Crew misread a clearance to maintain an assigned altitude and continued climb.

Attributes
ACN	490002
Time
Date	200010
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mmun.airport
State Reference	FO
Altitude	msl bound lower : 2000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mmun.tracon
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
ASRS Report	490002
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	490000
Events
Anomaly	altitude deviation : overshoot non adherence : company policies non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Flight Crew Human Performance Environmental Factor
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On visual departure from cancun, misunderstood controller's instruction to maintain 2000 ft MSL. Started climb to FL310 as previously assigned as was questioned climbing through approximately 5000 ft MSL. Controller advised it was not a problem.

Original NASA ASRS Text

Title: CREW MISREAD A CLRNC TO MAINTAIN AN ASSIGNED ALT AND CONTINUED CLB.

Narrative: ON VISUAL DEP FROM CANCUN, MISUNDERSTOOD CTLR'S INSTRUCTION TO MAINTAIN 2000 FT MSL. STARTED CLB TO FL310 AS PREVIOUSLY ASSIGNED AS WAS QUESTIONED CLBING THROUGH APPROX 5000 FT MSL. CTLR ADVISED IT WAS NOT A PROB.

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.