Narrative:

Departing bfi runway 31R to direct yakima on VFR flight plan. Initial tower controller before takeoff asked me for right turn and then turn on course via 'the island' to stay clear of renton, wa, airspace. Said I was unfamiliar with that VFR chkpoint and he explained. Upon takeoff, tower asked for right downwind departure. I executed that, but it did take me over renton tower-controled airspace when I was in contact only with bfi tower. I tried to clarify, but by that time I was just past bfi heading 130 degrees and it was too late. In retrospect, I likely should have combined the two: not turned downwind until a couple of mi crosswind on a heading of about 040 degrees. Alternatively, the tower could have clarified where/when he wanted downwind turn when he specifically asked for that. I generally think of a downwind departure as being 'when altitude permits a safe turn to downwind,' which is pretty close-in when climbing from sea level in this aircraft. I think we both could have done a better job of it -- though, for the record, the responsibility lies in the cockpit, in my view. (I did not have current sea terminal area chart open and available, as well as current sea sectional.)

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Original NASA ASRS Text

Title: BEING UNFAMILIAR WITH THE AREA, A PA28 PLT WAS UNABLE TO UNDERSTAND AND COMPLY WITH TWR INSTRUCTIONS TO REMAIN CLR OF RENTON, WA, AIRSPACE.

Narrative: DEPARTING BFI RWY 31R TO DIRECT YAKIMA ON VFR FLT PLAN. INITIAL TWR CTLR BEFORE TKOF ASKED ME FOR R TURN AND THEN TURN ON COURSE VIA 'THE ISLAND' TO STAY CLR OF RENTON, WA, AIRSPACE. SAID I WAS UNFAMILIAR WITH THAT VFR CHKPOINT AND HE EXPLAINED. UPON TKOF, TWR ASKED FOR R DOWNWIND DEP. I EXECUTED THAT, BUT IT DID TAKE ME OVER RENTON TWR-CTLED AIRSPACE WHEN I WAS IN CONTACT ONLY WITH BFI TWR. I TRIED TO CLARIFY, BUT BY THAT TIME I WAS JUST PAST BFI HDG 130 DEGS AND IT WAS TOO LATE. IN RETROSPECT, I LIKELY SHOULD HAVE COMBINED THE TWO: NOT TURNED DOWNWIND UNTIL A COUPLE OF MI XWIND ON A HDG OF ABOUT 040 DEGS. ALTERNATIVELY, THE TWR COULD HAVE CLARIFIED WHERE/WHEN HE WANTED DOWNWIND TURN WHEN HE SPECIFICALLY ASKED FOR THAT. I GENERALLY THINK OF A DOWNWIND DEP AS BEING 'WHEN ALT PERMITS A SAFE TURN TO DOWNWIND,' WHICH IS PRETTY CLOSE-IN WHEN CLBING FROM SEA LEVEL IN THIS ACFT. I THINK WE BOTH COULD HAVE DONE A BETTER JOB OF IT -- THOUGH, FOR THE RECORD, THE RESPONSIBILITY LIES IN THE COCKPIT, IN MY VIEW. (I DID NOT HAVE CURRENT SEA TERMINAL AREA CHART OPEN AND AVAILABLE, AS WELL AS CURRENT SEA SECTIONAL.)

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.