Narrative:

On dec/sat/89 I was flying from clt to ord on flight XXXX. Climbing out I distinctly heard the controller assign us FL330. My first officer acknowledged the altitude and set it in the altitude reminder window. Shortly we were given a frequency change. As I climbed through FL244, the controller said 'go back down to FL230'. The controller, the new one, asked what our assigned altitude was. We responded '330'. He then said we had been assigned 230 by the previous controller. A few mins later he called and informed me of a possible flight deviation. He gave me his supervisor's name and his phone number and asked me to call him upon arriving ord. I spoke to the supervisor and he told me that we had acknowledged the altitude assignment with our call sign only. My first officer and I feel strongly that we acknowledge with our call sign and altitude. I feel that the confusion or missed communication may have occurred because we switched frequency and controllers immediately after having received the altitude assignment. I was not advised that another aircraft was close to me until later. I descended to FL230 and subsequently was reclred to 330 and continued to ord. Radio static could have been a contributing factor.

Related reports:

Google
 

Original NASA ASRS Text

Title: ALT DEVIATION. OVERSHOOT IN CLIMB. READBACK HEARBACK ISSUE.

Narrative: ON DEC/SAT/89 I WAS FLYING FROM CLT TO ORD ON FLT XXXX. CLIMBING OUT I DISTINCTLY HEARD THE CTLR ASSIGN US FL330. MY FO ACKNOWLEDGED THE ALT AND SET IT IN THE ALT REMINDER WINDOW. SHORTLY WE WERE GIVEN A FREQ CHANGE. AS I CLIMBED THROUGH FL244, THE CTLR SAID 'GO BACK DOWN TO FL230'. THE CTLR, THE NEW ONE, ASKED WHAT OUR ASSIGNED ALT WAS. WE RESPONDED '330'. HE THEN SAID WE HAD BEEN ASSIGNED 230 BY THE PREVIOUS CTLR. A FEW MINS LATER HE CALLED AND INFORMED ME OF A POSSIBLE FLT DEVIATION. HE GAVE ME HIS SUPVR'S NAME AND HIS PHONE NUMBER AND ASKED ME TO CALL HIM UPON ARRIVING ORD. I SPOKE TO THE SUPVR AND HE TOLD ME THAT WE HAD ACKNOWLEDGED THE ALT ASSIGNMENT WITH OUR CALL SIGN ONLY. MY FO AND I FEEL STRONGLY THAT WE ACKNOWLEDGE WITH OUR CALL SIGN AND ALT. I FEEL THAT THE CONFUSION OR MISSED COM MAY HAVE OCCURRED BECAUSE WE SWITCHED FREQ AND CTLRS IMMEDIATELY AFTER HAVING RECEIVED THE ALT ASSIGNMENT. I WAS NOT ADVISED THAT ANOTHER ACFT WAS CLOSE TO ME UNTIL LATER. I DSNDED TO FL230 AND SUBSEQUENTLY WAS RECLRED TO 330 AND CONTINUED TO ORD. RADIO STATIC COULD HAVE BEEN A CONTRIBUTING FACTOR.

Data retrieved from NASA's ASRS site as of August 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.