An air carrier large transport climbed through its assigned altitude.

Attributes
ACN	250608
Time
Date	199309
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hvq
State Reference	WV
Altitude	msl bound lower : 33000 msl bound upper : 33500
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 9000
ASRS Report	250608
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 240 flight time total : 24000 flight time type : 13000
ASRS Report	250609
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were climbing from FL310 to FL330 behind traffic ahead at FL350. Traffic on same track. We had slowed to gain spacing and when we were at FL310 the controller said as soon as we picked up spacing we would be cleared to requested altitude. When we cleared out of FL310, I interpreted the clearance incorrectly as FL350 instead of FL330. The aircraft climbed to 33500 ft when we caught my error and descended to FL330. Supplemental information from acn 250676: first officer thought we were cleared to FL350 and climbed through FL330. He was watching aircraft in front of us, which was also on TCASII.

Original NASA ASRS Text

Title: AN ACR LGT CLBED THROUGH ITS ASSIGNED ALT.

Narrative: WE WERE CLBING FROM FL310 TO FL330 BEHIND TFC AHEAD AT FL350. TFC ON SAME TRACK. WE HAD SLOWED TO GAIN SPACING AND WHEN WE WERE AT FL310 THE CTLR SAID AS SOON AS WE PICKED UP SPACING WE WOULD BE CLRED TO REQUESTED ALT. WHEN WE CLRED OUT OF FL310, I INTERPRETED THE CLRNC INCORRECTLY AS FL350 INSTEAD OF FL330. THE ACFT CLBED TO 33500 FT WHEN WE CAUGHT MY ERROR AND DSNDED TO FL330. SUPPLEMENTAL INFO FROM ACN 250676: FO THOUGHT WE WERE CLRED TO FL350 AND CLBED THROUGH FL330. HE WAS WATCHING ACFT IN FRONT OF US, WHICH WAS ALSO ON TCASII.

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.