S56 controller described conflict at 11000 ft when one aircraft ascended above assigned altitude.

Attributes
ACN	682936
Time
Date	200512
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : ffu.vortac
State Reference	UT
Altitude	msl single value : 11000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : s56.tracon
Operator	general aviation : personal
Make Model Name	Beechjet 400
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : s56.tracon
Operator	common carrier : air taxi
Make Model Name	Airliner 99
Operating Under FAR Part	Part 135
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Experience	controller radar : 16 controller time certified in position1 : 15
ASRS Report	682936
Person 2
Affiliation	other
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne critical
Independent Detector	aircraft equipment : tcas other controllera
Resolutory Action	flight crew : took evasive action
Consequence	faa : investigated
Miss Distance	horizontal : 3000 vertical : 100
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The BE99 was northbound level at 11000 ft. The BE40 was swbound converging with the BE99 at 9000 ft given climb clearance to 10000 ft. BE40 was observed by me climbing out of 10200 ft. I issued a traffic alert and an immediate turn. All readbacks were correct. The pilot of the BE40 claimed he got a TCAS alert advising them to climb. The BE99 advised that he saw the BE40 climb in front of them. It's unknown at this time whether the BE99 is filing an near midair collision or not.

Original NASA ASRS Text

Title: S56 CTLR DESCRIBED CONFLICT AT 11000 FT WHEN ONE ACFT ASCENDED ABOVE ASSIGNED ALT.

Narrative: THE BE99 WAS NBOUND LEVEL AT 11000 FT. THE BE40 WAS SWBOUND CONVERGING WITH THE BE99 AT 9000 FT GIVEN CLB CLRNC TO 10000 FT. BE40 WAS OBSERVED BY ME CLBING OUT OF 10200 FT. I ISSUED A TFC ALERT AND AN IMMEDIATE TURN. ALL READBACKS WERE CORRECT. THE PLT OF THE BE40 CLAIMED HE GOT A TCAS ALERT ADVISING THEM TO CLB. THE BE99 ADVISED THAT HE SAW THE BE40 CLB IN FRONT OF THEM. IT'S UNKNOWN AT THIS TIME WHETHER THE BE99 IS FILING AN NMAC OR NOT.

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.