Narrative:

ATC facility: ZDC. Location: somto intersection. The flight was cleared to lga on the minks 1 arrival. We were given clearance to cross somto intersection at 13000 ft or below, descend to and maintain 11000 ft. I interpreted this to mean start the descent at our discretion, and upon crossing somto intersection at 13000 ft or below, that the descent to 11000 ft was at our discretion. As such, we crossed somto intersection at 13000 ft and did not descend until instructed to do so by ZDC which took place several mins after crossing somto intersection. The controller sounded a bit upset that we were not level at 11000 ft yet and turned us over to another frequency. After further research, I determined that we were wrong by not descending to 11000 ft after crossing somto intersection at 13000 ft or below.

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Original NASA ASRS Text

Title: FLC OF B727 MISINTERPS DSCNT CLRNC AND DOES NOT ARRIVE AT DSCNT ALT AT SPECIFIED POS.

Narrative: ATC FACILITY: ZDC. LOCATION: SOMTO INTXN. THE FLT WAS CLRED TO LGA ON THE MINKS 1 ARR. WE WERE GIVEN CLRNC TO CROSS SOMTO INTXN AT 13000 FT OR BELOW, DSND TO AND MAINTAIN 11000 FT. I INTERPRETED THIS TO MEAN START THE DSCNT AT OUR DISCRETION, AND UPON XING SOMTO INTXN AT 13000 FT OR BELOW, THAT THE DSCNT TO 11000 FT WAS AT OUR DISCRETION. AS SUCH, WE CROSSED SOMTO INTXN AT 13000 FT AND DID NOT DSND UNTIL INSTRUCTED TO DO SO BY ZDC WHICH TOOK PLACE SEVERAL MINS AFTER XING SOMTO INTXN. THE CTLR SOUNDED A BIT UPSET THAT WE WERE NOT LEVEL AT 11000 FT YET AND TURNED US OVER TO ANOTHER FREQ. AFTER FURTHER RESEARCH, I DETERMINED THAT WE WERE WRONG BY NOT DSNDING TO 11000 FT AFTER XING SOMTO INTXN AT 13000 FT OR BELOW.

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.