Narrative:

We checked in with las approach on kepec arrival. Controller advised that we would receive vectors to runway 7R and gave us clarr at 13000 ft. He subsequently gave us 10000 ft and then 8000 ft. We continued on the arrival and it became obvious that there was a mistake as our descent took us below the MSA for our course. I directed the first officer to ask the controller his intentions. He informed us that we should be proceeding direct to las VOR and that we were left of course. I radioed that we were on the kepec as last cleared. He then stated we had been cleared clarr las. I told him that we never received that clearance. Just before we switched to the next frequency we were asked to call them about a possible pilot deviation. Once on the ground I contacted the manager of ATC system and explained the situation. He called las approach to discuss the situation. He quickly returned my call and stated that they had listened to the tapes and that it was controller error. Problem solved. This brings up the importance of the epgws terrain display. This occurred in day VMC conditions. We were able to visually see the terrain conflict early in the game. It was also obvious on the terrain display. Had it been nighttime and terrain was not selected this event could have been catastrophic.

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Original NASA ASRS Text

Title: B737 FLT CREW REPORTS MISCOMMUNICATION WITH LAS TRACON DURING KEPEC1 ARRIVAL AND DESCENT BELOW MSA IN VFR CONDITIONS.

Narrative: WE CHKED IN WITH LAS APCH ON KEPEC ARR. CTLR ADVISED THAT WE WOULD RECEIVE VECTORS TO RWY 7R AND GAVE US CLARR AT 13000 FT. HE SUBSEQUENTLY GAVE US 10000 FT AND THEN 8000 FT. WE CONTINUED ON THE ARR AND IT BECAME OBVIOUS THAT THERE WAS A MISTAKE AS OUR DSCNT TOOK US BELOW THE MSA FOR OUR COURSE. I DIRECTED THE FO TO ASK THE CTLR HIS INTENTIONS. HE INFORMED US THAT WE SHOULD BE PROCEEDING DIRECT TO LAS VOR AND THAT WE WERE L OF COURSE. I RADIOED THAT WE WERE ON THE KEPEC AS LAST CLRED. HE THEN STATED WE HAD BEEN CLRED CLARR LAS. I TOLD HIM THAT WE NEVER RECEIVED THAT CLRNC. JUST BEFORE WE SWITCHED TO THE NEXT FREQ WE WERE ASKED TO CALL THEM ABOUT A POSSIBLE PLTDEV. ONCE ON THE GND I CONTACTED THE MGR OF ATC SYS AND EXPLAINED THE SITUATION. HE CALLED LAS APCH TO DISCUSS THE SITUATION. HE QUICKLY RETURNED MY CALL AND STATED THAT THEY HAD LISTENED TO THE TAPES AND THAT IT WAS CTLR ERROR. PROB SOLVED. THIS BRINGS UP THE IMPORTANCE OF THE EPGWS TERRAIN DISPLAY. THIS OCCURRED IN DAY VMC CONDITIONS. WE WERE ABLE TO VISUALLY SEE THE TERRAIN CONFLICT EARLY IN THE GAME. IT WAS ALSO OBVIOUS ON THE TERRAIN DISPLAY. HAD IT BEEN NIGHTTIME AND TERRAIN WAS NOT SELECTED THIS EVENT COULD HAVE BEEN CATASTROPHIC.

Data retrieved from NASA's ASRS site as of January 2009 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.