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

Attributes
ACN	154415
Time
Date	199008
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : roa
State Reference	VA
Altitude	msl bound lower : 3800 msl bound upper : 5000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : roa
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 3300 flight time type : 500
ASRS Report	154415
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 4300 flight time type : 1200
ASRS Report	154959
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 6000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Approach control was sequencing 3 air carrier's for an ILS 33 at roa. Air carrier X was #2 to follow air carrier Y light transport. We were cleared to maintain 3800'. We watched as air carrier Y got closer and closer to us, and queried the approach controller about the traffic. His response was that 'traffic is 1000' below you.' I said to the captain, 'he sure looks like he's at our altitude.' just then the controller told us to maintain 5000'. We climbed to 5000' and remainder of flight was noneventful. Throughout this situation the controller seemed to be confused and not at all on top of the situation.

Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: APCH CTL WAS SEQUENCING 3 ACR'S FOR AN ILS 33 AT ROA. ACR X WAS #2 TO FOLLOW ACR Y LTT. WE WERE CLRED TO MAINTAIN 3800'. WE WATCHED AS ACR Y GOT CLOSER AND CLOSER TO US, AND QUERIED THE APCH CTLR ABOUT THE TFC. HIS RESPONSE WAS THAT 'TFC IS 1000' BELOW YOU.' I SAID TO THE CAPT, 'HE SURE LOOKS LIKE HE'S AT OUR ALT.' JUST THEN THE CTLR TOLD US TO MAINTAIN 5000'. WE CLBED TO 5000' AND REMAINDER OF FLT WAS NONEVENTFUL. THROUGHOUT THIS SITUATION THE CTLR SEEMED TO BE CONFUSED AND NOT AT ALL ON TOP OF THE SITUATION.

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.