Narrative:

While level at FL310, we were in contact with ZDV. They gave us a clearance to descend to FL260, then pilot's discretion to 14000 ft. The first officer and I each wrote these instructions on our respective scratch pads and it was read back to ATC by the first officer. The lower altitude was entered into the alerter by the first officer and confirmed by me in accordance with our operating procedures. I initiated the descent and the first officer reported us out of FL310 for 14000 ft. After several mins of level flight at 14000 ft, we called den for a lower altitude. At this point, the controller advised us that our clearance was only to 15000 ft. We each quickly checked our notes and had both written 14000 ft as the limit of our descent clearance. This was done based solely on the transmission from ZDV and without a conference between the first officer, flight engineer and myself. The first officer advised ATC that we had received a descent to 14000 ft, to which there was no response. It is my belief that ATC made an error in the issuance of descent clearance to 14000 ft. As a crew, we performed in accordance with our company procedures, and afforded ATC 2 opportunities to correct their apparent mistake. It is especially unsettling that this mistake can occur in mountainous terrain.

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Original NASA ASRS Text

Title: B727 FLT CREW IS QUESTIONED BY ZDV CTLR AFTER RPTING LEVEL AT 14000 FT, THE PREVIOUS ASSIGNED ALT. B727 WAS DIRECT TO JNL, OFF AIRWAYS.

Narrative: WHILE LEVEL AT FL310, WE WERE IN CONTACT WITH ZDV. THEY GAVE US A CLRNC TO DSND TO FL260, THEN PLT'S DISCRETION TO 14000 FT. THE FO AND I EACH WROTE THESE INSTRUCTIONS ON OUR RESPECTIVE SCRATCH PADS AND IT WAS READ BACK TO ATC BY THE FO. THE LOWER ALT WAS ENTERED INTO THE ALERTER BY THE FO AND CONFIRMED BY ME IN ACCORDANCE WITH OUR OPERATING PROCS. I INITIATED THE DSCNT AND THE FO RPTED US OUT OF FL310 FOR 14000 FT. AFTER SEVERAL MINS OF LEVEL FLT AT 14000 FT, WE CALLED DEN FOR A LOWER ALT. AT THIS POINT, THE CTLR ADVISED US THAT OUR CLRNC WAS ONLY TO 15000 FT. WE EACH QUICKLY CHKED OUR NOTES AND HAD BOTH WRITTEN 14000 FT AS THE LIMIT OF OUR DSCNT CLRNC. THIS WAS DONE BASED SOLELY ON THE XMISSION FROM ZDV AND WITHOUT A CONFERENCE BTWN THE FO, FE AND MYSELF. THE FO ADVISED ATC THAT WE HAD RECEIVED A DSCNT TO 14000 FT, TO WHICH THERE WAS NO RESPONSE. IT IS MY BELIEF THAT ATC MADE AN ERROR IN THE ISSUANCE OF DSCNT CLRNC TO 14000 FT. AS A CREW, WE PERFORMED IN ACCORDANCE WITH OUR COMPANY PROCS, AND AFFORDED ATC 2 OPPORTUNITIES TO CORRECT THEIR APPARENT MISTAKE. IT IS ESPECIALLY UNSETTLING THAT THIS MISTAKE CAN OCCUR IN MOUNTAINOUS TERRAIN.

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.