ASSUMED CLEARED FOR DESCENT WHEN CLEARED VIA TRANSITION ROUTING.

Narrative

SOMEWHERE CLOSE TO THE VOR WE WERE TOLD BY PHL APCH TO DEPART THE POTTSTOWN VOR ON THE POTTSTOWN TRANSITION TO THE ILS 17 APCH TO PHL INTL ARPT. THIS TRANSITION CALLS FOR A 2500' ALT AND USING THE 141 DEG OUTBND R. WE PROCEEDED TO DEPART THE POTTSTOWN VOR ON THE 141 DEG R AND UPO STATION PASSAGE DSNDED FROM 3000 TO 2500' MSL AS CALLED FOR ON THE PUBLISHED TRANSITION. HOWEVER; SHORTLY AFTER LEVELING AT 2500'; THE APCH CTLR INFORMED US THAT WE SHOULD NOT HAVE DSNDED TO 2500' BECAUSE; IN HIS WORDS; HE ONLY TOLD US TO DEPART THE VOR ON THE PUBLISHED TRANSITION AND HE DID NOT CLR US FOR THE APCH. WE WERE TOLD TO AND IMMEDIATELY CLBED BACK TO 3000'. I BELIEVE THAT THIS SITUATION OCCURRED BECAUSE OF AMBIGUITY IN THE TERMS USED. IF THE CTLR WANTED US ONLY TO DEPART ON A PARTICULAR R OFF OF THE VOR; HE SHOULD OF SIMPLY SAID; 'DEPART POTTSTOWN ON THE 141 DEG R.' I FEEL THAT BY SAYING 'DEPART POTTSTOWN ON THE PUBLISHED TRANSITION;' HE IMPLIED TO FOLLOW THE PUBLISHED PROC WHICH INDICATES A 2500' ALT. IT IS JUST AS EASY AND BRIEF TO SAY 'DEPART POTTSTOWN ON THE 141 DEG R' AS TO SAY 'FLY THE PUBLISHED TRANSITION TO THE ILS 17 APCH.' I BELIEVE THAT THIS HAPPENED BECAUSE OF UNCLEAR TERMINOLOGY. UPON DISCUSSING THIS OCCURRENCE WITH OTHER PLTS I FOUND THAT 90% OF THEM WERE UNSURE OF WHAT EXACTLY THIS TERMINOLOGY IMPLIED ALSO. WE ARE SO USED TO HAVING CTLRS SAY DEPART SO AND SO VOR ON THE SO AND SO R; THAT WHEN WE HEAR THE WORDS 'FLY THE PUBLISHED TRANSITION;' IT IMPLIES MORE THAN JUST A RADIAL. TO SUMMARIZE; WHEN YOU TELL A PLT TO FLY THE PUBLISHED TRANSITION INSTEAD OF JUST TO DEPART ON A CERTAIN R; YOU ARE IMPLYING THAT YOU SHOULD USE THE PUBLISHED ALT FOR THAT TRANSITION. I CERTAINLY LEARNED SOMETHING; BUT I SHOULDN'T HAVE HAD TO LEARN ANYTHING. IT SHOULD HAVE BEEN CRYSTAL CLEAR TO BEGIN WITH BY HAVING THE CTLR USE CLEARER TERMINOLOGY. ALSO; I BELIEVE THIS HAS TO BE PUT INTO CONTEXT. WE WERE TOLD TO FLY THE PUBLISHED TRANSITION ABOUT 1 OR 2 MI AWAY FROM THE VOR. THIS SHORT NOTICE WHILE WE WERE FLYING THE AIRPLANE; PERFORMING CHKLISTS; SETTING UP FOR THE APCH; MAKING MANDATORY PAX ANNOUNCEMENTS; ETC.