Clearance misinterp by PIC leads to an altitude deviation.

Attributes
ACN	137684
Time
Date	199002
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : mol
State Reference	VA
Altitude	msl bound lower : 33000 msl bound upper : 33600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tower : mke
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 1500
ASRS Report	137684
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During climb to requested cruise altitude of 35000' we were stepped from 4000 to 12000 to 16000 to 19000, etc and stopped at 33000 for a short period of time (5 min). I heard ATC say 340 for traffic and started a climb to FL340. My first officer responded to the center then noted that I was climbing instead of turning to a heading of 340 degree for traffic. I stopped the climb at 33,600 and returned to 33000. ATC questioned my altitude. When error was clarified we were turned to a heading of 360 degree. I made the mistake of thinking ahead and hearing what I expected to hear and not what was said.

Original NASA ASRS Text

Title: CLRNC MISINTERP BY PIC LEADS TO AN ALT DEVIATION.

Narrative: DURING CLIMB TO REQUESTED CRUISE ALT OF 35000' WE WERE STEPPED FROM 4000 TO 12000 TO 16000 TO 19000, ETC AND STOPPED AT 33000 FOR A SHORT PERIOD OF TIME (5 MIN). I HEARD ATC SAY 340 FOR TFC AND STARTED A CLIMB TO FL340. MY F/O RESPONDED TO THE CENTER THEN NOTED THAT I WAS CLIMBING INSTEAD OF TURNING TO A HDG OF 340 DEG FOR TFC. I STOPPED THE CLIMB AT 33,600 AND RETURNED TO 33000. ATC QUESTIONED MY ALT. WHEN ERROR WAS CLARIFIED WE WERE TURNED TO A HDG OF 360 DEG. I MADE THE MISTAKE OF THINKING AHEAD AND HEARING WHAT I EXPECTED TO HEAR AND NOT WHAT WAS SAID.

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.