Narrative:

Climbing through approximately 24500 ft, ATC controller on ZFW called and said we were only cleared to FL230. We responded that we had been cleared to FL290, it had been confirmed by both captain and first officer, entered in the altitude window and pointed out as per company procedures, and read back to ATC. He stated negative, that we had been assigned an airspeed of 290 KTS. We needed 280 KTS for turbulence and he had said maintain 280 KTS. We thought we had been cleared to FL290. He then cleared us to FL310. There obviously was an unintentional misunderstanding regarding the 290 speed and clearance to FL290. The captain asked if there had been a conflict and I believe he said possibly. Then later on the same frequency, we were asked to call ZFW as soon as possible because there had been a conflict. The flight continued normally to lgb and the captain called the above phone number and initially spoke with the watch supervisor, mr X, about the incident, and was later switched to mr Y at ft worth quality assurance and discussed the situation further. Apparently when we read back climb to FL290, mr Y stated to the captain that the controller missed this readback. The captain extended his apologies regarding the incident and said that we would pay closer attention in the future. In summary, I think that both the captain and first officer should have listened more closely to our ATC clrncs. Both pilots have learned a valuable lesson regarding the importance of readbacks and hearbacks.

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Original NASA ASRS Text

Title: MD80 FLT CREW CLBS THROUGH ASSIGNED ALT, BECAUSE OF INCORRECT READBACK AT DFW.

Narrative: CLBING THROUGH APPROX 24500 FT, ATC CTLR ON ZFW CALLED AND SAID WE WERE ONLY CLRED TO FL230. WE RESPONDED THAT WE HAD BEEN CLRED TO FL290, IT HAD BEEN CONFIRMED BY BOTH CAPT AND FO, ENTERED IN THE ALT WINDOW AND POINTED OUT AS PER COMPANY PROCS, AND READ BACK TO ATC. HE STATED NEGATIVE, THAT WE HAD BEEN ASSIGNED AN AIRSPD OF 290 KTS. WE NEEDED 280 KTS FOR TURB AND HE HAD SAID MAINTAIN 280 KTS. WE THOUGHT WE HAD BEEN CLRED TO FL290. HE THEN CLRED US TO FL310. THERE OBVIOUSLY WAS AN UNINTENTIONAL MISUNDERSTANDING REGARDING THE 290 SPD AND CLRNC TO FL290. THE CAPT ASKED IF THERE HAD BEEN A CONFLICT AND I BELIEVE HE SAID POSSIBLY. THEN LATER ON THE SAME FREQ, WE WERE ASKED TO CALL ZFW ASAP BECAUSE THERE HAD BEEN A CONFLICT. THE FLT CONTINUED NORMALLY TO LGB AND THE CAPT CALLED THE ABOVE PHONE NUMBER AND INITIALLY SPOKE WITH THE WATCH SUPVR, MR X, ABOUT THE INCIDENT, AND WAS LATER SWITCHED TO MR Y AT FT WORTH QUALITY ASSURANCE AND DISCUSSED THE SIT FURTHER. APPARENTLY WHEN WE READ BACK CLB TO FL290, MR Y STATED TO THE CAPT THAT THE CTLR MISSED THIS READBACK. THE CAPT EXTENDED HIS APOLOGIES REGARDING THE INCIDENT AND SAID THAT WE WOULD PAY CLOSER ATTN IN THE FUTURE. IN SUMMARY, I THINK THAT BOTH THE CAPT AND FO SHOULD HAVE LISTENED MORE CLOSELY TO OUR ATC CLRNCS. BOTH PLTS HAVE LEARNED A VALUABLE LESSON REGARDING THE IMPORTANCE OF READBACKS AND HEARBACKS.

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.