Narrative:

Clearance given by las vegas approach to cross lynsy intersection at 250 KTS at 12000 ft. Did not receive clearance to descend past lynsy. Continued to descend to cross utare at 210 KTS 8000 ft. Approaching utare approach frequency given may have been incorrectly set. We never heard any further instructions. After 1 to 2 mins of silence we determined the frequency to be in error. Called tower who put us on correct frequency and we continued approach. Tower informed us to call approach supervisor, which the captain did at the gate. Supervisor was concerned about descent without clearance and lapse in communication. No further statements were made between us and supervisor. If we would have questioned the descent past lynsy, we would have figured out sooner that we were on wrong frequency and that we did not have clearance to descend. Another contributing factor could have been that while I was making a PA to customers, center cleared us to cross lynsy at 250 KTS 12000 ft. I assumed that the clearance was also clearance to descend on the arrival. This coupled with being on the wrong approach frequency were major contributors to altitude conflict.

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Original NASA ASRS Text

Title: ON THE WRONG FREQUENCY DURING THE LYNSY RNAV ONE ARR TO LAS, NV. HAVING NO CLRNC TO DESCEND VIA THE ARR, AN ACR CREW DESCENDS WITHOUT CLRNC.

Narrative: CLRNC GIVEN BY LAS VEGAS APCH TO CROSS LYNSY INTXN AT 250 KTS AT 12000 FT. DID NOT RECEIVE CLRNC TO DESCEND PAST LYNSY. CONTINUED TO DESCEND TO CROSS UTARE AT 210 KTS 8000 FT. APCHING UTARE APCH FREQUENCY GIVEN MAY HAVE BEEN INCORRECTLY SET. WE NEVER HEARD ANY FURTHER INSTRUCTIONS. AFTER 1 TO 2 MINS OF SILENCE WE DETERMINED THE FREQUENCY TO BE IN ERROR. CALLED TWR WHO PUT US ON CORRECT FREQUENCY AND WE CONTINUED APCH. TWR INFORMED US TO CALL APCH SUPVR, WHICH THE CAPT DID AT THE GATE. SUPVR WAS CONCERNED ABOUT DESCENT WITHOUT CLRNC AND LAPSE IN COM. NO FURTHER STATEMENTS WERE MADE BETWEEN US AND SUPVR. IF WE WOULD HAVE QUESTIONED THE DESCENT PAST LYNSY, WE WOULD HAVE FIGURED OUT SOONER THAT WE WERE ON WRONG FREQUENCY AND THAT WE DID NOT HAVE CLRNC TO DESCEND. ANOTHER CONTRIBUTING FACTOR COULD HAVE BEEN THAT WHILE I WAS MAKING A PA TO CUSTOMERS, CTR CLRED US TO CROSS LYNSY AT 250 KTS 12000 FT. I ASSUMED THAT THE CLRNC WAS ALSO CLRNC TO DESCEND ON THE ARR. THIS COUPLED WITH BEING ON THE WRONG APCH FREQ WERE MAJOR CONTRIBUTORS TO ALT CONFLICT.

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.