Narrative:

VFR small aircraft was handed off at 5 mi west of dca, en route to bwi. A handwritten strip was handed to me showing the small aircraft assigned altitude of 2500'. ARTS III-a scratch pad information also showed 2500' and no mode C was displayed. I don't recall the small aircraft stating his altitude upon initial contact with my sector and it is not a requirement of an intrafac handoff (7110.65, paragraph 5-38d). The small aircraft was instructed to depart dca heading 070 degrees, vectors to bwi. During the same period an air carrier medium large transport was descending, inbound to dca from ensue/balance. The medium large transport was observed out of 10000' in the right downwind for runway 36 and was on approach frequency. No traffic advisory or alert was issued to the small aircraft single all flight data indicated that the 2 aircraft were vertical separated. The medium large transport altitude entering the downwind would restrict it to no lower than 5000'. After the 2 targets passed a computer generated flight progress strip was brought to me showing the small aircraft VFR flight plan. I also noticed that the small aircraft was romeo equipped and I asked the pilot if his mode C worked. The small aircraft mode C then came on with an indication of 6600'. The mode C verified with the pilot's report and the small aircraft continued his descent for bwi. It was brought to my attention later that medium large transport complained of unk traffic approaching from his right as he entered the downwind. It was then apparent that the small aircraft transitioned the washington TCA at 7500', not at 2500' as was presumed the clearance from the previous controller on departure 1 low. All flight data given to me before the occurrence was showing the small aircraft at 2500' and no evidence to the contrary was available until the computer generated flight progress strip was brought to my sector. The proximity of the 2 aircraft at the time of convergence is unknown to me since the incorrect altitude report mislead me to believe that the small aircraft was going to conflict with another aircraft operating at 2000' within the washington TCA and this controller spent most of his time during this period calling traffic that was not a factor to the small aircraft. These are the facts that were brought to my attention after the occurrence: 1) the small aircraft was cleared to enter the TCA at 2500'. 2) the small transport was apparently at 7500', above the TCA during his entire flight over washington. 3) the incorrect altitude information was incorrectly verified at the time of an interfacility handoff from dulles approach control. 4) the mode C of the small aircraft was turned off and appeared functional after the occurrence.

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Original NASA ASRS Text

Title: SMA HANDED OFF TO ADJACENT FAC AT DIFFERENT ALT THAN SHOWN ON FLT STRIP AND CONFLICTED WITH AN MLG.

Narrative: VFR SMA WAS HANDED OFF AT 5 MI W OF DCA, ENRTE TO BWI. A HANDWRITTEN STRIP WAS HANDED TO ME SHOWING THE SMA ASSIGNED ALT OF 2500'. ARTS III-A SCRATCH PAD INFO ALSO SHOWED 2500' AND NO MODE C WAS DISPLAYED. I DON'T RECALL THE SMA STATING HIS ALT UPON INITIAL CONTACT WITH MY SECTOR AND IT IS NOT A REQUIREMENT OF AN INTRAFAC HDOF (7110.65, PARAGRAPH 5-38D). THE SMA WAS INSTRUCTED TO DEPART DCA HDG 070 DEGS, VECTORS TO BWI. DURING THE SAME PERIOD AN ACR MLG WAS DSNDING, INBND TO DCA FROM ENSUE/BAL. THE MLG WAS OBSERVED OUT OF 10000' IN THE RIGHT DOWNWIND FOR RWY 36 AND WAS ON APCH FREQ. NO TFC ADVISORY OR ALERT WAS ISSUED TO THE SMA SINGLE ALL FLT DATA INDICATED THAT THE 2 ACFT WERE VERT SEPARATED. THE MLG ALT ENTERING THE DOWNWIND WOULD RESTRICT IT TO NO LOWER THAN 5000'. AFTER THE 2 TARGETS PASSED A COMPUTER GENERATED FLT PROGRESS STRIP WAS BROUGHT TO ME SHOWING THE SMA VFR FLT PLAN. I ALSO NOTICED THAT THE SMA WAS ROMEO EQUIPPED AND I ASKED THE PLT IF HIS MODE C WORKED. THE SMA MODE C THEN CAME ON WITH AN INDICATION OF 6600'. THE MODE C VERIFIED WITH THE PLT'S RPT AND THE SMA CONTINUED HIS DSCNT FOR BWI. IT WAS BROUGHT TO MY ATTN LATER THAT MLG COMPLAINED OF UNK TFC APCHING FROM HIS RIGHT AS HE ENTERED THE DOWNWIND. IT WAS THEN APPARENT THAT THE SMA TRANSITIONED THE WASHINGTON TCA AT 7500', NOT AT 2500' AS WAS PRESUMED THE CLRNC FROM THE PREVIOUS CTLR ON DEP 1 LOW. ALL FLT DATA GIVEN TO ME BEFORE THE OCCURRENCE WAS SHOWING THE SMA AT 2500' AND NO EVIDENCE TO THE CONTRARY WAS AVAILABLE UNTIL THE COMPUTER GENERATED FLT PROGRESS STRIP WAS BROUGHT TO MY SECTOR. THE PROX OF THE 2 ACFT AT THE TIME OF CONVERGENCE IS UNKNOWN TO ME SINCE THE INCORRECT ALT RPT MISLEAD ME TO BELIEVE THAT THE SMA WAS GOING TO CONFLICT WITH ANOTHER ACFT OPERATING AT 2000' WITHIN THE WASHINGTON TCA AND THIS CTLR SPENT MOST OF HIS TIME DURING THIS PERIOD CALLING TFC THAT WAS NOT A FACTOR TO THE SMA. THESE ARE THE FACTS THAT WERE BROUGHT TO MY ATTN AFTER THE OCCURRENCE: 1) THE SMA WAS CLRED TO ENTER THE TCA AT 2500'. 2) THE SMT WAS APPARENTLY AT 7500', ABOVE THE TCA DURING HIS ENTIRE FLT OVER WASHINGTON. 3) THE INCORRECT ALT INFO WAS INCORRECTLY VERIFIED AT THE TIME OF AN INTERFAC HDOF FROM DULLES APCH CTL. 4) THE MODE C OF THE SMA WAS TURNED OFF AND APPEARED FUNCTIONAL AFTER THE OCCURRENCE.

Data retrieved from NASA's ASRS site as of August 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.