An air carrier descends without clearance on the ksino RNAV 2 arrival to las, nv.

Attributes
ACN	574481
Time
Date	200302
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	intersection : luxor
State Reference	NV
Altitude	msl bound lower : 11600 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : l30.tracon tower : ind.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach descent : intermediate altitude
Route In Use	arrival star : ksino.rnav
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 18500 flight time type : 1800
ASRS Report	574481
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance
Independent Detector	other controllerb
Resolutory Action	controller : issued new clearance controller : issued advisory
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On the arrival route to las vegas ATC cleared us to proceed direct to luxor fix and the remainder of the ksino RNAV 2 arrival. Shortly thereafter, we were cleared to cross luxor at 12000 ft and 250 KTS. After meeting the luxor requirements, both pilots thought we had been cleared to descend to the next crossing altitude on the arrival, which was 10000 ft. At 11600 ft, ATC told us to climb back to and maintain 12000 ft, which we immediately did. The remainder of the approach and landing in las vegas was standard and routine. As in our case, a clearance to fly a STAR route only, as opposed to flying the route and descending to the published fix crossing altitudes, can be misunderstood. We were led to believe that the latter was the case. After clearing us to the luxor fix and to the published luxor altitude and speed. More verbiage from the controller might have prevented the further descent.

Original NASA ASRS Text

Title: AN ACR DSNDS WITHOUT CLRNC ON THE KSINO RNAV 2 ARR TO LAS, NV.

Narrative: ON THE ARR RTE TO LAS VEGAS ATC CLRED US TO PROCEED DIRECT TO LUXOR FIX AND THE REMAINDER OF THE KSINO RNAV 2 ARR. SHORTLY THEREAFTER, WE WERE CLRED TO CROSS LUXOR AT 12000 FT AND 250 KTS. AFTER MEETING THE LUXOR REQUIREMENTS, BOTH PLTS THOUGHT WE HAD BEEN CLRED TO DSND TO THE NEXT XING ALT ON THE ARR, WHICH WAS 10000 FT. AT 11600 FT, ATC TOLD US TO CLB BACK TO AND MAINTAIN 12000 FT, WHICH WE IMMEDIATELY DID. THE REMAINDER OF THE APCH AND LNDG IN LAS VEGAS WAS STANDARD AND ROUTINE. AS IN OUR CASE, A CLRNC TO FLY A STAR RTE ONLY, AS OPPOSED TO FLYING THE RTE AND DSNDING TO THE PUBLISHED FIX XING ALTS, CAN BE MISUNDERSTOOD. WE WERE LED TO BELIEVE THAT THE LATTER WAS THE CASE. AFTER CLRING US TO THE LUXOR FIX AND TO THE PUBLISHED LUXOR ALT AND SPD. MORE VERBIAGE FROM THE CTLR MIGHT HAVE PREVENTED THE FURTHER DSCNT.

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.