Air carrier X climb through occupied altitude had less than standard separation from Y. System error...

Attributes
ACN	270933
Time
Date	199405
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : loa
State Reference	TX
Altitude	msl bound lower : 24000 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu artcc : sjt
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : developmental controller : radar
Experience	controller non radar : 2 controller radar : 1
ASRS Report	270933
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 controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 22200 vertical : 700
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

A king air Y departed the houston terminal area nwbound. I climbed the aircraft to FL240, the king air's requested final. I then received a handoff on a DC9. I climbed X to FL330 assuming I would have lateral separation with the king air. A falcon jet checked on and I climbed him to FL280 with a restr to top the king air. In later traffic searches, I noted the rate of climb of the DC9 as acceptable to clear the king air that X was overtaking. On my next scan X was 7 mi and 120 KTS faster than the traffic. I issued a 60 degree left turn but separation was lost. I assumed I had given X the same restr to top the king air when I had only given it to the falcon. Traffic was light but building, and the number of flight progress strips I had received did distract me. Better strip marking (putting the restr on X's strip) and not letting the impending traffic situation (strips to be posted) distract me would have prevented this occurrence. A lack of experience (3 weeks radar) was a contributing factor as I did not have an assistant controller on the sector.

Original NASA ASRS Text

Title: ACR X CLB THROUGH OCCUPIED ALT HAD LTSS FROM Y. SYS ERROR.

Narrative: A KING AIR Y DEPARTED THE HOUSTON TERMINAL AREA NWBOUND. I CLBED THE ACFT TO FL240, THE KING AIR'S REQUESTED FINAL. I THEN RECEIVED A HDOF ON A DC9. I CLBED X TO FL330 ASSUMING I WOULD HAVE LATERAL SEPARATION WITH THE KING AIR. A FALCON JET CHKED ON AND I CLBED HIM TO FL280 WITH A RESTR TO TOP THE KING AIR. IN LATER TFC SEARCHES, I NOTED THE RATE OF CLB OF THE DC9 AS ACCEPTABLE TO CLR THE KING AIR THAT X WAS OVERTAKING. ON MY NEXT SCAN X WAS 7 MI AND 120 KTS FASTER THAN THE TFC. I ISSUED A 60 DEG L TURN BUT SEPARATION WAS LOST. I ASSUMED I HAD GIVEN X THE SAME RESTR TO TOP THE KING AIR WHEN I HAD ONLY GIVEN IT TO THE FALCON. TFC WAS LIGHT BUT BUILDING, AND THE NUMBER OF FLT PROGRESS STRIPS I HAD RECEIVED DID DISTRACT ME. BETTER STRIP MARKING (PUTTING THE RESTR ON X'S STRIP) AND NOT LETTING THE IMPENDING TFC SIT (STRIPS TO BE POSTED) DISTRACT ME WOULD HAVE PREVENTED THIS OCCURRENCE. A LACK OF EXPERIENCE (3 WKS RADAR) WAS A CONTRIBUTING FACTOR AS I DID NOT HAVE AN ASSISTANT CTLR ON THE SECTOR.

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.