Air carrier X had less than standard separation from cpr Y. System error.

Attributes
ACN	196527
Time
Date	199112
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : aml
State Reference	VA
Altitude	msl bound lower : 3000 msl bound upper : 3200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iad
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	approach : straight in
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	departure other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 247 flight time total : 6600 flight time type : 1700
ASRS Report	196527
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	faa : investigated faa : reviewed incident with flight crew
Miss Distance	horizontal : 500 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X was descending on the GS and localizer 11 mi from runway 19R at iad. My first officer pointed out traffic ahead which I did not see. The aircraft ahead said something to the controller about an light transport. We then saw cpr Y at 11:30 lower turning towards us and climbing. The controller issued him at 12:00 and 1 mi at 3000 ft MSL. We saw him as he kept turning wbound and appeared to level off at 3000 ft. Our altitude was 3200 descending as he passed 200 ft below and 500 ft to our right. The controller stated to both of us that they did not know where cpr Y had come from. After landing I called the TRACON supervisor and was informed that cpr Y had taken off from leesburg, va, (IFR) under their control. He had made a left turn to martinsburg VOR as he was directed. He said he didn't know why he had turned so slowly. He told me that he was calling the regional headquarters and filing an operational deviation. Luckily it was VFR and all aircraft saw each other though cpr Y did not know he was flying through ILS (IFR) traffic.

Original NASA ASRS Text

Title: ACR X HAD LTSS FROM CPR Y. SYS ERROR.

Narrative: ACR X WAS DSNDING ON THE GS AND LOC 11 MI FROM RWY 19R AT IAD. MY FO POINTED OUT TFC AHEAD WHICH I DID NOT SEE. THE ACFT AHEAD SAID SOMETHING TO THE CTLR ABOUT AN LTT. WE THEN SAW CPR Y AT 11:30 LOWER TURNING TOWARDS US AND CLBING. THE CTLR ISSUED HIM AT 12:00 AND 1 MI AT 3000 FT MSL. WE SAW HIM AS HE KEPT TURNING WBOUND AND APPEARED TO LEVEL OFF AT 3000 FT. OUR ALT WAS 3200 DSNDING AS HE PASSED 200 FT BELOW AND 500 FT TO OUR R. THE CTLR STATED TO BOTH OF US THAT THEY DID NOT KNOW WHERE CPR Y HAD COME FROM. AFTER LNDG I CALLED THE TRACON SUPVR AND WAS INFORMED THAT CPR Y HAD TAKEN OFF FROM LEESBURG, VA, (IFR) UNDER THEIR CTL. HE HAD MADE A L TURN TO MARTINSBURG VOR AS HE WAS DIRECTED. HE SAID HE DIDN'T KNOW WHY HE HAD TURNED SO SLOWLY. HE TOLD ME THAT HE WAS CALLING THE REGIONAL HEADQUARTERS AND FILING AN OPERATIONAL DEV. LUCKILY IT WAS VFR AND ALL ACFT SAW EACH OTHER THOUGH CPR Y DID NOT KNOW HE WAS FLYING THROUGH ILS (IFR) TFC.

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.