|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||atc facility : ptw|
airport : phl
|Altitude||msl bound lower : 2500|
msl bound upper : 3000
|Controlling Facilities||tracon : phl|
|Operator||common carrier : air carrier|
|Make Model Name||Small Transport, Low Wing, 2 Turboprop Eng|
|Flight Phase||descent : approach|
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : commercial|
pilot : instrument
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Anomaly||altitude deviation : excursion from assigned altitude|
non adherence : clearance
|Independent Detector||other controllera|
|Resolutory Action||flight crew : returned to intended course or assigned course|
|Primary Problem||Flight Crew Human Performance|
|Air Traffic Incident||Pilot Deviation|
Somewhere close to the VOR we were told by phl approach to depart the pottstown VOR on the pottstown transition to the ILS 17 approach to phl international airport. This transition calls for a 2500' altitude and using the 141 degree outbnd right. We proceeded to depart the pottstown VOR on the 141 degree right and upo station passage descended from 3000 to 2500' MSL as called for on the published transition. However, shortly after leveling at 2500', the approach controller informed us that we should not have descended to 2500' because, in his words, he only told us to depart the VOR on the published transition and he did not clear us for the approach. We were told to and immediately climbed back to 3000'. I believe that this situation occurred because of ambiguity in the terms used. If the controller wanted us only to depart on a particular right off of the VOR, he should of simply said, 'depart pottstown on the 141 degree right.' I feel that by saying 'depart pottstown on the published transition,' he implied to follow the published procedure which indicates a 2500' altitude. It is just as easy and brief to say 'depart pottstown on the 141 degree right' as to say 'fly the published transition to the ILS 17 approach.' I believe that this happened because of unclear terminology. Upon discussing this occurrence with other pilots I found that 90% of them were unsure of what exactly this terminology implied also. We are so used to having controllers say depart so and so VOR on the so and so right, that when we hear the words 'fly the published transition,' it implies more than just a radial. To summarize, when you tell a pilot to fly the published transition instead of just to depart on a certain right, you are implying that you should use the published altitude 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 controller 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 checklists, setting up for the approach, making mandatory passenger announcements, etc.
Original NASA ASRS Text
Title: 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.
Data retrieved from NASA's ASRS site as of August 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.