Narrative:

As we were given a descent instruction to FL240, I immediately started my descent. Established in the descent, a cabin crew member called the cockpit to verify our estimated time of arrival. As the aircraft was on autoplt, I answered the call. In the meantime, the captain (PNF) received another descent clearance with a crossing restriction of 10 mi west of pullman at FL200. As I had not heard the clearance due to the call from the cabin, I assumed by seeing 20000' in the 'altitude setting window' that we were given an unrestricted descent. The captain then immediately became occupied with the responsibilities of completing the descent checklist including obtaining the ATIS and company information. As we were leveling off at FL200, the captain discovered that we had not complied with the crossing restriction. This was the first I had learned of the crossing restriction. The captain at that time tried to establish communication with center, however unsuccessfully. We later learned that there was a stuck microphone on that frequency. The captain then established communication with chicago approach and we proceeded to land uneventfully. The incident could have been avoided by simple communication between the captain and myself. After observing 20000' in the 'altitude set window', I should have asked the captain if there were any restrictions involved as I had not heard the clearance myself. The captain on the other hand could have informed me of the restriction to ensure that we both were aware of the restriction.

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Original NASA ASRS Text

Title: FLT CREW OF ACR MLG IS DISTRACTED BY CHECKLIST AND CALL FROM CABIN CREW. FO (PF) MISSES ATC DESCENT INSTRUCTION INCLUDING CROSSING RESTRICTION AND MISSES THE RESTRICTION.

Narrative: AS WE WERE GIVEN A DSNT INSTRUCTION TO FL240, I IMMEDIATELY STARTED MY DSNT. ESTABLISHED IN THE DSNT, A CABIN CREW MEMBER CALLED THE COCKPIT TO VERIFY OUR ESTIMATED TIME OF ARR. AS THE ACFT WAS ON AUTOPLT, I ANSWERED THE CALL. IN THE MEANTIME, THE CAPT (PNF) RECEIVED ANOTHER DSNT CLRNC WITH A XING RESTRICTION OF 10 MI W OF PULLMAN AT FL200. AS I HAD NOT HEARD THE CLRNC DUE TO THE CALL FROM THE CABIN, I ASSUMED BY SEEING 20000' IN THE 'ALT SETTING WINDOW' THAT WE WERE GIVEN AN UNRESTRICTED DSNT. THE CAPT THEN IMMEDIATELY BECAME OCCUPIED WITH THE RESPONSIBILITIES OF COMPLETING THE DSNT CHKLIST INCLUDING OBTAINING THE ATIS AND COMPANY INFO. AS WE WERE LEVELING OFF AT FL200, THE CAPT DISCOVERED THAT WE HAD NOT COMPLIED WITH THE XING RESTRICTION. THIS WAS THE FIRST I HAD LEARNED OF THE XING RESTRICTION. THE CAPT AT THAT TIME TRIED TO ESTABLISH COM WITH CENTER, HOWEVER UNSUCCESSFULLY. WE LATER LEARNED THAT THERE WAS A STUCK MIKE ON THAT FREQ. THE CAPT THEN ESTABLISHED COM WITH CHICAGO APCH AND WE PROCEEDED TO LAND UNEVENTFULLY. THE INCIDENT COULD HAVE BEEN AVOIDED BY SIMPLE COM BTWN THE CAPT AND MYSELF. AFTER OBSERVING 20000' IN THE 'ALT SET WINDOW', I SHOULD HAVE ASKED THE CAPT IF THERE WERE ANY RESTRICTIONS INVOLVED AS I HAD NOT HEARD THE CLRNC MYSELF. THE CAPT ON THE OTHER HAND COULD HAVE INFORMED ME OF THE RESTRICTION TO ENSURE THAT WE BOTH WERE AWARE OF THE RESTRICTION.

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.