> Why do you suggest that having an EFIS display (or two on separate busses) and a backup electrical gyro or T&B is any more unsafe than the traditional setup of a vacuum gyro and an electric T&B? This of course assumes that your exp has a very robust and redundant dual batt/dual alt electrical system with separate busses. I am a proponent of the all-electric panel and do not beleive that the vacuum backup is any better than dual electric systems...just to add that to the equation. Are you implying that all the certified and tested Cessnas/Pipers/Diamonds out there will not give you an acceptable level of safety with their traditional setup? Now I digress.... BTW, I don't think you are a fool, quite the contrary actually...I just think that having developed the CFS system and having tested it for certification, you're very aware of the risks inherent in using such a system and maybe you focus on them more than the rest of us. Obviously, you're quite biased towards CFS as it's the only unit out there that's actually been tested. Who could argue with that if you've got the cash? But how likely are we to see all or any of the conditions that you tested for? The military routinely pays extravagant amounts for parts that need to be certified/tested to extreme levels regardless of their intended use, but is it always necessary? Did we really need the MILSPEC hammer and the MILSPEC toilet? Many times the answer would be yes but just as often it might be no! Only the individual builder/pilot can say for sure how much risk he/she is willing to accept and how much the perceived benefit of EFIS really is to them. I will be very happy if my CFS EFIS survives that lightning strike, but if it's not my lucky day and my fiberglass tail gets melted off in the process.... then it may not matter to me much anymore that my EFIS is telling me I'm upside down headed toward the ground at 300 knots. There are many systems on our planes that are NOT redundant and will cause certain death if failure occurs; yet we don't worry about them very often. I think that even some of the untested EFIS units out there may be more reliable than my Lycoming up front! Will I die if my engine quits? Not necessarily, but it's possible. Will I die if my EFIS quits? Not necessarily, but again, it's certainly possible given the right circumstances. How much training has the pilot had. As for me I have thousands of hours of instrument training on steam gauges and plenty of partial panel, so I feel relatively confident...BUT you (or I) could always be led astray by the partial attitude failure or the display of incorrect or partial data (despite all the best training in the world). There is a first-hand account by a shuttle astronaut crew who experienced an unplanned attitude gyro failure during a landing scenario practice sim. The only malfunction was in the attitude indicator and it was simply displaying incorrect attitude information. You guessed it. They got themselves into an unrecoverable situation before they realized what the problem was...good thing it was only the sim. The Airbus that crashed last year due to the "rudder swap" also comes to mind, speaking of the inherent risk in flying. No amount of testing will prevent you from crashing if your vertical stab falls off. Would you agree that many of the less severe problems will eventually be found and fixed on the "untested" units? Barring a lawsuit that puts the company outof business, I tend to think that most problems will eventually surface. If you fly IMC with your "untested" unit before this and before you have complete faith in it and before there is an acceptable amount of flight experience with it, then you're asking for trouble, IMHO. I don't know the numbers but I vaguely recall from one of my CRM classes that most accidents are caused by pilot error, not aircraft malfunctions....maybe this will change in the future if planes start crashing due to EFIS problems. But compared to the other risks that we live with every day, how does this risk stack up? That's the question we need to answer before we go spend a year's worth of pay on an EFIS system. Yes I know for some out there it may only be a few days/weeks worth but for the rest of us (gov't employees) it's a lot of $$$! I would never intentionally put my family (or yours or Brent's for that matter) at risk for a few dollars, but the risk here needs to be defined and compared to other risks that we blindly accept each time we raise the gear handle. Don't worry Brent - I won't be flying my plane for a long time...plenty of time to find some of those problems. So you can still go outside and enjoy the mountains or whatever! When I do start flying though, watch out because I know exactly who I want to put my EFIS through it's paces...I'm heading straight for Coeur d'Alene and your little strip! Regards, Brian Shannon --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.525 / Virus Database: 322 - Release Date: 10/9/2003 ------=_NextPart_000_0028_01C39368.E4AF2030 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Thanks=20 Brent...great reply to my post - now we're getting to the real = issue. =20 Obviously I wasn't really confused, but I'm glad you elaborated on the = subject=20 anyway! I think all of us would advocate further testing of the = EFIS units=20 we are interested in. I am curious about this statement=20 though:

<<Having a "Primary" electric gyro may = keep you=20 legal but it may not keep you safe.>>

Why do = you suggest=20 that having an EFIS display (or two on separate busses) and a = backup=20 electrical gyro or T&B is any more unsafe than the traditional = setup of=20 a vacuum gyro and an electric T&B? This of course assumes that = your=20 exp has a very robust and redundant dual batt/dual alt electrical = system=20 with separate busses. I am a proponent of the all-electric panel = and do=20 not beleive that the vacuum backup is any better than dual electric=20 systems...just to add that to the equation. Are you implying = that=20 all the certified and tested Cessnas/Pipers/Diamonds out there will not = give you=20 an acceptable level of safety with their traditional setup? =20

Now I=20 digress....

BTW, I = don't think=20 you are a fool, quite the contrary actually...I just think that having = developed=20 the CFS system and having tested it for certification, you're very aware = of the=20 risks inherent in using such a system and maybe you focus on them more = than the=20 rest of us. Obviously, you're quite biased towards CFS as it's the = only=20 unit out there that's actually been tested. Who could argue with = that if=20 you've got the cash? But how likely are we to see all or any of = the=20 conditions that you tested for? The military routinely pays = extravagant=20 amounts for parts that need to be certified/tested to extreme levels = regardless=20 of their intended use, but is it always necessary? Did we = really need=20 the MILSPEC hammer and the MILSPEC toilet? Many times the answer = would be=20 yes but just as often it might be no! Only the individual=20 builder/pilot can say for sure how much risk he/she is willing to accept = and how=20 much the perceived benefit of EFIS really is to=20 them.

I will = be very happy=20 if my CFS EFIS survives that lightning strike, but if it's not my lucky = day and=20 my fiberglass tail gets melted off in the process.... then it = may not=20 matter to me much anymore that my EFIS is telling me I'm upside down = headed=20 toward the ground at 300 knots. There are many systems = on our=20 planes that are NOT redundant and will cause certain death if failure = occurs;=20 yet we don't worry about them very often. I think that even some = of the=20 untested EFIS units out there may be more reliable than my Lycoming up=20 front! Will I die if my engine quits? Not necessarily, but = it's=20 possible. Will I die if my EFIS quits? Not necessarily, but = again,=20 it's certainly possible given the right circumstances. How much = training=20 has the pilot had. As for me I have thousands of hours of = instrument=20 training on steam gauges and plenty of partial panel, so I feel = relatively=20 confident...BUT you (or I) could always be led astray by the = partial=20 attitude failure or the display of incorrect or partial data = (despite all=20 the best training in the world). There is a first-hand account by = a=20 shuttle astronaut crew who experienced an unplanned attitude gyro = failure during=20 a landing scenario practice sim. The only malfunction was in the = attitude=20 indicator and it was simply displaying incorrect attitude = information. You=20 guessed it. They got themselves into an unrecoverable situation = before=20 they realized what the problem was...good thing it was only the=20 sim.

The = Airbus that=20 crashed last year due to the "rudder swap" also comes to = mind,=20 speaking of the inherent risk in flying. No amount of testing = will=20 prevent you from crashing if your vertical stab falls off. =20

Would = you agree that=20 many of the less severe problems will eventually be found and fixed on = the=20 "untested" units? Barring a lawsuit that puts the company outof = business,=20 I tend to think that most problems will eventually surface. If you = fly IMC=20 with your "untested" unit before this and before you have complete = faith in=20 it and before there is an acceptable amount of flight experience with = it, then=20 you're asking for trouble, IMHO. I don't know the numbers = but I=20 vaguely recall from one of my CRM classes that most accidents are caused = by=20 pilot error, not aircraft malfunctions....maybe this will change in = the=20 future if planes start crashing due to EFIS = problems.

But = compared to the=20 other risks that we live with every day, how does this risk stack = up? =20 That's the question we need to answer before we go spend a year's worth = of pay=20 on an EFIS system. Yes I know for some out there it may only = be a=20 few days/weeks worth but for the rest of us (gov't employees) it's a lot = of=20 $$$! I would never intentionally put my family (or yours or = Brent's for=20 that matter) at risk for a few dollars, but the risk here needs to be = defined=20 and compared to other risks that we blindly accept each time we raise = the gear=20 handle.

Don't = worry Brent -=20 I won't be flying my plane for a long time...plenty of time to find = some of=20 those problems. So you can still go outside and enjoy the = mountains or=20 whatever! When I do start flying though, watch out because I = know=20 exactly who I want to put my EFIS through it's paces...I'm heading = straight=20 for Coeur d'Alene and your little strip!

Regards,

Brian=20 Shannon

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