transponder check?

[Russell Duffy]

Greetings,

I'm expecting to make the first flight of an RV-3 later this month, and am
trying to figure out exactly what needs to be done about the transponder.
Does anyone know for sure? Since the plane is day VFR only, I'm pretty sure
I don't need to have the pitot static system tested.

Lots of people don't have any sort of certification done on experimentals,
but I think something is probably required. It seems like I've seen a
statement that says the manufacturer of the aircraft (that's me) is
responsible for verifying the operation of the transponder. If I call up
ATC from outside their airspace, and ask for a readout, isn't that verifying
the operation.

The minimum that I imagine, is having the transponder bench tested, which is
stupid, since it's a new unit, and was certainly tested at the factory.
More likely, the encoder (also factory new) should be tested with the
transponder on the bench to verify altitude readings, but that doesn't test
my wiring, which is the only real variable. No local avionics shop will come
to the airport to do a field test either.

FWIW, I called AOPA, and they didn't seem to really know. I have a call
into the EAA, and hope to get a reply later today. Naturally, the avionics
shops tell you that you need "the works". What do I really need?

Rusty
Turbo Mazda 13B powered RV-3 (zoom, zoom, zoom)

[Ken Sandyeggo]

"Russell Duffy" > wrote in message >...
> Greetings,
>
> I'm expecting to make the first flight of an RV-3 later this month, and am
> trying to figure out exactly what needs to be done about the transponder.
> Does anyone know for sure? Since the plane is day VFR only, I'm pretty sure
> I don't need to have the pitot static system tested.
>
> Lots of people don't have any sort of certification done on experimentals,
> but I think something is probably required. It seems like I've seen a
> statement that says the manufacturer of the aircraft (that's me) is
> responsible for verifying the operation of the transponder. If I call up
> ATC from outside their airspace, and ask for a readout, isn't that verifying
> the operation.
>
> The minimum that I imagine, is having the transponder bench tested, which is
> stupid, since it's a new unit, and was certainly tested at the factory.
> More likely, the encoder (also factory new) should be tested with the
> transponder on the bench to verify altitude readings, but that doesn't test
> my wiring, which is the only real variable. No local avionics shop will come
> to the airport to do a field test either.
>
> FWIW, I called AOPA, and they didn't seem to really know. I have a call
> into the EAA, and hope to get a reply later today. Naturally, the avionics
> shops tell you that you need "the works". What do I really need?
>
> Rusty
> Turbo Mazda 13B powered RV-3 (zoom, zoom, zoom)

Rusty,

What you really need is to stop asking questions at this point. I
agree with you that as the manufacturer, we are allowed to verify its
operation as stated in the FARS. I'm constantly in radar coverage and
a quick "whats my readout?" gets you the info you need. The FAR
addicts will jump in here about now and quote dozens of regulations of
why this is not allowed, but I say phhhhhht. Works for me.

Ken J. - Sandy, egg ho

[Russell Duffy]

> It is my understanding you need to have this certification done every
> 24 months if you either (a) fly IFR, or (b) fly anywhere that Mode
> C is required.

Sorry to make you do all that typing Ross. I actually know how they do it,
since I watched them do my previous RV-8. Unfortunately, the avionics guy
is so busy now that he doesn't make trips to the local airports anymore. We
even tried to lure him over to do two of these, but no joy. I can't even
fly the plane to his shop because it's outside my test area. I may just
have to take my transponder and encoder over to let him do it on the bench.
That would make it legal I think, but still silly.

Thanks for the comments,
Rusty

[Russell Duffy]

The FAR
> addicts will jump in here about now and quote dozens of regulations of
> why this is not allowed, but I say phhhhhht. Works for me.
>
> Ken J. - Sandy, egg ho

Yeah, that worked for about a year and a half on my RV-8, until the POS
Narco transponder crapped out. The guy at the avionics shop was the one who
pointed out that I needed to get it re-certified. Of course my response was
"what do you mean RE-certified" :-)

Thanks for the comments. Maybe I won't call the FSDO about this :-)

Rusty

[Gerry Caron]

"Russell Duffy" > wrote in message
...
> Greetings,
>
> I'm expecting to make the first flight of an RV-3 later this month, and am
> trying to figure out exactly what needs to be done about the transponder.
> Does anyone know for sure? Since the plane is day VFR only, I'm pretty
sure
> I don't need to have the pitot static system tested.
>
> Lots of people don't have any sort of certification done on experimentals,
> but I think something is probably required. It seems like I've seen a
> statement that says the manufacturer of the aircraft (that's me) is
> responsible for verifying the operation of the transponder. If I call up
> ATC from outside their airspace, and ask for a readout, isn't that
verifying
> the operation.

The following are from Part 91 which covers all operations not under Parts
121 or 135. It doesn't matter whether you are flying an experimental, a
C172, or a Citation.

Part 91.413 for transponder checks applies regardless.

You're correct in that 91.411 for altimeter systems (incl: static system)
only applies if you want to fly IFR. But even VFR you may want ATC services
and if your altitude reporting is off, you may get a request to stop
altitude squawk.

Don't know what the reaction might be if you're in a Mode C required area
with a continually bad Mode C. But from a practical point of view; if
you've got Mode C, make sure it's working right. If it isn't working, it
certainly doesn't contribute much to safety and at worse could be a hazard
(If somebody else thinks you're at a given altitude when you're really at a
different altitude--think TCAS.)

The rules spell out the verification and who may do them. The tests are in
Appendix E and F of Part 43.

[Russell Duffy]

> The rules spell out the verification and who may do them. The tests are
in
> Appendix E and F of Part 43.
>

First, I should point out that I DO care that the altimeter, and mode-C
agree, and are correct. That's actually more important to me than whether
it's legal, and there are simple ways to verify this, without having a
signature from an avionics shop.

I've been reading through appendix E and F, and the best I can tell, I can
take the transponder and encoder to an avionics shop, and have them bench
tested. This should be legal, though still absolutely meaningless, since my
wiring and antenna are still unknowns. Realistically, the only thing that
matters is having ATC confirm the readout, and having a formation aircraft
confirm my altimeter.

I'll call the avionics shop tomorrow and see if they agree to this plan.
I'd already be willing to wager that they won't.

Thanks,
Rusty

[Ken Sandyeggo]

It's all so nebulous. There's one section on transponders and
altitude reporting equipment requirements that says it applies to
"airplanes and helicopters." An "experimental" is neither, it's an
"experimental" aircraft period. A gyroplane is not an airplane or a
helicopter. The FARS are such a general can of worms, if you ask 5
FAA employees for an interpretation, you'll usually get at least 3
differing answers. I'se keeps me mouf' shut, don't axe questions an'
goes about me bidniss.

KJSDCAUSA



"Gerry Caron" > wrote in message >...
> "Russell Duffy" > wrote in message
> ...
> > Greetings,
> >
> > I'm expecting to make the first flight of an RV-3 later this month, and am
> > trying to figure out exactly what needs to be done about the transponder.
> > Does anyone know for sure? Since the plane is day VFR only, I'm pretty
> sure
> > I don't need to have the pitot static system tested.
> >
> > Lots of people don't have any sort of certification done on experimentals,
> > but I think something is probably required. It seems like I've seen a
> > statement that says the manufacturer of the aircraft (that's me) is
> > responsible for verifying the operation of the transponder. If I call up
> > ATC from outside their airspace, and ask for a readout, isn't that
> verifying
> > the operation.
>
> The following are from Part 91 which covers all operations not under Parts
> 121 or 135. It doesn't matter whether you are flying an experimental, a
> C172, or a Citation.
>
> Part 91.413 for transponder checks applies regardless.
>
> You're correct in that 91.411 for altimeter systems (incl: static system)
> only applies if you want to fly IFR. But even VFR you may want ATC services
> and if your altitude reporting is off, you may get a request to stop
> altitude squawk.
>
> Don't know what the reaction might be if you're in a Mode C required area
> with a continually bad Mode C. But from a practical point of view; if
> you've got Mode C, make sure it's working right. If it isn't working, it
> certainly doesn't contribute much to safety and at worse could be a hazard
> (If somebody else thinks you're at a given altitude when you're really at a
> different altitude--think TCAS.)
>
> The rules spell out the verification and who may do them. The tests are in
> Appendix E and F of Part 43.

[Dave]

It's the 91.411 and 91.413 deal. Legally only the transponder check
(91.413) is required for VFR every 24 months.
But to use your encoder you also have to comply with part 43 appendix e
paragraph C, or anytime work has been done that could effect the mode c
output.

If your looking for someone to do this work in the DFW area I'll be
available in the next couple of weeks.
I'm just getting my repair station up and going for doing the VFR and
IFR system inspections.

Dave
Dallas tx


Ken Sandyeggo wrote:
> It's all so nebulous. There's one section on transponders and
> altitude reporting equipment requirements that says it applies to
> "airplanes and helicopters." An "experimental" is neither, it's an
> "experimental" aircraft period. A gyroplane is not an airplane or a
> helicopter. The FARS are such a general can of worms, if you ask 5
> FAA employees for an interpretation, you'll usually get at least 3
> differing answers. I'se keeps me mouf' shut, don't axe questions an'
> goes about me bidniss.
>
> KJSDCAUSA
>
>
>
> "Gerry Caron" > wrote in message >...
>
>>"Russell Duffy" > wrote in message
...
>>
>>>Greetings,
>>>
>>>I'm expecting to make the first flight of an RV-3 later this month, and am
>>>trying to figure out exactly what needs to be done about the transponder.
>>>Does anyone know for sure? Since the plane is day VFR only, I'm pretty
>>
>> sure
>>
>>>I don't need to have the pitot static system tested.
>>>
>>>Lots of people don't have any sort of certification done on experimentals,
>>>but I think something is probably required. It seems like I've seen a
>>>statement that says the manufacturer of the aircraft (that's me) is
>>>responsible for verifying the operation of the transponder. If I call up
>>>ATC from outside their airspace, and ask for a readout, isn't that
>>
>> verifying
>>
>>>the operation.
>>
>>The following are from Part 91 which covers all operations not under Parts
>>121 or 135. It doesn't matter whether you are flying an experimental, a
>>C172, or a Citation.
>>
>>Part 91.413 for transponder checks applies regardless.
>>
>>You're correct in that 91.411 for altimeter systems (incl: static system)
>>only applies if you want to fly IFR. But even VFR you may want ATC services
>>and if your altitude reporting is off, you may get a request to stop
>>altitude squawk.
>>
>>Don't know what the reaction might be if you're in a Mode C required area
>>with a continually bad Mode C. But from a practical point of view; if
>>you've got Mode C, make sure it's working right. If it isn't working, it
>>certainly doesn't contribute much to safety and at worse could be a hazard
>>(If somebody else thinks you're at a given altitude when you're really at a
>>different altitude--think TCAS.)
>>
>>The rules spell out the verification and who may do them. The tests are in
>>Appendix E and F of Part 43.

[Russell Duffy]

"Dave" > wrote in message
et...
> It's the 91.411 and 91.413 deal. Legally only the transponder check
> (91.413) is required for VFR every 24 months.
> But to use your encoder you also have to comply with part 43 appendix e
> paragraph C, or anytime work has been done that could effect the mode c
> output.

Thanks. I've talked to another shop, and have been told that they can come
to the airport for at least part of the check. They want to check the
transponder on the bench, then put it in the plane to check the system. I'm
trying to talk them into skipping the bench check, since it's a brand new
Garmin transponder. Unfortunately, the owner of the shop is the one I need
to talk to, and he's failed to return my call twice now.

How hard is it to get started as a repair station :-) (only half kidding)

Thanks,
Rusty

[Dave]

Russell Duffy wrote:
> "Dave" > wrote in message
> et...
>
>>It's the 91.411 and 91.413 deal. Legally only the transponder check
>>(91.413) is required for VFR every 24 months.
>>But to use your encoder you also have to comply with part 43 appendix e
>>paragraph C, or anytime work has been done that could effect the mode c
>>output.
>
>
> Thanks. I've talked to another shop, and have been told that they can come
> to the airport for at least part of the check. They want to check the
> transponder on the bench, then put it in the plane to check the system. I'm
> trying to talk them into skipping the bench check, since it's a brand new
> Garmin transponder. Unfortunately, the owner of the shop is the one I need
> to talk to, and he's failed to return my call twice now.
>
> How hard is it to get started as a repair station :-) (only half kidding)
>
> Thanks,
> Rusty
>
>
There is no real reason to bench check then check it in the airplane
except to verify the transponder works prior to a new installation or if
it is a mode "s" transponder, he may only have bench equipment to test it.
A bad antenna or antenna connection can swing a transponders frequency
out of range to pass the test.
He may be trying to get a baseline to validate the installation.
If he isn't charging more for the bench check and it's not a mode "s" go
for it. If he is charging lots more and your confident that the
installation is sound, make a few more calls.

Since your static system is new, it should be checked for leaks. That
can be done by an A&P, manufacturer or the guy who does your transponder
check.

You as the manufacutrer of the aircraft who installed the transponder
can also test and inspect the transponder installation, but it still
needs to comply with appendix f.

dave

[Russell Duffy]

> There is no real reason to bench check then check it in the airplane
> except to verify the transponder works prior to a new installation or if
> it is a mode "s" transponder, he may only have bench equipment to test it.
> A bad antenna or antenna connection can swing a transponders frequency
> out of range to pass the test.
> He may be trying to get a baseline to validate the installation.
> If he isn't charging more for the bench check and it's not a mode "s" go
> for it. If he is charging lots more and your confident that the
> installation is sound, make a few more calls.
>
> Since your static system is new, it should be checked for leaks. That
> can be done by an A&P, manufacturer or the guy who does your transponder
> check.
>
> You as the manufacutrer of the aircraft who installed the transponder
> can also test and inspect the transponder installation, but it still
> needs to comply with appendix f.
>
> dave
>

Thanks for all the extra info Dave. I talked to my preferred avionics shop
today, the one who said they wouldn't come to my airport. When he really
understook that I couldn't bring the plane to him, he agreed to come over
next week to do a "functional test". He's the one that tested my RV-8 a
year or so ago, so I'm pretty happy that he's agreed to do this. I think
I'm all set now.

Thanks again,
Rusty