Air carrier medium large transport overshoots altitude in climb.

Attributes
ACN	140503
Time
Date	199003
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ama
State Reference	TX
Altitude	msl bound lower : 3100 msl bound upper : 3300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw
Operator	common carrier : air carrier
Make Model Name	Small Aircraft
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : instrument
ASRS Report	140503
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial
Experience	flight time last 90 days : 180 flight time total : 6000 flight time type : 580
ASRS Report	140483
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

We were operating flight from dfw to slc. During the climb, after passing FL310, we were instructed to change frequencys to 134.55. On the new frequency we reported to ZFW that we were out of FL320, climbing to FL330. ZFW asked us to confirm the altitude that we had been cleared to. 33000' was displayed in the autoplt altitude display and we told the controller that we were cleared to FL330L. The center controller asked if we could reach FL350 in 2 mins or if we would rather descend back to FL310. We told him that we could reach FL350 in 2 mins and we continued our climb to FL350. The controller then informed us that our clearance had been to FL310. Our flight plan called for an initial cruising altitude of FL310 and FL330 would have been the wrong altitude for the direction of flight. I do not know the reason for the excursion. It is possible, but unlikely, that the previous controller cleared us to FL330. It is possible that we mis-set the altitude in the autoplt altitude window. The FGS on this particular aircraft is a new, improved type. On earlier (and the most common) models, the altitude knob must be pulled to arm the altitude. On this model the knob only needs to be set. It is possible that one of us inadvertently bumped the altitude knob and accidentally changed the altitude setting.

Original NASA ASRS Text

Title: ACR MLG OVERSHOOTS ALT IN CLIMB.

Narrative: WE WERE OPERATING FLT FROM DFW TO SLC. DURING THE CLB, AFTER PASSING FL310, WE WERE INSTRUCTED TO CHANGE FREQS TO 134.55. ON THE NEW FREQ WE RPTED TO ZFW THAT WE WERE OUT OF FL320, CLBING TO FL330. ZFW ASKED US TO CONFIRM THE ALT THAT WE HAD BEEN CLRED TO. 33000' WAS DISPLAYED IN THE AUTOPLT ALT DISPLAY AND WE TOLD THE CTLR THAT WE WERE CLRED TO FL330L. THE CENTER CTLR ASKED IF WE COULD REACH FL350 IN 2 MINS OR IF WE WOULD RATHER DSND BACK TO FL310. WE TOLD HIM THAT WE COULD REACH FL350 IN 2 MINS AND WE CONTINUED OUR CLB TO FL350. THE CTLR THEN INFORMED US THAT OUR CLRNC HAD BEEN TO FL310. OUR FLT PLAN CALLED FOR AN INITIAL CRUISING ALT OF FL310 AND FL330 WOULD HAVE BEEN THE WRONG ALT FOR THE DIRECTION OF FLT. I DO NOT KNOW THE REASON FOR THE EXCURSION. IT IS POSSIBLE, BUT UNLIKELY, THAT THE PREVIOUS CTLR CLRED US TO FL330. IT IS POSSIBLE THAT WE MIS-SET THE ALT IN THE AUTOPLT ALT WINDOW. THE FGS ON THIS PARTICULAR ACFT IS A NEW, IMPROVED TYPE. ON EARLIER (AND THE MOST COMMON) MODELS, THE ALT KNOB MUST BE PULLED TO ARM THE ALT. ON THIS MODEL THE KNOB ONLY NEEDS TO BE SET. IT IS POSSIBLE THAT ONE OF US INADVERTENTLY BUMPED THE ALT KNOB AND ACCIDENTALLY CHANGED THE ALT SETTING.

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.