I found that restriction puzzling. Why on earth not?
Not sure, I think Garmin might have found out the two don’t play nice together.
then obviously having the same indications on both of these is desirable.
If having the same indications is the pain point, you will be infinitely better served by a GI275 duo versus having to d!ck around connecting the Sandel (STC restriction nonwithstanding…). For a net 1’500 USD extra you gain full reversion, moving map, weather, terrain etc, no lamp change hassle… It’s a no-brainer really, on top of being plug-and-play.
That’s a gross over-simplification of the situation, and the SN3500 capability, but never mind.
Unless your SN can drive the GFC autopilot (or any autopilot) on its own, serve as AI + DG on top of doing what it does, serve as stadby VFR GPS navigator with integrated GPS source, care explaining where the simplification is or what secret features your SN has that we don’t know about?
T28 wrote:
Not sure, I think Garmin might have found out the two don’t play nice together.
I just recalled a discussion I had with my avionics shop which might be the reason. Some indicators for VOR/ILS accept a signal (“composite”) from the navigator which has the actual radial information. Thus the indicator itself determines the needle deflection depending on its OBS setting. Other indicators transmit their OBS setting to the navigator which determines and transmits back the appropriate needle deflection. A GPS navigator must use the latter kind as it needs to know the OBS setting anyway.
Obviously only one indicator of the latter kind can be connected to any one navigator. Using a navigator which has both composite and non-composite (or digital) outputs, the avionics guy could see no reason why it shouldn’t work to have it connected both to a G5 and to an separate indicator accepting a composite signal
The GFC 500 system only has digital interfaces. There is no way to connect analog signals.
It’s been posted on a US site that the GFC500 STC is running into issues with later TB20 / TB21 aircraft and some mods installed on these (presumably by the factory) which affect the GFC500 performance.
Doesn’t sound good…
Peter wrote:
It’s been posted on a US site that the GFC500 STC is running into issues with later TB20 / TB21 aircraft and some mods installed on these (presumably by the factory) which affect the GFC500 performance.Doesn’t sound good…
Can you share some more info? What can influence GFC500 performance – it’s practically standalone product, delivered with G5 or GI 275?
The Socata US guy, who is working with Garmin, wasn’t giving any detail.
My reading of it is that the GFC500 control algorithms are marginal and the GT version handles sufficiently differently to break it. It does sound pretty weird though. I don’t think the GT handles really differently, although it is possible that full TKS system changes things at the low speed end of the envelope. It changes the stall behaviour from mushy to a fairly rapid breakaway and a left wing drop. I can’t think of any other mods, especially ones which could, as one solution suggested in the report, be removed.
Peter wrote:
I can’t think of any other mods, especially ones which could, as one solution suggested in the report, be removed.
But I guess those stuff can be adjusted by changing envelope parameters.
Latest from the US:
GFC500 base unit is about $7000 plus about $2000 per servo. It can drive up to 4 servos (roll, pitch, yaw and trim). Plus installation. I don’t know if these prices include the servo mounting brackets.
A TB20 would normally have 3 servos. A yaw damper did exist as an option on some system many years ago, but the only guy I ever heard of who had it (in the US) didn’t know whether it ever worked (it was already installed on a plane he bought).
