on EFIS Placement and redundancy

[Ian_Brown]

What do people think about the need for the standard six-pack for backup to the EFIS D10A? I'm putting in an air speed indicator and an altimeter but which of the other 10 functions do people typically duplicate, and why?

On a separate topic (sorry) I don't think I got any guidance with my EFIS on OAT Sensor location. What have other people done?

Ian Brown,
Rockwood, Ontario

 

[dynonsupport]

Re: on EFIS Placement and redundancy

Ian,
We suggest placing the OAT under the horizontal stabilizer, sticking out of the "side" of the airplane, not straight down.

This location puts the OAT out of direct sunlight and does a good job of keeping it out of the heated exhaust stream. Many of our customers have had good success here. Obvioulsy if you have a non-conventional design like a pusher, exhaust is not a problem, so I would focus on getting it out of the sun.

Remember that you can not extend the wire on the OAT, so if you have your EDC out in the wing, another good location is the underside of the wing.

 

[dynonsupport]

Re: on EFIS Placement and redundancy

Ian,

Also, did I understand you correctly that you did not receive an OAT installation guide with your EFIS-D10A? If that's the case, we do apologize. You can download it from:

http://www.dynonavionics.com/downloads/oat_installation_guide_20040108.PDF

 

[Gerry Holland(Guest)]

Re: on EFIS Placement and redundancy

I have just duplicated Altimeter and ASI in my D10 install. Experimental A/C in UK can only fly daylight VFR so that basic redundancy is adequate. I placed those two Instruments on P2 side.

 

[Larry Dagley(Guest)]

Re: on EFIS Placement and redundancy

If you look at most of the "magic" air carrier airplanes they have attitude, altitude and airspeed backups.

Regard,
LD

 

[Twomoons]

Re:  on EFIS Placement and redundancy

As for the OAT, I mounted the remote compass in the tail of my C172 (337 field approved) just behind the luggage area and mounted the OAT probe on top of tail just behind the rear window. It is out of the engine heat and it doesn't seem to be bothered by the sun as it indicates within +- 2 degrees of the vent thermometer.

 

[ksouthar]

Re: on EFIS Placement and redundancy

I'm a total rogue.

No airspeed backup - GPS provides some guidance in the way of groundspeed. Absent very strong wind conditions, this is going to be pretty close to the airspeed at the critical point - landing. I have enough time in the airplane that I can fly within a few mph of the target airspeed on feel alone.

Heading - Both GPS and traditional liquid compass will serve as backup.

Attitude - Turn coordinator installed. 2 axis Autopilot to take the workload out of keeping it straight and level.

Altitude - GPS provides altitude within a couple hundred feet.

I have installed a backup battery in the EFIS that is sufficient to get me to a landing point in the event of a power failure. The biggest risk a malfunction of the unit itself or having the 'bulb' burn out.

It is much like flying IFR partial panel. You don't have everything you want, but what you have is enough to get you to a safe landing if you use it.

Thinking about a 2nd EFIS to act as a back-up or to run the engine management.

 

[N941WR]

Re:  on EFIS Placement and redundancy

Having owned a '41 T-Craft w/ no electrics the thought of just having a starter is high tech in my mind.

However, after talking the redundancy issue over with a number of people who have installed Dynon units and other EFIS displays I’ve decided to install a wet compass, airspeed indicator, altimeter, and slip ball.  (What the heck, the balls are cheap enough.)

That is for a day/night VFR ship.  If my RV-9 was going to be IRF equipped I doubt I would add much more.

Before you can really answer the question of what redundant equipment is needed, you have to look at your mission profile and comfort level with flying with minimum instruments.  I’m probably one of the few pilots left in the world that have never flown with a GPS but plan on installing one in my -9.  Will I use it for a back instrument?  I won’t know until I fly the airplane.

The Dynon units are proving to be very reliable but one of our chapter members had an over voltage condition on his first flight and his electrics went Tango Uniform on him and he had to land w/o any airspeed indications on his first flight.  Not a situation I want to find myself in.  (The cause was a new alternator that was faulty.)

I also hope to equip my -9 with the Dynon EMS w/o back up.  I figure if the EMS goes south and that big chunk of aluminum out front continues to make noise, then I’m in good enough shape to find the closest airport.  On the other hand, if every thing goes silent on me then what good is the EMS unit going to do for me.  I will already know the RPMs will be zero along with the oil pressure and a few other important readings.  (You would be surprised at how many pilots think that is crazy.)

Again, it comes down to your mission profile and what you are comfortable with.

BTW, there are some pictures of what I think my panel might look like on my web site. Let me know what you think after looking them over. I value everyone's input on this subject.

Bill
www.repucci.com/bill/baf.html