Narrative:

I was descending from 5500 MSL along V-23 through the sea TCA. I had been cleared to operate in the TCA and had a beacon code, contact, etc. I had started my descent some 20 mi out from boeing field (my destination). At one point, the controller said 'leaving the 5000 section of the TCA. Descend below the TCA.' I said I was descending at 500 FPM. I was not told to remain clear of the TCA or to squawk 1200 and change frequency. A min later, the controller informed me I was entering the 3000 ft section of the TCA. At all times I was in a stable 500 FPM rate of descent which would put me right into the pattern at boeing field. (I was on VFR with flight following, all airports on north flow.) when less than 4 mi from boeing, the controller all of a sudden said 'remain clear of the 1100 ft section of the TCA.' I had no idea where that section started. When in a TCA, you are in the TCA, not a segment of it. He asked if I could not avoid it, advise immediately. I said I might not be able to avoid and did he want a left 360 degree and down to 1000 MSL. He said yes, immediately. I was at about 1700 MSL 10 NM from sea VOR. I did the left 360 which put me at 1000 right next to towers which extend up to 1050. I saw them and avoided them. He immediately said 1200 and change frequency. I then contacted boeing tower and diverted east so as to enter on a 45 right traffic for 31L. While no FARS were violated, this was sloppy controling. After 20 mi of descent, a panicked maneuver was requested which could have resulted in a tower strike. If I was cleared into the TCA, I was cleared into all the TCA unless vectored or the clearance somehow revoked (?). Controllers should know that pilots operating in a TCA may not think it as important to know what segment of the TCA they are in. Pilots do not have a moving map depicting their position on a TCA chart. A pilot outside the TCA cares more about where the sections begin and end of course. A good lesson for me as well. Always know where the floor of the TCA is where you are located as you may be instantly required to duck below it and your TCA clearance 'revoked.' callback conversation with reporter revealed the following information: reporter states he has never had such an experience with ATC. After speaking with a friend who is a radar controller, reporter feels he was being vectored below the MVA. When that was accomplished, controller immediately ended radar service. Very dangerous to be so close to those towers.

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Original NASA ASRS Text

Title: SMA CLRED INTO TCA, DSNDING. TOLD HE IS ENTERING LOWER SEGMENT OF TCA, THEN TOLD TO DSND BELOW AND REMAIN CLR OF TCA.

Narrative: I WAS DSNDING FROM 5500 MSL ALONG V-23 THROUGH THE SEA TCA. I HAD BEEN CLRED TO OPERATE IN THE TCA AND HAD A BEACON CODE, CONTACT, ETC. I HAD STARTED MY DSCNT SOME 20 MI OUT FROM BOEING FIELD (MY DEST). AT ONE POINT, THE CTLR SAID 'LEAVING THE 5000 SECTION OF THE TCA. DSND BELOW THE TCA.' I SAID I WAS DSNDING AT 500 FPM. I WAS NOT TOLD TO REMAIN CLR OF THE TCA OR TO SQUAWK 1200 AND CHANGE FREQ. A MIN LATER, THE CTLR INFORMED ME I WAS ENTERING THE 3000 FT SECTION OF THE TCA. AT ALL TIMES I WAS IN A STABLE 500 FPM RATE OF DSCNT WHICH WOULD PUT ME RIGHT INTO THE PATTERN AT BOEING FIELD. (I WAS ON VFR WITH FLT FOLLOWING, ALL ARPTS ON N FLOW.) WHEN LESS THAN 4 MI FROM BOEING, THE CTLR ALL OF A SUDDEN SAID 'REMAIN CLR OF THE 1100 FT SECTION OF THE TCA.' I HAD NO IDEA WHERE THAT SECTION STARTED. WHEN IN A TCA, YOU ARE IN THE TCA, NOT A SEGMENT OF IT. HE ASKED IF I COULD NOT AVOID IT, ADVISE IMMEDIATELY. I SAID I MIGHT NOT BE ABLE TO AVOID AND DID HE WANT A LEFT 360 DEG AND DOWN TO 1000 MSL. HE SAID YES, IMMEDIATELY. I WAS AT ABOUT 1700 MSL 10 NM FROM SEA VOR. I DID THE L 360 WHICH PUT ME AT 1000 RIGHT NEXT TO TWRS WHICH EXTEND UP TO 1050. I SAW THEM AND AVOIDED THEM. HE IMMEDIATELY SAID 1200 AND CHANGE FREQ. I THEN CONTACTED BOEING TWR AND DIVERTED E SO AS TO ENTER ON A 45 R TFC FOR 31L. WHILE NO FARS WERE VIOLATED, THIS WAS SLOPPY CTLING. AFTER 20 MI OF DSCNT, A PANICKED MANEUVER WAS REQUESTED WHICH COULD HAVE RESULTED IN A TWR STRIKE. IF I WAS CLRED INTO THE TCA, I WAS CLRED INTO ALL THE TCA UNLESS VECTORED OR THE CLRNC SOMEHOW REVOKED (?). CTLRS SHOULD KNOW THAT PLTS OPERATING IN A TCA MAY NOT THINK IT AS IMPORTANT TO KNOW WHAT SEGMENT OF THE TCA THEY ARE IN. PLTS DO NOT HAVE A MOVING MAP DEPICTING THEIR POS ON A TCA CHART. A PLT OUTSIDE THE TCA CARES MORE ABOUT WHERE THE SECTIONS BEGIN AND END OF COURSE. A GOOD LESSON FOR ME AS WELL. ALWAYS KNOW WHERE THE FLOOR OF THE TCA IS WHERE YOU ARE LOCATED AS YOU MAY BE INSTANTLY REQUIRED TO DUCK BELOW IT AND YOUR TCA CLRNC 'REVOKED.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES HE HAS NEVER HAD SUCH AN EXPERIENCE WITH ATC. AFTER SPEAKING WITH A FRIEND WHO IS A RADAR CTLR, RPTR FEELS HE WAS BEING VECTORED BELOW THE MVA. WHEN THAT WAS ACCOMPLISHED, CTLR IMMEDIATELY ENDED RADAR SVC. VERY DANGEROUS TO BE SO CLOSE TO THOSE TWRS.

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.