Avionics-List Digest Archive

Tue 04/22/08


Total Messages Posted: 3



Today's Message Index:
----------------------
 
     1. 06:26 AM - Encoding Altimeter ()
     2. 03:06 PM - Re: Encoding Altimeter (Charles Reiche)
     3. 06:54 PM - Re: Encoding Altimeter (William Gill)
 
 
 


Message 1


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    Time: 06:26:48 AM PST US
    From: <bakerocb@cox.net>
    Subject: Encoding Altimeter
    4/22/2008 Hello Bill, Thanks for your input. You wrote: 1) "OR...you could buy a Dynon ........." Since the Dynon units do not contain a TSO'd altitude encoder operating the Dynon unit alone to feed a transponder in flight would presently leave one in violation of FAR Sec 91.217 (as interpreted by FAA HQ). There are two ways to approach this condition: A) Purchase and install a separate TSO'd altitude encoder and use that encoder to feed the aircraft's transponder. B) Decide that violation of 91.217 is an acceptable risk and feed the transponder from the non TSO'd altitude encoder contained in the Dynon unit. 2) ".....and save even more during the IFR recertification check." My local avionics shop charges a flat fee for the FAR Sections 91.411 and 91.413 required testing. This fee has been the same no matter whether I do the labor of removing and reinstalling the altimeter and TSO'd altitude encoder, for bench testing and any adjustments needed prior to the airplane side testing, or they do that labor. (By the way, four years ago that flat fee was $150, now it is $300.) 3) "........the avionics shops actually prefer the Dynon due to their accuracy and simplicity." I hope that the avionics shops continue this practice without any regard for what FAR Sec 91.217 says. 4) ".......the avionics shops actually prefer the Dynon due to their accuracy and simplicity." I wonder about the complexity of removing and reinstalling an EFIS from the airplane compared to the complexity of removing and reinstalling an altimeter and separate TSO'd altitude encoder should any bench testing and adjusting be needed. A) Maybe EFIS removal and reinstallation is no big deal, but I envision a bunch of connections, particularly if it is the type of EFIS that also includes displaying engine performance parameters. B) Maybe the EFIS's have no means of local avionics shop adjustment. C) Maybe the EFIS's would never need adjustment. D) What has been the experience of EFIS operators that have actually been through FAR 91.411 and 91.413 checks, as appropriate, after flying for at least two years? Would any EFIS owners and operators care to comment on these points?. 'OC' Says: "The best investment we can make is the effort to gather and understand knowledge." --------------------------------------------------- Time: 09:05:34 PM PST US From: "William Gill" <wgill10@comcast.net> Subject: RE: Avionics-List: Encoding Altimeter OR...you could buy a Dynon and save even more during the IFR recertification check. In fact, the avionics shops actually prefer the Dynon due to their accuracy and simplicity. Bill


    Message 2


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    Time: 03:06:18 PM PST US
    From: "Charles Reiche" <reichec@verizon.net>
    Subject: Re: Encoding Altimeter
    I have no experience with the dynon other than I want my friend to put one in his rv7. But I can tell you that in installations such as this and like the G1000, its easier to certify devices in the airplane rather than removing them so you can be using whatever its readout is to certify it. I have run across one GDC 74A (Garmin g1000 air data computer) that failed a test point just slightly out of spec but garmin allows us to recalibrate and electrically slide the scale so everything is within spec all the way up. Remember that down low the tolerance is +/- 20 feet for altimeter certification and up over 20k its well over +/- 100 feet. Mechanical altimeters can and do sway their actual reading all over the place up at altitude, and generally the air data computer tpye devices are pretty darn close. YMMV Charlie ----- Original Message ----- From: <bakerocb@cox.net> <wgill10@comcast.net> Sent: Tuesday, April 22, 2008 9:23 AM Subject: Avionics-List: Encoding Altimeter > > 4/22/2008 > > Hello Bill, Thanks for your input. You wrote: > > 1) "OR...you could buy a Dynon ........." > > Since the Dynon units do not contain a TSO'd altitude encoder operating > the Dynon unit alone to feed a transponder in flight would presently leave > one in violation of FAR Sec 91.217 (as interpreted by FAA HQ). There are > two ways to approach this condition: > > A) Purchase and install a separate TSO'd altitude encoder and use that > encoder to feed the aircraft's transponder. > > B) Decide that violation of 91.217 is an acceptable risk and feed the > transponder from the non TSO'd altitude encoder contained in the Dynon > unit. > > 2) ".....and save even more during the IFR recertification check." > > My local avionics shop charges a flat fee for the FAR Sections 91.411 and > 91.413 required testing. This fee has been the same no matter whether I do > the labor of removing and reinstalling the altimeter and TSO'd altitude > encoder, for bench testing and any adjustments needed prior to the > airplane side testing, or they do that labor. (By the way, four years ago > that flat fee was $150, now it is $300.) > > 3) "........the avionics shops actually prefer the Dynon due to their > accuracy and simplicity." > > I hope that the avionics shops continue this practice without any regard > for what FAR Sec 91.217 says. > > 4) ".......the avionics shops actually prefer the Dynon due to their > accuracy and simplicity." > > I wonder about the complexity of removing and reinstalling an EFIS from > the airplane compared to the complexity of removing and reinstalling an > altimeter and separate TSO'd altitude encoder should any bench testing and > adjusting be needed. > > A) Maybe EFIS removal and reinstallation is no big deal, but I envision a > bunch of connections, particularly if it is the type of EFIS that also > includes displaying engine performance parameters. > > B) Maybe the EFIS's have no means of local avionics shop adjustment. > > C) Maybe the EFIS's would never need adjustment. > > D) What has been the experience of EFIS operators that have actually been > through FAR 91.411 and 91.413 checks, as appropriate, after flying for at > least two years? > > Would any EFIS owners and operators care to comment on these points?. > > 'OC' Says: "The best investment we can make is the effort to gather and > understand knowledge." > > --------------------------------------------------- > > Time: 09:05:34 PM PST US > From: "William Gill" <wgill10@comcast.net> > Subject: RE: Avionics-List: Encoding Altimeter > > > OR...you could buy a Dynon and save even more during the IFR > recertification check. In fact, the avionics shops actually prefer the > Dynon due to their accuracy and simplicity. > > Bill > > >


    Message 3


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    Time: 06:54:37 PM PST US
    From: "William Gill" <wgill10@comcast.net>
    Subject: Encoding Altimeter
    I have the Dynon and a mechanical altimeter...both remained in the plane for testing and both altimeters met the requirements. However, the transponder was removed for bench testing. Bill -----Original Message----- From: owner-avionics-list-server@matronics.com [mailto:owner-avionics-list-server@matronics.com] On Behalf Of Charles Reiche Sent: Tuesday, April 22, 2008 5:02 PM Subject: Re: Avionics-List: Encoding Altimeter <reichec@verizon.net> I have no experience with the dynon other than I want my friend to put one in his rv7. But I can tell you that in installations such as this and like the G1000, its easier to certify devices in the airplane rather than removing them so you can be using whatever its readout is to certify it. I have run across one GDC 74A (Garmin g1000 air data computer) that failed a test point just slightly out of spec but garmin allows us to recalibrate and electrically slide the scale so everything is within spec all the way up. Remember that down low the tolerance is +/- 20 feet for altimeter certification and up over 20k its well over +/- 100 feet. Mechanical altimeters can and do sway their actual reading all over the place up at altitude, and generally the air data computer tpye devices are pretty darn close. YMMV Charlie ----- Original Message ----- From: <bakerocb@cox.net> <wgill10@comcast.net> Sent: Tuesday, April 22, 2008 9:23 AM Subject: Avionics-List: Encoding Altimeter > > 4/22/2008 > > Hello Bill, Thanks for your input. You wrote: > > 1) "OR...you could buy a Dynon ........." > > Since the Dynon units do not contain a TSO'd altitude encoder operating > the Dynon unit alone to feed a transponder in flight would presently leave > one in violation of FAR Sec 91.217 (as interpreted by FAA HQ). There are > two ways to approach this condition: > > A) Purchase and install a separate TSO'd altitude encoder and use that > encoder to feed the aircraft's transponder. > > B) Decide that violation of 91.217 is an acceptable risk and feed the > transponder from the non TSO'd altitude encoder contained in the Dynon > unit. > > 2) ".....and save even more during the IFR recertification check." > > My local avionics shop charges a flat fee for the FAR Sections 91.411 and > 91.413 required testing. This fee has been the same no matter whether I do > the labor of removing and reinstalling the altimeter and TSO'd altitude > encoder, for bench testing and any adjustments needed prior to the > airplane side testing, or they do that labor. (By the way, four years ago > that flat fee was $150, now it is $300.) > > 3) "........the avionics shops actually prefer the Dynon due to their > accuracy and simplicity." > > I hope that the avionics shops continue this practice without any regard > for what FAR Sec 91.217 says. > > 4) ".......the avionics shops actually prefer the Dynon due to their > accuracy and simplicity." > > I wonder about the complexity of removing and reinstalling an EFIS from > the airplane compared to the complexity of removing and reinstalling an > altimeter and separate TSO'd altitude encoder should any bench testing and > adjusting be needed. > > A) Maybe EFIS removal and reinstallation is no big deal, but I envision a > bunch of connections, particularly if it is the type of EFIS that also > includes displaying engine performance parameters. > > B) Maybe the EFIS's have no means of local avionics shop adjustment. > > C) Maybe the EFIS's would never need adjustment. > > D) What has been the experience of EFIS operators that have actually been > through FAR 91.411 and 91.413 checks, as appropriate, after flying for at > least two years? > > Would any EFIS owners and operators care to comment on these points?. > > 'OC' Says: "The best investment we can make is the effort to gather and > understand knowledge." > > --------------------------------------------------- > > Time: 09:05:34 PM PST US > From: "William Gill" <wgill10@comcast.net> > Subject: RE: Avionics-List: Encoding Altimeter > > > OR...you could buy a Dynon and save even more during the IFR > recertification check. In fact, the avionics shops actually prefer the > Dynon due to their accuracy and simplicity. > > Bill > > >




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