Aircraft on converging course climbed through occupied altitude resulting in less than standard sepa...

Attributes
ACN	129185
Time
Date	198911
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ena
State Reference	AK
Altitude	msl bound lower : 8500 msl bound upper : 8500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : zan
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	129185
Person 2
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument
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 flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 1500 vertical : 600
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Atx X climbing to 10000' MSL. Atx Y descending to 5000' MSL, crossing courses. Atx X radar target not acquired were expected. When acquired, was in close proximity to atx Y descending. 600' sep by pilot report. Pilot of atx Y advised traffic in sight when issued evasive turn and was then advised to remain VFR otp. Pilot received and acknowledged. I believe atx X did not turn on his transponder until he had been airborne for more than 5 mins, whether intentional or not I do not know. It was an area of known radar coverage and target should have acquired but did not for whatever reason. Sector had just undergone a controller shift change (6 mins prior) and sector was busy. These may have all been contributing factors. There is some question whether radar target data (which must be input manually) was entered correctly. Enabling an ocs-ARTS interface (which we are able to do, but not authority/authorized to use at this time) would have relieved this problem (if it existed).

Original NASA ASRS Text

Title: ACFT ON CONVERGING COURSE CLIMBED THROUGH OCCUPIED ALT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: ATX X CLBING TO 10000' MSL. ATX Y DSNDING TO 5000' MSL, XING COURSES. ATX X RADAR TARGET NOT ACQUIRED WERE EXPECTED. WHEN ACQUIRED, WAS IN CLOSE PROX TO ATX Y DSNDING. 600' SEP BY PLT RPT. PLT OF ATX Y ADVISED TFC IN SIGHT WHEN ISSUED EVASIVE TURN AND WAS THEN ADVISED TO REMAIN VFR OTP. PLT RECEIVED AND ACKNOWLEDGED. I BELIEVE ATX X DID NOT TURN ON HIS XPONDER UNTIL HE HAD BEEN AIRBORNE FOR MORE THAN 5 MINS, WHETHER INTENTIONAL OR NOT I DO NOT KNOW. IT WAS AN AREA OF KNOWN RADAR COVERAGE AND TARGET SHOULD HAVE ACQUIRED BUT DID NOT FOR WHATEVER REASON. SECTOR HAD JUST UNDERGONE A CTLR SHIFT CHANGE (6 MINS PRIOR) AND SECTOR WAS BUSY. THESE MAY HAVE ALL BEEN CONTRIBUTING FACTORS. THERE IS SOME QUESTION WHETHER RADAR TARGET DATA (WHICH MUST BE INPUT MANUALLY) WAS ENTERED CORRECTLY. ENABLING AN OCS-ARTS INTERFACE (WHICH WE ARE ABLE TO DO, BUT NOT AUTH TO USE AT THIS TIME) WOULD HAVE RELIEVED THIS PROB (IF IT EXISTED).

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.

Aircraft on converging course climbed through occupied altitude resulting in less than standard separation.