DonFromTX

DonFromTX

Well Known Member
I learned something this morning over on the Dynon forum in a thread started by Bill H. I wonder how many people have violated this and turned on their transponder before having it certified:

"To be clear: 91.413 is a regulation that applies to all pilots in all aircraft in the USA, so it does apply to EAB aircraft.

You can fly the plane before you get the transponder certified, as long as you don't turn it on, which means you are fine in areas that do not require a transponder."
 
Wow Walt, thanks for that link. I have to admit I never went to that part of VAF before, did not even realize it existed.
I have in the past, just pulled the xponder from the panel and dropped it off at a local avionics shop, a few bucks and it is done with logbook entry. Now that I have a Skyview, can I just take the xponder module out and over to the Avionics shop for certification? I really don't want to fly over there, and besides I cannot anyway since my xponder is not certified.
It still seems to me that Dynon could certify it just as well for the initial two years of use, it makes no sense to me to take a TSO'd item fresh from the maker, over to some local yokel to pronounce it OK.
 
Its not just the transponder being checked, it is the static system, the encoder, the altimeter and the wiring/connections.

Its the whole package that the FAA wants to make sure is in compliance.

Example: It does no good to have a certified good Xponder if the encoder is off by a few thousand feet....or it is not talking properly to the unit.

How can Dynon certify your antenna and cable installation?
 
I disagree. I have never had an encoder or pitot static system checked for a VFR installation, not even required. Only the transponder is checked, that is why you can pull it from the panel and drive it over for a check. If I recall correctly, that is only required for IFR stuff (or is a VERY RECENT change). .

Brantel said:
Its not just the transponder being checked, it is the static system, the encoder, the altimeter and the wiring/connections.

Its the whole package that the FAA wants to make sure is in compliance.

Example: It does no good to have a certified good Xponder if the encoder is off by a few thousand feet....or it is not talking properly to the unit.

How can Dynon certify your antenna and cable installation?
Click to expand...
 
DonFromTX said:
I disagree. I have never had an encoder or pitot static system checked for a VFR installation, not even required. Only the transponder is checked, that is why you can pull it from the panel and drive it over for a check. If I recall correctly, that is only required for IFR stuff (or is a VERY RECENT change). .
Click to expand...

If someone brings me a transponder I can issue an 8130 or yellow tag for it, but I will not give you a sticker for your logbook unless I test it in the aircraft.

Installations must be checked "AS INSTALLED" (below is from my FAQ section and the relevent regs):

Note: For new certifications or if the encoder or altimeter has been replaced, a Data Correspondence Check must be accomplished to ensure the altitude data transmitted to ATC corresponds to within 125 feet of the altimeter normally used to maintain flight altitude per CFR 91.217.

§ 91.217 (Note the bold part of the reg req's it to be done in the aircraft)

Data correspondence between automatically reported pressure altitude data and the pilot's altitude reference.

(a) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder—

(1) When deactivation of that equipment is directed by ATC;

(2) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or

(3) Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively.

(b) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder or with ADS–B Out equipment unless the pressure altitude reported for ADS–B Out and Mode C/S is derived from the same source for aircraft equipped with both a transponder and ADS–B Out.


§ 91.413 ATC transponder tests and inspections.

(a) No persons may use an ATC transponder that is specified in 91.215(a), 121.345(c), or §135.143(c) of this chapter unless, within the preceding 24 calendar months, the ATC transponder has been tested and inspected and found to comply with appendix F of part 43 of this chapter; and

(b) Following any installation or maintenance on an ATC transponder where data correspondence error could be introduced, the integrated system has been tested, inspected, and found to comply with paragraph (c), appendix E, of part 43 of this chapter.


Appendix E to Part 43—Altimeter System Test and Inspection

(c) Automatic Pressure Altitude Reporting Equipment and ATC Transponder System Integration Test. The test must be conducted by an appropriately rated person under the conditions specified in paragraph (a). Measure the automatic pressure altitude at the output of the installed ATC transponder when interrogated on Mode C at a sufficient number of test points to ensure that the altitude reporting equipment, altimeters, and ATC transponders perform their intended functions as installed in the aircraft. The difference between the automatic reporting output and the altitude displayed at the altimeter shall not exceed 125 feet.
 
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I just love days when I think I learned something.
Although I can see your interpretation, I can also see the local Avionics shops interpretation. 91.413 requires transponder checks, but never even mentions the encoder. To comply with (a) and with appendix F to part 43, it specifically states a bench test as a method, and the log book entry states that 91-413 (a)and Appendix F to part 43 requirements have been met (if the transponder checks out.
His interpretation is that you are interjecting 91-413 (b) into the requirements, when that may not have anything to do with the 24 month checks.
 
DonFromTX said:
I just love days when I think I learned something.
Although I can see your interpretation, I can also see the local Avionics shops interpretation. 91.413 requires transponder checks, but never even mentions the encoder. To comply with (a) and with appendix F to part 43, it specifically states a bench test as a method, and the log book entry states that 91-413 (a)and Appendix F to part 43 requirements have been met (if the transponder checks out.
His interpretation is that you are interjecting 91-413 (b) into the requirements, when that may not have anything to do with the 24 month checks.
Click to expand...

Sure he is, that's because the rules use the word "AND" - this is not an "OR" - it's NOT optional, not something you can "interpret" and your avionics guy is not just wrong, but WAY wrong. There is a HUGE difference in legal speak between the word AND and the word OR. AND means flat out that BOTH sections apply, not one or the other. It may not mention the word encoder, but it does specifically say "the integrated system has been tested..."that's pretty clearly meaning not a transponder out of it's rack laying on a bench.

If you're flying around in an airplane with a simple bench checked txpdr thinking that complies with the regs, you're not legal, you're not right and you may have a system that is inaccurate to boot! You simply can't pick out the (a) when following that sentence in the reg us clearly the word AND along with a bunch of requirements. You can't pick the (a) and ignore the (b) and (c). If you do, then you're not being legal. It's not an option, it's not an OR.

If your log book states that you've complied with the entire test, yet nobody actually performed the test, then someone has lied in your logbook...which is not good.

Just my 2 cents as usual, but there really isn't any gray area with what Walt said here. Someone may be telling you otherwise, but they are just flat wrong. This is not one of those areas where people can interpret things differetly....the rules are quite clear.

Cheers,
Stein
 
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I'm at a bit of a loss...

When I purchased my -4 the transponder, static system, and encoder had not been tested. That was one of the first things on my list to get done. I had a guy come to my hangar and, even though for VFR the altimeter test was not required, I had him do the whole shebang. It was a 1.5 hour drive each way, and he was there about 90 minutes. It was less than $200.

What did I get for that?

- I knew that my static system was good
- I knew that my encoder was accurate.
- He DID find a loose nut inside the encoder, which he said was common on that make and model. He fixed it in the base price.
- I knew that my transponder worked
- I knew that my whole system worked.

And most of all, I knew that everyone, including other planes with avoidance systems, knew with accuracy my altitude and position.

For me it's a no-brainer. But, as always, this is just MHO...
 
OK guys - the reason I started the thread over at Dynon is because it looks like I have a problem with my transponder antenna CABLE and was asking for info about detailed transponder troubleshooting. I haven't checked that cable yet. The transponder itself - the box - thinks it is just fine according to its self diagnostics. But it is not receiving or responding to interrogations nor transmitting from an IDENT. I am flying in airspace that does not even NEED a transponder, but if I climb quite a bit I can get ATC to check the reception, which kicked all of this off.

Now, one bit of confusion is that the Skyview is IMMUNE from the specific 24-month check of altitude encoder vs altimeter readout. That is because the source (ADAHRS) of the altitude readout on the EFIS and the transponder broadcast is one and the same and cannot be different. Note I did NOT say "check of the static system itself," or an "IFR check," I was very specific and this is covered in the Skyview manual.

+++++
Per the Dynon blog: So the statement about the altitude encoder calibration is really aimed at 91.217(2)
(see http://www.risingup.com/fars/view_far.php?part=91&type=FAR&num=217), which says

...Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or...

So what we're (Dynon) saying in our manual is that these devices are one and the same. Therefore, the altimeter and encoder are within 0 feet of each other 100% of the time by definition, which satisfies the above test requirement.

Now, separate from that, you need to comply with 91.413 (http://www.risingup.com/fars/view_far.php?part=91&type=FAR&num=413), which says:

....No persons may use an ATC transponder that is specified in 91.215(a), 121.345(c), or §135.143(c) of this chapter unless, within the preceding 24 calendar months, the ATC transponder has been tested and inspected and found to comply with appendix F of part 43 of this chapter; and....

The above basically means that you can't use your transponder in any controlled airspace, you need to test the end to end system. We don't make any claims that this requirement is alleviated.
+++++++
 
Even though the Skyview (and every other glass panel for that matter) may be immune to the data correspondance check, it is not excluded from the regs, so technically, and legally, you need to have a shop sign off that it was tested and that it does indeed meet the requirements of 43 E (c) for a new installation or during an IFR check.

In a similar fashion, a glass panel altimeter needs to be tested for "friction" and "barometric scale error" which an ADAHRS is also immune to, I still have to check it because the regs do not give me the leeway to ignore it just because it's "immune".

Until the regs catch up to today's technology we still have to comply with the "old" regs.

PS: check for continuity and shorting of your antenna cable to start, thats the most likely source of your problem.
 
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Transponder Problem Found! Check your cable!

I have a defective transponder antenna cable. This is the RV-12 SKYVIEW update "adapter" cable- a short 11 inch cable is supplied to adapt from the new Dynon transponder component antenna connector to the existing cable already run in the plane to the antenna.

The adapter cable center pin is shorted to the connection hardware on both ends. This explains my problems in that the Dynon transponder's self-diagnostics are fine but it does not receive ATC interrogations nor transmit responses.

The plans page 42C-09 do not actually show this adapter cable. It is labeled "Coleman Cable, 988591, M17/28-RG058 MIL-DTL-17 OXDS2"
It has a male-pin/female threaded connector combo on one end and a female-pin BNC connector on the other, 11 inches long.

The short in it is a pretty good one, it does not alter if you bend or move the cable around. I checked the other existing cable to the antenna and the antenna itself and they are fine - the center pin conducter is isolated from ground and the antenna and cable itself is well grounded to the airframe. You might want to check yours.
 
Surfing the web shows me this is an often disussed and never settled dispute. I am glad I am not an avionics guy, there are plenty of such areas in the A&P area.
Here is an example: http://www.flightsimaviation.com/data/FARS/part_43-appF.html

SteinAir said:
Sure he is, that's because the rules use the word "AND" - this is not an "OR" - it's NOT optional, not something you can "interpret" and your avionics guy is not just wrong, but WAY wrong. There is a HUGE difference in legal speak between the word AND and the word OR. AND means flat out that BOTH sections apply, not one or the other. It may not mention the word encoder, but it does specifically say "the integrated system has been tested..."that's pretty clearly meaning not a transponder out of it's rack laying on a bench.

If you're flying around in an airplane with a simple bench checked txpdr thinking that complies with the regs, you're not legal, you're not right and you may have a system that is inaccurate to boot! You simply can't pick out the (a) when following that sentence in the reg us clearly the word AND along with a bunch of requirements. You can't pick the (a) and ignore the (b) and (c). If you do, then you're not being legal. It's not an option, it's not an OR.

If your log book states that you've complied with the entire test, yet nobody actually performed the test, then someone has lied in your logbook...which is not good.

Just my 2 cents as usual, but there really isn't any gray area with what Walt said here. Someone may be telling you otherwise, but they are just flat wrong. This is not one of those areas where people can interpret things differetly....the rules are quite clear.

Cheers,
Stein
Click to expand...
 
If you're interested check out Advisory Circular AC 43-6B

Subject: ALTITUDE REPORTING
EQUIPMENT AND TRANSPONDER
SYSTEM MAINTENANCE AND
INSPECTION PRACTICES

Quoted from the above in case you don't want to read the whole thing:

6. MAINTENANCE. Any appropriately rated person (as specified in ? 43.3) may perform maintenance or preventative maintenance on an aircraft altitude reporting and transponder system. This work may include the removal of and/or replacement with an identical component and aircraft altimeter, encoding altimeter, blind encoder, air data system component, or transponder. The approval of the aircraft for return to service can only be given after a suitable functional check of the entire system as installed in the aircraft has been performed in order to determine that the system, as well as the component, will perform its intended function(s). NOTE: In the instance when the services of a certificated repair station are used for the maintenance, preventative maintenance, or replacement of an
altitude reporting and transponder system, or for any portion of such a system, the repair station should be appropriately rated as described in the
note in paragraph 5. Repair station ratings may be limited to specific make(s) and model(s) of airframes, transponders, or encoding altimeters.

7. FUNCTIONAL TESTING. An appropriately rated person, as specified in ? 43.3, should make all MAJOR repairs (part 43, appendix A) to component parts of an aircraft altitude reporting and transponder system. Such repairs require testing and inspection before return to service. Following reinstallation into the aircraft, the entire system will be tested for proper function to ensure it performs its intended function(s). The scope of testing required in determining system functionality is dependent on the component parts that were repaired. See Appendix 1, Table 3 to determine the appropriate tests necessary.
 
DonFromTX said:
Surfing the web shows me this is an often disussed and never settled dispute. I am glad I am not an avionics guy, there are plenty of such areas in the A&P area.
Here is an example: http://www.flightsimaviation.com/data/FARS/part_43-appF.html
Click to expand...

Again...this is not a gray area....

The piece you posted is for the specifics of the test and it's related equipment. No debate there. The only time a bench check is good on a txpdr is if the ENTIRE system has already been checked in the past 24mo's and you've replaced, repaired, or maintained the txpdr (as it's clearly stated in plain language). This is very clear and if a shop or aircraft owner doesn't follow that they'll find themselves in trouble sooner or later - and - you'll be flying illegally. Bench checks are fine for checking a txpdr, NOT for an entire system. If you're flying around in a plane that has never had the entire sytem checked, you're NOT legal - period.

I've yet to find anyone in avionics besides a builder or pilot that doesn't ageee....

Cheers,
Stein
 
Quick question. Do I need proof of a transponder check to present to a DAR on initial inspection. I ask only out of curiosity. I've already made arrangements with Stein for a system checkout before I send in my MIDO paperwork.
 
SteinAir said:
Again...this is not a gray area....
I've yet to find anyone in avionics besides a builder or pilot that doesn't ageee....
Cheers,
Stein
Click to expand...
Well, there is at least one. I have taken several to the local avionics guru, who is quite capable and considered top notch by the locals, and it was he that told me I did not need to bring the aircraft, just the transponder, so I find this revelation most interesting. Before this thread I had no reason to question his direction. He has been at this for many many years, is it possible that there is a change that he is unaware of?
 
LettersFromFlyoverCountry said:
Quick question. Do I need proof of a transponder check to present to a DAR on initial inspection. I ask only out of curiosity. I've already made arrangements with Stein for a system checkout before I send in my MIDO paperwork.
Click to expand...

Nope, just before the first flight if you live in an area requiring a transponder (like I do).
 
DonFromTX said:
Well, there is at least one. I have taken several to the local avionics guru, who is quite capable and considered top notch by the locals, and it was he that told me I did not need to bring the aircraft, just the transponder, so I find this revelation most interesting. Before this thread I had no reason to question his direction. He has been at this for many many years, is it possible that there is a change that he is unaware of?
Click to expand...

There was a local repair station not long ago that did these checks, this guy had been around for a light year and many folks used him. After talking with some of his past customers that I have picked up, there seemed to be a lot of mis-information out there. I think he mis-interpreted and in some cases, just made up his own regs. FAA ended up pulling his license.
 
"I think he mis-interpreted and in some cases, just made up his own regs."

He wouldn't be the first and some of them have FAA on their paychecks. As Director of Quality Assurance for 10 years for Boeing Commercial Airplanes, I remember a particularly noteworthy meeting (with the MIDO) where I was showing our compliance with the FARs by showing a vue-graph. Our FAA Principal Inspector stood up, took my vue-graph off the machine and tossed it in the wastebasket - informing me in no uncertain words "Don't show me that stuff - I make the rules." And, like a traffic cop on the freeway - he did!

Another nit -

"Again...this is not a gray area...."

Well, yes it is - or at least insofar as quoting from an AC is concerned vs the FAR. The referenced AC - like ALL ACs says in its preamble that it NOT mandatory and does NOT constitute a regulation. Furthermore, it "grays" the subject matter even further by always declaring that "it provides a means, but not the only means....."

Bob Bogash
N737G
 
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