Narrative:

New york cleared the flight to cross CCC at and maintain 5000 ft then cleared the flight for the ILS runway 24 approach to islip long island airport. I started to descend to the initial approach altitude of 2000 as I was 'cleared for the approach.' my understanding being that this superseded the 5000 ft crossing altitude. At 4600 ft MSL, the captain, who was talking on company frequency, called my attention to the crossing restriction. I returned to 5000 ft. New york asked for aircraft altitude. We answered with 5000 ft as the aircraft was now back on altitude. Total time of incident: 30 seconds. My original question addressed to the captain was, 'do we still have to cross CCC at 5000 ft?' he was talking to flight control and did not answer. I understood the þclred for apchþ to supersede the crossing restriction. On review of the approach plate, the outbound course of 271 degrees at 2000 ft was the reason I began the descent. This was the cause of the ambiguity. Did the 'cleared for the approach' which was given during a second transmission from ATC, release me of the crossing restriction? ATC's request for altitude verification, makes me wonder about it!

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Original NASA ASRS Text

Title: ALTDEV, ALT EXCURSION IN PREMATURE DSCNT RESULTING IN A POSSIBLE XING RESTRICTION VIOLATION.

Narrative: NEW YORK CLRED THE FLT TO CROSS CCC AT AND MAINTAIN 5000 FT THEN CLRED THE FLT FOR THE ILS RWY 24 APCH TO ISLIP LONG ISLAND ARPT. I STARTED TO DSND TO THE INITIAL APCH ALT OF 2000 AS I WAS 'CLRED FOR THE APCH.' MY UNDERSTANDING BEING THAT THIS SUPERSEDED THE 5000 FT XING ALT. AT 4600 FT MSL, THE CAPT, WHO WAS TALKING ON COMPANY FREQ, CALLED MY ATTN TO THE XING RESTRICTION. I RETURNED TO 5000 FT. NEW YORK ASKED FOR ACFT ALT. WE ANSWERED WITH 5000 FT AS THE ACFT WAS NOW BACK ON ALT. TOTAL TIME OF INCIDENT: 30 SECONDS. MY ORIGINAL QUESTION ADDRESSED TO THE CAPT WAS, 'DO WE STILL HAVE TO CROSS CCC AT 5000 FT?' HE WAS TALKING TO FLT CTL AND DID NOT ANSWER. I UNDERSTOOD THE þCLRED FOR APCHþ TO SUPERSEDE THE XING RESTRICTION. ON REVIEW OF THE APCH PLATE, THE OUTBOUND COURSE OF 271 DEGS AT 2000 FT WAS THE REASON I BEGAN THE DSCNT. THIS WAS THE CAUSE OF THE AMBIGUITY. DID THE 'CLRED FOR THE APCH' WHICH WAS GIVEN DURING A SECOND XMISSION FROM ATC, RELEASE ME OF THE XING RESTRICTION? ATC'S REQUEST FOR ALT VERIFICATION, MAKES ME WONDER ABOUT IT!

Data retrieved from NASA's ASRS site as of July 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.