REFLECTOR: EFIS/WAAS GPS

Fri Mar 30 08:54:29 CDT 2012

This sounds like the best reason for getting synthetic vision.  I don't 
want to change my panel and have decided to go the WingX/ipad route.  
I'm adding the Skyradar box for weather (there is a special discount 
right now).  I was going to mount the ipad somewhere, but after seeing 
and trying the Brent Bourgeois lap pad (more like a conference table), I 
plan to copy that (hope you haven't patented it Brent).

John

On 3/27/2012 3:28 PM, Mark Magee wrote:
> You should call GRT, as I have many times, and was told their PRIMARY 
> flight data is from their AHRS which is an electronic INAV system that 
> adds in pitot static and RMI inputs. For glide slope (profile) info 
> that comes from the Garmin for it's certificated. As I understand it 
> should you lose your GPS on an IMC GPS approach on a GRT EFIS you will 
> lose your glide slope boxes but with Synthetic Vision you will be able 
> to complete the approach on synthetic vision, grey area legally, but 
> nonetheless safely. This is an area where the FAA is about 15 years 
> behind currently.
>
> Mark B. Magee
> Sent from IPhone 4
>
> On Mar 27, 2012, at 2:15 PM, Lawrence Epstein <ljepstein at hotmail.com 
> <mailto:ljepstein at hotmail.com>> wrote:
>
>> Really seems like we are talking about 2 different things.
>> 1)Attitude information
>> 2)Navigation/Approach/glideslope
>>
>> I don't think that GRT (which I also plan on using) uses INAV for map 
>> display/approach guidance/glideslope information (?). My guess is all 
>> of that comes from your Nav source (whether it is an internal GPS or 
>> a separate unit)
>>
>> If you can't depend on GPS, your only other choice is to have ILS/VOR.
>>
>> On Tue, Mar 27, 2012 at 2:57 PM, Mark Magee <edjonesbrady at gmail.com 
>> <mailto:edjonesbrady at gmail.com>> wrote:
>>
>>     Hi Brett,
>>     I mentioned in my earlier posts that GRT uses electronic INAV as
>>     primary with GPS cross referencing which is ideal. I didn't want
>>     to make my post about GPS Jamming concerns sound like an ad for
>>     GRT (I don't own anything of theirs -yet-), but since you said it
>>     I'll second it: buy an EFIS system that uses electronic INAV as
>>     primary and GPS as back up/cross referencing. I know GRT does and
>>     not sure who else does.
>>
>>
>>     Mark B. Magee
>>     Sent from IPhone 4
>>
>>     On Mar 27, 2012, at 1:01 PM, "Brett Ferrell"
>>     <reflector at velocityxl.com <mailto:reflector at velocityxl.com>> wrote:
>>
>>>     Mark,
>>>
>>>     Most EFIS don't depend exclusively on the GPS signal.  For
>>>     intance, I know that the GRT drops into "dead reckoning" mode
>>>     when the GPS signal is lost, using airspeed, static pressure,
>>>     accelerometers, and magnetometer to generate the display.  It
>>>     can also display a localizer and glideslope from the radio.  I
>>>     do have backup steam gauges for airspeed, altitude, and an
>>>     electric ADI (and slip/skid in my autopilot), and I'm not
>>>     instrument rated, but when GPS is up and working I plan to use
>>>     the heck out of it.
>>>
>>>     Brett
>>>
>>>
>>>     	-------Original Message-------
>>>     From: Mark Magee
>>>     To: Velocity Aircraft Owners and Builders list
>>>     Subject: Re: REFLECTOR: EFIS/WAAS GPS
>>>     Sent: 27 Mar '12 12:37
>>>
>>>     Hi Kevin,
>>>     Earlier I posted my concerns about GPS as the sole heart lungs
>>>     and brain of an EFIS package. Nobody added to my posts so I
>>>     don't know what that meant entirely, yet you might look them up
>>>     in the archives. GPS jamming is a known problem and growing.
>>>     There is a real chance your approach into (for instance) Branson
>>>     MO at night in IMC that a pharmaceutical salesman in a company
>>>     car will have deployed his EBay bought GPS jammer that will keep
>>>     his company from knowing where he/she was in the company vehicle
>>>     will drive on a county road intersecting your glide path to the
>>>     numbers. If your reliant on GPS only to get to the runway, you
>>>     could be in serious trouble. If you don't have Electronic INAV
>>>     or steam gauge back up, not good.
>>>     A more probable scenario is that the female Pharma salesperson
>>>     parked her company car in the Branson Airport parking lot, left
>>>     the GPS Jammer on (plugs into the cig adapter) and her pilot
>>>     boyfriend picks her up for a weekend in Vail. She leaves her GPS
>>>     jammer on all weekend long and you lose your NAV (EFIS) before
>>>     you descend below the soup.
>>>     I personally won't let GPS alone run an instrument approach
>>>     because of this issue. Apparently it is easily jammed
>>>
>>>     Mark B. Magee
>>>     Sent from IPhone 4
>>>
>>>     On Mar 27, 2012, at 7:48 AM, Kevin Baker <flykb at verizon.net
>>>     <http://compose.php?to=flykb@verizon.net>> wrote:
>>>
>>>     > Hi All,
>>>     > I was thinking about the glass panels and was wondering what
>>>     others experience was with these systems.
>>>     > I'm also interested in EFIS/GPS WAAS precision approaches and
>>>     folks that can speak to that equipment.
>>>     >
>>>     > Thanks
>>>     > Kevin Baker
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