A B737 flight crew feels that L30 TRACON issued them the wrong altitude.

Attributes
ACN	582628
Time
Date	200305
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl bound lower : 23000 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : aaces
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 205 flight time total : 12786 flight time type : 6258
ASRS Report	582628
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 180 flight time total : 6000 flight time type : 2000
ASRS Report	582526
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance

Narrative:

Departing las on the aaces 2. Cleared to FL230. Clearance modified at FL190 to maintain FL220. Leveled at FL220. Cleared to climb and maintain FL240. This was clearly heard by the first officer and I, properly read back by the first officer, set and confirmed in the MCP altitude window. Passing FL237 ZLA instructs us to maintain FL230. We comply. Contributing factors: ATC evidently erroneously cleared us to FL240 but intended FL230. Also, SID's are not standard. We like the shortcuts, maybe block altitudes for crossing restrs would reduce controller action and errors. They could monitor aircraft and look for deviations versus creating them. Perceptions: I thought the clearance to FL240 was out of the ordinary, however, being capped at FL220 just prior to this was also out of the ordinary. Anymore, what is ordinary leaving las? We clearly read the clearance back. How many times should we query ATC? I think having generous block altitudes at the SID fixes, then having ATC monitor aircraft performance might improve the operation.

Original NASA ASRS Text

Title: A B737 FLT CREW FEELS THAT L30 TRACON ISSUED THEM THE WRONG ALT.

Narrative: DEPARTING LAS ON THE AACES 2. CLRED TO FL230. CLRNC MODIFIED AT FL190 TO MAINTAIN FL220. LEVELED AT FL220. CLRED TO CLB AND MAINTAIN FL240. THIS WAS CLRLY HEARD BY THE FO AND I, PROPERLY READ BACK BY THE FO, SET AND CONFIRMED IN THE MCP ALT WINDOW. PASSING FL237 ZLA INSTRUCTS US TO MAINTAIN FL230. WE COMPLY. CONTRIBUTING FACTORS: ATC EVIDENTLY ERRONEOUSLY CLRED US TO FL240 BUT INTENDED FL230. ALSO, SID'S ARE NOT STANDARD. WE LIKE THE SHORTCUTS, MAYBE BLOCK ALTS FOR XING RESTRS WOULD REDUCE CTLR ACTION AND ERRORS. THEY COULD MONITOR ACFT AND LOOK FOR DEVS VERSUS CREATING THEM. PERCEPTIONS: I THOUGHT THE CLRNC TO FL240 WAS OUT OF THE ORDINARY, HOWEVER, BEING CAPPED AT FL220 JUST PRIOR TO THIS WAS ALSO OUT OF THE ORDINARY. ANYMORE, WHAT IS ORDINARY LEAVING LAS? WE CLRLY READ THE CLRNC BACK. HOW MANY TIMES SHOULD WE QUERY ATC? I THINK HAVING GENEROUS BLOCK ALTS AT THE SID FIXES, THEN HAVING ATC MONITOR ACFT PERFORMANCE MIGHT IMPROVE THE OP.

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.