Less than standard separation between 2 air carrier aircraft. Operational error.

Attributes
ACN	92742
Time
Date	198808
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : cvi
State Reference	VA
Altitude	msl bound lower : 31000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tower : lga
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller non radar : 2 controller radar : 2
ASRS Report	92742
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance none taken : unable
Consequence	faa : investigated
Miss Distance	horizontal : 25500 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was using the radar to separate 2 aircraft. I turned one of them to miss the other. At that time at least 2 radar returns were missed. I was unable to judge the rate of turn, and when radar coverage resumed, the aircraft had lost sep. Better radar coverage would have helped to prevent the incident. Less aircraft flying through the airspace (I was quite busy) would have helped. Callback conversation with reporter revealed the following: reporter supplied types of aircraft, headings and altitude involved. Antenna site was 'benson' and no history of target loss in that area. Reporter had to call air carrier X 3 times before aircraft acknowledged turn for traffic. Reporter could see that aircraft would be well clear of each other so did not want to use phraseology such as 'expedite' or 'immediately' because abrupt action was not called for and personnel are sometimes injured during abrupt maneuvers. Incident classified as minor.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN 2 ACR ACFT. OPERATIONAL ERROR.

Narrative: I WAS USING THE RADAR TO SEPARATE 2 ACFT. I TURNED ONE OF THEM TO MISS THE OTHER. AT THAT TIME AT LEAST 2 RADAR RETURNS WERE MISSED. I WAS UNABLE TO JUDGE THE RATE OF TURN, AND WHEN RADAR COVERAGE RESUMED, THE ACFT HAD LOST SEP. BETTER RADAR COVERAGE WOULD HAVE HELPED TO PREVENT THE INCIDENT. LESS ACFT FLYING THROUGH THE AIRSPACE (I WAS QUITE BUSY) WOULD HAVE HELPED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR SUPPLIED TYPES OF ACFT, HDGS AND ALT INVOLVED. ANTENNA SITE WAS 'BENSON' AND NO HISTORY OF TARGET LOSS IN THAT AREA. RPTR HAD TO CALL ACR X 3 TIMES BEFORE ACFT ACKNOWLEDGED TURN FOR TFC. RPTR COULD SEE THAT ACFT WOULD BE WELL CLEAR OF EACH OTHER SO DID NOT WANT TO USE PHRASEOLOGY SUCH AS 'EXPEDITE' OR 'IMMEDIATELY' BECAUSE ABRUPT ACTION WAS NOT CALLED FOR AND PERSONNEL ARE SOMETIMES INJURED DURING ABRUPT MANEUVERS. INCIDENT CLASSIFIED AS MINOR.

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.