Two aircraft passed with less than standard separation.

Attributes
ACN	162346
Time
Date	199011
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : iad
State Reference	VA
Altitude	msl bound lower : 9000 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iad
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	arrival other enroute : on vectors enroute airway : v143
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach instruction : instructor
Qualification	controller : radar
ASRS Report	162346
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : developmental
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was vectoring a widebody transport for a sequence to 'dulles runway 1L.' I had an small transport at 9000' on an arwy (V143) nebnd. I held the widebody transport at 9000' due to VFR traffic at 8500'. The aircraft were on converging courses. I turned the widebody transport and descended him to 7000'. The VFR traffic was no longer a factor and the widebody transport passed behind the small transport descending. The small transport had been issued the traffic and had the widebody transport visly. The small transport had been turned eastbound prior to the widebody transport instructions. Sep appeared to be compromised. Lack of proficiency was a major factor. Training was also a factor.

Original NASA ASRS Text

Title: TWO ACFT PASSED WITH LESS THAN STANDARD SEPARATION.

Narrative: I WAS VECTORING A WDB FOR A SEQUENCE TO 'DULLES RWY 1L.' I HAD AN SMT AT 9000' ON AN ARWY (V143) NEBND. I HELD THE WDB AT 9000' DUE TO VFR TFC AT 8500'. THE ACFT WERE ON CONVERGING COURSES. I TURNED THE WDB AND DSNDED HIM TO 7000'. THE VFR TFC WAS NO LONGER A FACTOR AND THE WDB PASSED BEHIND THE SMT DSNDING. THE SMT HAD BEEN ISSUED THE TFC AND HAD THE WDB VISLY. THE SMT HAD BEEN TURNED EBND PRIOR TO THE WDB INSTRUCTIONS. SEP APPEARED TO BE COMPROMISED. LACK OF PROFICIENCY WAS A MAJOR FACTOR. TRNING WAS ALSO A FACTOR.

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.