is now compatible with Sandel Demonstrator Box without the need
for special software.

1.12 01/02/99 Northstar receivers are now supported and selectable in
the LNAV setup pages.

1.11 12/15/98 Intermittent NAV bearing pointer fixed.  The acceptable
range of composite nav signal levels has been increased, preventing an
occasional flickering of the RMI bearing pointer when connected to
NAV1 or NAV2.

1.09 11/25/98 ILS lockout (forcing selection of NAV whenever ILS
ENERGIZE is valid) is now selectable in setup.  This allows installers
to decide whether or not tuning an ILS frequency on the NAV receiver
should force the HSI to having "NAV" selected as the primary nav
source.  Disabling ILS Lockout also allows for the display of GPS
vertical deviation, since the ILS ENERGIZE signal causes the vertical
scale to be displayed for either GPS or NAV.  Consult the latest
installation manual or contact Sandel for guidance on enabling GPS
vertical deviation.

1.08 10/29/98 Bootstrap outputs
Heading bootstrap outputs are now enabled, allowing the SN3308 to
provide heading information to an RMI, Stormscope, Strikefinder, or
Argus.

Nav/Glideslope Flag Displays
Nav and glideslope needles are now visible even if flagged, for the
first 2 minutes after power-up.  This is to allow pilot observation of
GPS self-test for the II Morrow GX-series.

Maintenance/Setup
Improvements to error handling of out-of-spec inverter frequencies
Addition of software H/C swap (180 degree phase reversal) for all XYZ inputs
Internal temp displays in both ÁF and ÁC
Actual cooling fan speed is now displayed

1.04 07/17/98 First major release
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