Narrative:

While acting as the PNF and as flight instructor, the following event occurred while inside hef class D airspace. We were cleared to land runway 34L at manassas regional airport. While entering a 2 mi left base for runway 34L, we were given 2 TA's: 1) traffic on the left downwind runway 34L does not have you in sight, 2) traffic on short final runway 34L, report them in sight. I was handling the radios as the safety pilot. I reported both TA's in sight. On short final, the runway was not completely clear from the aircraft that landed before us. I advised my student to go around. Hef is inside the washington ADIZ. I was on an ADIZ flight plan to hef and was squawking my discrete code. As we did the go around, hef tower advised us to squawk XXXX, I squawked 1200, and we made left traffic for runway 34L. Approximately 1-2 mins later, tower stated they received a call from approach about my 1200 squawk. Hef tower asked me to squawk XXXX. I immediately complied with no further incident. Solution: keep close watch on 1200 squawks inside the ADIZ. Advise controllers to alert all pilots who go around to verify the XXXX squawk, especially after these high workload sits, like runway not safe go around's.

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Original NASA ASRS Text

Title: PLT AND INSTRUCTOR ABOARD PA44 MAKE A GAR AT HEF IN THE DC ADIZ. WHEN ADVISED TO SQUAWK XXXX PER CLOSED PATTERN ADIZ PROCS, CHANGED XPONDER CODE TO 1200 INSTEAD.

Narrative: WHILE ACTING AS THE PNF AND AS FLT INSTRUCTOR, THE FOLLOWING EVENT OCCURRED WHILE INSIDE HEF CLASS D AIRSPACE. WE WERE CLRED TO LAND RWY 34L AT MANASSAS REGIONAL ARPT. WHILE ENTERING A 2 MI L BASE FOR RWY 34L, WE WERE GIVEN 2 TA'S: 1) TFC ON THE L DOWNWIND RWY 34L DOES NOT HAVE YOU IN SIGHT, 2) TFC ON SHORT FINAL RWY 34L, RPT THEM IN SIGHT. I WAS HANDLING THE RADIOS AS THE SAFETY PLT. I RPTED BOTH TA'S IN SIGHT. ON SHORT FINAL, THE RWY WAS NOT COMPLETELY CLR FROM THE ACFT THAT LANDED BEFORE US. I ADVISED MY STUDENT TO GO AROUND. HEF IS INSIDE THE WASHINGTON ADIZ. I WAS ON AN ADIZ FLT PLAN TO HEF AND WAS SQUAWKING MY DISCRETE CODE. AS WE DID THE GAR, HEF TWR ADVISED US TO SQUAWK XXXX, I SQUAWKED 1200, AND WE MADE L TFC FOR RWY 34L. APPROX 1-2 MINS LATER, TWR STATED THEY RECEIVED A CALL FROM APCH ABOUT MY 1200 SQUAWK. HEF TWR ASKED ME TO SQUAWK XXXX. I IMMEDIATELY COMPLIED WITH NO FURTHER INCIDENT. SOLUTION: KEEP CLOSE WATCH ON 1200 SQUAWKS INSIDE THE ADIZ. ADVISE CTLRS TO ALERT ALL PLTS WHO GO AROUND TO VERIFY THE XXXX SQUAWK, ESPECIALLY AFTER THESE HIGH WORKLOAD SITS, LIKE RWY NOT SAFE GAR'S.

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.