TCASII. RA kept reporter aircraft clear of VFR traffic.

Attributes
ACN	315070
Time
Date	199509
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ard
State Reference	PA
Altitude	msl bound lower : 11000 msl bound upper : 11500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lga
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	climbout : intermediate altitude
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 126 flight time total : 9200 flight time type : 900
ASRS Report	315070
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 185 flight time total : 19180 flight time type : 5000
ASRS Report	315499
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 5000 vertical : 400
Supplementary
Air Traffic Incident	other

Narrative:

Just after passing yardley VOR approximately 20 mi on the nanci 5 arrival into lga airport, level at 11000 ft we received a TCASII TA alert. TCASII showed an aircraft suddenly below us 600 ft climbing 1 mi in front or less. We asked lga approach about traffic, got no response, then we received a RA on TCASII telling us to climb. Aircraft showed 400 ft below us. We immediately started a climb and leveled off at 11500 ft. TCASII went back to TA. Lga approach was informed of our altitude and she said traffic just appeared at 10500 ft VFR, not talking to anyone. This time traffic behind us and no factor, returned to our assigned altitude of 11000 ft. No other traffic conflict.

Original NASA ASRS Text

Title: TCASII. RA KEPT RPTR ACFT CLR OF VFR TFC.

Narrative: JUST AFTER PASSING YARDLEY VOR APPROX 20 MI ON THE NANCI 5 ARR INTO LGA ARPT, LEVEL AT 11000 FT WE RECEIVED A TCASII TA ALERT. TCASII SHOWED AN ACFT SUDDENLY BELOW US 600 FT CLBING 1 MI IN FRONT OR LESS. WE ASKED LGA APCH ABOUT TFC, GOT NO RESPONSE, THEN WE RECEIVED A RA ON TCASII TELLING US TO CLB. ACFT SHOWED 400 FT BELOW US. WE IMMEDIATELY STARTED A CLB AND LEVELED OFF AT 11500 FT. TCASII WENT BACK TO TA. LGA APCH WAS INFORMED OF OUR ALT AND SHE SAID TFC JUST APPEARED AT 10500 FT VFR, NOT TALKING TO ANYONE. THIS TIME TFC BEHIND US AND NO FACTOR, RETURNED TO OUR ASSIGNED ALT OF 11000 FT. NO OTHER TFC CONFLICT.

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.