Air carrier crew descends too soon on nootn 2 arrival at las.

Attributes
ACN	459420
Time
Date	200001
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl bound lower : 7500 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : l30.tracon
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival star : nooln 2
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp pilot : multi engine
Experience	flight time last 90 days : 180 flight time total : 18000 flight time type : 50
ASRS Report	459802
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 200 flight time total : 7200 flight time type : 230
ASRS Report	459420
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance non adherence other
Independent Detector	other controllerb
Resolutory Action	controller : issued new clearance flight crew : returned to original clearance
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On nootn 2 STAR into las, we were level at 8000 ft between phigg and prino. First officer flying, captain talking to las approach control. ATC cleared us to descend to 7000 ft and slow to 170 KTS. Captain read back clearance and set 7000 ft in MCP. I started 500 FPM descent. At 7500 ft MSL, ATC said we were to maintain 8000 ft to tiffy, then descend to 7000 ft. Captain challenged controller saying we were cleared 7000 ft and were now climbing back to 8000 ft. No response from controller. Subsequently cleared for visual approach to runway 25L. Landed without further incident. There was evidently a miscom between our flight and ATC as to our descent clearance.

Original NASA ASRS Text

Title: ACR CREW DSNDS TOO SOON ON NOOTN 2 ARR AT LAS.

Narrative: ON NOOTN 2 STAR INTO LAS, WE WERE LEVEL AT 8000 FT BTWN PHIGG AND PRINO. FO FLYING, CAPT TALKING TO LAS APCH CTL. ATC CLRED US TO DSND TO 7000 FT AND SLOW TO 170 KTS. CAPT READ BACK CLRNC AND SET 7000 FT IN MCP. I STARTED 500 FPM DSCNT. AT 7500 FT MSL, ATC SAID WE WERE TO MAINTAIN 8000 FT TO TIFFY, THEN DSND TO 7000 FT. CAPT CHALLENGED CTLR SAYING WE WERE CLRED 7000 FT AND WERE NOW CLBING BACK TO 8000 FT. NO RESPONSE FROM CTLR. SUBSEQUENTLY CLRED FOR VISUAL APCH TO RWY 25L. LANDED WITHOUT FURTHER INCIDENT. THERE WAS EVIDENTLY A MISCOM BTWN OUR FLT AND ATC AS TO OUR DSCNT CLRNC.

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.