ZLA controller experienced operational error at FL260 when issuing climb through occupied altitude.

Attributes
ACN	706948
Time
Date	200608
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : trm.vortac
State Reference	CA
Altitude	msl single value : 26000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	general aviation : personal
Make Model Name	Citation V
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zla.artcc
Operator	general aviation : personal
Make Model Name	Premier 1
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : developmental
Experience	controller radar : 7 controller time certified in position2 : 4
ASRS Report	706948
Person 2
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment : conflict alert other controllera
Resolutory Action	controller : issued alert controller : issued new clearance
Consequence	faa : investigated
Miss Distance	horizontal : 28800 vertical : 300
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Climbing aircraft to FL250 under aircraft sbound at FL260. Issued climb to aircraft from FL250 to FL270. Noticed conflict tried to stop climb; but aircraft began climb so expedited descent to FL250 turned aircraft at FL260 30 degrees left. Time on position exceeded 2 hours.

Original NASA ASRS Text

Title: ZLA CTLR EXPERIENCED OPERROR AT FL260 WHEN ISSUING CLB THROUGH OCCUPIED ALT.

Narrative: CLBING ACFT TO FL250 UNDER ACFT SBOUND AT FL260. ISSUED CLB TO ACFT FROM FL250 TO FL270. NOTICED CONFLICT TRIED TO STOP CLB; BUT ACFT BEGAN CLB SO EXPEDITED DSCNT TO FL250 TURNED ACFT AT FL260 30 DEGS L. TIME ON POS EXCEEDED 2 HRS.

Data retrieved from NASA's ASRS site as of January 2009 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.