B727 flight crew misunderstood their clearance.

Attributes
ACN	448590
Time
Date	199909
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	navaid : sjc.vor
State Reference	CA
Altitude	msl single value : 12500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zoa.artcc tracon : o90.tracon tower : sjc.tower tower : bna.tower
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 333 flight time total : 10501 flight time type : 5000
ASRS Report	448590
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : company policies non adherence : published procedure non adherence : far non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance Chart Or Publication FAA
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Departed sjc runway 30L. Tower canceled SID restrs in turn at 3000 ft. Tower cleared us to cross sjc at (we think we heard or above) 12000 ft, climb to FL230. We (first officer) read back. We crossed at 12500 ft and ZOA said 'for future reference, crossing sjc at 12000 ft is on the SID.' there were no other aircraft in the area and no loss of separation. It's a busy SID at 12000 ft and sometimes difficult to achieve in a B727.

Original NASA ASRS Text

Title: B727 FLC MISUNDERSTOOD THEIR CLRNC.

Narrative: DEPARTED SJC RWY 30L. TWR CANCELED SID RESTRS IN TURN AT 3000 FT. TWR CLRED US TO CROSS SJC AT (WE THINK WE HEARD OR ABOVE) 12000 FT, CLB TO FL230. WE (FO) READ BACK. WE CROSSED AT 12500 FT AND ZOA SAID 'FOR FUTURE REF, XING SJC AT 12000 FT IS ON THE SID.' THERE WERE NO OTHER ACFT IN THE AREA AND NO LOSS OF SEPARATION. IT'S A BUSY SID AT 12000 FT AND SOMETIMES DIFFICULT TO ACHIEVE IN A B727.

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.