Narrative:

Following 2 weeks of long flying days with minimal rest, I was dispatched on a flight from ZZZ1-ZZZ2-gai-pdk. I was the sic for the trip and the PF for the first 2 legs. On initial taxi out we noticed the pitch trim was inoperative and therefore would be hand flying some long legs in very busy airspace. Upon completing my 2 legs I commented to the captain/PIC that I was 'cooked' and glad he was flying now. During descent into gai I twice attempted to get ATIS/WX. Though it was scratchy both times, I got the winds and subsequently never found time to rechk it. Later on the ground, it was found to give warning to inbound aircraft to maintain a discreet transponder code until touchdown. When we were approximately 3 NM from gai, we cancelled IFR. Controller apparently said 'cancellation received, maintain VFR, keep your code until landing.' I heard what I expected to hear 'cancellation received, squawk VFR...' hence, I inadvertently changed our code to 1200. After shutdown the FBO personnel instructed us to call approach. The supervisor advised us that in squawking 1200 we had violated the ADIZ procedure to have a discrete code at all times. We were not willfully attempting to violate the ADIZ or its procedures. Given the demands of hand flying the aircraft, flying into the sun, multiple VFR aircraft in the vicinity, and my tiredness, I defaulted to habit and squawked 1200 when canceling IFR as is normal 99.99% of the time. We made no threatening movements and only entered the pattern and landed. Obviously approach knew who we were and what we were doing as they tracked us and contacted us. Thus we apparently violated the 'letter' of the NOTAM, but not the intended meaning (to protect national assets) potomac approach supervisor advised he was writing up the violation and recorded the PIC's contact information.

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Original NASA ASRS Text

Title: A C550 IN AN ADIZ MISSED AN ATIS ANNOUNCEMENT DUE TO CREW FATIGUE, ACFT HANDLING AND ENVIRONMENTAL CONDITIONS THAT INBOUND ACFT SQUAWK A DISCRETE CODE UNTIL LNDG.

Narrative: FOLLOWING 2 WKS OF LONG FLYING DAYS WITH MINIMAL REST, I WAS DISPATCHED ON A FLT FROM ZZZ1-ZZZ2-GAI-PDK. I WAS THE SIC FOR THE TRIP AND THE PF FOR THE FIRST 2 LEGS. ON INITIAL TAXI OUT WE NOTICED THE PITCH TRIM WAS INOP AND THEREFORE WOULD BE HAND FLYING SOME LONG LEGS IN VERY BUSY AIRSPACE. UPON COMPLETING MY 2 LEGS I COMMENTED TO THE CAPT/PIC THAT I WAS 'COOKED' AND GLAD HE WAS FLYING NOW. DURING DSCNT INTO GAI I TWICE ATTEMPTED TO GET ATIS/WX. THOUGH IT WAS SCRATCHY BOTH TIMES, I GOT THE WINDS AND SUBSEQUENTLY NEVER FOUND TIME TO RECHK IT. LATER ON THE GND, IT WAS FOUND TO GIVE WARNING TO INBOUND ACFT TO MAINTAIN A DISCREET XPONDER CODE UNTIL TOUCHDOWN. WHEN WE WERE APPROX 3 NM FROM GAI, WE CANCELLED IFR. CTLR APPARENTLY SAID 'CANCELLATION RECEIVED, MAINTAIN VFR, KEEP YOUR CODE UNTIL LNDG.' I HEARD WHAT I EXPECTED TO HEAR 'CANCELLATION RECEIVED, SQUAWK VFR...' HENCE, I INADVERTENTLY CHANGED OUR CODE TO 1200. AFTER SHUTDOWN THE FBO PERSONNEL INSTRUCTED US TO CALL APCH. THE SUPVR ADVISED US THAT IN SQUAWKING 1200 WE HAD VIOLATED THE ADIZ PROC TO HAVE A DISCRETE CODE AT ALL TIMES. WE WERE NOT WILLFULLY ATTEMPTING TO VIOLATE THE ADIZ OR ITS PROCS. GIVEN THE DEMANDS OF HAND FLYING THE ACFT, FLYING INTO THE SUN, MULTIPLE VFR ACFT IN THE VICINITY, AND MY TIREDNESS, I DEFAULTED TO HABIT AND SQUAWKED 1200 WHEN CANCELING IFR AS IS NORMAL 99.99% OF THE TIME. WE MADE NO THREATENING MOVEMENTS AND ONLY ENTERED THE PATTERN AND LANDED. OBVIOUSLY APCH KNEW WHO WE WERE AND WHAT WE WERE DOING AS THEY TRACKED US AND CONTACTED US. THUS WE APPARENTLY VIOLATED THE 'LETTER' OF THE NOTAM, BUT NOT THE INTENDED MEANING (TO PROTECT NATIONAL ASSETS) POTOMAC APCH SUPVR ADVISED HE WAS WRITING UP THE VIOLATION AND RECORDED THE PIC'S CONTACT INFO.

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.