X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 12 Aug 2011 09:05:33 -0400 Message-ID: X-Original-Return-Path: Received: from imr-da06.mx.aol.com ([205.188.169.203] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5089491 for lml@lancaironline.net; Thu, 11 Aug 2011 18:40:13 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.169.203; envelope-from=vtailjeff@aol.com Received: from mtaomg-da04.r1000.mx.aol.com (mtaomg-da04.r1000.mx.aol.com [172.29.51.140]) by imr-da06.mx.aol.com (8.14.1/8.14.1) with ESMTP id p7BMdUge006912 for ; Thu, 11 Aug 2011 18:39:30 -0400 Received: from core-mnc004a.r1000.mail.aol.com (core-mnc004.r1000.mail.aol.com [172.29.106.205]) by mtaomg-da04.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 553D9E00008D for ; Thu, 11 Aug 2011 18:39:29 -0400 (EDT) References: X-Original-To: lml@lancaironline.net Subject: Re: [LML] Re: Re-doing my panel - carefully thinking through failures X-AOL-IP: 75.33.127.82 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: vtailjeff@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CE268EAA538D8D_1960_E6FC7_webmail-d066.sysops.aol.com" X-Mailer: AOL Webmail 34007-STANDARD Received: from 75.33.127.82 by webmail-d066.sysops.aol.com (205.188.59.131) with HTTP (WebMailUI); Thu, 11 Aug 2011 18:39:29 -0400 X-Original-Message-Id: <8CE268EAA1F2EF5-1960-56912@webmail-d066.sysops.aol.com> X-Originating-IP: [75.33.127.82] X-Original-Date: Thu, 11 Aug 2011 18:39:29 -0400 (EDT) x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:433097824:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d338c4e445a210e6c This is a multi-part message in MIME format. ----------MB_8CE268EAA538D8D_1960_E6FC7_webmail-d066.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" its not whether one will fail or not but whether BOTH will fail at the same= time! -----Original Message----- From: GT Phantom To: lml Sent: Thu, Aug 11, 2011 3:33 pm Subject: [LML] Re: Re-doing my panel - carefully thinking through failures A point that has not been brought up by the proponents of spinning mass is = the fact that their degradation modes are often far more insidious / undete= ctable than power failure or EFIS failure. Whether powered by vacuum or by electrons, spinning gyros can become "insid= iously inaccurate" for a number of reasons. Off flags meant to warn of suc= h problems fail. Gyros may retain some spin, but gently wobble (or be simp= ly wrong). Stopped gyros still display some attitude, even if wrong. Each of these modes of failure are common, and have resulted in deaths. I will not even attempt to argue which is "more likely" - EFIS or gyro fail= ure - simply pointing out that both have failure modes which render them in= accurate (or worse, appear to be accurate). As someone else pointed out, these days often the most likely piece of equi= pment to become unreliable in flight is the Mk I brain. Thanks to your tax contributions, I received more comprehensive flight trai= ning than most of you on this forum - and it instilled in me a strong sense= of responsibility to know everything about every system on my plane, inclu= ding possible degraded modes and insidious failure modes. Along with other= situations I've mentioned, I've also had the displeasure of flying a Phant= om home in the soup over the North Atlantic with only my turn and bank and = a ground controller calling my turns. Of all the arguments for a spinning = gyro, I think I'd buy one for an electric T&B over an electric AI, because = it is only attempting to tell you relative rate of rotation around your ver= tical axis and will continue to work in degraded modes. As for spinning gy= ro AIs, I've simply seen too many of them telling people to "go the wrong w= ay" to consider them "better." Not "worse," just not "better." If you want to be prepared for any possible situation in life, there is not= hing wrong with having one of every piece of equipment ever dreamed up on y= our airplane. Odds will definitely be better that way, with the dual costs= imposed both to your wallet and to your obligation as a responsible pilot = to completely know, and to be able to recognize and respond appropriately t= o, all of the failure modes of every piece of equipment. If, however, you = are willing to accept the 1:1,000,000 risk associated with "only" having 3 = or 4 working pieces of equipment in the aircraft, then my recommendation is= simply: Choose wisely. Fly Safe! Bill On 01/-10/-28163 02:59 PM, Gary Casey wrote:=20 I think there might be a difference of understanding regarding failure mode= s. I don=E2=80=99t think anyone is proposing that we abandon all electronic= devices and go back to vacuum-powered gyros. What is being proposed by Bre= nt (and me, I suppose) is that a vacuum-power spinning gyro is perhaps the = most reliable backup system available. How can the =E2=80=9Cleast reliable= =E2=80=9D system be the =E2=80=9Cmost reliable=E2=80=9D backup? Two reasons= : First, the spinning gyro is not susceptible to catastrophic electrical fa= ilures (like a lightning strike) and will keep running as long as the engin= e is turning. Second, it is logical to limit one=E2=80=99s thinking to =E2= =80=9Csingle failure modes=E2=80=9D. In other words the ONLY requirement of= the gyro system is that it keep working from the time of the electrical fa= ilure to the earliest possible landing. What is the likelihood that the gyr= o will fail in those 15 minutes? What is the likelihood that the electrical= system would quit and then the engine stop turning? All this is dependent = on the vacuum system being =E2=80=9Crequired equipment=E2=80=9D for IMC ope= ration (if the vacuum system fails on the ground, it is a no-go. If it fail= s in the air under IMC, it is a =E2=80=9Cland immediately=E2=80=9D conditio= n). The poorest choice for a primary system then becomes the best choice as a b= ackup. Logical, I think. Gary Casey From: GT Phantom=20 Sent: Tuesday, August 09, 2011 5:55 AM To: lml@lancaironline.net=20 Subject: Re: Re: Re-doing my panel - carefully thinking through failures Brent, I suppose I should have been more specific - I assume that pilots of experi= mental aircraft will exercise sufficient judgment not be flying into thunde= rstorms, and thus the likelihood of in-flight lightning strike is nearly ni= l. Not absolutely nil, naturally, but approaching or below the likelihood o= f vacuum failure, which is fairly common. Of course, perhaps I should not m= ake such an assumption given that a very famous pilot died just last year f= lying his Bonanza into thunderstorms. Absent thunderstorms, we will simply have to agree to disagree. Vacuum pump= s and vacuum-operated artificial horizons are notoriously fallible, and a p= oor vacuum can give insidious symptoms causing catastrophic results. While = there have been some experimental EFIS units (notably one you mention, also= the original pioneer Blue Mountain) which had early individual failure rat= es much higher than vacuum equipment, still the likelihood of two or more g= oing down simultaneously is rather rare. In my personal experience my TSO G= armins failed just as often as my experimental equipment - anecdotal eviden= ce, to be sure, but 3 TSO failures in 600 hrs not counting vacuum pump fail= ure and attitude indicator partial failure ("lazy" attitude, "sort of" work= ing). None of this absolves individuals contemplating use of experimental equipme= nt from the burden of research to draw their own conclusions about reliabil= ity. Your statement that TSO is required for legal flight is simply untrue. If y= ou wish to dispute this, please feel free to point out the section of the F= ARs that you believe says otherwise (it does not exist, but knock yourself = out). I don't expect to convince you of that; it seems that there are some = folks who have made up their minds and aren't interested in anyone else's o= pinion. That's fine, you are entitled to yours. I, like many, have reviewed= the pertinent FARs along with (among others) my mechanic who was a chief a= vionics safety inspector for a major airline. For the type of flying for wh= ich Experimental aircraft are authorized there is no such rule stating that= each piece of equipment must be certified to pass TSO. The altimeter must,= or pass the test for equivalent accuracy (performed during the annual pito= t-static check). Doesn't mean it's a bad thing, only unnecessary for legal = flight. Just as you admonish people who are not engineers (I too was a soft= ware engineer by trade) to form unwarranted opinions about avionics, you to= o should not consider yourself an expert on FARs simply because you build a= vionics. Glass houses, etc. Blocked pitot or static tubes are no longer a killer for correct attitude i= ndication on any of the three leading experimental EFIS units (GRT, Dynon, = MGL). May also not be on others, haven't kept up. Of course, you will not g= et accurate airspeed with either blocked and will not get accurate barometr= ic altitude with static blocked, but that would happen irrespective of the = type of avionics you use. However, you will still have accurate horizon, an= d GPS can provide altitude and ground speed which, combined with a pilot's = knowledge of their aircraft power settings, etc. should enable you to fly s= afely to landing.=20 At the end of the day, you are putting your own life on the line. If you fe= el more comfortable with spinning gyros, by all means load up. However, if = you feel you have done your research and would rather replace that vacuum p= ump for a second alternator to prevent power-out and ditch the gyro for a s= mall self-contained backup EFIS, then your odds of total failure will ultim= ately be about the same - just different causes. Fly safe! Bill On 01/-10/-28163 02:59 PM, Brent Regan wrote:=20 Bill speculates: <> The primary assumption here is false. It is not "given" that "two EFIS unit= s with battery backup are more reliable than a single vacuum pump". Analysi= s and data show the opposite is true.=20 -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html ----------MB_8CE268EAA538D8D_1960_E6FC7_webmail-d066.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" its not whether one will fa= il or not but whether BOTH will fail at the same time!



= -----Original Message-----
From: GT Phantom <gt_phantom@hotmail.com>
To: lml <lml@lancaironline.net>
Sent: Thu, Aug 11, 2011 3:33 pm
Subject: [LML] Re: Re-doing my panel - carefully thinking through failures<= br>
A point that ha= s not been brought up by the proponents of spinning mass is the fact that t= heir degradation modes are often far more insidious / undetectable than pow= er failure or EFIS failure.

Whether powered by vacuum or by electrons, spinning gyros can become "insid= iously inaccurate" for a number of reasons.  Off flags meant to warn o= f such problems fail.  Gyros may retain some spin, but gently w= obble (or be simply wrong).  Stopped gyros still display some a= ttitude, even if wrong.

Each of these modes of failure are common, and have resulted in deaths.

I will not even attempt to argue which is "more likely" - EFIS or gyro fail= ure - simply pointing out that both have failure modes which render them in= accurate (or worse, appear to be accurate).

As someone else pointed out, these days often the most likely piece of equi= pment to become unreliable in flight is the Mk I brain.

Thanks to your tax contributions, I received more comprehensive flight trai= ning than most of you on this forum - and it instilled in me a strong sense= of responsibility to know everything about every system on my plane, inclu= ding possible degraded modes and insidious failure modes.  Along with = other situations I've mentioned, I've also had the displeasure of flying a = Phantom home in the soup over the North Atlantic with only my turn and bank= and a ground controller calling my turns.  Of all the arguments for a= spinning gyro, I think I'd buy one for an electric T&B over an electri= c AI, because it is only attempting to tell you relative rate of rot= ation around your vertical axis and will continue to work in degraded modes= .  As for spinning gyro AIs, I've simply seen too many of them telling= people to "go the wrong way" to consider them "better."  Not "worse,"= just not "better."

If you want to be prepared for any possible situation in life, there is not= hing wrong with having one of every piece of equipment ever dreamed up on y= our airplane.  Odds will definitely be better that way, with the dual = costs imposed both to your wallet and to your obligation as a responsible p= ilot to completely know, and to be able to recognize and respond appropriat= ely to, all of the failure modes of every piece of equipment.  If, how= ever, you are willing to accept the 1:1,000,000 risk associated with "only"= having 3 or 4 working pieces of equipment in the aircraft, then my recomme= ndation is simply: Choose wisely.

Fly Safe!

Bill



On 01/-10/-28163 02:59 PM, Gary Casey wrote:=20
I think there might be a difference of understanding regarding failure= modes. I don=E2=80=99t think anyone is proposing that we abandon all elect= ronic devices and go back to vacuum-powered gyros. What is being proposed b= y Brent (and me, I suppose) is that a vacuum-power spinning gyro is perhaps= the most reliable backup system available. How can the =E2=80=9Cleast reli= able=E2=80=9D system be the =E2=80=9Cmost reliable=E2=80=9D backup? Two rea= sons: First, the spinning gyro is not susceptible to catastrophic electrica= l failures (like a lightning strike) and will keep running as long as the e= ngine is turning. Second, it is logical to limit one=E2=80=99s thinking to = =E2=80=9Csingle failure modes=E2=80=9D. In other words the ONLY requirement= of the gyro system is that it keep working from the time of the electrical= failure to the earliest possible landing. What is the likelihood that the = gyro will fail in those 15 minutes? What is the likelihood that the electri= cal system would quit and then the engine stop turning? All this is depende= nt on the vacuum system being =E2=80=9Crequired equipment=E2=80=9D for IMC = operation (if the vacuum system fails on the ground, it is a no-go. If it f= ails in the air under IMC, it is a =E2=80=9Cland immediately=E2=80=9D condi= tion).
The poorest choice for a primary system then becomes the best choice a= s a backup. Logical, I think.
Gary Casey
From: GT Phantom
Sent: Tuesday, August 09, 2011 5:55 AM
Subject: Re: Re: Re-doing my panel - carefully thinking through= failures
Brent,

I suppose I should have been more specific - I assume that pilots of experi= mental aircraft will exercise sufficient judgment not be flying into thunde= rstorms, and thus the likelihood of in-flight lightning strike is nearly ni= l. Not absolutely nil, naturally, but approaching or below the likelihood o= f vacuum failure, which is fairly common. Of course, perhaps I should not m= ake such an assumption given that a very famous pilot died just last year f= lying his Bonanza into thunderstorms.

Absent thunderstorms, we will simply have to agree to disagree. Vacuum pump= s and vacuum-operated artificial horizons are notoriously fallible, and a p= oor vacuum can give insidious symptoms causing catastrophic results. While = there have been some experimental EFIS units (notably one you mentio= n, also the original pioneer Blue Mountain) which had early individual fail= ure rates much higher than vacuum equipment, still the likelihood of two or= more going down simultaneously is rather rare. In my personal experience m= y TSO Garmins failed just as often as my experimental equipment - anecdotal= evidence, to be sure, but 3 TSO failures in 600 hrs not counting vacuum pu= mp failure and attitude indicator partial failure ("lazy" attitude, "sort o= f" working).

None of this absolves individuals contemplating use of experimental equipme= nt from the burden of research to draw their own conclusions about reliabil= ity.

Your statement that TSO is required for legal flight is simply untrue. If y= ou wish to dispute this, please feel free to point out the section of the F= ARs that you believe says otherwise (it does not exist, but knock yourself = out). I don't expect to convince you of that; it seems that there are some = folks who have made up their minds and aren't interested in anyone else's o= pinion. That's fine, you are entitled to yours. I, like many, have reviewed= the pertinent FARs along with (among others) my mechanic who was a chief a= vionics safety inspector for a major airline. For the type of flying for wh= ich Experimental aircraft are authorized there is no such rule stating that= each piece of equipment must be certified to pass TSO. The altimeter must,= or pass the test for equivalent accuracy (performed during the annual pito= t-static check). Doesn't mean it's a bad thing, only unnecessary for legal = flight. Just as you admonish people who are not engineers (I too was a soft= ware engineer by trade) to form unwarranted opinions about avionics, you to= o should not consider yourself an expert on FARs simply because you build a= vionics. Glass houses, etc.

Blocked pitot or static tubes are no longer a killer for correct attitude i= ndication on any of the three leading experimental EFIS units (GRT, Dynon, = MGL). May also not be on others, haven't kept up. Of course, you will not g= et accurate airspeed with either blocked and will not get accurate barometr= ic altitude with static blocked, but that would happen irrespective of the = type of avionics you use. However, you will still have accurate horizon, an= d GPS can provide altitude and ground speed which, combined with a pilot's = knowledge of their aircraft power settings, etc. should enable you to fly s= afely to landing.

At the end of the day, you are putting your own life on the line. If you fe= el more comfortable with spinning gyros, by all means load up. However, if = you feel you have done your research and would rather replace that vacuum p= ump for a second alternator to prevent power-out and ditch the gyro for a s= mall self-contained backup EFIS, then your odds of total failure will ultim= ately be about the same - just different causes.


Fly safe!

Bill


On 01/-10/-28163 02:59 PM, Brent Regan wrote:=20
Bill speculates:
<<Given that two EFIS units with battery backup are more reliable tha= n a single vacuum pump, your argument that people must have "TSO'd" = equipment is logically ridiculous - especially if they also have as = part of their panel an independent 2-axis autopilot.>>

The primary assumption here is false. It is not "given" that "two EFIS unit= s with battery backup are more reliable than a single vacuum pump". Analysi= s and data show the opposite is true.


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