Today's Message Index:
----------------------
1. 04:13 AM - Encoding Altimeter ()
2. 08:01 AM - Re: Encoding Altimeter (Noel Loveys)
3. 03:34 PM - Re: Encoding Altimeter (Charles Reiche)
4. 09:05 PM - Re: Encoding Altimeter (William Gill)
Message 1
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| Subject: | Encoding Altimeter |
4/20/2008
Hello Anonymous, You wrote:
1) "You seem to be saying that the only practical way to meet the
requirements is to use a TSO'd source for the altitude information the
transponder is transmitting."
That is close. Here is how I would phrase it: "At present the only practical
way to be in compliance with FAR Section 91.217, Data Correspondence Between
Automatically Reported Pressure Altitude Data and the Pilot's Altitude
Reference, is to use a TSO'd equipment source for the altitude information
the transponder is transmitting."
2) "That, of course, would eliminate valuable functionality of many
non-TSO'd electronic EFISs including the serial output to the transponder."
Specifically, the serial altitude data output to the transponder from a non
TSO'd altitude encoder within an EFIS would not, at present, be in
compliance
with either 91.217 (b) or (c).
3) "Clearly, that isn't happening in the real world. These are selling
well."
Correct.
4) "Are you against that?"
Not at all. Here are my positions:
A) People should make informed decisions.
B) If I can provide accurate information to people that will permit them to
make informed decisions I should do so.
C) The decisions that those people make, after I have given them the best
information that I have available, is theirs to make, not mine. The risks
that they chose to take, or not take, are theirs, not mine.
D) Most of the EFIS available to the amateur built community represent a
significant improvement in performance, reliability, and safety over
previously available flight instrument technology.
E) Most of the EFIS available to the homebuilt community contain a non-TSO'd
altitude encoder that is superior in performance, reliability, granularity,
and accuracy over altitude encoding equipment that was manufactured to
versions of TSO-C88 prior to TSO-C88b.
F) Amateur built experimental aircraft have flown thousands of hours using
EFIS with non-TSO'd altitude encoders feeding their transponders with no
apparent problems.
G) Hundreds of amateur built experimental airplanes are under construction
using EFIS containing non-TSO'd altitude encoders.
H) The FAA should recognize and accept the real world conditions described
in D, E, F, and G above.
I) The best way for the FAA to accept the real world conditions described in
D, E, F, and G above is to interpret the tests required by FAR Secs 91.411
and 91.413 (as appropriate) as fulfilling the requirements of FAR Sec 91.217
(b).
J) My initial attempts to accomplish H and I above with FAA HQ were met with
resistance and I ceased activity in this regard.**
K) If the FAA, and the people / entities who perform the tests required by
91.411 / 91.413, decided that every non-TSO'd altitude encoder in an EFIS
was not airworthy because it did not meet the requirements of either 91.217
(b) or (c) this decision would be a serious blow to the amateur built
community.**
L) I do not proactively broadcast the information in K above, but if someone
asks a specific question on this issue or posts a position that I know to be
in error I revert to my positions A and B above.
M) I am open to improvements or changes in my positions.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
**PS: The FAA decision makers who perpetrated the recent fiasco involving
hundreds of airline flights being canceled and thousands of people being
stranded over the issue of the exact spacing of electrical wire cable ties
in the landing gear wheel wells of airline aircraft are capable of such
thinking and actions.
------------------------------------------------------------
----- Original Message -----
From: Anonymous
Sent: Sunday, April 20, 2008 9:20 AM
Subject: Encoding Altimeter
> OC,
>
> I don't understand what you are trying to say with your posts
> to
> the AeroElectric List. You seem to be saying that the only practical way
> to
> meet the requirements is to use a TSO'd source for the altitude
> information
> the transponder is transmitting. That, of course, would eliminate
> valuable
> functionality of many non-TSO'd electronic EFISs including the serial
> output
> to the transponder. Clearly, that isn't happening in the real world.
> These
> are selling well. Are you against that?
Anonymous
Message 2
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| Subject: | Encoding Altimeter |
One factor to remember is the operation of the encoding altimeter. To send
the correct information it needs to be set at 29.92 in. hg.. That for all
intents and purposes means you would have to either turn off your Xpndr or
have a second altimeter for lower altitudes. The big deal is every one
reports altitude to the same reference and the system as a whole operates
within parameters.
Noel
-----Original Message-----
From: owner-avionics-list-server@matronics.com
[mailto:owner-avionics-list-server@matronics.com] On Behalf Of
bakerocb@cox.net
Sent: Monday, April 21, 2008 8:40 AM
Subject: Avionics-List: Encoding Altimeter
4/20/2008
Hello Anonymous, You wrote:
1) "You seem to be saying that the only practical way to meet the
requirements is to use a TSO'd source for the altitude information the
transponder is transmitting."
That is close. Here is how I would phrase it: "At present the only practical
way to be in compliance with FAR Section 91.217, Data Correspondence Between
Automatically Reported Pressure Altitude Data and the Pilot's Altitude
Reference, is to use a TSO'd equipment source for the altitude information
the transponder is transmitting."
2) "That, of course, would eliminate valuable functionality of many
non-TSO'd electronic EFISs including the serial output to the transponder."
Specifically, the serial altitude data output to the transponder from a non
TSO'd altitude encoder within an EFIS would not, at present, be in
compliance
with either 91.217 (b) or (c).
3) "Clearly, that isn't happening in the real world. These are selling
well."
Correct.
4) "Are you against that?"
Not at all. Here are my positions:
A) People should make informed decisions.
B) If I can provide accurate information to people that will permit them to
make informed decisions I should do so.
C) The decisions that those people make, after I have given them the best
information that I have available, is theirs to make, not mine. The risks
that they chose to take, or not take, are theirs, not mine.
D) Most of the EFIS available to the amateur built community represent a
significant improvement in performance, reliability, and safety over
previously available flight instrument technology.
E) Most of the EFIS available to the homebuilt community contain a non-TSO'd
altitude encoder that is superior in performance, reliability, granularity,
and accuracy over altitude encoding equipment that was manufactured to
versions of TSO-C88 prior to TSO-C88b.
F) Amateur built experimental aircraft have flown thousands of hours using
EFIS with non-TSO'd altitude encoders feeding their transponders with no
apparent problems.
G) Hundreds of amateur built experimental airplanes are under construction
using EFIS containing non-TSO'd altitude encoders.
H) The FAA should recognize and accept the real world conditions described
in D, E, F, and G above.
I) The best way for the FAA to accept the real world conditions described in
D, E, F, and G above is to interpret the tests required by FAR Secs 91.411
and 91.413 (as appropriate) as fulfilling the requirements of FAR Sec 91.217
(b).
J) My initial attempts to accomplish H and I above with FAA HQ were met with
resistance and I ceased activity in this regard.**
K) If the FAA, and the people / entities who perform the tests required by
91.411 / 91.413, decided that every non-TSO'd altitude encoder in an EFIS
was not airworthy because it did not meet the requirements of either 91.217
(b) or (c) this decision would be a serious blow to the amateur built
community.**
L) I do not proactively broadcast the information in K above, but if someone
asks a specific question on this issue or posts a position that I know to be
in error I revert to my positions A and B above.
M) I am open to improvements or changes in my positions.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
**PS: The FAA decision makers who perpetrated the recent fiasco involving
hundreds of airline flights being canceled and thousands of people being
stranded over the issue of the exact spacing of electrical wire cable ties
in the landing gear wheel wells of airline aircraft are capable of such
thinking and actions.
------------------------------------------------------------
----- Original Message -----
From: Anonymous
Sent: Sunday, April 20, 2008 9:20 AM
Subject: Encoding Altimeter
> OC,
>
> I don't understand what you are trying to say with your posts
> to
> the AeroElectric List. You seem to be saying that the only practical way
> to
> meet the requirements is to use a TSO'd source for the altitude
> information
> the transponder is transmitting. That, of course, would eliminate
> valuable
> functionality of many non-TSO'd electronic EFISs including the serial
> output
> to the transponder. Clearly, that isn't happening in the real world.
> These
> are selling well. Are you against that?
Anonymous
Message 3
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| Subject: | Re: Encoding Altimeter |
What?
The code that the encoding altimiter sends out is the altitude when you set
the alitimiter to 29.92, thats called pressure altitude. No matter where
you set the altimeter, the encoder portion still reports the altitude as if
the thing is set to 29.92. That never changes. You twist the knob to set
your local atimiter setting so your dial reads zero when you are at sea
level or actual field elevation for you locale. The system is calibrated at
29.92 and certified as to scale error +/- 25 feet when the altimiter is
certified every 2 years. You dont need 2 altimeters. Setting the dial
anywhere you want on an encoding altimeter has no effect on the encoder
portion of the device. Some encoding altimeters have what is called a baro
pot to send altimeter setting info to certain autopilots. Anyhow. ATC
corrects the number that your encoder sends out to the transponder and then
out to ATC for local altitude changes in pressure. You dont need to do this
for them and I certainly hope none of you have been leaving your encoding
altimeters on 29.92 thinking that you are doing them a favor.
In fact I would discourage people from owning an encoding altimeter as the
are a maintenance nightmare in some cases. They are expensive to overhaul
and if it comes up at your 2 year inspection that either the altimeter half
or the encoder half is out of spec, it makes the whole thing unairworthy.
Its cheaper in the long run to stick with good certified altimeters like
United instrument and encoders like the trans-cal SSD120-30A.
ACK/narco/Ameri-king encoders are cheaply built and you get what you pay
for.
Charles Reiche
----- Original Message -----
From: "Noel Loveys" <noelloveys@yahoo.ca>
Sent: Monday, April 21, 2008 10:57 AM
Subject: RE: Avionics-List: Encoding Altimeter
>
> One factor to remember is the operation of the encoding altimeter. To
> send
> the correct information it needs to be set at 29.92 in. hg.. That for all
> intents and purposes means you would have to either turn off your Xpndr or
> have a second altimeter for lower altitudes. The big deal is every one
> reports altitude to the same reference and the system as a whole operates
> within parameters.
>
> Noel
>
> -----Original Message-----
> From: owner-avionics-list-server@matronics.com
> [mailto:owner-avionics-list-server@matronics.com] On Behalf Of
> bakerocb@cox.net
> Sent: Monday, April 21, 2008 8:40 AM
> To: avionics-list@matronics.com; aeroelectric-list@matronics.com
> Subject: Avionics-List: Encoding Altimeter
>
>
>
> 4/20/2008
>
> Hello Anonymous, You wrote:
>
> 1) "You seem to be saying that the only practical way to meet the
> requirements is to use a TSO'd source for the altitude information the
> transponder is transmitting."
>
> That is close. Here is how I would phrase it: "At present the only
> practical
> way to be in compliance with FAR Section 91.217, Data Correspondence
> Between
> Automatically Reported Pressure Altitude Data and the Pilot's Altitude
> Reference, is to use a TSO'd equipment source for the altitude information
> the transponder is transmitting."
>
> 2) "That, of course, would eliminate valuable functionality of many
> non-TSO'd electronic EFISs including the serial output to the
> transponder."
>
> Specifically, the serial altitude data output to the transponder from a
> non
> TSO'd altitude encoder within an EFIS would not, at present, be in
> compliance
> with either 91.217 (b) or (c).
>
> 3) "Clearly, that isn't happening in the real world. These are selling
> well."
>
> Correct.
>
> 4) "Are you against that?"
>
> Not at all. Here are my positions:
>
> A) People should make informed decisions.
>
> B) If I can provide accurate information to people that will permit them
> to
> make informed decisions I should do so.
>
> C) The decisions that those people make, after I have given them the best
> information that I have available, is theirs to make, not mine. The risks
> that they chose to take, or not take, are theirs, not mine.
>
> D) Most of the EFIS available to the amateur built community represent a
> significant improvement in performance, reliability, and safety over
> previously available flight instrument technology.
>
> E) Most of the EFIS available to the homebuilt community contain a
> non-TSO'd
> altitude encoder that is superior in performance, reliability,
> granularity,
> and accuracy over altitude encoding equipment that was manufactured to
> versions of TSO-C88 prior to TSO-C88b.
>
> F) Amateur built experimental aircraft have flown thousands of hours using
> EFIS with non-TSO'd altitude encoders feeding their transponders with no
> apparent problems.
>
> G) Hundreds of amateur built experimental airplanes are under construction
> using EFIS containing non-TSO'd altitude encoders.
>
> H) The FAA should recognize and accept the real world conditions described
> in D, E, F, and G above.
>
> I) The best way for the FAA to accept the real world conditions described
> in
> D, E, F, and G above is to interpret the tests required by FAR Secs 91.411
> and 91.413 (as appropriate) as fulfilling the requirements of FAR Sec
> 91.217
> (b).
>
> J) My initial attempts to accomplish H and I above with FAA HQ were met
> with
> resistance and I ceased activity in this regard.**
>
> K) If the FAA, and the people / entities who perform the tests required by
> 91.411 / 91.413, decided that every non-TSO'd altitude encoder in an EFIS
> was not airworthy because it did not meet the requirements of either
> 91.217
> (b) or (c) this decision would be a serious blow to the amateur built
> community.**
>
> L) I do not proactively broadcast the information in K above, but if
> someone
> asks a specific question on this issue or posts a position that I know to
> be
> in error I revert to my positions A and B above.
>
> M) I am open to improvements or changes in my positions.
>
> 'OC' Says: "The best investment we can make is the effort to gather and
> understand knowledge."
>
> **PS: The FAA decision makers who perpetrated the recent fiasco involving
> hundreds of airline flights being canceled and thousands of people being
> stranded over the issue of the exact spacing of electrical wire cable ties
> in the landing gear wheel wells of airline aircraft are capable of such
> thinking and actions.
>
> ------------------------------------------------------------
>
> ----- Original Message -----
> From: Anonymous
> To: <bakerocb@cox.net>
> Sent: Sunday, April 20, 2008 9:20 AM
> Subject: Encoding Altimeter
>
>
>> OC,
>>
>> I don't understand what you are trying to say with your posts
>> to
>> the AeroElectric List. You seem to be saying that the only practical way
>> to
>> meet the requirements is to use a TSO'd source for the altitude
>> information
>> the transponder is transmitting. That, of course, would eliminate
>> valuable
>> functionality of many non-TSO'd electronic EFISs including the serial
>> output
>> to the transponder. Clearly, that isn't happening in the real world.
>> These
>> are selling well. Are you against that?
>
> Anonymous
>
>
>
Message 4
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| Subject: | 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
-----Original Message-----
From: owner-avionics-list-server@matronics.com
[mailto:owner-avionics-list-server@matronics.com] On Behalf Of Charles
Reiche
Sent: Monday, April 21, 2008 5:30 PM
Subject: Re: Avionics-List: Encoding Altimeter
<reichec@verizon.net>
What?
The code that the encoding altimiter sends out is the altitude when you
set
the alitimiter to 29.92, thats called pressure altitude. No matter
where
you set the altimeter, the encoder portion still reports the altitude as
if
the thing is set to 29.92. That never changes. You twist the knob to
set
your local atimiter setting so your dial reads zero when you are at sea
level or actual field elevation for you locale. The system is
calibrated at
29.92 and certified as to scale error +/- 25 feet when the altimiter is
certified every 2 years. You dont need 2 altimeters. Setting the dial
anywhere you want on an encoding altimeter has no effect on the encoder
portion of the device. Some encoding altimeters have what is called a
baro
pot to send altimeter setting info to certain autopilots. Anyhow. ATC
corrects the number that your encoder sends out to the transponder and
then
out to ATC for local altitude changes in pressure. You dont need to do
this
for them and I certainly hope none of you have been leaving your
encoding
altimeters on 29.92 thinking that you are doing them a favor.
In fact I would discourage people from owning an encoding altimeter as
the
are a maintenance nightmare in some cases. They are expensive to
overhaul
and if it comes up at your 2 year inspection that either the altimeter
half
or the encoder half is out of spec, it makes the whole thing
unairworthy.
Its cheaper in the long run to stick with good certified altimeters like
United instrument and encoders like the trans-cal SSD120-30A.
ACK/narco/Ameri-king encoders are cheaply built and you get what you pay
for.
Charles Reiche
----- Original Message -----
From: "Noel Loveys" <noelloveys@yahoo.ca>
Sent: Monday, April 21, 2008 10:57 AM
Subject: RE: Avionics-List: Encoding Altimeter
<noelloveys@yahoo.ca>
>
> One factor to remember is the operation of the encoding altimeter. To
> send
> the correct information it needs to be set at 29.92 in. hg.. That for
all
> intents and purposes means you would have to either turn off your
Xpndr or
> have a second altimeter for lower altitudes. The big deal is every
one
> reports altitude to the same reference and the system as a whole
operates
> within parameters.
>
> Noel
>
> -----Original Message-----
> From: owner-avionics-list-server@matronics.com
> [mailto:owner-avionics-list-server@matronics.com] On Behalf Of
> bakerocb@cox.net
> Sent: Monday, April 21, 2008 8:40 AM
> To: avionics-list@matronics.com; aeroelectric-list@matronics.com
> Subject: Avionics-List: Encoding Altimeter
>
>
>
> 4/20/2008
>
> Hello Anonymous, You wrote:
>
> 1) "You seem to be saying that the only practical way to meet the
> requirements is to use a TSO'd source for the altitude information the
> transponder is transmitting."
>
> That is close. Here is how I would phrase it: "At present the only
> practical
> way to be in compliance with FAR Section 91.217, Data Correspondence
> Between
> Automatically Reported Pressure Altitude Data and the Pilot's Altitude
> Reference, is to use a TSO'd equipment source for the altitude
information
> the transponder is transmitting."
>
> 2) "That, of course, would eliminate valuable functionality of many
> non-TSO'd electronic EFISs including the serial output to the
> transponder."
>
> Specifically, the serial altitude data output to the transponder from
a
> non
> TSO'd altitude encoder within an EFIS would not, at present, be in
> compliance
> with either 91.217 (b) or (c).
>
> 3) "Clearly, that isn't happening in the real world. These are
selling
> well."
>
> Correct.
>
> 4) "Are you against that?"
>
> Not at all. Here are my positions:
>
> A) People should make informed decisions.
>
> B) If I can provide accurate information to people that will permit
them
> to
> make informed decisions I should do so.
>
> C) The decisions that those people make, after I have given them the
best
> information that I have available, is theirs to make, not mine. The
risks
> that they chose to take, or not take, are theirs, not mine.
>
> D) Most of the EFIS available to the amateur built community represent
a
> significant improvement in performance, reliability, and safety over
> previously available flight instrument technology.
>
> E) Most of the EFIS available to the homebuilt community contain a
> non-TSO'd
> altitude encoder that is superior in performance, reliability,
> granularity,
> and accuracy over altitude encoding equipment that was manufactured to
> versions of TSO-C88 prior to TSO-C88b.
>
> F) Amateur built experimental aircraft have flown thousands of hours
using
> EFIS with non-TSO'd altitude encoders feeding their transponders with
no
> apparent problems.
>
> G) Hundreds of amateur built experimental airplanes are under
construction
> using EFIS containing non-TSO'd altitude encoders.
>
> H) The FAA should recognize and accept the real world conditions
described
> in D, E, F, and G above.
>
> I) The best way for the FAA to accept the real world conditions
described
> in
> D, E, F, and G above is to interpret the tests required by FAR Secs
91.411
> and 91.413 (as appropriate) as fulfilling the requirements of FAR Sec
> 91.217
> (b).
>
> J) My initial attempts to accomplish H and I above with FAA HQ were
met
> with
> resistance and I ceased activity in this regard.**
>
> K) If the FAA, and the people / entities who perform the tests
required by
> 91.411 / 91.413, decided that every non-TSO'd altitude encoder in an
EFIS
> was not airworthy because it did not meet the requirements of either
> 91.217
> (b) or (c) this decision would be a serious blow to the amateur built
> community.**
>
> L) I do not proactively broadcast the information in K above, but if
> someone
> asks a specific question on this issue or posts a position that I know
to
> be
> in error I revert to my positions A and B above.
>
> M) I am open to improvements or changes in my positions.
>
> 'OC' Says: "The best investment we can make is the effort to gather
and
> understand knowledge."
>
> **PS: The FAA decision makers who perpetrated the recent fiasco
involving
> hundreds of airline flights being canceled and thousands of people
being
> stranded over the issue of the exact spacing of electrical wire cable
ties
> in the landing gear wheel wells of airline aircraft are capable of
such
> thinking and actions.
>
> ------------------------------------------------------------
>
> ----- Original Message -----
> From: Anonymous
> To: <bakerocb@cox.net>
> Sent: Sunday, April 20, 2008 9:20 AM
> Subject: Encoding Altimeter
>
>
>> OC,
>>
>> I don't understand what you are trying to say with your
posts
>> to
>> the AeroElectric List. You seem to be saying that the only practical
way
>> to
>> meet the requirements is to use a TSO'd source for the altitude
>> information
>> the transponder is transmitting. That, of course, would eliminate
>> valuable
>> functionality of many non-TSO'd electronic EFISs including the serial
>> output
>> to the transponder. Clearly, that isn't happening in the real world.
>> These
>> are selling well. Are you against that?
>
> Anonymous
>
>
>
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