Bits and Pieces
Word of the Month - Recycle
By Ian Brown, Editor - Bits and Pieces, EAA 657159
We don't all fly with transponders, but those of us who do find them invaluable on longer flights where we can get flight following.
We're all into recycling these days, but if ATC asks you to "recycle your transponder", they aren't asking you to rip it out and put it in the blue bin. So what are they looking for? Well, they are asking for your help in diagnosing a problem. Most of the time it's because they do not see your Mode C readout.
The first thing you should do is check that your transponder is actually on and set to ALT. Next, you can ask the controller if he sees your "primary target," which means "Can you see me in the horizontal plane?" (And without any transponder information.) You can also ask if the controller can see your transponder at all. If the controller says you are "radar identified", he's telling you he sees your transponder and the code you are squawking but not necessarily your altitude. If they do see your Mode C information, it's worthwhile checking what they are receiving for altitude.
You can try recycling just the code you have been asked to squawk, or switching to standby and back to ALT. Finally, you can recycle power to the transponder, but remember that it may take a few minutes to warm up again.
Your transponder antenna needs to be cleaned and inspected regularly. How many times do we remember to duck under the fuselage to check the transponder antenna? If you'd forgotten to switch your transponder on, don't try to hide it from the ATC. They know we're human, just fess up.
Remember, when testing a transponder with ATC, you should be at least 1,200 feet AGL.