Narrative:

Approximately 100-150 mi east of las vegas, nv, we continued a climb out of FL290. At FL294 the center controller asked our altitude. I responded (the captain was on the P/a) that we were out of FL294. He stated we were only cleared to FL290. I stated that it was our understanding we were cleared to FL310. (Looking at the altitude alert verified 31000' set in the window.) the captain had completed the passenger announcement, overheard the previous transmission and simultaneously with descending the aircraft back down to FL290 stated that obviously there was some confusion and misunderstanding re: the altitude clearance limit. We never ascended to higher than FL295. Factors affecting human performance were that one person, the first officer, was handling both the communications as well as flying the aircraft. The F/east was unattentive and could not recall the clearance limit. Another consideration may be that the first officer had been ill earlier in the month. He had been trying to fly while still ill with a not too dehabiliatory virus and had reported ear trouble 1 1/2 weeks earlier, thinking it had cleared by now. Basically, the first officer was not 100% physically able to fly, perhaps all contributing to understanding a long drawn out clearance after an altitude request for 'higher' to be interpreted as cleared to a higher altitude than actually given. (Traffic advisory re: an aircraft in the distance was given during the context of the clearance.) callback conversation with reporter revealed the following: reporter called 10/thurs/88 and said he had not received his identification strip on this incident. Reporter insisted he had mailed report on 9/sun/88 by regular mail. The report was not received at ASRS until 10/tue/88 and came in express mail envelope with reporter's name and address on receipt. Reason for call was that FAA inquiring about his altitude deviation as it caused less than standard separation with another aircraft. Apparently reporter took traffic advisory as an altitude assignment causing this incident. Reporter admitted he had had some ear problems prior to this flight, but thought he was healthy and hearing was ok. Other crewmembers were occupied by other duties and could not substantiate the report's claim that a clearance to FL310 had been received. Analyst suspect that reporter did not mail the report until after receiving FAA notification of pending action.

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Original NASA ASRS Text

Title: LGT MISTOOK TRAFFIC ADVISORY FOR AN ALT ASSIGNMENT AND HAD LESS THAN STANDARD SEPARATION WITH ANOTHER ACFT.

Narrative: APPROX 100-150 MI E OF LAS VEGAS, NV, WE CONTINUED A CLB OUT OF FL290. AT FL294 THE CENTER CTLR ASKED OUR ALT. I RESPONDED (THE CAPT WAS ON THE P/A) THAT WE WERE OUT OF FL294. HE STATED WE WERE ONLY CLRED TO FL290. I STATED THAT IT WAS OUR UNDERSTANDING WE WERE CLRED TO FL310. (LOOKING AT THE ALT ALERT VERIFIED 31000' SET IN THE WINDOW.) THE CAPT HAD COMPLETED THE PAX ANNOUNCEMENT, OVERHEARD THE PREVIOUS XMISSION AND SIMULTANEOUSLY WITH DSNDING THE ACFT BACK DOWN TO FL290 STATED THAT OBVIOUSLY THERE WAS SOME CONFUSION AND MISUNDERSTANDING RE: THE ALT CLRNC LIMIT. WE NEVER ASCENDED TO HIGHER THAN FL295. FACTORS AFFECTING HUMAN PERFORMANCE WERE THAT ONE PERSON, THE F/O, WAS HANDLING BOTH THE COMS AS WELL AS FLYING THE ACFT. THE F/E WAS UNATTENTIVE AND COULD NOT RECALL THE CLRNC LIMIT. ANOTHER CONSIDERATION MAY BE THAT THE F/O HAD BEEN ILL EARLIER IN THE MONTH. HE HAD BEEN TRYING TO FLY WHILE STILL ILL WITH A NOT TOO DEHABILIATORY VIRUS AND HAD RPTED EAR TROUBLE 1 1/2 WKS EARLIER, THINKING IT HAD CLRED BY NOW. BASICALLY, THE F/O WAS NOT 100% PHYSICALLY ABLE TO FLY, PERHAPS ALL CONTRIBUTING TO UNDERSTANDING A LONG DRAWN OUT CLRNC AFTER AN ALT REQUEST FOR 'HIGHER' TO BE INTERPRETED AS CLRED TO A HIGHER ALT THAN ACTUALLY GIVEN. (TFC ADVISORY RE: AN ACFT IN THE DISTANCE WAS GIVEN DURING THE CONTEXT OF THE CLRNC.) CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR CALLED 10/THURS/88 AND SAID HE HAD NOT RECEIVED HIS ID STRIP ON THIS INCIDENT. RPTR INSISTED HE HAD MAILED RPT ON 9/SUN/88 BY REGULAR MAIL. THE RPT WAS NOT RECEIVED AT ASRS UNTIL 10/TUE/88 AND CAME IN EXPRESS MAIL ENVELOPE WITH RPTR'S NAME AND ADDRESS ON RECEIPT. REASON FOR CALL WAS THAT FAA INQUIRING ABOUT HIS ALT DEVIATION AS IT CAUSED LTSS WITH ANOTHER ACFT. APPARENTLY RPTR TOOK TFC ADVISORY AS AN ALT ASSIGNMENT CAUSING THIS INCIDENT. RPTR ADMITTED HE HAD HAD SOME EAR PROBS PRIOR TO THIS FLT, BUT THOUGHT HE WAS HEALTHY AND HEARING WAS OK. OTHER CREWMEMBERS WERE OCCUPIED BY OTHER DUTIES AND COULD NOT SUBSTANTIATE THE RPT'S CLAIM THAT A CLRNC TO FL310 HAD BEEN RECEIVED. ANALYST SUSPECT THAT RPTR DID NOT MAIL THE RPT UNTIL AFTER RECEIVING FAA NOTIFICATION OF PENDING ACTION.

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.