Narrative:

While flying a C182 skylane, I inadvertently committed an ADIZ violation. I was PIC, giving a proficiency check to another pilot. We departed freeway (W00) to go to the maryland eastern shore practice area. Freeway is located in the washington dc air defense identify zone. Upon departing freeway, we were squawking our assigned discrete code, xyzw. We established radar and radio contact with potomac TRACON and were told to proceed. After several mins en route, about 6-8 mi east of freeway, the controller gave a frequency change. The new controller immediately gave us another frequency change. The third controller asked for an identify and for us to state our position. I then noticed that the transponder was squawking 1200 (VFR). I immediately reset it to our discrete code. Soon thereafter, the controller questioned us as to whether we had been squawking VFR earlier. We advised 'affirmative,' stating that we had a transponder problem. He then gave us a telephone number to call when we got on the ground. We landed at easton (esn) and I called the number and answered a list of questions. Here's what I think happened! This aircraft has a commercial vendor transponder. This transponder has a 'VFR' button on its panel that, when pushed, resets the code to 1200. Apparently, I somehow bumped that button thereby resetting the transponder code to 1200. Another possibility is that I pushed the 'VFR' button when asked to identify.

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Original NASA ASRS Text

Title: PLT OF C182 INADVERTENTLY CHANGES SQUAWK TO VFR WHILE IN DC ADIZ.

Narrative: WHILE FLYING A C182 SKYLANE, I INADVERTENTLY COMMITTED AN ADIZ VIOLATION. I WAS PIC, GIVING A PROFICIENCY CHK TO ANOTHER PLT. WE DEPARTED FREEWAY (W00) TO GO TO THE MARYLAND EASTERN SHORE PRACTICE AREA. FREEWAY IS LOCATED IN THE WASHINGTON DC AIR DEFENSE IDENT ZONE. UPON DEPARTING FREEWAY, WE WERE SQUAWKING OUR ASSIGNED DISCRETE CODE, XYZW. WE ESTABLISHED RADAR AND RADIO CONTACT WITH POTOMAC TRACON AND WERE TOLD TO PROCEED. AFTER SEVERAL MINS ENRTE, ABOUT 6-8 MI E OF FREEWAY, THE CTLR GAVE A FREQ CHANGE. THE NEW CTLR IMMEDIATELY GAVE US ANOTHER FREQ CHANGE. THE THIRD CTLR ASKED FOR AN IDENT AND FOR US TO STATE OUR POS. I THEN NOTICED THAT THE XPONDER WAS SQUAWKING 1200 (VFR). I IMMEDIATELY RESET IT TO OUR DISCRETE CODE. SOON THEREAFTER, THE CTLR QUESTIONED US AS TO WHETHER WE HAD BEEN SQUAWKING VFR EARLIER. WE ADVISED 'AFFIRMATIVE,' STATING THAT WE HAD A XPONDER PROB. HE THEN GAVE US A TELEPHONE NUMBER TO CALL WHEN WE GOT ON THE GND. WE LANDED AT EASTON (ESN) AND I CALLED THE NUMBER AND ANSWERED A LIST OF QUESTIONS. HERE'S WHAT I THINK HAPPENED! THIS ACFT HAS A COMMERCIAL VENDOR XPONDER. THIS XPONDER HAS A 'VFR' BUTTON ON ITS PANEL THAT, WHEN PUSHED, RESETS THE CODE TO 1200. APPARENTLY, I SOMEHOW BUMPED THAT BUTTON THEREBY RESETTING THE XPONDER CODE TO 1200. ANOTHER POSSIBILITY IS THAT I PUSHED THE 'VFR' BUTTON WHEN ASKED TO IDENT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.