ACR X NON ADHERENCE TO ATC INSTRUCTIONS AFTER TKOF. PLTDEV.

Narrative

ACR X WAS CLRED FOR TKOF ON RWY 10C AT PIT; AND WERE INSTRUCTED BY THE TWR CTLR TO 'FLY RWY HDG.' WE COMPLIED WITH THESE INSTRUCTIONS. AS WE WERE ABOUT TO LEVEL OFF AT 5000 FT MSL; WHILE STILL FLYING RWY HDG; I ASKED THE LCL CTLR IF HE WANTED US TO 'CHANGE TO DEP.' HE INSTRUCTED US TO CHANGE TO DEP CTL. AFTER WE CONTACTED DEP; WE BEGAN TO RECEIVE VECTORS TO THE E OF OUR ROUTING. AFTER WE WERE SWITCHED TO THE CTR; THE CTR CTLR TOLD US THAT THE PIT ATC SUPVR WANTED TO TALK TO US BRIEFLY. THE SUPVR ASKED US IF WE HAD SWITCHED OVER TO THE DEP CTLR 'ON OUR OWN?' I INDICATED THAT WE SPECIFICALLY ASKED THE LCL CTLR; USING OUR FULL CALL SIGN; SO THERE COULD BE NO MISUNDERSTANDING; AND WE ACKNOWLEDGED USING OUR FULL CALL SIGN. THE PROBLEM; APPARENTLY; WAS THAT THE LCL TWR CTLR DID NOT INSTRUCT US TO MAKE A TURN NBOUND; AT SOME POINT PRIOR TO SWITCHING US OVER TO DEP; THEREBY GETTING US TOO FAR E OF THE DESIRED TFC FLOW; REQUIRING SOME VECTOR COORD BY DEP CTL AND THE CTR. IT APPARENTLY IS 'PROC' FOR THE PIT TWR CTLR TO ISSUE TURNS; AND KEEP DEPARTING ACFT ON THE TWR FREQ AFTER TKOF; THEN ISSUING TURNS WHEN THE ACFT IS AIRBORNE. THE TWR CTLR WAS VERY BUSY; AND MAY HAVE FALSELY 'ASSUMED' THAT HE HAD ALREADY ISSUED A TURN NBOUND; BUT; IN FACT; HAD NOT. REQUIRING DEPARTING ACFT TO 'REMAIN WITH THE TWR' FOR EXTENDED PERIODS AFTER TKOF AT A BUSY FACILITY INCREASES THE 'EXPOSURE' TO THIS TYPE OF ATC ERROR; AS IT INCREASES THE LCL CTLR WORKLOAD. IN SHORT; HE 'FORGOT' ABOUT US. I'M GLAD THAT I USED THE FULL ACFT CALL SIGN IN ALL TRANSMISSIONS.