Narrative:

We were in cruise to miami along jet 79 from lga at FL280 near stary intersection. We received an RA on TCASII (no TA was issued) 'descend, descend now.' a rapid descent was initiated. Copilot was flying aircraft. When RA was issued aircraft was on autoplt. Aircraft was taken off autoplt and descended to FL270 where a 'clear of conflict' was issued. Intruder aircraft showed 800 ft above on TCASII when descent was started. Captain notified ATC we were descending for an RA.

Google
 

Original NASA ASRS Text

Title: POTENTIAL CONFLICT SENSED BY TCASII RA AND FLC RESPONSE WAS TO INITIATE EVASIVE ACTION DSCNT.

Narrative: WE WERE IN CRUISE TO MIAMI ALONG JET 79 FROM LGA AT FL280 NEAR STARY INTXN. WE RECEIVED AN RA ON TCASII (NO TA WAS ISSUED) 'DSND, DSND NOW.' A RAPID DSCNT WAS INITIATED. COPLT WAS FLYING ACFT. WHEN RA WAS ISSUED ACFT WAS ON AUTOPLT. ACFT WAS TAKEN OFF AUTOPLT AND DSNDED TO FL270 WHERE A 'CLR OF CONFLICT' WAS ISSUED. INTRUDER ACFT SHOWED 800 FT ABOVE ON TCASII WHEN DSCNT WAS STARTED. CAPT NOTIFIED ATC WE WERE DSNDING FOR AN RA.

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.