Narrative:

Arriving at hpn, while on approach control, we were given a left turn to 180 degrees and a descent to 3000' from 4000'. The PF understood the clearance to read left to 180 degrees and descend to 2000'. While passing 3000' the PNF called the deviation and we leveled at 3000' west/O significant deviation (200'). Confirmation of the clearance was requested and approach read back what again sounded like 2000' and the descent was continued. Shortly thereafter, approach noted the altitude on his radar and said we were cleared to 3000', but since we were at 2000' we should stay there. Subsequently we were vectored to final approach for landing west/O further incident. Due to the vol of traffic, approach was speaking at a very high rate of speed which caused the clarity of his message to diminish. Speaking slower and enunciating his words more clearly would reduce the chance of this happening again. Also, had the confirmation of the clearance to 2000' been read back by the crew, it may have been caught by the person working approach control on that day.

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Original NASA ASRS Text

Title: CORPORATE FLT CREW REQUESTED CLARIFICATION OF ASSIGNED ALT. SECOND TIME 'HEARD' 2000'. CTLR SAID, '3000', BUT STAY THERE NOW.'

Narrative: ARRIVING AT HPN, WHILE ON APCH CTL, WE WERE GIVEN A LEFT TURN TO 180 DEGS AND A DSCNT TO 3000' FROM 4000'. THE PF UNDERSTOOD THE CLRNC TO READ LEFT TO 180 DEGS AND DSND TO 2000'. WHILE PASSING 3000' THE PNF CALLED THE DEVIATION AND WE LEVELED AT 3000' W/O SIGNIFICANT DEVIATION (200'). CONFIRMATION OF THE CLRNC WAS REQUESTED AND APCH READ BACK WHAT AGAIN SOUNDED LIKE 2000' AND THE DSCNT WAS CONTINUED. SHORTLY THEREAFTER, APCH NOTED THE ALT ON HIS RADAR AND SAID WE WERE CLRED TO 3000', BUT SINCE WE WERE AT 2000' WE SHOULD STAY THERE. SUBSEQUENTLY WE WERE VECTORED TO FINAL APCH FOR LNDG W/O FURTHER INCIDENT. DUE TO THE VOL OF TFC, APCH WAS SPEAKING AT A VERY HIGH RATE OF SPD WHICH CAUSED THE CLARITY OF HIS MESSAGE TO DIMINISH. SPEAKING SLOWER AND ENUNCIATING HIS WORDS MORE CLEARLY WOULD REDUCE THE CHANCE OF THIS HAPPENING AGAIN. ALSO, HAD THE CONFIRMATION OF THE CLRNC TO 2000' BEEN READ BACK BY THE CREW, IT MAY HAVE BEEN CAUGHT BY THE PERSON WORKING APCH CTL ON THAT DAY.

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.