Transponder Check

[tonycondon]

What is involved in a VFR Transponder check? i've tried to read through Pt. 43 and various appendices and it seems to me that it is just a signal strength test and encoder accuracy check? Does the VFR check require a cross reference to the aircrafts altimeter?

 

[Greg Bockelman]

What is involved in a VFR Transponder check? i've tried to read through Pt. 43 and various appendices and it seems to me that it is just a signal strength test and encoder accuracy check? Does the VFR check require a cross reference to the aircrafts altimeter?

I just did one of those on the 195. It did not involve anything inside the plane other than turning the Transponder on. In other words, you have it about right. As far as I know, it did not involve anything in the Pitot Static system. The test took about 5 minutes and the paperwork took about 45 minutes. Go figure.

 

[tonycondon]

cool greg. i need to call an avionics shop. i wonder if they can just do the test on the bench or if it needs to be installed. maybe I can find a guy with a portable setup if it needs to be installed.

 

[Greg Bockelman]

cool greg. i need to call an avionics shop. i wonder if they can just do the test on the bench or if it needs to be installed. maybe I can find a guy with a portable setup if it needs to be installed.

I can't answer 100%, but I would bet that it needs to be installed because you have to get the signal to the transponder. That involves the antenna, cable, transponder, encoder and all the connections.

Glider? Just haul it to the shop.

 

[tonycondon]

I can't answer 100%, but I would bet that it needs to be installed because you have to get the signal to the transponder. That involves the antenna, cable, transponder, encoder and all the connections.

Glider? Just haul it to the shop.

true, but the antenna, cable, tranpsonder, and encoder are all sitting on my dining room table right now.

trailering it to the shop would normally be a fine option, but right now the trailer is stripped down to the frame. if there is a reasonable sounding avionics guy at a nearby airport i could always take a tow and glide in i guess.

 

[ScottM]

true, but the antenna, cable, tranpsonder, and encoder are all sitting on my dining room table right now.

trailering it to the shop would normally be a fine option, but right now the trailer is stripped down to the frame. if there is a reasonable sounding avionics guy at a nearby airport i could always take a tow and glide in i guess.

I would be surprised if you could not find an avionics guy who makes house calls for these sorts of things. There a couple in this area that do exactly that. The come to the airport and knock out several checks and work.

 

[SCCutler]

I would be surprised if you could not find an avionics guy who makes house calls for these sorts of things. There a couple in this area that do exactly that. The come to the airport and knock out several checks and work.

What he said.

Some guys around here who specialize in roving pitot, static and transponder checks... and they do nothing else.

 

[tonycondon]

hopefully i can find one of 'those guys'. otherwise the airport about 3 miles from the gliderport does transponder checks. wouldnt be too difficult to take a short tow and land on their ramp. do the check and get a tow back. plus it'd be fun

 

[t0r0nad0]

Yeah, we just had that done on the raffle plane - guy came out to the airport where the annual was being done and did the test there.

 

[ScottM]

hopefully i can find one of 'those guys'. otherwise the airport about 3 miles from the gliderport does transponder checks. wouldnt be too difficult to take a short tow and land on their ramp. do the check and get a tow back. plus it'd be fun

Check with some of the local wrenches, they might already know who can do this at your airport.

 

[tonycondon]

the place next door can do it for 80 bucks if i take the glider there, or 160 if they come to me. M-F.

 

[poadeleted20]

The "VFR check" is the Appendix F test, while the "IFR check" is the Appendix E check. As noted, the Appendix F test is pretty quick and easy, but even for VFR, "Following any installation or maintenance on an ATC transponder where data correspondence error could be introduced," you must also do the paragraph (c) portion of the Appendix E check, which is done "on wing" and requires a lot more than the Appendix F check. Ref 91.413 and Part 43 Appendices E and F.

 

[tonycondon]

ok so they'll have to check my altimeter against the encoder. Up to 125 ft error though so I think I'll be OK. IIRC when I tested my altimeter on the stand last year it was less than 50 or 75 ft error at the worst.

I suppose Im going to have to hunt down the gremlins in my static system, so that I can hook everything up, so that the mechanic can disconnect everything to hook up to the encoder and altimeter...