A B757 first officer reported a traffic conflict during descent from a hold in the vicinity of pvd.

Attributes
ACN	480630
Time
Date	200007
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : pvd.vortac
State Reference	RI
Altitude	msl bound lower : 11000 msl bound upper : 13000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : a90.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : approach
Route In Use	approach : instrument precision arrival star : n/s
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : bos.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	480630
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne critical other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	other
Miss Distance	horizontal : 24000 vertical : 800
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

Bos approach vectored us, air carrier 1ABC, out of holding and descended us to 11000 ft. Another air carrier, abc, was also being vectored at 11000 ft. TCASII alerted us of the conflict and we climbed immediately. The controller queried us on our altitude and instructed us to climb back to 13000 ft. The problem arose because of controller error. Contributing factors include: similar call signs, WX and holding pattern. Conflict was discovered via TCASII (great tool). We were aware of the other air carrier, abc, and very conscious of controller's instructions. Holdings and altitudes were read back clearly and double-pointing at the new mode control panel altitude was accomplished.

Original NASA ASRS Text

Title: A B757 FO RPTED A TFC CONFLICT DURING DSCNT FROM A HOLD IN THE VICINITY OF PVD.

Narrative: BOS APCH VECTORED US, ACR 1ABC, OUT OF HOLDING AND DSNDED US TO 11000 FT. ANOTHER ACR, ABC, WAS ALSO BEING VECTORED AT 11000 FT. TCASII ALERTED US OF THE CONFLICT AND WE CLBED IMMEDIATELY. THE CTLR QUERIED US ON OUR ALT AND INSTRUCTED US TO CLB BACK TO 13000 FT. THE PROB AROSE BECAUSE OF CTLR ERROR. CONTRIBUTING FACTORS INCLUDE: SIMILAR CALL SIGNS, WX AND HOLDING PATTERN. CONFLICT WAS DISCOVERED VIA TCASII (GREAT TOOL). WE WERE AWARE OF THE OTHER ACR, ABC, AND VERY CONSCIOUS OF CTLR'S INSTRUCTIONS. HOLDINGS AND ALTS WERE READ BACK CLRLY AND DOUBLE-POINTING AT THE NEW MODE CTL PANEL ALT WAS ACCOMPLISHED.

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.