Transponder Testing

[jiott]

Transponders are supposed to be tested every 2 years. I have been trying to remember to do this but sometimes it slides by for many months. Do you all do this religiously? Anyone ever failed the test? Has anyone ever been checked for currency of this test? I always have them do the less complete VFR test; its roughly $80.

[PapuaPilot]

FAR 91.413 doesn't give us any wiggle room on the biennial, but it would be easy to forget. I use a spreadsheet to track all of my calendar and hour requirements. I routinely update the current date and TT of my plane, and anything coming due is flagged.

I have had mine done every 2 years, no problems, but it is only 5 years old. I haven't had pay, we have an avionics department where I work and my buddy does the test. Pretty nice.

[jrevens]

Not saying it's right, but I know several VFR only owners of homebuilts who don't get it done biennially on a consistent basis. I had a friend who bought his homebuilts (Rutan EZ & Long EZ), and was amazed when he told me he had never had it done, and he flew out of my current home field that requires Mode C. He used to tell me that he would regularly "self-test" by asking the tower what his altitude was showing, and comparing that to his own instruments (which is not a bad thing to do occasionally anyway). I too have been lax in the past, and have inadvertently run over the 24 month period. I've never been checked for compliance in my 46 years as a pilot (30 plus years of flying homebuilts), but I also only fly VFR now FWIW.

[Dave S]

I have always complied with the time limits of the regulation. Had a failure once - not discovered during the scheduled test; but, when the tower wanted to know exactly what altitude I was at - it was reading 2,000' high. Easy to get a wavier - called up approach control who provided that and turned the thing off - went back to home base to get it resolved. The encoder was purchased new when the plane was built - unfortunately it was one of the ameriking models which was later identified as having been assembled with unapproved parts which did not meet specification. My shop attempted to recalibrate it but it was hopeless so it was replaced (that was before the unapproved parts notification). Since the fix, I have made a practice of periodically verifying the mode C readback with a tower/ATC. The bit of good luck of the day the failure occurred is that I was planning on going to a non towered field with a 2,300 foot base to the class B; and, instead decided to go to a neighboring tower controlled field for what I needed and that field had a 4,000' base to the same class B. I am reasonable certain that there would have been questions to answer if I had gone to the other field that day and pinged well above the lower shelf of the class B!

FWIW - probably would not be a good confluence of circumstances if an encoder shows a person in airspace requiring contact or a clearance and the investigation revealed a transponder/encoder had not been checked within the required time limit. I make it a practice to never fail to comply with a regulatory time limit.

Jim - wish I only had to pay $80 for a VFR check!:eek:

[jiott]

Thanks for the comments. I will try to get mine done on time in the future.

[jrevens]

I agree with Dave's comments fully, and just to be clear - I am very careful about getting it done on time now also, although I admit that wasn't always the case in the "good old days". Not purposely, but it happened. My airport is located within the 30 NM radius veil of the DIA Class B airspace, and I fly under that Class B very frequently.

[efwd]

Yeah, I appreciate the comments on the subject as well. I think I was forgetting that requirement. I have 6 more months. I don't want to be getting any calls from the FAA either.

[Shadowrider]

Wonder what the least expensive test equipment that is needed? If we had the test equipment could we do it ourselves? Maybe we buy the test equipment and rent it out like the dynavibe?

Garmin has a self test ground feature. I wish you could do this ground test and then fly and have your altitude verified by atc along with WAAS altitude, log it and call it good. Just saying this would be nice if we could do this.

[PapuaPilot]

Wonder what the least expensive test equipment that is needed? If we had the test equipment could we do it ourselves? Maybe we buy the test equipment and rent it out like the dynavibe?

We can't do it. Even if some were to layout thousands of $ to buy the test equipment, which also needs to be sent off for calibration annually (more$), we still can't do it.

Here is who can do it. This is from CFR 91.413:
(c) The tests and inspections specified in this section must be conducted by -
(1) A certificated repair station properly equipped to perform those functions and holding -
(i) A radio rating (https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=5e04dbe216da194fe7f0e9b20dcdc53a&term_occur=999&term_src=Title:14:Chapter:I:Subchapter:F:Part:91:S ubpart:E:91.413), Class III;
(ii) A limited radio rating (https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=5e04dbe216da194fe7f0e9b20dcdc53a&term_occur=999&term_src=Title:14:Chapter:I:Subchapter:F:Part:91:S ubpart:E:91.413) appropriate to the make and model transponder to be tested;
(iii) A limited rating (https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=5e04dbe216da194fe7f0e9b20dcdc53a&term_occur=999&term_src=Title:14:Chapter:I:Subchapter:F:Part:91:S ubpart:E:91.413) appropriate to the test to be performed;
(2) A holder of a continuous airworthiness maintenance (https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=fc2f07b03933ee61135b3c5de147ca70&term_occur=999&term_src=Title:14:Chapter:I:Subchapter:F:Part:91:S ubpart:E:91.413) program as provided in part 121 or § 135.411(a)(2) (https://www.law.cornell.edu/cfr/text/14/135.411#a_2) of this chapter; or
(3) The manufacturer of the aircraft (https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=8e9caab04f792d93d0738c9d3290164e&term_occur=999&term_src=Title:14:Chapter:I:Subchapter:F:Part:91:S ubpart:E:91.413) on which the transponder to be tested is installed, if the transponder was installed by that manufacturer.

[Shadowrider]

Well.....I guess that settles that.

[efwd]

Number 3 identifies me as an entity who is eligible. I suppose if I had the test equipment I could do it No? Not saying I would be in for all that investment but....

[Shadowrider]

On one hand they consider you the manufacturer. It’s on the data tag of your aircraft. On the other hand they do not consider you the manufacturer.

https://www.eaa.org/eaa/aircraft-building/intro-to-aircraft-building/frequently-asked-questions/transponder-and-pitot-static-tests

[efwd]

My turn. Well.... that settles that.