Narrative:

Until approximately 4000' MSL, our approach to runway 25L had proceeded normally. At that point (approximately 12 mi out), approach control cleared us for the approach. I armed the approach for the captain. Subsequently I set the MCP altitude indicator for 2000', our missed approach altitude. We started drifting to the right of course. The captain started a correction to the left. He used a substantial bank (250 degrees). Before much time had elapsed, we had shot through the localizer course and we were on the left side of the track. I called this out to him and pointed to the alternate ADI (standby horizon), which showed only a 1 1/2 DOT deflection, but increasing. He made the correction back to the localizer track at a smaller angle of convergence. Approach control had contacted us and asked us to state our intentions. I checked with the captain. He indicated we should continue the approach. The controller acknowledged and recommended that we fly a heading of 270 degrees until reintercepting the final approach course. He told us to hold 2000' until passing the final approach fix. We reintercepted the localizer. As he adjusted the heading of the aircraft to maintain the localizer at FAF, the captain allowed the aircraft to become slightly high (1 1/2 dots). He corrected this through the use of gear, flaps and speedbrake, consistent with the aircraft's limitations. I made all required callouts, including recommendations to limit bank angle, and rate of turn, and to trust the standby horizon's localizer information (which is less sensitive that those of the primary ADI's). With the exception of being slightly above the G/south inside fueler, we continued a normal approach. Our landing was on or about the 2000' point on runway 25L. The runway is over 9000' long. Some other observations: 1) this was a very new captain on his first trip after initial operations experience. He told me to offer any assistance I felt would be appropriate. (This request was made at the beginning of the trip series.) the cockpit environment was one of cooperation. This encouraged me to provide the information I gave. 2) mfr taught us to use the standby VASI more as a back up to a possible failure of the primary ari than as a tool to use in correcting localizer deviations. It might have been better to show us this type of incident in training and let the captain apply the use of the sby ADI to make corrections there, than to let us discover it for the first time on a tight approach.

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Original NASA ASRS Text

Title: TRACK DEVIATION BY WDB CONDUCTING ILS APCH.

Narrative: UNTIL APPROX 4000' MSL, OUR APCH TO RWY 25L HAD PROCEEDED NORMALLY. AT THAT POINT (APPROX 12 MI OUT), APCH CTL CLRED US FOR THE APCH. I ARMED THE APCH FOR THE CAPT. SUBSEQUENTLY I SET THE MCP ALT INDICATOR FOR 2000', OUR MISSED APCH ALT. WE STARTED DRIFTING TO THE RIGHT OF COURSE. THE CAPT STARTED A CORRECTION TO THE LEFT. HE USED A SUBSTANTIAL BANK (250 DEGS). BEFORE MUCH TIME HAD ELAPSED, WE HAD SHOT THROUGH THE LOC COURSE AND WE WERE ON THE LEFT SIDE OF THE TRACK. I CALLED THIS OUT TO HIM AND POINTED TO THE ALTERNATE ADI (STANDBY HORIZON), WHICH SHOWED ONLY A 1 1/2 DOT DEFLECTION, BUT INCREASING. HE MADE THE CORRECTION BACK TO THE LOC TRACK AT A SMALLER ANGLE OF CONVERGENCE. APCH CTL HAD CONTACTED US AND ASKED US TO STATE OUR INTENTIONS. I CHKED WITH THE CAPT. HE INDICATED WE SHOULD CONTINUE THE APCH. THE CTLR ACKNOWLEDGED AND RECOMMENDED THAT WE FLY A HDG OF 270 DEGS UNTIL REINTERCEPTING THE FINAL APCH COURSE. HE TOLD US TO HOLD 2000' UNTIL PASSING THE FINAL APCH FIX. WE REINTERCEPTED THE LOC. AS HE ADJUSTED THE HDG OF THE ACFT TO MAINTAIN THE LOC AT FAF, THE CAPT ALLOWED THE ACFT TO BECOME SLIGHTLY HIGH (1 1/2 DOTS). HE CORRECTED THIS THROUGH THE USE OF GEAR, FLAPS AND SPEEDBRAKE, CONSISTENT WITH THE ACFT'S LIMITATIONS. I MADE ALL REQUIRED CALLOUTS, INCLUDING RECOMMENDATIONS TO LIMIT BANK ANGLE, AND RATE OF TURN, AND TO TRUST THE STANDBY HORIZON'S LOC INFO (WHICH IS LESS SENSITIVE THAT THOSE OF THE PRIMARY ADI'S). WITH THE EXCEPTION OF BEING SLIGHTLY ABOVE THE G/S INSIDE FUELER, WE CONTINUED A NORMAL APCH. OUR LNDG WAS ON OR ABOUT THE 2000' POINT ON RWY 25L. THE RWY IS OVER 9000' LONG. SOME OTHER OBSERVATIONS: 1) THIS WAS A VERY NEW CAPT ON HIS FIRST TRIP AFTER INITIAL OPS EXPERIENCE. HE TOLD ME TO OFFER ANY ASSISTANCE I FELT WOULD BE APPROPRIATE. (THIS REQUEST WAS MADE AT THE BEGINNING OF THE TRIP SERIES.) THE COCKPIT ENVIRONMENT WAS ONE OF COOPERATION. THIS ENCOURAGED ME TO PROVIDE THE INFO I GAVE. 2) MFR TAUGHT US TO USE THE STANDBY VASI MORE AS A BACK UP TO A POSSIBLE FAILURE OF THE PRIMARY ARI THAN AS A TOOL TO USE IN CORRECTING LOC DEVIATIONS. IT MIGHT HAVE BEEN BETTER TO SHOW US THIS TYPE OF INCIDENT IN TRNING AND LET THE CAPT APPLY THE USE OF THE SBY ADI TO MAKE CORRECTIONS THERE, THAN TO LET US DISCOVER IT FOR THE FIRST TIME ON A TIGHT APCH.

Data retrieved from NASA's ASRS site as of August 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.