Narrative:

Flight from las on the boach 2 departure. At about 300 ft AGL on takeoff; I noticed the HSI course pointer swing hard left. Checking the legs page; boach is listed at the top. Rebel and roppr are no longer displayed. The WX in las is VFR and with no crossing traffic; departure control was more than happy to clear us direct to boach with a climb to FL190. Later during the flight; ZLA gave us the phone number for las TRACON. On the ground in lax; I called and talked to the supervisor whose concern was that this was the sixth company flight in 5 days that has had an RNAV departure problem. While I was on the phone; I had lax maintenance run a bite test to see if it showed any faults. None were found. My first officer and I are pretty sure we had the FMC programmed correctly as a side note; flight to las 2 days after the above event; aircraft on the granpa arrival. We were assigned a heading of 180 degrees for a vector to prino for the visual approach to runway 25L. When approach clears us direct to prino; it's 'exec' and airplane starts a hard right turn to the northwest; at least that's what the course pointer was showing. I disengaged navigation and control wheel steering backward to the south. My first officer puts prino back at the top of the page and 'exec.' no help; prino still shows off the northwest with a discontinuity between prino and larre. We try larre at the top; same result. We try runway 25L; same result. Everything according to the FMC is off to our right rear somewhere. I give up on the navigation and go VOR to intercept the localizer.

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Original NASA ASRS Text

Title: B737-300 FLT CREW HAS AN RNAV ANOMALY DURING THE BOACH 2 DEP FROM LAS.

Narrative: FLT FROM LAS ON THE BOACH 2 DEP. AT ABOUT 300 FT AGL ON TKOF; I NOTICED THE HSI COURSE POINTER SWING HARD L. CHKING THE LEGS PAGE; BOACH IS LISTED AT THE TOP. REBEL AND ROPPR ARE NO LONGER DISPLAYED. THE WX IN LAS IS VFR AND WITH NO XING TFC; DEP CTL WAS MORE THAN HAPPY TO CLR US DIRECT TO BOACH WITH A CLB TO FL190. LATER DURING THE FLT; ZLA GAVE US THE PHONE NUMBER FOR LAS TRACON. ON THE GND IN LAX; I CALLED AND TALKED TO THE SUPVR WHOSE CONCERN WAS THAT THIS WAS THE SIXTH COMPANY FLT IN 5 DAYS THAT HAS HAD AN RNAV DEP PROB. WHILE I WAS ON THE PHONE; I HAD LAX MAINT RUN A BITE TEST TO SEE IF IT SHOWED ANY FAULTS. NONE WERE FOUND. MY FO AND I ARE PRETTY SURE WE HAD THE FMC PROGRAMMED CORRECTLY AS A SIDE NOTE; FLT TO LAS 2 DAYS AFTER THE ABOVE EVENT; ACFT ON THE GRANPA ARR. WE WERE ASSIGNED A HDG OF 180 DEGS FOR A VECTOR TO PRINO FOR THE VISUAL APCH TO RWY 25L. WHEN APCH CLRS US DIRECT TO PRINO; IT'S 'EXEC' AND AIRPLANE STARTS A HARD R TURN TO THE NW; AT LEAST THAT'S WHAT THE COURSE POINTER WAS SHOWING. I DISENGAGED NAV AND CTL WHEEL STEERING BACKWARD TO THE S. MY FO PUTS PRINO BACK AT THE TOP OF THE PAGE AND 'EXEC.' NO HELP; PRINO STILL SHOWS OFF THE NW WITH A DISCONTINUITY BTWN PRINO AND LARRE. WE TRY LARRE AT THE TOP; SAME RESULT. WE TRY RWY 25L; SAME RESULT. EVERYTHING ACCORDING TO THE FMC IS OFF TO OUR R REAR SOMEWHERE. I GIVE UP ON THE NAV AND GO VOR TO INTERCEPT THE LOC.

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.