N

N999BT

Well Known Member
Patron
I have an RV-4 and am considering adding standby instrument(s) in case my AFS-3500 decides to turn off in the soup (IMC)? I have very limited panel space, so I can't add 3 more instruments like a spam can. My current instrument list is:

AFS-3500 EE
Garmin 496 with weather
SL-30 Nav/com/Localizer/GS
SL-40 Com
Garmin Gtx-327 transponder
Digiflight II VS two axis autopilot
Garmin audio panel with marker beacon receiver

the following is my thinking and may not be for everyone:

I think that my 496 is probably good enough for a standby altimeter, airspeed indicator, and MAYBE even turn coordinator in SMOOTH air. When it is not smooth is what I am really worried about.

Altimeter: The 496 is always within 50 feet or so of the regular altimeter, so I think using GPS altitude for the most part is good enough in an emergency.

Airspeed: If you have the wind aloft forcast, and can get wind speeds on the ground for an airport near where you land you can do some mental math, add some margin, and be OK on airspeed, especially in an RV. You could come over the fence pretty hot, and still get is slowed down and landed.

Horizon: ? What would you suggest?

Money and panel space are at a premium, but I also want to survive a complete failure of any single peice of equipment, inluding the EFIS. What should I add to this?
 
GrayHawk said:
MGL Avionics Flight II on it's own separate electrical supply/battery.
Click to expand...
Dynon 10A also works - light, small, internal backup battery. However, there are failure modes that could (unlikely, but possible) take out all of your electronics (e.g., lightning), so you need to decide how realistic that is for your flying. Mechanical ASI, ALT and TC or attiude gyro would seem to be the gold standard in terms of dissimilar redundancy, although it's debatable about the reliability of mechanical gyros.

TODR
 
I wished TruTrak would come out with an ADI Pilot with GPSS and to a lesser extent, the vertical speed feature of the Digiflight. But if it had GPSS it would be a great autopilot AND a backup for the horizon.

Personally, I'd scrap the SL-30 and SL-40 and put the money toward a GNS-430 and a handheld com. For the cost of those two SL units, you are only about $1500 away from a 430 and then you would have a WAAS GPS and can file /G. For the longest time I had incorporated a portable in my panel, however, AFS offerings reduce the need for a portable such as the 496. If you add the cost of the AFS moving map ($800), AFS XM weather ($800), and battery ($127), you save $800 vs. going with a 496. Then with the free space from the 496, you can put in some true steam gauge backups.

So your new panel would be as follows:
AFS-3500 EE (with XM weather, moving map and battery) -add the ARINC interface for the 430
Garmin GNS-430 (Nav/com/Localizer/GS and WAAS GPS)
Garmin Gtx-327 transponder
Digiflight II VS two axis autopilot or ADI Pilot II
Garmin audio panel with marker beacon receiver


2 1/4" Steam gauge Altimeter, Airspeed

Of course this opinion is worth all that you paid for it.;)
 
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