Narrative:

I was flying a C182 from fdk to fme, a distance of 35 NM. The trip requires travel into the washington ADIZ. Entering the ADIZ, a pilot must file VFR ADIZ flight plan by phone with a local FSS before departure and receive a discrete transponder code from potomac TRACON, either by phone or in the air. I filed a VFR flight plan with leesburg FSS at about XA00 and departed frederick airport about XA15. I departed the pattern and during climb out attempted to contact potomac approach for my transponder code. The transmission from my aircraft was broken at times due to an intermittent yoke switch. The WX was clear but with mild to moderate turbulence. The controller seemed frustrated with our communications and requested that I recontact him just before entering the ADIZ. I was able to establish contact with potomac about 3 NM before entering the defense zone. I received a transponder code and proceeded on course. Immediately after receiving the code and entering it into the transponder, the potomac controller informed me that, although I was outside the defense perimeter when I asked for my code, he did not appreciate the short distance I had allowed. I indicated that it was not intentional but I was following his request and I was distraction by the radio and turbulence issues. The controller informed me 'not to make excuse.' I thanked him and continued on. The balance of the flight was quite bumpy, but without incident. 4 mi from tipton airport, potomac terminated radar service, requested that I remain on my beacon code until landing and frequency change to tipton unicom approved. The flight lasted about 30 mins. Shortly thereafter, I received a call from the FBO at tipton reporting that potomac TRACON wanted to speak to me by phone. I returned the call immediately and supervisor informed me that I had violated ADIZ regulations by switching my transponder code to 1200 for VFR some time before landing and formal charges would follow. I have flown within the washington ADIZ since its inception. I know the procedures and I have never before switched transponder codes within the perimeter. I believe unforeseen circumstances are the cause for the transponder code change, not negligence. The C182 I was flying has an altitude encoding transponder with a VFR button that switches the broadcast code to 1200 at activation. The VFR button is less than 1.75 inches from the flap activation lever. The flap lever is located on the copilot's side to the left and behind the copilot's yoke. I have found, upon further investigation, that it is very easy to push the VFR switch on the transponder with my thumb, while activating the flap switch with my index finger. I have found through conversation with FSDO, a preflight process many pilots follow is to receive the transponder code by phone before departure. The pilot never notices that the code has been changed to 1200 for VFR flight. Summary: I was unaware of the possibility the transponder can be reset by inadvertent bumping. The moderate turbulence experienced during the flight contributed to pilot distraction and the possibility of bumping the VFR button. The communication problems contributed to pilot distraction and the attitude of the ATC controller. The termination of radar services and change of communication frequency from ATC to airport unicom prevented the controller from alerting me of the transponder problem. The controller had me under constant observation until landing so there was no security threat. I did not know a problem existed until receiving a phone call from potomac TRACON informing me of a violation. Corrective actions: I don't believe the transponder manufacturer ever anticipated the possibility a transponder code could be changed inadvertently. I really do not see a valid reason for the button other than convenience. Maybe the button can be deactivated. I believe the controller had an axe to grind and took the opportunity to file a complaint against me. He has the discretion to dismiss the incident and also let the pilot know by phone what occurred.

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Original NASA ASRS Text

Title: FLYING IN TURBULENT CONDITIONS, PLT OF C182 VIOLATES DC ADIZ PROCS WHEN HE ACCIDENTALLY PUSHES 'VFR' BUTTON ON XPONDER WHILE ACTIVATING FLAP EXTENSION UTILIZING SWITCH IN CLOSE PROX TO THE 'VFR' BUTTON.

Narrative: I WAS FLYING A C182 FROM FDK TO FME, A DISTANCE OF 35 NM. THE TRIP REQUIRES TRAVEL INTO THE WASHINGTON ADIZ. ENTERING THE ADIZ, A PLT MUST FILE VFR ADIZ FLT PLAN BY PHONE WITH A LCL FSS BEFORE DEP AND RECEIVE A DISCRETE XPONDER CODE FROM POTOMAC TRACON, EITHER BY PHONE OR IN THE AIR. I FILED A VFR FLT PLAN WITH LEESBURG FSS AT ABOUT XA00 AND DEPARTED FREDERICK ARPT ABOUT XA15. I DEPARTED THE PATTERN AND DURING CLBOUT ATTEMPTED TO CONTACT POTOMAC APCH FOR MY XPONDER CODE. THE XMISSION FROM MY ACFT WAS BROKEN AT TIMES DUE TO AN INTERMITTENT YOKE SWITCH. THE WX WAS CLR BUT WITH MILD TO MODERATE TURB. THE CTLR SEEMED FRUSTRATED WITH OUR COMS AND REQUESTED THAT I RECONTACT HIM JUST BEFORE ENTERING THE ADIZ. I WAS ABLE TO ESTABLISH CONTACT WITH POTOMAC ABOUT 3 NM BEFORE ENTERING THE DEFENSE ZONE. I RECEIVED A XPONDER CODE AND PROCEEDED ON COURSE. IMMEDIATELY AFTER RECEIVING THE CODE AND ENTERING IT INTO THE XPONDER, THE POTOMAC CTLR INFORMED ME THAT, ALTHOUGH I WAS OUTSIDE THE DEFENSE PERIMETER WHEN I ASKED FOR MY CODE, HE DID NOT APPRECIATE THE SHORT DISTANCE I HAD ALLOWED. I INDICATED THAT IT WAS NOT INTENTIONAL BUT I WAS FOLLOWING HIS REQUEST AND I WAS DISTR BY THE RADIO AND TURB ISSUES. THE CTLR INFORMED ME 'NOT TO MAKE EXCUSE.' I THANKED HIM AND CONTINUED ON. THE BAL OF THE FLT WAS QUITE BUMPY, BUT WITHOUT INCIDENT. 4 MI FROM TIPTON ARPT, POTOMAC TERMINATED RADAR SVC, REQUESTED THAT I REMAIN ON MY BEACON CODE UNTIL LNDG AND FREQ CHANGE TO TIPTON UNICOM APPROVED. THE FLT LASTED ABOUT 30 MINS. SHORTLY THEREAFTER, I RECEIVED A CALL FROM THE FBO AT TIPTON RPTING THAT POTOMAC TRACON WANTED TO SPEAK TO ME BY PHONE. I RETURNED THE CALL IMMEDIATELY AND SUPVR INFORMED ME THAT I HAD VIOLATED ADIZ REGS BY SWITCHING MY XPONDER CODE TO 1200 FOR VFR SOME TIME BEFORE LNDG AND FORMAL CHARGES WOULD FOLLOW. I HAVE FLOWN WITHIN THE WASHINGTON ADIZ SINCE ITS INCEPTION. I KNOW THE PROCS AND I HAVE NEVER BEFORE SWITCHED XPONDER CODES WITHIN THE PERIMETER. I BELIEVE UNFORESEEN CIRCUMSTANCES ARE THE CAUSE FOR THE XPONDER CODE CHANGE, NOT NEGLIGENCE. THE C182 I WAS FLYING HAS AN ALT ENCODING XPONDER WITH A VFR BUTTON THAT SWITCHES THE BROADCAST CODE TO 1200 AT ACTIVATION. THE VFR BUTTON IS LESS THAN 1.75 INCHES FROM THE FLAP ACTIVATION LEVER. THE FLAP LEVER IS LOCATED ON THE COPLT'S SIDE TO THE L AND BEHIND THE COPLT'S YOKE. I HAVE FOUND, UPON FURTHER INVESTIGATION, THAT IT IS VERY EASY TO PUSH THE VFR SWITCH ON THE XPONDER WITH MY THUMB, WHILE ACTIVATING THE FLAP SWITCH WITH MY INDEX FINGER. I HAVE FOUND THROUGH CONVERSATION WITH FSDO, A PREFLT PROCESS MANY PLTS FOLLOW IS TO RECEIVE THE XPONDER CODE BY PHONE BEFORE DEP. THE PLT NEVER NOTICES THAT THE CODE HAS BEEN CHANGED TO 1200 FOR VFR FLT. SUMMARY: I WAS UNAWARE OF THE POSSIBILITY THE XPONDER CAN BE RESET BY INADVERTENT BUMPING. THE MODERATE TURB EXPERIENCED DURING THE FLT CONTRIBUTED TO PLT DISTR AND THE POSSIBILITY OF BUMPING THE VFR BUTTON. THE COM PROBS CONTRIBUTED TO PLT DISTR AND THE ATTITUDE OF THE ATC CTLR. THE TERMINATION OF RADAR SVCS AND CHANGE OF COM FREQ FROM ATC TO ARPT UNICOM PREVENTED THE CTLR FROM ALERTING ME OF THE XPONDER PROB. THE CTLR HAD ME UNDER CONSTANT OBSERVATION UNTIL LNDG SO THERE WAS NO SECURITY THREAT. I DID NOT KNOW A PROB EXISTED UNTIL RECEIVING A PHONE CALL FROM POTOMAC TRACON INFORMING ME OF A VIOLATION. CORRECTIVE ACTIONS: I DON'T BELIEVE THE XPONDER MANUFACTURER EVER ANTICIPATED THE POSSIBILITY A XPONDER CODE COULD BE CHANGED INADVERTENTLY. I REALLY DO NOT SEE A VALID REASON FOR THE BUTTON OTHER THAN CONVENIENCE. MAYBE THE BUTTON CAN BE DEACTIVATED. I BELIEVE THE CTLR HAD AN AXE TO GRIND AND TOOK THE OPPORTUNITY TO FILE A COMPLAINT AGAINST ME. HE HAS THE DISCRETION TO DISMISS THE INCIDENT AND ALSO LET THE PLT KNOW BY PHONE WHAT OCCURRED.

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.