Possible less than standard separation between air carrier X and Y. Possible system error.

Attributes
ACN	145624
Time
Date	199005
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : lga
State Reference	NY
Altitude	msl bound lower : 7200 msl bound upper : 7200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90 tower : mdw
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 16450 flight time type : 1000
ASRS Report	145624
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Miss Distance	horizontal : 5000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error other

Narrative:

Air carrier X on a milton 5 arrival to lga. Just past solberg lga assigned heading 150 degree and airspeed 210 KTS for sequencing. As we approached 7000' on descent, traffic was issued at 2 O'clock which we saw simultaneously. Traffic was air carrier Y, medium large transport, and it appeared to be within a mi crossing in front of us, heading of air carrier Y was approximately 060 degree and descending also. No evasive action was required however, normal sep seemed to be compromised. We followed air carrier Y for approach and landing at lga. I think the controller compromised normal sep and then failed to issue traffic to us in a timely manner.

Original NASA ASRS Text

Title: POSSIBLE LESS THAN STANDARD SEPARATION BETWEEN ACR X AND Y. POSSIBLE SYSTEM ERROR.

Narrative: ACR X ON A MILTON 5 ARR TO LGA. JUST PAST SOLBERG LGA ASSIGNED HDG 150 DEG AND AIRSPD 210 KTS FOR SEQUENCING. AS WE APCHED 7000' ON DSNT, TFC WAS ISSUED AT 2 O'CLOCK WHICH WE SAW SIMULTANEOUSLY. TFC WAS ACR Y, MLG, AND IT APPEARED TO BE WITHIN A MI XING IN FRONT OF US, HDG OF ACR Y WAS APPROX 060 DEG AND DSNDING ALSO. NO EVASIVE ACTION WAS REQUIRED HOWEVER, NORMAL SEP SEEMED TO BE COMPROMISED. WE FOLLOWED ACR Y FOR APCH AND LNDG AT LGA. I THINK THE CTLR COMPROMISED NORMAL SEP AND THEN FAILED TO ISSUE TFC TO US IN A TIMELY MANNER.

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.