If your Altitude Encoder is out of spec, functionally, ATC would rather you operate with the transponder on so they get a target, but not in Altitude reporting mode since the altitude is bad data. Most encoders do have an zero and span adjustment. Whether yours can or can't be adjusted is something you might want to determine. Sometimes they get so far out of spec that they can not be corrected. They do fail, but typically they hold their settings without needing to be adjusted. The newer solid state encoders can be adjusted with the firmware.
For IFR flight, a static system check is required. For VFR flight, the static system check is not required. But the transponder check is. Thus the two prices. An IFR transponder check includes a static system pressure and leakdown check as well as the transponder check. A VFR transponder check typically just includes checking the transponder frequency for accuracy and output, and checking and adjusting the Altitude Encoder. To properly adjust the encoder, they will bench check it and your altimeter together and run them from sea level up through 20,000'. They should give you a table showing the errors in your altimeter at 2000' intervals throughout it's range. However, most shops will shortcut the whole process by just verifying that it's all working and within range sitting on the ground and sign it off. That makes a quick buck for them and doesn't waste your time waiting for them to do a certification that you don't really care about to begin with. So yes, it's pretty common for most of the transponder check to get pencil whipped. -Jeff Scott > Sent: Monday, December 23, 2019 at 6:45 PM > From: "Flesner via KRnet" <[email protected]> > To: [email protected] > Cc: Flesner <[email protected]> > Subject: Re: KR> transponder / encoder? > > On 12/23/2019 2:54 PM, Jeff Scott via KRnet wrote: > > While many choose to ignore the 2 year requirement, as Glenn correctly > > points out by posting the reg, a transponder verification check is required > > every 24 months. > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > I'm one of the many up to this point. I read the reg's on when / where > transponder is required, which I basically knew, but with a fair amount > of searching I'm unable to come up with the specifications the unit is > required to meet and if there is a different requirement between IFR and > VFR operations. The young tech at the shop, speaking with a heavy > Chinese accent and hard to understand, quoted two different prices. > One for a static system check and the other for a transponder check. > The first was double the second. > > As a lawyer never ask a question unless he already knows the answer, I'd > like to know what my requirements are before I go back to the shop. > Jeff indicated the encoder is adjustable. The tech indicated it was > not. I've not gotten by the hangar to verify which encoder I have > installed and I'm out of town for Christmas so that will have to wait. > I could just put an inop tag on the transponder and fly legal till I > need it for nest years Gathering but I'd really like to get it operating > "legally" or at least functionally accurate. > > Merry Christmas to all................. > > Larry Flesner > > > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/[email protected]/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to [email protected] > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/[email protected]/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to [email protected]
