Narrative:

Near filps intersection, we received a radar vector of 170 degrees toward the ILS runway 9 final approach. From 6000 ft, we were issued a descent to 3000 ft (250 KTS/approximately 1900 FPM). During the descent, we had occasional ground contact, which later seemed as if we were getting closer to the ground than normal. A few seconds later, the GPWS issued a 'terrain, terrain' warning, to which I immediately executed the approved escape maneuver in the flight standards manual to a leveloff of 4000 ft. As I was doing this, the controller stated that the altitude should be 4000 ft. No other conflict resulted from this event. My captain and I both heard the clearance to descend to 3000 ft, which was read back properly with no corrections from the controller. We didn't take issue with ATC at any time. Supplemental information from acn 617750: going into swf, N90 approach gave us a heading of 170 degrees and 6000 ft on the 170 degree heading. ATC told us to descend and maintain 3000 ft. I read back 'descend and maintain 3000 ft.' (there was no correction to my readback) 3000 ft was set and confirmed and my first officer began the descent. At 4000 ft, we confirmed descending from 4000 ft to 3000 ft and 1000 ft to go. At approximately 3450 ft, we received a GPWS 'terrain.' the escape maneuver was performed simultaneously as ATC called and stated 'air carrier X, you were cleared to 4000 ft.' we leveled at 4000 ft and landed without further incident.

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Original NASA ASRS Text

Title: CL65 CREW GOT A GPWS TERRAIN WARNING WHEN THE APCH CTLR DSNDED THE ACFT TO 3000 FT VERSUS 4000 FT.

Narrative: NEAR FILPS INTXN, WE RECEIVED A RADAR VECTOR OF 170 DEGS TOWARD THE ILS RWY 9 FINAL APCH. FROM 6000 FT, WE WERE ISSUED A DSCNT TO 3000 FT (250 KTS/APPROX 1900 FPM). DURING THE DSCNT, WE HAD OCCASIONAL GND CONTACT, WHICH LATER SEEMED AS IF WE WERE GETTING CLOSER TO THE GND THAN NORMAL. A FEW SECONDS LATER, THE GPWS ISSUED A 'TERRAIN, TERRAIN' WARNING, TO WHICH I IMMEDIATELY EXECUTED THE APPROVED ESCAPE MANEUVER IN THE FLT STANDARDS MANUAL TO A LEVELOFF OF 4000 FT. AS I WAS DOING THIS, THE CTLR STATED THAT THE ALT SHOULD BE 4000 FT. NO OTHER CONFLICT RESULTED FROM THIS EVENT. MY CAPT AND I BOTH HEARD THE CLRNC TO DSND TO 3000 FT, WHICH WAS READ BACK PROPERLY WITH NO CORRECTIONS FROM THE CTLR. WE DIDN'T TAKE ISSUE WITH ATC AT ANY TIME. SUPPLEMENTAL INFO FROM ACN 617750: GOING INTO SWF, N90 APCH GAVE US A HDG OF 170 DEGS AND 6000 FT ON THE 170 DEG HDG. ATC TOLD US TO DSND AND MAINTAIN 3000 FT. I READ BACK 'DSND AND MAINTAIN 3000 FT.' (THERE WAS NO CORRECTION TO MY READBACK) 3000 FT WAS SET AND CONFIRMED AND MY FO BEGAN THE DSCNT. AT 4000 FT, WE CONFIRMED DSNDING FROM 4000 FT TO 3000 FT AND 1000 FT TO GO. AT APPROX 3450 FT, WE RECEIVED A GPWS 'TERRAIN.' THE ESCAPE MANEUVER WAS PERFORMED SIMULTANEOUSLY AS ATC CALLED AND STATED 'ACR X, YOU WERE CLRED TO 4000 FT.' WE LEVELED AT 4000 FT AND LANDED WITHOUT FURTHER INCIDENT.

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.