SMT ENTERS ATA CTL ZONE WITHOUT CONTACT.

Narrative

THIS INVOLVES FLT IN AN ATA CTL ZONE (CTL ZONE) WITHOUT 2-WAY COM WITH THE CTL TWR. THE ATA CTL ZONE FOR BOEING FIELD AND RENTON ARPT INTERSECT. BECAUSE OF THIS; A PORTION OF THE BOEING ATA CTL ZONE IS ASSIGNED TO RENTON; BUT ONLY BELOW 800 FT AGL. ONE APCH TO LNDG AT RENTON (NOT PUBLISHED; BUT COMMONLY USED AND APPROVED BY RENTON TWR) REQUIRES FLT THROUGH THE EDGE OF THE BOEING ATA CTL ZONE 2 AT 1200 FT AGL; IMMEDIATELY ABOVE THE PORTION OF THE BOEING ATA CTL ZONE ASSIGNED TO RENTON. TYPICALLY; IN ORDER TO FLY THIS APCH; A RADIO CALL IS MADE TO RENTON TWR OUTSIDE BOTH THE BOEING AND RENTON ATA CTL ZONE'S; AND RENTON TWR AND BOEING TWR COMMUNICATE/COORDINATE CTL OF THE ACFT. WHEN FLYING THIS APCH; I MADE THE RADIO CALL TO RENTON TWR OUTSIDE BOTH THE BOEING AND RENTON ATA CTL ZONE'S; BUT JUST OUTSIDE -- THAT IS; BEFORE RENTON TWR AND BOEING TWR COULD COMMUNICATE; I WAS ALREADY IN THE BOEING ATA CTL ZONE; BUT NOT IN CONTACT WITH BOEING TWR. INSTEAD; I WAS IN CONTACT WITH RENTON TWR; APPROX 5 MI AWAY FROM THE ARPT. RENTON TWR INQUIRED WHETHER I WAS IN CONTACT WITH BOEING TWR; THEN OFFERED TO COMMUNICATE WITH THEM BY LANDLINE TO ADVISE THEM OF MY PRESENCE. RATHER THEN RELYING ON THE TWR TO COMMUNICATE; I SHOULD HAVE CONTACTED BOEING TWR FIRST WITH THE REQUEST THAT I BE HANDED OFF TO RENTON TWR. ALSO; THIS CALL SHOULD HAVE BEEN MADE FARTHER FROM THE ATA CTL ZONE; RATHER THAN JUST OUTSIDE. IN SUMMARY; THE SIT COULD HAVE BEEN AVOIDED BY ALLOWING MORE TIME TO ESTABLISH COM WITH THE FIRST ATA CTL ZONE ENCOUNTERED; AND ALSO; THIS WOULD HAVE AVOIDED THE NEED FOR THE SECOND ATA CTL ZONE AUTH TO COMMUNICATE WITH THE FIRST ATA CTL ZONE AUTH.