Air carrier came in close proximity to an unidentified small aircraft while on approach.

Attributes
ACN	126031
Time
Date	198910
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bpi airport : pbi
State Reference	FL
Altitude	msl bound lower : 6500 msl bound upper : 6900
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : pbi
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach descent other
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 2 controller radar : 6
ASRS Report	126031
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 180 flight time total : 7500 flight time type : 1800
ASRS Report	127108
Events
Anomaly	conflict : airborne less severe non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 500 vertical : 400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was working arrival/departure radar (north sector) at pbi. Traffic was heavy and a few aircraft had to be held outside the arsa due to controller workload. I was working air carrier X descending from 10,000 to 4000. Due to workload and number of VFR targets, constant surveillance of air carrier X's track was impossible. As air carrier X was descending through 6500, the pilot advised they had come within close proximity of an small aircraft that I was not working and who had no mode C transponder. Supplemental information from acn 127108: at 6500' on the pbi VOR 277 degree radial, 20 DME, I spotted a single engine small aircraft coming straight at us, at our altitude, on approximately a 300 degree heading. I had my copilot increase our descent rate to avoid the small aircraft aircraft by about 400' vertical and 400' horizontal. No warning was given by the controller.

Original NASA ASRS Text

Title: ACR CAME IN CLOSE PROX TO AN UNIDENTIFIED SMA WHILE ON APCH.

Narrative: I WAS WORKING ARR/DEP RADAR (N SECTOR) AT PBI. TFC WAS HEAVY AND A FEW ACFT HAD TO BE HELD OUTSIDE THE ARSA DUE TO CTLR WORKLOAD. I WAS WORKING ACR X DESCENDING FROM 10,000 TO 4000. DUE TO WORKLOAD AND NUMBER OF VFR TARGETS, CONSTANT SURVEILLANCE OF ACR X'S TRACK WAS IMPOSSIBLE. AS ACR X WAS DESCENDING THROUGH 6500, THE PLT ADVISED THEY HAD COME WITHIN CLOSE PROX OF AN SMA THAT I WAS NOT WORKING AND WHO HAD NO MODE C XPONDER. SUPPLEMENTAL INFORMATION FROM ACN 127108: AT 6500' ON THE PBI VOR 277 DEG RADIAL, 20 DME, I SPOTTED A SINGLE ENGINE SMA COMING STRAIGHT AT US, AT OUR ALT, ON APPROX A 300 DEG HDG. I HAD MY COPLT INCREASE OUR DSCNT RATE TO AVOID THE SMA ACFT BY ABOUT 400' VERTICAL AND 400' HORIZONTAL. NO WARNING WAS GIVEN BY THE CTLR.

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.