Narrative:

After instructed to hold at macey on our arrival into atl we were told to descend to FL240. The copilot read back FL240 and we started our descent. We were being what we thought was very conscious of our altitude because, just a few mins before on a previous flight, we had discovered our altitude arm function of the autoplt was not working. I, as flight engineer had missed the descent and hold instruction because I was busy getting the ATIS, getting a gate assignment and reporting to our maintenance coordinator our altitude arm malfunction. When I came back in the loop, ATC asked us what altitude we were at. We responded FL240. He said he thought he had assigned us FL250, but no problem, remain at FL240. We told him we understood and read back FL240 and thanked him. Although we still don't know who exactly was at fault, we did everything presently in place to prevent such an error. We had 2 pilots monitoring the radio, confirmed the correct altitude was set in the altitude window, read back the assigned altitude and leveled at the proper altitude. It's the same old communication problem. We can only work to prevent it from happening by having both ends of the radio being as conscientious about a clrncs and readbacks as possible until datalink clrncs come along.

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Original NASA ASRS Text

Title: ALTDEV DURING DSCNT.

Narrative: AFTER INSTRUCTED TO HOLD AT MACEY ON OUR ARR INTO ATL WE WERE TOLD TO DSND TO FL240. THE COPLT READ BACK FL240 AND WE STARTED OUR DSCNT. WE WERE BEING WHAT WE THOUGHT WAS VERY CONSCIOUS OF OUR ALT BECAUSE, JUST A FEW MINS BEFORE ON A PREVIOUS FLT, WE HAD DISCOVERED OUR ALT ARM FUNCTION OF THE AUTOPLT WAS NOT WORKING. I, AS FE HAD MISSED THE DSCNT AND HOLD INSTRUCTION BECAUSE I WAS BUSY GETTING THE ATIS, GETTING A GATE ASSIGNMENT AND RPTING TO OUR MAINT COORDINATOR OUR ALT ARM MALFUNCTION. WHEN I CAME BACK IN THE LOOP, ATC ASKED US WHAT ALT WE WERE AT. WE RESPONDED FL240. HE SAID HE THOUGHT HE HAD ASSIGNED US FL250, BUT NO PROB, REMAIN AT FL240. WE TOLD HIM WE UNDERSTOOD AND READ BACK FL240 AND THANKED HIM. ALTHOUGH WE STILL DON'T KNOW WHO EXACTLY WAS AT FAULT, WE DID EVERYTHING PRESENTLY IN PLACE TO PREVENT SUCH AN ERROR. WE HAD 2 PLTS MONITORING THE RADIO, CONFIRMED THE CORRECT ALT WAS SET IN THE ALT WINDOW, READ BACK THE ASSIGNED ALT AND LEVELED AT THE PROPER ALT. IT'S THE SAME OLD COM PROB. WE CAN ONLY WORK TO PREVENT IT FROM HAPPENING BY HAVING BOTH ENDS OF THE RADIO BEING AS CONSCIENTIOUS ABOUT A CLRNCS AND READBACKS AS POSSIBLE UNTIL DATALINK CLRNCS COME ALONG.

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.