Narrative:

We were being vectored to a downwind for runway 27R at phl. Airspeed was 210 KTS, 6000 ft. Traffic seemed about normal, not too much for phl. We were cleared to leave 6000 ft and descend to 3000 ft. I responded and we began our descent on autoplt. There were a few targets on TCASII but none were of concern to the TCASII. At 5700 ft we received an RA to climb. Captain responded by disconnecting autoplt and climbing. As this was happening, ATC told us to climb to 6000 ft. We saw westwind on TCASII only, never visually. Captain talked to approach on phone and controller admitted it was a bad clearance on their part. Captain said from what we could see on TCASII it looked very close had we continued descent. Controller said they were pretty sure it would have been a hit. I have had to respond to several RA's over the past few yrs, this is the first one that was a life saver. The controller said he did make the bad call, but in his own defense he said he then told us to climb. What if we had missed the call or there had been a stuck microphone on the frequency? TCASII is worth its weight in gold.

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Original NASA ASRS Text

Title: OPERROR LTSS BTWN AN ACR B737 AND WESTWIND WHEN THE ACR DSNDED FROM AND CONFLICTED WITH THE WESTWIND.

Narrative: WE WERE BEING VECTORED TO A DOWNWIND FOR RWY 27R AT PHL. AIRSPD WAS 210 KTS, 6000 FT. TFC SEEMED ABOUT NORMAL, NOT TOO MUCH FOR PHL. WE WERE CLRED TO LEAVE 6000 FT AND DSND TO 3000 FT. I RESPONDED AND WE BEGAN OUR DSCNT ON AUTOPLT. THERE WERE A FEW TARGETS ON TCASII BUT NONE WERE OF CONCERN TO THE TCASII. AT 5700 FT WE RECEIVED AN RA TO CLB. CAPT RESPONDED BY DISCONNECTING AUTOPLT AND CLBING. AS THIS WAS HAPPENING, ATC TOLD US TO CLB TO 6000 FT. WE SAW WESTWIND ON TCASII ONLY, NEVER VISUALLY. CAPT TALKED TO APCH ON PHONE AND CTLR ADMITTED IT WAS A BAD CLRNC ON THEIR PART. CAPT SAID FROM WHAT WE COULD SEE ON TCASII IT LOOKED VERY CLOSE HAD WE CONTINUED DSCNT. CTLR SAID THEY WERE PRETTY SURE IT WOULD HAVE BEEN A HIT. I HAVE HAD TO RESPOND TO SEVERAL RA'S OVER THE PAST FEW YRS, THIS IS THE FIRST ONE THAT WAS A LIFE SAVER. THE CTLR SAID HE DID MAKE THE BAD CALL, BUT IN HIS OWN DEFENSE HE SAID HE THEN TOLD US TO CLB. WHAT IF WE HAD MISSED THE CALL OR THERE HAD BEEN A STUCK MIKE ON THE FREQ? TCASII IS WORTH ITS WT IN GOLD.

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.