Two D180 Installs with Autopilot Options

[joehopwood]

I have been considering a D180 with steam guages for backup for my Zodiac 601XL.  However, lately I have been thinking about two D180s and using the new servos for the autopilot.  If I go with two D180s I really wanted to be able to isolate the electrical systems, two batteries and if possible two alternators.  Can something like this be done and still share GPS, NAV and AP servos?

 

[dynonsupport]

Overall, yes - that gives you two complete sets of flight instruments, with one unit acting as an autopilot. Most people wouldn't go with two FlightDEK-D180s though since you can't route a bunch of the engine sensors to two instruments. Instead, consider an EFIS-D100 and a FlightDEK-D180. When connected together, the engine instruments from the FlightDEK-D180 can be shown on the EFIS-D100.

 

[joehopwood]

Thank you for the speedy reply. If I were to loose power to the D180 could I still display engine instruments on the D100? I was hoping for redundancy of 100% or near that. No way to share probe output to two D180s, huh?

 

[dynonsupport]

There is no way to do redundant engine monitoring without redundant sensors on the engine. If you have a D100 and a D180, and the D180 fails, you can no longer see engine stuff on the D100. If you have two D180's, only one can be hooked to the engine sensors at one time.

If one D180 fails, you could move the harness from one to the other so you could fly home, but this is not in-flight redundancy.

 

[joehopwood]

I wonder if a multi-pole switch or possible a relay would be an option. Just flip a switch to send engine data to the display you wish. I am still aways from purchasing. Just finishing tail feathers and will order the wings soon. Thanks for your help.

 

[dynonsupport]

Yes, that is a possibility, but you are talking about switching 10-20 wires, so it's a big switch or a big relay array.

Most people find that they can land an airplane safely with no engine data, but the Attitude / Altitude / Airspeed is a totally different story.

 

[Brantel]

Although it is major overkill, there are multipole relays sold that have that many poles.  They are used in aircraft all the time to switch the source of CDI/GS or HSI heads between two different sources.

This one is by Ameri-King but there are others:

 

[joehopwood]

Thanks

 

[PhantomPholly]

Most aircraft operations include (at minimum) two audio engine monitors which can accurately identify engine operating condition.

If your primary flight display fails and the engine is still running, it is probably a good idea to land.

Just my 2 cents.

 

[joehopwood]

Obvious you are not an engineer. ;D Part of building your own plane is doing it the way you want to.

 

[N941WR]

Joe,

I went through the same thought process you did when I built my RV-9.  This was just before the D180 came out so I installed a D100 EFIS on the left and D10 EMS on the right.

Most of the time I have the engine instruments displayed on the D100 and depending on the right seat passenger, either the EFIS or EMS displayed on the D10 as it is right in front of the passenger.

In the end I realized that should the EMS go black and the big chunk of aluminum and steel up front continue to make noise, I figure I can get on the ground easy enough. That would be on the ground and a designated airport with the rubber side down.

The truth is, the simpler you make your installation, the more reliable it will be and the less chance of anything going dark. Just a thought.

 

[joehopwood]

Thanks for the feedback. Understand that the more you have the more that can fail and require maintenance.

 

[PilotKris]

In my Sky Arrow, I've got a D180 with a mechanical Tach and warning lights for, Oil Press, CHT (coolant), Oil Temp and Low Fuel Level that use simple automotive style switch-senders.

If the D180 fails, I have pretty much everything I need to be sure there is no problem with the engine. VDO makes a neat combo oil press gage/warning light sender as well as the other warning light senders for oil temp, coolant temp and even a fuel level gage/warning light sender.

I've had the oil pressure sender fail and indicate zero oil pressure. Rather than make a precautionary off-field landing, I continued back to the airport (after a "press-to-test" of the lamp) as the warning light indicated that I did have oil pressure.

I like that I have 2 independent warning systems with completely different audio/visual indications that can be use to cross check each other rather than two identical systems.

But if you have identical systems, which one do you believe if they don't agree? Shouldn't you have 3? Or maybe 5 like the Space Shuttle?

You can go crazy duplicating systems just for "redundantcy" but would a 5,000lb Zodiac ever get airborne?

PilotKris