Phl approach controller descends a B767 into a helicopter; resulting in an RA.

Attributes
ACN	690012
Time
Date	200603
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : phl.airport
State Reference	PA
Altitude	msl single value : 6000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : phl.tracon
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : phl.tracon
Make Model Name	Helicopter
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 50 flight time total : 7000 flight time type : 767
ASRS Report	690012
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : military controller : radar
Experience	controller military : 5 controller radar : 23
ASRS Report	690386
Events
Anomaly	conflict : airborne critical non adherence : required legal separation
Independent Detector	atc equipment : conflict alert aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 500 vertical : 500
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

During descent into phl on a direct to bunts routing; we were told to descend and maintain 6000 ft on an altimeter of 29.45. Both the captain (PF) and I (captain flying as a first officer and pilot monitoring) heard the descent clearance altitude of 6000 ft and verified it in the MCP altitude window. Passing 8300 ft or so; the controller told us that there would be traffic; a helicopter at 11 O'clock and 6000 ft. We noted it and started to look for it both visually and with the TCAS. Also; to each other; noting that it was going to be at the same altitude; figuring it was going out of our path on a different direction. We picked it up on the TCAS at about 12 mi and about the time that we leveled at 6000 ft. We mentioned it to each other again and thought we had it in sight. I counted off the mi verbally. Also; we started discussing whether this was becoming a conflict; and wondering why we had been given this clearance. Just as I (pilot monitoring) was keying the microphone to verify the controller's instructions; we got the 'traffic' alert; rapidly followed by a 'descent RA' from the TCAS. We complied immediately and I told the controller of our RA and maneuvering. He then responded that he claimed to have given us a descent only to 7000 ft. I replied that we had been given 6000 ft. He didn't argue. Both the captain and I agreed that 6000 ft was the clearance that we were given and stated it to each other. I queried the controller if he wanted us to climb up to 7000 ft after the RA; at which time he told us to continue down to 3000 ft. Nothing more was said by ATC phl approach; and the rest of the approach and landing was uneventful. Supplemental information from acn 690386: air carrier X checked in descending over bunts to 10000 ft. After crossing bunts; I descended him to 7000 ft (after tape review it appears I descended the aircraft to 6000 ft. I issued traffic to air carrier X reference aircraft Y swbound at 6000 ft. Air carrier X advised that he was responding to RA and I instructed the pilot to climb to 7000 ft.

Original NASA ASRS Text

Title: PHL APCH CTLR DSNDS A B767 INTO A HELI; RESULTING IN AN RA.

Narrative: DURING DSCNT INTO PHL ON A DIRECT TO BUNTS ROUTING; WE WERE TOLD TO DSND AND MAINTAIN 6000 FT ON AN ALTIMETER OF 29.45. BOTH THE CAPT (PF) AND I (CAPT FLYING AS A FO AND PLT MONITORING) HEARD THE DSCNT CLRNC ALT OF 6000 FT AND VERIFIED IT IN THE MCP ALT WINDOW. PASSING 8300 FT OR SO; THE CTLR TOLD US THAT THERE WOULD BE TFC; A HELI AT 11 O'CLOCK AND 6000 FT. WE NOTED IT AND STARTED TO LOOK FOR IT BOTH VISUALLY AND WITH THE TCAS. ALSO; TO EACH OTHER; NOTING THAT IT WAS GOING TO BE AT THE SAME ALT; FIGURING IT WAS GOING OUT OF OUR PATH ON A DIFFERENT DIRECTION. WE PICKED IT UP ON THE TCAS AT ABOUT 12 MI AND ABOUT THE TIME THAT WE LEVELED AT 6000 FT. WE MENTIONED IT TO EACH OTHER AGAIN AND THOUGHT WE HAD IT IN SIGHT. I COUNTED OFF THE MI VERBALLY. ALSO; WE STARTED DISCUSSING WHETHER THIS WAS BECOMING A CONFLICT; AND WONDERING WHY WE HAD BEEN GIVEN THIS CLRNC. JUST AS I (PLT MONITORING) WAS KEYING THE MIKE TO VERIFY THE CTLR'S INSTRUCTIONS; WE GOT THE 'TFC' ALERT; RAPIDLY FOLLOWED BY A 'DSCNT RA' FROM THE TCAS. WE COMPLIED IMMEDIATELY AND I TOLD THE CTLR OF OUR RA AND MANEUVERING. HE THEN RESPONDED THAT HE CLAIMED TO HAVE GIVEN US A DSCNT ONLY TO 7000 FT. I REPLIED THAT WE HAD BEEN GIVEN 6000 FT. HE DIDN'T ARGUE. BOTH THE CAPT AND I AGREED THAT 6000 FT WAS THE CLRNC THAT WE WERE GIVEN AND STATED IT TO EACH OTHER. I QUERIED THE CTLR IF HE WANTED US TO CLB UP TO 7000 FT AFTER THE RA; AT WHICH TIME HE TOLD US TO CONTINUE DOWN TO 3000 FT. NOTHING MORE WAS SAID BY ATC PHL APCH; AND THE REST OF THE APCH AND LNDG WAS UNEVENTFUL. SUPPLEMENTAL INFO FROM ACN 690386: ACR X CHKED IN DSNDING OVER BUNTS TO 10000 FT. AFTER XING BUNTS; I DSNDED HIM TO 7000 FT (AFTER TAPE REVIEW IT APPEARS I DSNDED THE ACFT TO 6000 FT. I ISSUED TFC TO ACR X REF ACFT Y SWBOUND AT 6000 FT. ACR X ADVISED THAT HE WAS RESPONDING TO RA AND I INSTRUCTED THE PLT TO CLB TO 7000 FT.

Data retrieved from NASA's ASRS site as of January 2009 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.