Narrative:

The autoplt was engaged in LNAV and vertical speed mode. We had been cleared direct to een, then mht, and we were also instructed to cross 25 mi west of mht at 9000 ft. As directed in our new procedures, we were navigating via LNAV in a -300, so both of our HSI selector switches were in navigation. I do not recall what was set in our manual VOR windows. Based on my previous habits, IM fairly certain I had the localizer frequency for runway 17 at mht set in mine, since thatsouth the approach I was planning. Passing FL190 on profile, the aircraft began a r-hand turn using 15-20 degrees of bank. At the time, I thought that was odd, but I was mainly concentrating on calling for the descent checklist. As the turn continued and the bank increased, I quit worrying about the checklist and devoted my full attention to where the aircraft was going. Based on the way we were approaching een, I had expected a slight right turn. However, the extent of the turn being conducted didnT seem right. I checked the scoreboard and confirmed LNAV was still engaged -- it was. I then looked at the legs page -- still showed een-mht although the headings were different than where we were turning. I quickly tried to xchk raw data, but we didnT have een in either window, so it took a moment to find the frequency and dial it in. As I was doing all this, I disconnected the autoplt and began a l-hand turn back to our original course. (I would estimate the aircraft had turned about 45 degrees to the right by the time I disconnected the autoplt.) during the l-hand turn, I looked back down at the FMS and noticed it was blank with FMC fail displayed. About this time, ZBW began inquiring about where we were going. Boston gave us a clearance to turn left to 020 degrees and to maintain 16000 ft. At this time, we were already below 16000 ft and the captain asked if they wanted us to climb back up. Boston said affirmative and so I climbed the aircraft and leveled at 16000 ft and rolled out on the 020 degree heading. I asked the captain to do the descent checklist to get our altimeters set. During this time, boston was also giving control instructions to at least 1 other aircraft who I perceived we had become in conflict with. After a couple more heading and altitude changes, we were given direct mht again. During all the talking on the radio, we were trying to do the challenge and response checklist. At some point, ATC called and said that everything was sorted out and that there had been no problem. As you might guess, this is my best recollection of the events which transpired. It all happened very quickly and at a significant point in the flight when we were descending quickly and transitioning through FL180. Lessons learned: well, for one thing, I donT like the new LNAV guidance. Had we been flying this same flight 2 weeks ago, I have no doubt the pilot monitoring would have had the appropriate NAVAID tuned up and when the turn started, I could have known immediately that something was wrong and made the appropriate correction right away. I also think the new policy of not having silent checklists is flawed as well. Itsouth dark and IM trying to hand fly the aircraft to avoid a traffic conflict and IM having to read and respond to a new checklist -- not good. Of course, I was flying and accept full responsibility for my role in this incident. My criticism of the new procedures is they led me down the primrose path to a state of reduced situational awareness. My criticism also applies to the new climb check. During a very busy phase of flight, we have to divert our attention from flying the aircraft to provide aural responses to another guy reading a checklist. Supplemental information from acn 615900: thinking back on it, I think the new procedures set us up for that conflict. First we were both in navigation, which I disagree with. In the -300 I think the pilot monitoring needs to monitor the progress of the flight. Thatsouth tough to do on the descent page with both in navigation. Secondly, we were both out of the loop initially because we were challenging and responding to the descent checklist. Therefore, both pilots were distraction from flying rather than 1 pilot. I think that checklist and the clbchklist need to be adjusted, or changed to silent completion. We had an FMC abnormality that needed to be thought through to completion. That is a lot of distrs during a short period of time. Some of it was self-imposed due to the new procedures.

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Original NASA ASRS Text

Title: A B737-300 CREW HAD A TRACK DEV IN ZBW CLASS E AIRSPACE.

Narrative: THE AUTOPLT WAS ENGAGED IN LNAV AND VERT SPD MODE. WE HAD BEEN CLRED DIRECT TO EEN, THEN MHT, AND WE WERE ALSO INSTRUCTED TO CROSS 25 MI W OF MHT AT 9000 FT. AS DIRECTED IN OUR NEW PROCS, WE WERE NAVING VIA LNAV IN A -300, SO BOTH OF OUR HSI SELECTOR SWITCHES WERE IN NAV. I DO NOT RECALL WHAT WAS SET IN OUR MANUAL VOR WINDOWS. BASED ON MY PREVIOUS HABITS, IM FAIRLY CERTAIN I HAD THE LOC FREQ FOR RWY 17 AT MHT SET IN MINE, SINCE THATS THE APCH I WAS PLANNING. PASSING FL190 ON PROFILE, THE ACFT BEGAN A R-HAND TURN USING 15-20 DEGS OF BANK. AT THE TIME, I THOUGHT THAT WAS ODD, BUT I WAS MAINLY CONCENTRATING ON CALLING FOR THE DSCNT CHKLIST. AS THE TURN CONTINUED AND THE BANK INCREASED, I QUIT WORRYING ABOUT THE CHKLIST AND DEVOTED MY FULL ATTN TO WHERE THE ACFT WAS GOING. BASED ON THE WAY WE WERE APCHING EEN, I HAD EXPECTED A SLIGHT R TURN. HOWEVER, THE EXTENT OF THE TURN BEING CONDUCTED DIDNT SEEM RIGHT. I CHKED THE SCOREBOARD AND CONFIRMED LNAV WAS STILL ENGAGED -- IT WAS. I THEN LOOKED AT THE LEGS PAGE -- STILL SHOWED EEN-MHT ALTHOUGH THE HDGS WERE DIFFERENT THAN WHERE WE WERE TURNING. I QUICKLY TRIED TO XCHK RAW DATA, BUT WE DIDNT HAVE EEN IN EITHER WINDOW, SO IT TOOK A MOMENT TO FIND THE FREQ AND DIAL IT IN. AS I WAS DOING ALL THIS, I DISCONNECTED THE AUTOPLT AND BEGAN A L-HAND TURN BACK TO OUR ORIGINAL COURSE. (I WOULD ESTIMATE THE ACFT HAD TURNED ABOUT 45 DEGS TO THE R BY THE TIME I DISCONNECTED THE AUTOPLT.) DURING THE L-HAND TURN, I LOOKED BACK DOWN AT THE FMS AND NOTICED IT WAS BLANK WITH FMC FAIL DISPLAYED. ABOUT THIS TIME, ZBW BEGAN INQUIRING ABOUT WHERE WE WERE GOING. BOSTON GAVE US A CLRNC TO TURN L TO 020 DEGS AND TO MAINTAIN 16000 FT. AT THIS TIME, WE WERE ALREADY BELOW 16000 FT AND THE CAPT ASKED IF THEY WANTED US TO CLB BACK UP. BOSTON SAID AFFIRMATIVE AND SO I CLBED THE ACFT AND LEVELED AT 16000 FT AND ROLLED OUT ON THE 020 DEG HDG. I ASKED THE CAPT TO DO THE DSCNT CHKLIST TO GET OUR ALTIMETERS SET. DURING THIS TIME, BOSTON WAS ALSO GIVING CTL INSTRUCTIONS TO AT LEAST 1 OTHER ACFT WHO I PERCEIVED WE HAD BECOME IN CONFLICT WITH. AFTER A COUPLE MORE HDG AND ALT CHANGES, WE WERE GIVEN DIRECT MHT AGAIN. DURING ALL THE TALKING ON THE RADIO, WE WERE TRYING TO DO THE CHALLENGE AND RESPONSE CHKLIST. AT SOME POINT, ATC CALLED AND SAID THAT EVERYTHING WAS SORTED OUT AND THAT THERE HAD BEEN NO PROB. AS YOU MIGHT GUESS, THIS IS MY BEST RECOLLECTION OF THE EVENTS WHICH TRANSPIRED. IT ALL HAPPENED VERY QUICKLY AND AT A SIGNIFICANT POINT IN THE FLT WHEN WE WERE DSNDING QUICKLY AND TRANSITIONING THROUGH FL180. LESSONS LEARNED: WELL, FOR ONE THING, I DONT LIKE THE NEW LNAV GUIDANCE. HAD WE BEEN FLYING THIS SAME FLT 2 WKS AGO, I HAVE NO DOUBT THE PLT MONITORING WOULD HAVE HAD THE APPROPRIATE NAVAID TUNED UP AND WHEN THE TURN STARTED, I COULD HAVE KNOWN IMMEDIATELY THAT SOMETHING WAS WRONG AND MADE THE APPROPRIATE CORRECTION RIGHT AWAY. I ALSO THINK THE NEW POLICY OF NOT HAVING SILENT CHKLISTS IS FLAWED AS WELL. ITS DARK AND IM TRYING TO HAND FLY THE ACFT TO AVOID A TFC CONFLICT AND IM HAVING TO READ AND RESPOND TO A NEW CHKLIST -- NOT GOOD. OF COURSE, I WAS FLYING AND ACCEPT FULL RESPONSIBILITY FOR MY ROLE IN THIS INCIDENT. MY CRITICISM OF THE NEW PROCS IS THEY LED ME DOWN THE PRIMROSE PATH TO A STATE OF REDUCED SITUATIONAL AWARENESS. MY CRITICISM ALSO APPLIES TO THE NEW CLB CHK. DURING A VERY BUSY PHASE OF FLT, WE HAVE TO DIVERT OUR ATTN FROM FLYING THE ACFT TO PROVIDE AURAL RESPONSES TO ANOTHER GUY READING A CHKLIST. SUPPLEMENTAL INFO FROM ACN 615900: THINKING BACK ON IT, I THINK THE NEW PROCS SET US UP FOR THAT CONFLICT. FIRST WE WERE BOTH IN NAV, WHICH I DISAGREE WITH. IN THE -300 I THINK THE PLT MONITORING NEEDS TO MONITOR THE PROGRESS OF THE FLT. THATS TOUGH TO DO ON THE DSCNT PAGE WITH BOTH IN NAV. SECONDLY, WE WERE BOTH OUT OF THE LOOP INITIALLY BECAUSE WE WERE CHALLENGING AND RESPONDING TO THE DSCNT CHKLIST. THEREFORE, BOTH PLTS WERE DISTR FROM FLYING RATHER THAN 1 PLT. I THINK THAT CHKLIST AND THE CLBCHKLIST NEED TO BE ADJUSTED, OR CHANGED TO SILENT COMPLETION. WE HAD AN FMC ABNORMALITY THAT NEEDED TO BE THOUGHT THROUGH TO COMPLETION. THAT IS A LOT OF DISTRS DURING A SHORT PERIOD OF TIME. SOME OF IT WAS SELF-IMPOSED DUE TO THE NEW PROCS.

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.