VFR Transponder Checks

[Llewtrah381]

I’d appreciate the inputs of those in the know on this topic.

For the biennial VFR checks (91.413, I think), in a day and age of ADS-B, PAPR reports, integrated Mode C/ADS-B Out transponders, solid state transponders, etc., what would be the down side of eliminating the checks and having the owner run and record a PAPR report every two years instead?

I suspect legacy transponders with cavity oscillators are the most likely to fail but even there, if they do, it seems like ATC is using the ADS-B more than the Mode C these days and can tell a pilot of a failure yet still effectively manage them.

Basically, what would be the risk of going to PAPR reports instead of shelling out for a 10-minute check every two years?

 

[AV8R_87]

ADS-B is not mandated in a large portion of US airspace, and there are plenty of aircraft without it. That alone makes a VFR transponder check still a requirement.

For 1090ES ADS-B out installs, it's the same transponder that sends out mode A/C that is being used for Mode S ADS-B out. As such, you still need to check the transponder. That check is actually verifying the transponder is putting out the correct amount of power and such, to ensure adequate range. Other transponder output parameters are also checked to make sure they're in spec.

For UAT installs, they depend on a properly operating transponder (mainly, its ability to reply with a proper power level when interrogated) to extract the information they need for ADS-B to work. Goes back to ensuring the transponder output is in spec.

 

[Clip4]

I’d appreciate the inputs of those in the know on this topic.

For the biennial VFR checks (91.413, I think), in a day and age of ADS-B, PAPR reports, integrated Mode C/ADS-B Out transponders, solid state transponders, etc., what would be the down side of eliminating the checks and having the owner run and record a PAPR report every two years instead?

I suspect legacy transponders with cavity oscillators are the most likely to fail but even there, if they do, it seems like ATC is using the ADS-B more than the Mode C these days and can tell a pilot of a failure yet still effectively manage them.

Basically, what would be the risk of going to PAPR reports instead of shelling out for a 10-minute check every two years?

Shelling out? I just had a transponder/IFR cert done for $350. You should t be paying more than $150 for a VFR transponder cert.

 

[Bell206]

Basically, what would be the risk of going to PAPR reports instead of shelling out for a 10-minute check every two years?

To add, the VFR 413 inspection checks a lot more than just a signal which is all the PAPR test does and specifically for the ADSB. Plus only a repair station can perform the 411/413 inspection, which is outside even an A&P can perform. Regardless, having seen the PAPR test fail on such basic problems as coverage area or operator error, how many attempts would one be permitted every 2 years before it was considered failed?

 

[Llewtrah381]

I appreciate the comments.

I guess my basic questions are, how often do modern transponders fail compared to the ones that generated the requirement for biennial checks? How often is the check the thing that detects the failure in these new ones, rather than feedback from ATC? Given the dependence on ADS-B, how is that checked periodically (I’m pretty sure it’s not part of the cert but could be mistaken) and should it be?

Yeah, $150 isn’t a lot compared to the altimeter check but there’s also the gas getting to and from in many cases, etc. Plus it’s $150 and I’m a cranky old penny-pincher.

 

[Bell206]

I guess my basic questions are, how often do modern transponders fail compared to the ones that generated the requirement for biennial checks? How often is the check the thing that detects the failure in these new ones, rather than feedback from ATC?

The 411/413 inspections are not looking for failures per se but are verifying the equipment meets a minimum regulatory performance standard due to its interaction within the controlled NAS. This is also why only repair stations can perform these inspections due to this elevated requirement.

Given the dependence on ADS-B, how is that checked periodically (I’m pretty sure it’s not part of the cert but could be mistaken) and should it be?

Its not and not really. ADSB equipment must meet specific standards when produced and installed, similar to equipment certified to perform IFR approaches. So, no other performance checks are usually required just as no regular checks are required for that type of equipment as well.

 

[AV8R_87]

how often do modern transponders fail compared to the ones that generated the requirement for biennial checks?

Antennas and their connections can degrade suddenly.
I've had a Garmin transponder (solid state) fail in a low output power state.