[Gary 40274]

Garmin 900X-Digiflight II VSVG

I am interested in comparing notes with folks that have the above combination. There is a bit more knob turning and finger polking if you don't have the Sorcerer AP and It would be nice to sort that out first on the ground and save some $$ in fuel.

Gary Specketer

 

[breister]

With the II series you will not get any VOR/LOC/ILS tracking capability.

Unless you have the II VSGV model you will not get vertical steering, so your autopilot will not fly a precision GPSS approach for you.

TruTrak has an upgrade path which essentially credits you full value for your current model towards an upgraded model (I think they may actually plug in a new circuit to your existing control head).

The II series has two GPS input channels: 1 Serial (1 wire) and 1 ARINC (2 wires). There is an interesting "undocumented feature" that has to do with how the unit responds to GPS info. If, for example, you had both a G900X and a 2/3/496, you might connect the G900X using the ARINC lines and the 496 via the Serial lines.

According to TruTrak, the Autopilot will always use the ARINC signal, if available. If your G900X fails in flight, the autopilot will revert to GPS (true) course on the last heading, using the 2/3/496 as it's GPS source. If you then press "MODE" it will start following the flight plan in the 2/3/496.

There is no reason to hook up both the serial and ARINC lines to your G900X unless you just want protection against ARINC "wire failure."

 

[Gary 40274]

oops

I misspoke (mistyped) I do have the II VSVG. I have coupled nicely with a GPS approach, but have not tried the ILS. Does it work exactly the same way?

 

[w1curtis]

There is a bit more knob turning and finger polking if you don't have the Sorcerer AP and It would be nice to sort that out first on the ground and save some $$ in fuel.

Gary Specketer

"more knob turning" How so? The primary difference between the Sorcerer and the II VSGV is that the Sorcerer can track VOR/LOC/ILS signals. Having the capability to track an ILS would be nice but since a GPS navigator such as the G900X will allow an overlay of the ILS using GPS signals, as long as your are monitoring the actual ILS signals, the benefits of the Sorcerer are greatly diminished. Nice but not worth the almost 100% increase in cost over the II VSG/V.

Regardless of which autopilot, the primary button pushing will be to determine the source data for the autopilot, that is GPS, Heading or (in the case of the Sorcerer) VHF Nav.

 

[Gary 40274]

I am still learning but I think

During radar vectors I think I need to put the heading into the AP and not the Garmin. Also the altitude setting on the Garmin only sets the alarm for when you reach that altitude it does not signal the AP to capture that altitude, so I need to first use the AP for verticle speed and then when at appropriate altitude go to altitude hold.

So the Digiflight II VSVG AP will not track either loc or GS on an ILS approach?

Gary Specketer

 

[w1curtis]

So the Digiflight II VSVG AP will not track either loc or GS on an ILS approach?

Gary Specketer

That is correct. The GPS will however provide overlay guidance so you can leave the autopilot in GPS mode (while you monitor the actual ILS glidescope on the CDI) and let it fly the approach. Some of the new EFIS features such as AFS will be able to provide VHF/LOC/ILS guidance to a II VSGV by feeding the EFIS CDI signals to the autopilot via GPSS/V.

 

[rjtjrt]

I've been wondering about this for a long time.
Are the Digiflight II or Sorcerer able drive the flight director bars on the Garmin 900? Or is the flight director not available?

John
If you feel I am hijacking the discussion let me know and I will delete this post.

 

[breister]

I misspoke (mistyped) I do have the II VSVG. I have coupled nicely with a GPS approach, but have not tried the ILS. Does it work exactly the same way?

Right up to the point where you intercept the Localizer - then you have to hand fly or use a combination of heading set and vertical speed to follow the ILS needles on whatever indicator you use. This is because the VSGV has NO capability to follow a Localizer or Glideslope signal.

Now, someday if one of the EFIS makers figures out a way to simulate the GPSS steering commands while deriving them from the ILS signal, then the VSGV will "couple" (but it will really be coupling to a synthetic approach).

I don't consider this a problem, as most airports I fly into don't have ILS and many of them will start to go away as they are replaced by GPSS.

 

[breister]

I've been wondering about this for a long time.
Are the Digiflight II or Sorcerer able drive the flight director bars on the Garmin 900? Or is the flight director not available?

John
If you feel I am hijacking the discussion let me know and I will delete this post.

Sadly, the answer is all too simple - the TruTrak has ZERO outputs to anything other than the servos. I once asked if it would be possible to output the internal calculated attitude to drive an external backup attitude indicator - no dice.

Still, I DO consider my TruTrak to be a backup "attitude indicator" - because if it is flying the airplane straight and level and my other attitude indicator indicates something different, then I at least know ONE of them is wrong!

 

[glenn654]

I'm not an IfR guy yet but learning here and there. My question is: can these autopilots fly all the way down to MDA with great accuracy? And should that be enough to let you fly down to touch down?

Glenn Wilkinson

 

[breister]

I'm not an IfR guy yet but learning here and there. My question is: can these autopilots fly all the way down to MDA with great accuracy? And should that be enough to let you fly down to touch down?

Glenn Wilkinson

When coupled with an IFR capable GPSS unit such as the Garmin 430W/530W or the now out of production GNS 480, it will indeed. What the autopilot will do is limited only by the capability of the controlling unit.