Guest DWB Posted October 18, 2011 Share Posted October 18, 2011 Just returned from flight to Mudgee, Airborne Avionics, to have my Transponder, Bendix King KT76A, re-certified. It is getting to be a sick puppy apparently, but managed to scrape through OK. Was told I would have to replace it before the next check due in 2 years as parameters are tightening up & it won't meet requirements then. I was intrigued that only the txpdr had to be checked & not the encoder as well. Encoders only have to be checked on IFR AC. Link to comment Share on other sites More sharing options...
Guest avi8tr Posted October 18, 2011 Share Posted October 18, 2011 Yep that's right... recent changes have meant that only the transponder needs to be checked now for the code output. Seems crazy really! Link to comment Share on other sites More sharing options...
Scotty 1 Posted October 18, 2011 Share Posted October 18, 2011 How can that be? The encoder gives the height in mode C. Wrong height could lead to all sorts of trouble. Seems dumb to me. I was going to get mine checked in the Hornet but now I don't know if it is worth it. I set the alt to standard atmosphere and the transponder was reading 300ft different. So that is ok? Cheers Scotty Link to comment Share on other sites More sharing options...
Guest avi8tr Posted October 18, 2011 Share Posted October 18, 2011 From memory the tolerance somewhere less than 200ft. I got picked up on it recently in a hired aircraft, I was just over the tolerance. The only option would be to have it adjusted or adjust your QNH and you know that option 2 is not the correct one. The RAD43/47 requirements changed a couple of years back and they dropped the altitude calibration requirement - seems silly though, it's one thing that you want to be correct. Link to comment Share on other sites More sharing options...
Guest DWB Posted October 18, 2011 Share Posted October 18, 2011 I set the alt to standard atmosphere and the transponder was reading 300ft different. So that is ok? Scotty I'm curious - how did you know what altitude the transponder was transmitting? Do the latest ones do that? What brand / model is yours. Link to comment Share on other sites More sharing options...
Guest Michael Coates Posted October 18, 2011 Share Posted October 18, 2011 Many units will actually show you the alt they are squawking.... IMO the Garmin 327 is the best and cheapest currently available and it has automatic Mode C on take-off and has some nice things built in like a flight tomes etc.... Link to comment Share on other sites More sharing options...
Scotty 1 Posted October 18, 2011 Share Posted October 18, 2011 Scotty I'm curious - how did you know what altitude the transponder was transmitting? Do the latest ones do that? What brand / model is yours.Cheers Dexter Hi Dex .Mine is the Garmin 327 with a Ameri-King AK 350 encoder. As Michael said it does display the alt in ft, mtrs or FL. Factory setting was FL so I changed it to ft and thats when I noticed the difference. I was setting it up in the hanger so not a real test yet. The encoder is adjustable with the directions in the manual but when I noticed the difference I made a note to have it callibrated but if thay don't do the encoder anymore whats the point. I won't be in CTA Cheers Scotty Link to comment Share on other sites More sharing options...
Guest DWB Posted October 18, 2011 Share Posted October 18, 2011 Yeah Scotty have since looked at those Garmin's on the net & I guess I can see one in my panel within the next 2 years. With regards installing a new one, the tech out there today told me that when I install one I will have to have it certified by a tech after installation. When he checked mine today it read 1100' on his test gadget. Mudgee is 1545' Pressure was 1032Hpa. Winding altimeter back to 1013 = 400' (round figures) so mine was right. Maybe if it was wrong he would have adjusted the encoder. Maybe I'll ask more questions next time. Bottom line, whether or not you fly into CTA, your transponder has to be certified when it is installed then every 2 years or you are not supposed to use it. That's my take on it but I am happy to be corrected by anyone. Cheers Dexter Link to comment Share on other sites More sharing options...
Wayne T Mathews Posted October 18, 2011 Share Posted October 18, 2011 Hi Guys, My take on transponders is that if you have it you should use it, and it should be checked by a radio doctor every two years so as to comply with CASA AD/RAD/47, irrespective of whether you are or are not going into controlled airspace. I say that because if you're flying at Narrabri say, with your transponder on, and an RPT is inbound, he'll "see" you on his TCAS and make decisions accordingly. If your transponder is lying to him though, can you see the potential for a disaster? Bottom line, in my opinion: If the aircraft I'm in has a transponder that complies with RAD/47, I'll turn it on and use it. But if the transponder doesn't comply with RAD/47, I won't turn it on. Because when the RPT guys are making separation decisions that relate to me, I'd rather they had no TCAS information about me than what may be wrong TCAS information. Link to comment Share on other sites More sharing options...
Guest avi8tr Posted October 18, 2011 Share Posted October 18, 2011 Yep, the transponder needs to be tested every 2 years with an entry in the maintenance release or airframe log book if you don't have one. If not calibrated it must be rendered and labelled as un-serviceable. Contrary to what many people believe, RA-Aus aircraft are not exempt from this requirement. Link to comment Share on other sites More sharing options...
bas Posted October 19, 2011 Share Posted October 19, 2011 The only option would be to have it adjusted or adjust your QNH and you know that option 2 is not the correct one. So not correct that you should never even consider this! Fly the correct altitude, ATC will call you up and verify, then they will put a correction in for the remainder of your flight. If you fiddle with QNH because you know the encoder is 400' out, you WILL be flying on the wrong altitude! Link to comment Share on other sites More sharing options...
Guest avi8tr Posted October 19, 2011 Share Posted October 19, 2011 That's right Bas, not option 2! You'd have to think quickly on your feet if they told you that it was out and come up with a good answer otherwise they'll call your bluff and tell you that you're not welcome in CTA. Link to comment Share on other sites More sharing options...
Scotty 1 Posted October 19, 2011 Share Posted October 19, 2011 Hi Guys,My take on transponders is that if you have it you should use it, and it should be checked by a radio doctor every two years so as to comply with CASA AD/RAD/47, irrespective of whether you are or are not going into controlled airspace. I say that because if you're flying at Narrabri say, with your transponder on, and an RPT is inbound, he'll "see" you on his TCAS and make decisions accordingly. If your transponder is lying to him though, can you see the potential for a disaster? Bottom line, in my opinion: If the aircraft I'm in has a transponder that complies with RAD/47, I'll turn it on and use it. But if the transponder doesn't comply with RAD/47, I won't turn it on. Because when the RPT guys are making separation decisions that relate to me, I'd rather they had no TCAS information about me than what may be wrong TCAS information. Thats how I see it too Wayne and mine will be tested and certified but it worried me when it was said that the encoder is not tested. Good to get the frequency right but what good is that if you are transmitting the wrong height? I will ask a few questions before I book it in to be tested. Cheers Scotty Link to comment Share on other sites More sharing options...
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