Xpndr Check: How 20th century...

[TedK]

If I have ADS-B Out, why do I need to do a "Transponder Check?"

Can't the FAA take the GPS altitude, the Pressure Altitude, the local Baro Pressure and run it backward to see if my reported Altitude is within limits?

I suspect so...and like we can go online to check our ADS-B performance, why not include this in that report?

Taking it one step further, rather than do the Check once every two years, why can't the FAA let me know if my systems is approaching limits before it goes out of limits?

Maybe this won't work as you go to the FLight Levels and RVSM regime given the tolerances needed, but what if us airbreathers in the lower Angels (cherubs?) got the cost avoidance of avoiding a Xpndr Check every two years?

Please toss you stones now.

Ted

[FlyingRon]

Transponder certification has little to do with altitude. If your mode S interrogation isn't working properly your 1090ES isn't going to mean much. Much of ATC still relies on Mode A/C interrogations as well. Your transponder screws up the timing or side lobe suppression on mode A, and you're going to mislocate you aircraft.

[TedK]

Transponder certification has little to do with altitude. If your mode S interrogation isn't working properly your 1090ES isn't going to mean much. Much of ATC still relies on Mode A/C interrogations as well. Your transponder screws up the timing or side lobe suppression on mode A, and you're going to mislocate you aircraft.

If the Squits are incorrect, then that shows up in today's report. If your Squawks are incorrect, that shows up in improper Geo-Location by secondary radar. Prior to an ADS-B Out GPS Position, it was more difficult for the ATC system to determine if your Xpndr timing was correct.

Today, ADS-B provides truth data (with quality data) to allow ATC to easily determine if your Squits and Squawks coincide.

BTW, Multilateration overcomes many of the timing issues and can report sideline transmission exceedences, independent of ADS-B.

GA ought to get something out of NextGen. The Feds now have the tools to inform us when our systems are performing near or outside of limits. I see no reason to do it the way it was done in the Stone Age when this information exists or is easily generated.

[Auburntsts]

So how about going to the source and send an email to the same FAA guys who provide the ADS-B tests results?

[TedK]

So how about going to the source and send an email to the same FAA guys who provide the ADS-B tests results?

Eventually, I intend to approach the FAA, but I would like to test my thesis on this and other boards to see if it is flawed. You only get one chance to get the FAA on your side.