Air carrier a had less than standard separation from air carrier B. Operational error.

Attributes
ACN	117700
Time
Date	198907
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : den
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct enroute : on vectors enroute airway : zdv
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller non radar : 7 controller radar : 6
ASRS Report	117700
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : developmental
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 24600 vertical : 1700
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was instructing a radar trainee at the time separation was lost. Air carrier a was at FL310 filed hct.J60.den.J128. Air carrier B was at FL330 filed den.J130. Air carrier a was climbed from FL310 to FL350 for traffic converging at den. At the time the climb was initiated, I was aware that air carrier B was traffic for air carrier a during the climb. Air carrier B flts normally fly out J80 from den on the route air carrier B was on, so I was not sure my trainee was aware that air carrier B would be turning left into air carrier a. After air carrier B started his turn at den I was about to intervene to separate the aircraft when the trainee noticed that he would not have separation. I decided to let the trainee separate the aircraft. He told air carrier a to expedite his climb to FL350 and then realized that would not be enough and then turned air carrier a 30 degree right. At this point I intervened and turned air carrier a 40 degree right. I waited too long to intervene in this situation. The trainee is having problems on this sector. I am sure that is why I waited to give him a chance to solve this problem on his own and not intervene as soon as I should have.

Original NASA ASRS Text

Title: ACR A HAD LESS THAN STANDARD SEPARATION FROM ACR B. OPERATIONAL ERROR.

Narrative: I WAS INSTRUCTING A RADAR TRAINEE AT THE TIME SEPARATION WAS LOST. ACR A WAS AT FL310 FILED HCT.J60.DEN.J128. ACR B WAS AT FL330 FILED DEN.J130. ACR A WAS CLIMBED FROM FL310 TO FL350 FOR TFC CONVERGING AT DEN. AT THE TIME THE CLIMB WAS INITIATED, I WAS AWARE THAT ACR B WAS TFC FOR ACR A DURING THE CLIMB. ACR B FLTS NORMALLY FLY OUT J80 FROM DEN ON THE ROUTE ACR B WAS ON, SO I WAS NOT SURE MY TRAINEE WAS AWARE THAT ACR B WOULD BE TURNING LEFT INTO ACR A. AFTER ACR B STARTED HIS TURN AT DEN I WAS ABOUT TO INTERVENE TO SEPARATE THE ACFT WHEN THE TRAINEE NOTICED THAT HE WOULD NOT HAVE SEPARATION. I DECIDED TO LET THE TRAINEE SEPARATE THE ACFT. HE TOLD ACR A TO EXPEDITE HIS CLIMB TO FL350 AND THEN REALIZED THAT WOULD NOT BE ENOUGH AND THEN TURNED ACR A 30 DEG RIGHT. AT THIS POINT I INTERVENED AND TURNED ACR A 40 DEG RIGHT. I WAITED TOO LONG TO INTERVENE IN THIS SITUATION. THE TRAINEE IS HAVING PROBLEMS ON THIS SECTOR. I AM SURE THAT IS WHY I WAITED TO GIVE HIM A CHANCE TO SOLVE THIS PROBLEM ON HIS OWN AND NOT INTERVENE AS SOON AS I SHOULD HAVE.

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.