While attempting to vector around IFR traffic, separation was lost.

Attributes
ACN	128301
Time
Date	198911
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ctr
State Reference	MA
Altitude	msl bound lower : 14800 msl bound upper : 15000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude
Route In Use	departure other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude
Route In Use	departure other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	128301
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 27000 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X was off albany proceeding to islip, ny. After I took handoff from albany approach, I climbed and vectored the aircraft around an small transport. Air carrier Y was off bradley (bdl) to chicago. I climbed him to 17,000', handed him off, and switched him to the next sector. After I cleared the small transport, I initiated vectors for air carrier X who was climbing to 15,000' to the south, to stay west of the air carrier Y projected flight path. I corrected my first heading as air carrier X seemed to be very slow in making his turn. After a few more seconds, I corrected the heading another 30 degree to the right, and noticed his altitude readout was not updating. As I asked the pilot for his current altitude, I knew it was about a 50% chance that I'd be able to maintain the required 5 mi separation from air carrier Y then I lost entire radar data on air carrier X (his beacon was no longer tracking on my display). I advised the pilot of that and reverted to vertical separation (non radar separation), but air carrier X was climbing so fast he was already above air carrier Y's altitude. I attempted to stop him at 14,000 but it was too late. He was at 14,800'. When the beacon reappeared on the screen, it was about 4 1/2 mi from air carrier Y's beacon. Air carrier Y had visually sighted and inquired about visual separation, but it is not allowed in the ARTCC environment. That may have been another reason for his slow turn.

Original NASA ASRS Text

Title: WHILE ATTEMPTING TO VECTOR AROUND IFR TRAFFIC, SEPARATION WAS LOST.

Narrative: ACR X WAS OFF ALBANY PROCEEDING TO ISLIP, NY. AFTER I TOOK HANDOFF FROM ALBANY APCH, I CLIMBED AND VECTORED THE ACFT AROUND AN SMT. ACR Y WAS OFF BRADLEY (BDL) TO CHICAGO. I CLIMBED HIM TO 17,000', HANDED HIM OFF, AND SWITCHED HIM TO THE NEXT SECTOR. AFTER I CLRED THE SMT, I INITIATED VECTORS FOR ACR X WHO WAS CLIMBING TO 15,000' TO THE S, TO STAY W OF THE ACR Y PROJECTED FLT PATH. I CORRECTED MY FIRST HDG AS ACR X SEEMED TO BE VERY SLOW IN MAKING HIS TURN. AFTER A FEW MORE SECONDS, I CORRECTED THE HDG ANOTHER 30 DEG TO THE RIGHT, AND NOTICED HIS ALT READOUT WAS NOT UPDATING. AS I ASKED THE PLT FOR HIS CURRENT ALT, I KNEW IT WAS ABOUT A 50% CHANCE THAT I'D BE ABLE TO MAINTAIN THE REQUIRED 5 MI SEPARATION FROM ACR Y THEN I LOST ENTIRE RADAR DATA ON ACR X (HIS BEACON WAS NO LONGER TRACKING ON MY DISPLAY). I ADVISED THE PLT OF THAT AND REVERTED TO VERTICAL SEPARATION (NON RADAR SEPARATION), BUT ACR X WAS CLIMBING SO FAST HE WAS ALREADY ABOVE ACR Y'S ALT. I ATTEMPTED TO STOP HIM AT 14,000 BUT IT WAS TOO LATE. HE WAS AT 14,800'. WHEN THE BEACON REAPPEARED ON THE SCREEN, IT WAS ABOUT 4 1/2 MI FROM ACR Y'S BEACON. ACR Y HAD VISUALLY SIGHTED AND INQUIRED ABOUT VISUAL SEPARATION, BUT IT IS NOT ALLOWED IN THE ARTCC ENVIRONMENT. THAT MAY HAVE BEEN ANOTHER REASON FOR HIS SLOW TURN.

Data retrieved from NASA's ASRS site as of August 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.