A commuter flight crew climbed above the assigned altitude near phl.

Attributes
ACN	451290
Time
Date	199910
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : phl.airport
State Reference	PA
Altitude	msl bound lower : 12000 msl bound upper : 13300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny.artcc
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Experience	flight time last 90 days : 140 flight time total : 1100 flight time type : 140
ASRS Report	451290
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

As we were climbing out of phl, we were cleared by center up to 12000 ft. I misunderstood this call and thought we were cleared up to 15000 ft. When we were passing through 13000 ft, the captain asked if we were cleared to 15000 ft and I responded saying that I believed center had cleared us to 15000 ft originally. He was the PNF so he called center to confirm our assigned altitude. The reporter stated 12000 ft. I immediately descended back down to 12000 ft. Miscom was a factor.

Original NASA ASRS Text

Title: A COMMUTER FLC CLBED ABOVE THE ASSIGNED ALT NEAR PHL.

Narrative: AS WE WERE CLBING OUT OF PHL, WE WERE CLRED BY CTR UP TO 12000 FT. I MISUNDERSTOOD THIS CALL AND THOUGHT WE WERE CLRED UP TO 15000 FT. WHEN WE WERE PASSING THROUGH 13000 FT, THE CAPT ASKED IF WE WERE CLRED TO 15000 FT AND I RESPONDED SAYING THAT I BELIEVED CTR HAD CLRED US TO 15000 FT ORIGINALLY. HE WAS THE PNF SO HE CALLED CTR TO CONFIRM OUR ASSIGNED ALT. THE RPTR STATED 12000 FT. I IMMEDIATELY DSNDED BACK DOWN TO 12000 FT. MISCOM WAS A FACTOR.

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.