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

Attributes
ACN	136949
Time
Date	199002
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : okc
State Reference	OK
Altitude	msl bound lower : 3800 msl bound upper : 3800
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : okc tower : oun
Operator	common carrier : air carrier
Make Model Name	Heavy Transport, Low Wing, 4 Turbojet Eng
Flight Phase	climbout : initial
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : initial
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : radar
Experience	controller radar : 7
ASRS Report	136949
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 non adherence : published procedure
Independent Detector	other other : unspecified atc
Resolutory Action	none taken : anomaly accepted
Consequence	faa : investigated
Miss Distance	horizontal : 5460 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X departed runway 35R, turned east, air carrier Y departed runway 35L was turned east by departure. Aircraft courses diverged by only 10 degree and were .9148224 NM apart. Callback conversation with reporter revealed the following: the reporter was working the tower local control position. Air carrier X was a heavy, air carrier Y was an medium large transport. Air carrier X started his turn late, and air carrier Y started his turn early. The local controller is responsible for providing initial separation. Reporter used visual separation till the aircraft went in the clouds. An operational error was filed. Conflict alert activated in the TRACON.

Original NASA ASRS Text

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

Narrative: ACR X DEPARTED RWY 35R, TURNED E, ACR Y DEPARTED RWY 35L WAS TURNED E BY DEP. ACFT COURSES DIVERGED BY ONLY 10 DEG AND WERE .9148224 NM APART. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THE REPORTER WAS WORKING THE TWR LCL CTL POSITION. ACR X WAS A HVY, ACR Y WAS AN MLG. ACR X STARTED HIS TURN LATE, AND ACR Y STARTED HIS TURN EARLY. THE LCL CTLR IS RESPONSIBLE FOR PROVIDING INITIAL SEPARATION. REPORTER USED VISUAL SEPARATION TILL THE ACFT WENT IN THE CLOUDS. AN OPERATIONAL ERROR WAS FILED. CONFLICT ALERT ACTIVATED IN THE TRACON.

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.