Narrative:

ZLA cleared us to descend via the civet 2 arrival. My copilot was flying. I observed that my copilot was descending with the autoplt engaged in VNAV. He had set 14000 ft in the autoplt altitude window and was setting each subsequent crossing restr as we crossed fixes civet and bremr. Each time the autoplt leveled off in altitude hold, he re-selected VNAV in anticipation of descending to the next altitude restr. This method is considered technique, and although not my technique, he was doing it correctly. Approaching arnes we were cleared for the ILS runway 25L approach. My copilot then set 3500 ft in the altitude window. By selecting the final altitude restr prior to commencing the ILS approach he would only have to monitor VNAV in the descent. This is the technique most commonly used. At arnes we began to descend on the approach. I reminded him not to engage approach mode until passing hunda. Socal approach had issued traffic at 1 to 2 O'clock position that would enter on right base and precede us to runway 25L. I began to scan for the traffic, but could not see it and advised them so. I returned my scan to the panel and observed we were below 9000 ft and had not yet reached suzzi. I immediately called this to my copilot's attention and instructed him to return to 9000 ft. I then noticed that flight level change was the descent mode. (We were no longer in VNAV.) I looked at the autoplt and observed it was not on. I re- engaged VNAV myself and instructed him to use his flight director and vertical deviation indicator to xchk his descent with reference to each of the crossing restrs. Once we regained the approach profile we remained well above all subsequent crossing restrs. This deviation occurred because my copilot hand flew the aircraft with no FMS guidance and failed to maintain altitude awareness. We debriefed the approach at the gate with emphasis on differences between VNAV and flight level change with regard to the crossing restrs. In the future I will require that a discussion of descent technique be made a part of the briefing for this approach. I will make autoplt engagement and VNAV use mandatory, citing visual traffic scanning as a high priority, and autoflt as a tool to reduce workload.

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Original NASA ASRS Text

Title: AN ACR FLC IN AN LGT GETS DISTRACTED SEARCHING FOR TFC AND THE FO DSNDS TOO LOW AT A XING POINT. THE ERROR WAS, IN PART, DUE TO USING IMPROPER TECHNIQUE AND MODE SELECTION.

Narrative: ZLA CLRED US TO DSND VIA THE CIVET 2 ARR. MY COPLT WAS FLYING. I OBSERVED THAT MY COPLT WAS DSNDING WITH THE AUTOPLT ENGAGED IN VNAV. HE HAD SET 14000 FT IN THE AUTOPLT ALT WINDOW AND WAS SETTING EACH SUBSEQUENT XING RESTR AS WE CROSSED FIXES CIVET AND BREMR. EACH TIME THE AUTOPLT LEVELED OFF IN ALT HOLD, HE RE-SELECTED VNAV IN ANTICIPATION OF DSNDING TO THE NEXT ALT RESTR. THIS METHOD IS CONSIDERED TECHNIQUE, AND ALTHOUGH NOT MY TECHNIQUE, HE WAS DOING IT CORRECTLY. APCHING ARNES WE WERE CLRED FOR THE ILS RWY 25L APCH. MY COPLT THEN SET 3500 FT IN THE ALT WINDOW. BY SELECTING THE FINAL ALT RESTR PRIOR TO COMMENCING THE ILS APCH HE WOULD ONLY HAVE TO MONITOR VNAV IN THE DSCNT. THIS IS THE TECHNIQUE MOST COMMONLY USED. AT ARNES WE BEGAN TO DSND ON THE APCH. I REMINDED HIM NOT TO ENGAGE APCH MODE UNTIL PASSING HUNDA. SOCAL APCH HAD ISSUED TFC AT 1 TO 2 O'CLOCK POS THAT WOULD ENTER ON R BASE AND PRECEDE US TO RWY 25L. I BEGAN TO SCAN FOR THE TFC, BUT COULD NOT SEE IT AND ADVISED THEM SO. I RETURNED MY SCAN TO THE PANEL AND OBSERVED WE WERE BELOW 9000 FT AND HAD NOT YET REACHED SUZZI. I IMMEDIATELY CALLED THIS TO MY COPLT'S ATTN AND INSTRUCTED HIM TO RETURN TO 9000 FT. I THEN NOTICED THAT FLT LEVEL CHANGE WAS THE DSCNT MODE. (WE WERE NO LONGER IN VNAV.) I LOOKED AT THE AUTOPLT AND OBSERVED IT WAS NOT ON. I RE- ENGAGED VNAV MYSELF AND INSTRUCTED HIM TO USE HIS FLT DIRECTOR AND VERT DEV INDICATOR TO XCHK HIS DSCNT WITH REF TO EACH OF THE XING RESTRS. ONCE WE REGAINED THE APCH PROFILE WE REMAINED WELL ABOVE ALL SUBSEQUENT XING RESTRS. THIS DEV OCCURRED BECAUSE MY COPLT HAND FLEW THE ACFT WITH NO FMS GUIDANCE AND FAILED TO MAINTAIN ALT AWARENESS. WE DEBRIEFED THE APCH AT THE GATE WITH EMPHASIS ON DIFFERENCES BTWN VNAV AND FLT LEVEL CHANGE WITH REGARD TO THE XING RESTRS. IN THE FUTURE I WILL REQUIRE THAT A DISCUSSION OF DSCNT TECHNIQUE BE MADE A PART OF THE BRIEFING FOR THIS APCH. I WILL MAKE AUTOPLT ENGAGEMENT AND VNAV USE MANDATORY, CITING VISUAL TFC SCANNING AS A HIGH PRIORITY, AND AUTOFLT AS A TOOL TO REDUCE WORKLOAD.

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.