A B727 FLC ON A TEST FLT FLYING A BACK COURSE APCH REQUEST A L TURN FOR THE MISSED APCH AND IT IS APPROVED BY TWR. WHEN CHKING IN WITH CTR THEY ARE QUESTIONED ABOUT THE L TURNOUT. ON LNDG THEY ARE REQUESTED TO CONTACT CTR; AT WHICH TIME THEY ARE CHASTISED BY THE CTLR FOR NOT MAKING THE STANDARD MISSED APCH PROC. HE INFORMED THEM THAT THE TWR HAS NO AUTH TO ISSUE SUCH A TURN.

Narrative

ON BACK COURSE APCH TO RWY 13; ZSE ADVISED TO FLY PUBLISHED MISSED APCH. AFTER HDOF TO TWR; CREW ASKED IF L TURN NBOUND COULD BE EXECUTED IF APCH ABORTED EARLY. TWR INDICATED AFFIRMATIVE. APPROX 2 MI SHORT OF RWY; CREW ASKED IF L TURN NBOUND WAS APPROVED. TWR SAID 'AFFIRMATIVE; CONTACT SEATTLE 125.8.' WHEN ON WITH ZSE; CTR ASKED WHY WE WEREN'T ON PUBLISHED MISSED APCH. CREW RPTED THAT L TURN WAS APPROVED BY THE TWR. CREW WANTED TO MAINTAIN IFR; RECEIVE VECTORS TOWARD FINAL APCH TO HAVE COMPANY ACFT TO PARALLEL FOR CONTINUATION OF TEST FLT. ZSE INFORMED US TO MAINTAIN VFR. CREW COMPLIED. AFTER COMPLETING TEST FLT; CREW INFORMED ZSE THAT IT WAS READY TO RETURN TO SLE VISUALLY. THE FO SAID THAT WE COULD CANCEL IFR. WE WERE NOT REALLY SURE WHETHER OUR IFR FLT PLAN WAS STILL ACTIVE. LNDG WAS MADE AT SLE UNEVENTFULLY. AFTER LNDG; SLE TWR TOLD US THAT ZSE WOULD LIKE US TO CALL. WE WERE TOLD BY THE CTR THAT THE TWR HAD NO AUTH TO AUTHORIZE OUR TURN AND CHASTISED US FOR TURNING. OUR REPLY WAS THAT IF CTLR APPROVED; WE ASSUME IT'S OK. COMS BTWN TWR AND APCH CTR ARE NOT OUR RESPONSIBILITY. DISCUSSION ENSUED ABOUT DIFFERENCES BTWN CTR AND TWR AND WHETHER FLT WAS VFR OR IFR. MAIN POINT IS THAT PLTS ASSUME CTLR'S CLRNCS ARE OK. NO QUESTIONS ASKED. COM BTWN LCL TWRS AND CTR CTLRS IS NOT ALWAYS GOOD. LCL TWR SHOULD BE TOLD WHAT IS EXPECTED BY CTR TO AVOID MISUNDERSTANDING.