Finished the pitot static transponder test today. The FAA-certified test station had some specialized electronic and pneumatic test sets along with hoses and adapters to fit every kind of pitot and static port. One test set simulated an ATC radar to get the transponder to reply and then displayed the altitude being transmitted. Another set would input the correct pressures for any and all speeds, altitudes and VSI rates. Very impressive when it all works. When (not if) the aircraft hoses leak, then comes the troubleshooting at shop rates. Then the sticker shock got impressive too. (This also says nothing about the correct location of any particular pitot tube or static port(s) installation.) One electrical problem was the xponder would not transmit mode C. There was serious talk of tearing the wire bundle apart to verify that all those grey-code wires were correctly installed. And are you sure that funky little serial to grey-code box is working? Perusing the Dynon D-10A installation manual, there was mention of the procedure to tell the D10A to recognize that there was a xponder waiting for the one-way altitude message. A few just-right button jabs on the D10A and the computer magic happened. Then the read-out was 180 feet off at all altitudes. OK, you got to pull the D10A and send it back to the factory for cal and then we can start all over. Not so fast: the installation manual calls out the procedure. Do a few button jabs and dial in the correction factor. More computer magic happens. Then the barometric correction would not drive the read-out beyond minus 1200-foot altitude like the test sheet asks for. (I am reasonably sure there is no place on this planet that low.) Dynon Tech Support was quick to respond in writing that the D10A read-out only went from minus 1,200 feet to 30,000 feet per the FAA standards. The FAA is considering a change to the test sheet. So, the pitot static transponder system for N6242 is good to go. I collected an autograph in the aircraft log book, applied plastic to the bill, and can just barely wait to do it again in two years.
Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA smw...@md.metrocast.net
