Matronics Email Lists :: View topic - EFIS as only reference???

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

EFIS as only reference???
Goto page 1, 2, 3 Next

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

flyboyron(at)gmail.com
Guest

Posted: Mon Sep 17, 2007 9:50 am Post subject: EFIS as only reference???

 	  Quote: 	
		   Time: 01:24:52 PM PST US

 Subject: RE: switch suitability?

 From: "Chris Johnston" <CJohnston(at)popsound.com>

..

 	  Quote: 	
		   your reply that i have too many and the

 wrong things is curious to me.  the aircraft has no "conventional"

 instruments, so the EFIS and AHRS are essential.

Chris,

This statement indicates to me that you may harbor a certain naivete about 

the current state of development and reliability of EFIS/AHRS systems.  As a 

new pilot with an instrument rating, it's natural to want to have the 

greatest thing that comes along.  I just bought a really cool EFIS add-on 

system for my Glasair project and I use it in my Cessna now, but it's not 

the only way to fly the airplane.  I like it alot, but I don't count on it 

to keep my body parts within their casing.  IT will be the backup in case of 

failure of my primary (traditional) instruments.

But if you are working on a plane you intend to fly in real IFR, and do 

indeed have NO backup instruments, I'm afraid your electrical distribution 

system is far from the weakest point in your airplane.  If you plan to fly 

only VFR, then the systems are even less "essential", and again, they don't 

need to be on the "E-bus".

There are currently NO EFIS systems out there for the market most of us are 

looking at (i.e. non-military, non-$100K) that have the kind of proven 

reliability and lack of single-point failure possibilities that even the old 

vacuum gyro systems should be configured to give you.

In other words, if you do have, say an internal power supply failure, or 

complete display failure in your EFIS system, what is your plan?  Your E-bus 

may be powered, and if you follow Bob's advice, it almost surely will be, 

but how are you going to control the airplane????

Bob's advice to look again at your system is good advice (as it usuallyall 

is.)   He always reminds us to look at the possible failure points in a 

design, and decide which are not problems, which are, and to figure out how 

to assure that those which are problems are prevented to the greatest extent 

possible.

I strongly suggest you do some additional research before trusting your life 

to what's really generation 1.5 of general aviation EFIS systems.  They're 

great, when they work, and they usually do, but it's nothing short of 

criminally negligent to put ALL your eggs in that kind of basket.  There 

isn't anywhere near enough industry-wide experience with these systems yet 

to even KNOW what their real in-service failure rate is, let alone determine 

whether it's low enough or not.

Do a little Googling on EFIS systems, no matter which brand, and you'll find 

a legion of folks who love them, but don't trust them, and they'll tell you 

perfectly good reasons why.  EVERY system I've looked into has its share of 

"boy am I glad I had a backup" stories.

What GA airplane do you see out there that has only an EFIS and no backups? 

There's a reason for that.

Ron Cox

(Old pilot with an instrument rating, and one who has well over 10,000 hours 

flying behind fantastically expensive commercial EFIS systems, but we have 

backups!)

deej(at)deej.net
Guest

Posted: Mon Sep 17, 2007 10:42 am Post subject: EFIS as only reference???

Ron Cox wrote:

 	  Quote: 	
		  

 There are currently NO EFIS systems out there for the market most of

 us are looking at (i.e. non-military, non-$100K) that have the kind of

 proven reliability and lack of single-point failure possibilities that

 even the old vacuum gyro systems should be configured to give you.



 In other words, if you do have, say an internal power supply failure,

 or complete display failure in your EFIS system, what is your plan? 

 Your E-bus may be powered, and if you follow Bob's advice, it almost

 surely will be, but how are you going to control the airplane????



    I'm not Chris, but I'll byte.  You control the airplane with the
	


second smaller EFIS that is installed as a backup, of course...  



    From a reliability/lack-of-single-point-failure perspective, it is

not necessary to have vacuum gauges in an airplane.  Two EFIS systems of

different make (ie, a Dynon and a GRT for example) have such a

statistically small chance of failing during the same flight that it

approaches zero.  A redundant electrical system and redundant EFIS units

are pretty much guaranteed to give you enough instrumentation to control

the airplane.



    If one EFIS starts having the leans, which one do you believe?  You

need a tie-breaker, which in my case is going to be an autopilot that

has its own reference source (separate from the EFIS units) and attitude

display indicator, such as the TruTrak ADI Pilot II that has an internal

gyro for example.  With 3 references (2 EFIS units and the autopilot

display), it should be clear which is the faulty instrument. 



    It really comes down to training.  If you are properly trained in

using the new EFIS systems, and scanning all three redundant sources,

there is no reason why the new systems would not be as safe, or perhaps

even safer, than the old systems that use vacuum gauges.



    My opinion only,



-Dj

do not archive



-- 

Dj Merrill - N1JOV

Glastar Sportsman 2+2 Builder #7118 N421DJ

http://econ.duke.edu/~deej/sportsman/



"Many things that are unexplainable happen during the construction of an 

airplane."  --Dave Prizio, 30 Aug 2005

CJohnston(at)popsound.com
Guest

Posted: Mon Sep 17, 2007 10:44 am Post subject: EFIS as only reference???

Sorry, I didn't intend to imply that I have no backups, but that the

backups are indeed electric.  In the event of an alternator failure,

only the primary electric instruments are on the E-bus.  The Backup

instrumentation has an internal battery that will keep it powered for

over an hour when power is removed.  I definitely appreciate the

watchful eye that the more experienced pilots on the list have on us

young pups though!  



cj



--

Bruce(at)glasair.org
Guest

Posted: Mon Sep 17, 2007 11:22 am Post subject: EFIS as only reference???

I can see you flying along, solid IMC with a happy smile on you face when

all of a sudden you sniff that odor that all of us fear - smoke. The pungent

smell of burning insulation hits your nose. What's the first thing you do?

Hit the master switch and turn all electrical off, Woops, gota fly the

airplane, but with what? Turn all electrical whizzies off, switch or pull

breakers and turn the master back on. Bring up the first EFIS and hope you

don't smell anything. But wait, it takes 2 minutes to boot, not good. Still

have to fly the airplane. Hope it's not bumpy or you have a high ceiling to

recover before the splat.



Give me a vacuum backup AI gyro and all you'll have left is a dark and

stormy night story.



Bruce

www.Glasair.org

 



--

deej(at)deej.net
Guest

Posted: Mon Sep 17, 2007 11:43 am Post subject: EFIS as only reference???

Bruce Gray wrote:

 	  Quote: 	
		   



 I can see you flying along, solid IMC with a happy smile on you face when

 all of a sudden you sniff that odor that all of us fear - smoke. The pungent

 smell of burning insulation hits your nose. What's the first thing you do?

 Hit the master switch and turn all electrical off, Woops, gota fly the

   


	


    In an all-electric airplane (including the engine computer), that

would not be the prudent procedure.  You have two independent electrical

sources, each separately controlled, PLUS each EFIS has its own internal

battery backup.  You don't turn both of your EFIS units or both

electrical systems off at the same time, that would be a bit foolish. 

You turn one electrical system off, and if the smoke does not stop, you

turn the first back on the the other off.  The most important thing is

not to lose your head, that's where the proper training comes in.



    Give me a properly wired airplane and training on how to use it, and

all you'll have left is a dark and stormy night story. 



-Dj

do not archive



-- 

Dj Merrill - N1JOV

Glastar Sportsman 2+2 Builder #7118 N421DJ

http://econ.duke.edu/~deej/sportsman/



"Many things that are unexplainable happen during the construction of an 

airplane."  --Dave Prizio, 30 Aug 2005

Bruce(at)glasair.org
Guest

Posted: Mon Sep 17, 2007 12:10 pm Post subject: EFIS as only reference???

I've had electrical fires in flight, at night, in IMC. Believe me, your

rational mind won't help you. You think fire and your hand reaches for the

master switch. I don't know how you plan to wire your airplane but I stand

with my earlier assessment. You need a backup AI powered by a different

system. It's so much easier to hit one switch (the master) and then go

through your rational trouble shooting procedure or better yet, wait to do

it on the ground.

Bruce

www.Glasair.org

 



--

echristley(at)nc.rr.com
Guest

Posted: Mon Sep 17, 2007 12:16 pm Post subject: EFIS as only reference???

Bruce Gray wrote:

 	  Quote: 	
		   



 I can see you flying along, solid IMC with a happy smile on you face when

 all of a sudden you sniff that odor that all of us fear - smoke. The pungent

 smell of burning insulation hits your nose. What's the first thing you do?

 Hit the master switch and turn all electrical off, Woops, gota fly the

 airplane, but with what? Turn all electrical whizzies off, switch or pull

 breakers and turn the master back on. Bring up the first EFIS and hope you

 don't smell anything. But wait, it takes 2 minutes to boot, not good. Still

 have to fly the airplane. Hope it's not bumpy or you have a high ceiling to

 recover before the splat.



 Give me a vacuum backup AI gyro and all you'll have left is a dark and

 stormy night story.



 Bruce

 www.Glasair.org

   

Bruce, I've installed a vacuum powered T&B, and I have a steam powered 
	


ASI and altimeter, so I'm on board with you about the steam backups to 

the Dynon I'm planning.



But...2 minutes to reboot?  I thought the Grand Rapids was ridiculously 

long at 30 seconds or so (don't remember exactly).  The Dynon comes up 

and orients itself fast enough not to matter.



The argument is sound, let's just keep it real on the details 8*)

harley(at)AgelessWings.co
Guest

Posted: Mon Sep 17, 2007 12:24 pm Post subject: EFIS as only reference???

Hence the P-Mag for an EIS...all power on the aircraft can fail, and it 

keeps on chugging away with it's own internal alternator.



Harley Dixon

------------------------------------------------------------------------



Bruce Gray wrote:

[quote] 



 I've had electrical fires in flight, at night, in IMC. Believe me, your

 rational mind won't help you. You think fire and your hand reaches for the

 master switch. I don't know how you plan to wire your airplane but I stand

 with my earlier assessment. You need a backup AI powered by a different

 system. It's so much easier to hit one switch (the master) and then go

 through your rational trouble shooting procedure or better yet, wait to do

 it on the ground.

 Bruce

 www.Glasair.org

  



 --

BobsV35B(at)aol.com
Guest

Posted: Mon Sep 17, 2007 12:35 pm Post subject: EFIS as only reference???

Good Afternoon Bruce, 

  

 A standard needle and ball Turn and Bank instrument is more reliable,  lighter, and cheaper than any attitude gyro.

  

 Even the crummy Turn Coordinator is cheaper, lighter, and more reliable  than the Attitude Gyro, but not quite as reliable as the T&B.

  

 While I certainly expect someone to design a more modern rate of turn  instrument, the T&B is still the best safety instrument you can have on the  airplane.

  

 Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503



  

 In a message dated 9/17/2007 2:25:14 P.M. Central Daylight Time,  Bruce(at)glasair.org writes:

  	  Quote: 	
		  Give me    a vacuum backup AI gyro and all you'll have left is a dark and

stormy night    story.



Bruce

	


 



See what's new at AOL.com and Make AOL Your Homepage.

  [quote][b]

LloydDR(at)wernerco.com
Guest

Posted: Mon Sep 17, 2007 12:45 pm Post subject: EFIS as only reference???

While with an older, certified plane the first thing you would do is

turn off the mater, in today's properly designed electrical system that

is the last thing you would do. A checklist with the proper steps

identified will help you properly identify the offending circuit and

solve the situation without going dark or engineless.



I also second what Dj is stating, if you build your electrically

dependant panel/ engine correctly you will not have an issue such as the

one described. My panel is such that I select essential and the

engine/prop controller and fuel pump stay on, everything else is dumped.

Then I have a fully charged Dynon, fully charged 496, and a fully

charged handheld radio to continue the flight with, and following my

checklist I can begin to bring systems back on line until I find the

offending circuit.

The key to flying glass is redundancy, with backup power, and the proper

training to understand the systems you are working with. In the modern

day world of 'tron dependant engines, it is with Bob's and others help

that we will build robust electrical systems that will support the

mission for each builder. The experimental category is there for us to

learn, and lamb basting a fellow builder for their choice solves

nothing. But educating them on the associated risks and helping

determine the best backup solutions is better. 

But more importantly just doing things one way because that is the way

we always have done it is ridiculous and counter productive to what we

are trying to accomplish in the experimental world. Rather it is us

crazy builders who continue to push the envelope that make progress, and

with well thought out plans and the proper execution it is done safely,

or at least safely as can be.

Dan

N289DT RV10E

 



--

deej(at)deej.net
Guest

Posted: Mon Sep 17, 2007 1:22 pm Post subject: EFIS as only reference???

Bruce Gray wrote:

 	  Quote: 	
		   You need a backup AI powered by a different

 system. It's so much easier to hit one switch (the master) and then go

 through your rational trouble shooting procedure or better yet, wait to do

 it on the ground.

   


	


    I agree, but that backup AI can be another EFIS from a different

manufacturer, with its own internal battery, on a backup electrical

system.  It does not need to be vacuum gauges.



    In an electrically dependent airplane, having a single switch that

can fail and take out your entire electrical system is a Bad Design.  In

a non-electrically dependent airplane, it doesn't matter as much.



    I don't think it is terribly difficult to design a safe, reliable

and redundant electrical system for an electrically dependent airplane. 

That is, after all, one of the primary discussion points for this

mailing list...  



-Dj

do not archive



-- 

Dj Merrill - N1JOV

Glastar Sportsman 2+2 Builder #7118 N421DJ

http://econ.duke.edu/~deej/sportsman/



"Many things that are unexplainable happen during the construction of an 

airplane."  --Dave Prizio, 30 Aug 2005

rvbuilder(at)sausen.net
Guest

Posted: Mon Sep 17, 2007 1:29 pm Post subject: EFIS as only reference???

Hmmm, the P-Mag doesn't have the best operational history yet.  There are better ways to mitigate power failure to an all electric aircraft.  If it's still a concern I would suggest a standard mag over a p-mag.



Michael Sausen

RV-10



--

deej(at)deej.net
Guest

Posted: Mon Sep 17, 2007 1:29 pm Post subject: EFIS as only reference???

Ernest Christley wrote:

 	  Quote: 	
		  



 But...2 minutes to reboot?  I thought the Grand Rapids was

 ridiculously long at 30 seconds or so (don't remember exactly).  The

 Dynon comes up and orients itself fast enough not to matter.


	


Hi Ernest,

    Actually, some of the EFIS units do take 2 minutes to calibrate

(time from power up until they are useful).  Items like this need to be

taken into account in the design of the system and associated failure

modes and emergency checklists. 



    I agree completely with Bruce that backups are necessary, and

emergency responses should be easy and not require significant thought. 

I just don't agree that it needs to be done with vacuum gauges...   

Proper design and training is the key.



-Dj

do not archive



-- 

Dj Merrill - N1JOV

Glastar Sportsman 2+2 Builder #7118 N421DJ

http://econ.duke.edu/~deej/sportsman/



"Many things that are unexplainable happen during the construction of an 

airplane."  --Dave Prizio, 30 Aug 2005

rvbuilder(at)sausen.net
Guest

Posted: Mon Sep 17, 2007 1:30 pm Post subject: EFIS as only reference???

Hope you have a flashlight out and on to see that gyro!  



Do not archive



--

deej(at)deej.net
Guest

Posted: Mon Sep 17, 2007 1:42 pm Post subject: EFIS as only reference???

RV Builder (Michael Sausen) wrote:

 	  Quote: 	
		   



 Hope you have a flashlight out and on to see that gyro!  



 Do not archive

   


	


    Seriously, though, how about a backup battery on the lighting for

the gyro, with its own separate power switch?  If everything else goes

dark, you'd still be able to see and use your vacuum powered backup AI

without fumbling in the dark for a light.  Or you could just always wear

a clip-on mic light, and have it as a part of your night-flying

preflight checklist.



-Dj

do not archive



-- 

Dj Merrill - N1JOV

Glastar Sportsman 2+2 Builder #7118 N421DJ

http://econ.duke.edu/~deej/sportsman/



"Many things that are unexplainable happen during the construction of an 

airplane."  --Dave Prizio, 30 Aug 2005

mlas(at)cox.net
Guest

Posted: Mon Sep 17, 2007 2:43 pm Post subject: EFIS as only reference???

Ron,



I can name many airplanes that have EFIS only and are certified under

part 25.  The newer Airbus A318, 319, 320, 321, 330, 340, 380 and the

Boeing 777 just to name a few.  Take a close at the newest stuff, the

backup is now an EFIS display.



Mike Larkin



--

nghertner(at)verizon.net
Guest

Posted: Mon Sep 17, 2007 4:36 pm Post subject: EFIS as only reference???

As DJ probably knows from the Glasair user group, I slowly became a Bruce

Gray convert, particularly after I had a gyro failure on my Blue Mountain

EFIS/one and a complete and sudden failure with my "backup" Dynon D10. I

have backup standard instruments but the failure of both EFIS's did occur.

And that was on the ground.

Lory Ghertner

 	  Quote: 	

 Bruce Gray wrote:

> 

> 

> I can see you flying along, solid IMC with a happy smile on you face when

> all of a sudden you sniff that odor that all of us fear - smoke. The pungent

> smell of burning insulation hits your nose. What's the first thing you do?

> Hit the master switch and turn all electrical off, Woops, gota fly the

>   

   In an all-electric airplane (including the engine computer), that

 would not be the prudent procedure.  You have two independent electrical

 sources, each separately controlled, PLUS each EFIS has its own internal

 battery backup.  You don't turn both of your EFIS units or both

 electrical systems off at the same time, that would be a bit foolish.

 You turn one electrical system off, and if the smoke does not stop, you

 turn the first back on the the other off.  The most important thing is

 not to lose your head, that's where the proper training comes in.

   Give me a properly wired airplane and training on how to use it, and

 all you'll have left is a dark and stormy night story.

 -Dj

 do not archive

Mark Phillips in TN

Joined: 10 Jan 2006
Posts: 431
Location: Columbia, TN

Posted: Mon Sep 17, 2007 5:35 pm Post subject: EFIS as only reference???

In a message dated 09/17/2007 12:53:45 PM Central Daylight Time, flyboyron(at)gmail.com writes:

  	  Quote: 	
		  In other words, if you do have, say an internal power supply failure, or 

complete display failure in your EFIS system, what is your plan? 	


 >>>

  

 Trutrak ADI.

  

 However, with Z architecture, it will likely always be a panel ornament, but it is still there, JIC...

  

 Mark do not archive



See whattarget="_blank">Make AOL Your Homepage.

  [quote][b]

_________________
From The PossumWorks...

deej(at)deej.net
Guest

Posted: Mon Sep 17, 2007 5:48 pm Post subject: EFIS as only reference???

Nancy Ghertner wrote:

 	  Quote: 	
		   

 

 As DJ probably knows from the Glasair user group, I slowly became a Bruce

 Gray convert, particularly after I had a gyro failure on my Blue Mountain

 EFIS/one and a complete and sudden failure with my "backup" Dynon D10. I

 have backup standard instruments but the failure of both EFIS's did occur.

 And that was on the ground.


	


Hi Lory,

	Are you saying that both the Dynon and the Blue Mountain unit failed at

the same exact time?



-Dj

do not archive



-- 

Dj Merrill

Sportsman 2+2 Builder #7118

http://econ.duke.edu/~deej/sportsman/



"Many things that are unexplainable happen during the construction of an

airplane."  --Dave Prizio, 30 Aug 2005

Dave(at)AirCraftersLLC.co
Guest

Posted: Mon Sep 17, 2007 9:30 pm Post subject: EFIS as only reference???

Can you describe what happened to the D10?  That's my intended backup too.



Dave Saylor

AirCrafters LLC

140 Aviation Way

Watsonville, CA 

831-722-9141

831-750-0284 CL

www.AirCraftersLLC.com

 



--

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours Goto page 1, 2, 3 Next
Page 1 of 3

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum