Narrative:

We were cleared for the skebr RNAV one arrival into las. Heading approximately 349 degrees into kepec intersection, the FMC dropped kepec inside of 1 NM and the FMA changed to control wheel steering right. I proceeded to turn the aircraft manually to a heading of approximately 065 degrees. While in the turn ATC called and asked if we were in the turn. We responded yes, and then intercepted the course into ipumy with no further problems with LNAV. ATC asked us to call them via landline. I did so and he asked what happened. I told him, and he said he needed something to write down in the log. There was no mention of violation. I am new on single FMC, no GPS aircraft.

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Original NASA ASRS Text

Title: AN INTERMITTENT PROB WITH AUTOFLT SYS ENCOUNTERED IN A B737-300 WHILE FLYING THE SKEBR RNAV ONE ARR TO LAS, NV.

Narrative: WE WERE CLRED FOR THE SKEBR RNAV ONE ARR INTO LAS. HEADING APPROX 349 DEGS INTO KEPEC INTXN, THE FMC DROPPED KEPEC INSIDE OF 1 NM AND THE FMA CHANGED TO CTL WHEEL STEERING R. I PROCEEDED TO TURN THE ACFT MANUALLY TO A HEADING OF APPROX 065 DEGS. WHILE IN THE TURN ATC CALLED AND ASKED IF WE WERE IN THE TURN. WE RESPONDED YES, AND THEN INTERCEPTED THE COURSE INTO IPUMY WITH NO FURTHER PROBS WITH LNAV. ATC ASKED US TO CALL THEM VIA LANDLINE. I DID SO AND HE ASKED WHAT HAPPENED. I TOLD HIM, AND HE SAID HE NEEDED SOMETHING TO WRITE DOWN IN THE LOG. THERE WAS NO MENTION OF VIOLATION. I AM NEW ON SINGLE FMC, NO GPS ACFT.

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.