Narrative:

We were departing off of runway 1R at las. Our clearance was heading 050 degrees climb to 7000 ft, expect vectors for the cowby RNAV departure. All appropriate preflight procedures were accomplished using extra caution due to the problems discussed in the recent flight bulletin. After takeoff, we were given further clearance to climb to FL190, proceed direct to napse and comply with restrs. We both confirmed 7000 ft in the altitude window and napse was input in the LNAV and executed. Initially, the aircraft began a turn to the right which was as expected. About this time, las departure called out traffic and both of us began to clear outside. When I came back in to check the instruments, the aircraft had turned past the course by about 30-40 degrees. There was the typical response of where is this thing taking us when I noticed we were also climbing at a pretty good clip and approaching the lead point for leveloff at 7000 ft. I decided to disengage the autoplt and manually leveloff and turn back toward napse when the TCASII emitted an RA (reduce climb). Since I was already leveling off, I continued. I overshot 7000 ft by about 200 ft and immediately descended back to 7000 ft. Both of us thought the autoplt had gone haywire but honestly, after some reflection, I don't remember engaging it. Normally, we select LNAV at 400 ft and engage the autoplt at 1000 ft. We were on a vector this time and not on the LNAV departure so LNAV wasn't selected at 400 ft and although I remember thinking about engaging it at 1000 ft, I don't think I did because: 1) the autoplt did not take us where the flight director was directing us to go. 2) I don't believe 7000 ft was ever acquired. 3) although a lot was going on in the cockpit with the TCASII RA, I don't recall a horn when I hit the disengage switch on the yoke. I guess all that time in the -200 combined with the information in the recent flight bulletin probably kept us out of trouble. I think perhaps the moving map display would have helped, but with the traffic call distracting us I can't say that for certain either. It's an old lesson, but when all else fails, flying the aircraft is always a good idea. Supplemental information from acn 602015: as for lessons learned, we must diligently monitor the courses displayed on the legs page in case the autoplt starts to wander. Both pilots must verify a command before it is executed. Although we did this, it's possible that I simply saw what I wanted to see. In this world of increasing automation, we must be ready to fly the airplane if the autoplt will not.

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Original NASA ASRS Text

Title: B737-500 CREW HAD A TRACK AND ALTDEV DEPARTING LAS ON A RNAV DEP. THE ACFT OVERTURNED TOWARD THE FIX CLRED TO.

Narrative: WE WERE DEPARTING OFF OF RWY 1R AT LAS. OUR CLRNC WAS HEADING 050 DEGS CLB TO 7000 FT, EXPECT VECTORS FOR THE COWBY RNAV DEP. ALL APPROPRIATE PREFLT PROCS WERE ACCOMPLISHED USING EXTRA CAUTION DUE TO THE PROBS DISCUSSED IN THE RECENT FLT BULLETIN. AFTER TKOF, WE WERE GIVEN FURTHER CLRNC TO CLB TO FL190, PROCEED DIRECT TO NAPSE AND COMPLY WITH RESTRS. WE BOTH CONFIRMED 7000 FT IN THE ALT WINDOW AND NAPSE WAS INPUT IN THE LNAV AND EXECUTED. INITIALLY, THE ACFT BEGAN A TURN TO THE R WHICH WAS AS EXPECTED. ABOUT THIS TIME, LAS DEP CALLED OUT TFC AND BOTH OF US BEGAN TO CLR OUTSIDE. WHEN I CAME BACK IN TO CHK THE INSTS, THE ACFT HAD TURNED PAST THE COURSE BY ABOUT 30-40 DEGS. THERE WAS THE TYPICAL RESPONSE OF WHERE IS THIS THING TAKING US WHEN I NOTICED WE WERE ALSO CLBING AT A PRETTY GOOD CLIP AND APCHING THE LEAD POINT FOR LEVELOFF AT 7000 FT. I DECIDED TO DISENGAGE THE AUTOPLT AND MANUALLY LEVELOFF AND TURN BACK TOWARD NAPSE WHEN THE TCASII EMITTED AN RA (REDUCE CLB). SINCE I WAS ALREADY LEVELING OFF, I CONTINUED. I OVERSHOT 7000 FT BY ABOUT 200 FT AND IMMEDIATELY DSNDED BACK TO 7000 FT. BOTH OF US THOUGHT THE AUTOPLT HAD GONE HAYWIRE BUT HONESTLY, AFTER SOME REFLECTION, I DON'T REMEMBER ENGAGING IT. NORMALLY, WE SELECT LNAV AT 400 FT AND ENGAGE THE AUTOPLT AT 1000 FT. WE WERE ON A VECTOR THIS TIME AND NOT ON THE LNAV DEP SO LNAV WASN'T SELECTED AT 400 FT AND ALTHOUGH I REMEMBER THINKING ABOUT ENGAGING IT AT 1000 FT, I DON'T THINK I DID BECAUSE: 1) THE AUTOPLT DID NOT TAKE US WHERE THE FLT DIRECTOR WAS DIRECTING US TO GO. 2) I DON'T BELIEVE 7000 FT WAS EVER ACQUIRED. 3) ALTHOUGH A LOT WAS GOING ON IN THE COCKPIT WITH THE TCASII RA, I DON'T RECALL A HORN WHEN I HIT THE DISENGAGE SWITCH ON THE YOKE. I GUESS ALL THAT TIME IN THE -200 COMBINED WITH THE INFO IN THE RECENT FLT BULLETIN PROBABLY KEPT US OUT OF TROUBLE. I THINK PERHAPS THE MOVING MAP DISPLAY WOULD HAVE HELPED, BUT WITH THE TFC CALL DISTRACTING US I CAN'T SAY THAT FOR CERTAIN EITHER. IT'S AN OLD LESSON, BUT WHEN ALL ELSE FAILS, FLYING THE ACFT IS ALWAYS A GOOD IDEA. SUPPLEMENTAL INFO FROM ACN 602015: AS FOR LESSONS LEARNED, WE MUST DILIGENTLY MONITOR THE COURSES DISPLAYED ON THE LEGS PAGE IN CASE THE AUTOPLT STARTS TO WANDER. BOTH PLTS MUST VERIFY A COMMAND BEFORE IT IS EXECUTED. ALTHOUGH WE DID THIS, IT'S POSSIBLE THAT I SIMPLY SAW WHAT I WANTED TO SEE. IN THIS WORLD OF INCREASING AUTOMATION, WE MUST BE READY TO FLY THE AIRPLANE IF THE AUTOPLT WILL NOT.

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.