ENTERED TCA WHEN ASSUMED CLEAR OF THE OUTER BOUNDARY.

Narrative

DEPARTED BFI APPROX XB00 UTC VFR RWY 31L. TWR CLRED; LEFT TURN END OF RWY (DECLARED DIRECTION TO BREMERTON INITIAL CONTACT) HDG SELECTED 270 DEGS MAGNETIC; GND CHK AND ALT 800'; XING THE SHORELINE AT 1000' STARTED TO CLB TO 1500'; GND CHK BLAKE ISLAND; TIME OUT APPROX 14 MINS; TWR TFC ADVISORIES INBND/OUTBND. BREMERTON; KITSAP NDB 206 VERIFIED AND AUDIO ON; ADF NEEDLE CENTERED FOR DIRECT TO BEACON; HDG 258 DEGS; TIME OUT NOW 17 MINS; INITIATED CLB TO 3000'; GND CHK PT ORCHARD; TIME OUT 21 MINS; LISTENING BREMERTON UNICOM 122.7 AND BFI TWR; GND CHK; BREMERTON ON MY RIGHT; PT ORCHARD CHANNEL BELOW; BREMERTON ARPT SIGHTED; TIME OUT 25 MINS; INITIATED CLB TO 3500'. BFI TWR CTLR REQUESTED MY PRESENT ALT. RPTED BACK 3500' LEVEL. CTLR STATED 'SHOWING 3600';' AND THAT THE FLOOR WAS 3000'. REQUESTED IMMEDIATE DSCNT TO 3000'. COMPLIED IMMEDIATELY AND FURTHER DSNDED TO 2500'. NOTHING ELSE WAS COMMUNICATED; AND AS I WAS APPROX 8 MI FROM THE BREMERTON ARPT REQUESTED FREQ CHANGE. CHANGE APPROVED. COMPLETED MY MISSION AND RETURNED TO BFI HOME BASE W/O FURTHER INCIDENT OR COMMENT. PREVENTION: MAINTAIN VFR BELOW THE FLOOR TILL ARRIVING AT DEST ARPT AREA; THEN DECLARE INTENTIONS AND ALT.