Glass cockpit without backup

RV10POLAND · #1 11-15-2007, 06:41 AM

I'm really surprised that so many RV builders go glass without any backup instrumentation

What are they going to do if electricity fails? All this stuff is great but as you know there are some incidents of misstated, inaccurate readings of altitiude, airspeed or unsafe attitude information. Even while flying under VMC you don't have airspeed and altitiude readings. I don't want to criticize nobody but we all are here to help each other. I'm sure that adding three analog instruments is not a big deal and can save your life.

Regards

Maciek

Ironflight · #2 11-15-2007, 07:06 AM

Backups are extremely important, as you say Maciek, but they don't necessarily have to be analog instruments. They can be additional glass instruments, an independent autopilot, etc. Your point about loss of electrical is true - so provide independent power sources. By independent, I mean that they can not be taken down by a single failure in the other system (they need to be isolatable, and have their own power source. The design goal is redundant function - if you can provide that, it really doesn't matter how. Almost everyone I know that is actively flying their RV IFR has a backup scheme of some kind - or at least I hope they do!

Paul

rvtach · #3 11-15-2007, 08:03 AM

I am building a day/night/X-C VFR -7A with a Dynon EFIS, 2 axis Auto Pilot driven by a Handheld GPS and no "back up instruments". I will have a single battery and dual alternators so the juice should continue to flow at all times.

Following 'Lectric Bob's philosophy that "no single failure should cause me to break a sweat" I'm keeping it simple. My thought process is: "What will I do when the _____ quits working?"

-If the Dynon bites the dust: Hand held GPS and 2 axis auto pilot will keep the wings level, allow accurate navigation and give altitude information.

-If A/P quits: Hand fly using the Dynon and GPS

-If GPS quits: Still have the Dynon. The A/P will independently fly a heading.

-As for back up airspeed, I have no PIC time in RVs but in my other flying I don't generally spend a lot of time looking at the ASI. I think I should be able to maintain a safe airspeed by sight picture, sound and feel (seat of the pants). Granted this may not be as simple in an RV as it is in a -182 but no one should crash because a bug flew up the pitot tube.

-This is taking things a step farther than I think is necessary but: If multiple instruments quit I'm still okay since whatever is left will give me at least heading info so I can still navigate and (most of the time) I can look outside and see that I'm not going to hit the ground. You can "What-if" this stuff to the N'th degree but I'm comfortable with stopping here. If you really want to cover your bases get a $100 el cheap-o gps and carry some fresh AA batteries with you.

Just my thoughts,

Jim McChesney
Tucson, AZ
-7A Finishing Kit

pierre smith · #4 11-15-2007, 08:10 AM

Quote:

Originally Posted by rvtach

-. I think I should be able to maintain a safe airspeed by sight picture, sound and feel (seat of the pants). Granted this may not be as simple in an RV as it is in a -182 but no one should crash because a bug flew up the pitot tube.

-This is taking things a step farther than I think is necessary but: If multiple instruments quit I'm still okay since whatever is left will give me at least heading info so I can still navigate and (most of the time) I can look outside and see that I'm not going to hit the ground. You can "What-if" this stuff to the N'th degree but I'm comfortable with stopping here. If you really want to cover your bases get a $100 el cheap-o gps and carry some fresh AA batteries with you.

Just my thoughts,

Jim McChesney
Tucson, AZ
-7A Finishing Kit

Jim,
Believe me, you can fly any RV without airspeed indications if you use the visual cues you know so well....I've done it quite few times either because I forgot the pitot cover or a mud dauber camped there. Besides I have a 496 with GS which is usually close enough.

Maciek,
No, I wouldn't fly hard IMC with no backup but I don't do that. My 496 has its own battery backup and shows altitude, heading, groundspeed, bearing to any airport and track....enough backup for me. Depends on what you're going to do with your airplane.

Regards,

keen9a · #5 11-15-2007, 08:40 AM

I carry my backup VFR altimeter and two airspeed indicators with me all the time. Most people call the altimeter "eyes" and the airspeed indicators "ears". The airspeed indicators work best when coupled with the altimeter

.

dynonsupport · #6 11-15-2007, 09:05 AM

The whole airplane losing power is why we at Dynon designed in an internal, self managed backup battery. Any Dynon EFIS can be equipped with this and it gives you hours of operation after your master power fails. Other EFIS manufacturers have done the same or support an external battery. In reality, it's easy to make the electricity needed to run an EFIS one of the most redundant, reliable things in your airplane.

That being said, we always recommend the builder equip with backups that are appropriate for their needs. You lose a lot if info if you lose any EFIS system, but it's easy to back all of that up by putting a second EFIS in.

Norman CYYJ · #7 11-15-2007, 09:15 AM

So someday you are flying on top. How are you going to come down if you can't see the ground safely if you have no backups. If you can come down thru the cloud layer without an airspeed and T&B you're a better pilot than most.

frankh · #8 11-15-2007, 09:42 AM

If its a VFR airplane you look out the window...Best instrument there is.

Autopilots are so cheap these days that a VFR X country machines are being fitted with them all the time and if you go IFR they make a perfect back up to whatever artificial horizon instrument you are using, especially the Trutrak line as these can have the turn coordinator display.

All electric airplanes can be designed to have redundant systems.

Frank

DGlaeser · #9 11-15-2007, 09:59 AM

Quote:

Originally Posted by frankh

If its a VFR airplane you look out the window...Best instrument there is.
. . .
Frank

I agree. My student pilots regularly fly with the IP totally covered, and must be able to do consistent takeoffs and landings in that configuration before solo. I tell them that the Wright brothers didn't have all this stuff, and they flew just fine

keen9a · #10 11-15-2007, 10:22 AM

Quote:

Originally Posted by Norman CYYJ

So someday you are flying on top. How are you going to come down if you can't see the ground safely if you have no backups. If you can come down thru the cloud layer without an airspeed and T&B you're a better pilot than most.

If I'm every flying VFR on top, and have a need to get down immediately, and have no hole to go through, and have an electrical failure of both the A/C power and backup battery, I guess I just won't buy a lottery ticket that day.