Narrative:

This event has happened to me three times over the past year where the navigation system will direct a right-hand turn to fly to the hiipr waypoint on the lax HOLTZ9 RNAV departure from runway 25L when in fact the climb out to this waypoint should generally be straight ahead. We departed runway 25L on HOLTZ9 trm transition (runway 25R is the usual departure runway but was closed). Captain was PF and he briefed engaging LNAV at 400 ft and use of autoplt at 1000 ft. Prior to taking the runway; the captain confirmed and I checked that the aircraft position was accurate and did not require a quick align. Somewhere after LNAV (400 ft) was selected but before autoplt selected (1000 ft); the magenta line to the hiipr waypoint (the first waypoint) indicated we needed to turn right. This was also confirmed by the FD's showing a right-hand turn. The HOLTZ9 indicates the departure for any runway to be an initial straight ahead climb; in general. So rather than blindly follow the FD's to fly the magenta course which didn't mirror the depicted HOLTZ9 departure; I advised the captain that he should not turn; he concurred and maintained runway heading for the moment. Ironically departure control gave us a heading of 235 degrees prior to hiipr for spacing behind a previous departed B767 from the same runway. When we checked the RNAV departure at the gate; the magenta line from the runway to hiipr matched the HOLTZ9 departure. The magenta course did not show hiipr north of the extended runway centerline. I am bringing this to your attention because this has occurred to me now on three separate occasions while departing from lax. The first event occurred when I was PF departing from runway 25L; the captain caught the error and told me not to initiate any turns and maintain runway heading. The second event occurred when I was PF departing runway 25L; neither of us caught the error. It's important to note that the right-hand turn is so insidious that following the FD's caused a slight right-hand turn; however the right turn is significant enough to the north which caused a potential conflict with another aircraft departing from runway 24L; and the subsequent violation. The third event occurred as I described above; but this time I was the PNF instead. The one common element is the error occurred departing from runway 25L. I've departed from runway 25L numerous times with no issues. However; this is just my observation. In each case the runway position was verified before departure. The ability to 'catch' the problem herein lies with someone maintaining the 'big picture.' I think we've been lulled into the belief that if the aircraft position is verified and the correct RNAV departure is properly loaded that following the 'magenta line' is what's expected and will keep us safe on the depicted route. However; this hasn't been the case. I am confident had we blindly followed the FD's and another aircraft was departing from the north parallel; a similar conflict event would have occurred. In each of the three events; all were non-pegasus aircraft. Again this is an observation. Also; we were not airborne long enough for ground based NAVAID updating. The course error depicted on the map to the hiipr waypoint reminded me of the typical 'map shift' that occurred after coming off the nat system once NAVAID updating corrected its position. At any rate; I think it is imperative this issue be brought to the forefront.callback conversation with reporter revealed the following information: the reporter stated that for an entire month he flew nothing but FMS departures from major us airports in both the B757 and B767 aircraft and both pegasus and non pegasus aircraft. This apparent map shift did not occur in the pegasus aircraft but did in some but not all non pegasus aircraft. The fact that it occurred on non pegasus aircraft made him uncertain about the ability of the aircraft to reliably fly RNAV departures which require a high degree of accuracy.

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Original NASA ASRS Text

Title: A B767-300 FMC DIRECTS A RIGHT TURN TO HIIPR INTXN ON THE LAX RWY 25L HOLTZ NINE RNAV DEP WHEN A STRAIGHT OUT IS REQUIRED. ACFT HAD A NON PEGASUS FMC.

Narrative: THIS EVENT HAS HAPPENED TO ME THREE TIMES OVER THE PAST YEAR WHERE THE NAVIGATION SYSTEM WILL DIRECT A RIGHT-HAND TURN TO FLY TO THE HIIPR WAYPOINT ON THE LAX HOLTZ9 RNAV DEP FROM RWY 25L WHEN IN FACT THE CLB OUT TO THIS WAYPOINT SHOULD GENERALLY BE STRAIGHT AHEAD. WE DEPARTED RWY 25L ON HOLTZ9 TRM TRANSITION (RWY 25R IS THE USUAL DEP RWY BUT WAS CLOSED). CAPT WAS PF AND HE BRIEFED ENGAGING LNAV AT 400 FT AND USE OF AUTOPLT AT 1000 FT. PRIOR TO TAKING THE RWY; THE CAPT CONFIRMED AND I CHKED THAT THE ACFT POSITION WAS ACCURATE AND DID NOT REQUIRE A QUICK ALIGN. SOMEWHERE AFTER LNAV (400 FT) WAS SELECTED BUT BEFORE AUTOPLT SELECTED (1000 FT); THE MAGENTA LINE TO THE HIIPR WAYPOINT (THE FIRST WAYPOINT) INDICATED WE NEEDED TO TURN RIGHT. THIS WAS ALSO CONFIRMED BY THE FD'S SHOWING A RIGHT-HAND TURN. THE HOLTZ9 INDICATES THE DEP FOR ANY RWY TO BE AN INITIAL STRAIGHT AHEAD CLB; IN GENERAL. SO RATHER THAN BLINDLY FOLLOW THE FD'S TO FLY THE MAGENTA COURSE WHICH DIDN'T MIRROR THE DEPICTED HOLTZ9 DEP; I ADVISED THE CAPT THAT HE SHOULD NOT TURN; HE CONCURRED AND MAINTAINED RWY HDG FOR THE MOMENT. IRONICALLY DEP CTL GAVE US A HDG OF 235 DEGS PRIOR TO HIIPR FOR SPACING BEHIND A PREVIOUS DEPARTED B767 FROM THE SAME RWY. WHEN WE CHKED THE RNAV DEP AT THE GATE; THE MAGENTA LINE FROM THE RWY TO HIIPR MATCHED THE HOLTZ9 DEP. THE MAGENTA COURSE DID NOT SHOW HIIPR NORTH OF THE EXTENDED RWY CTRLINE. I AM BRINGING THIS TO YOUR ATTENTION BECAUSE THIS HAS OCCURRED TO ME NOW ON THREE SEPARATE OCCASIONS WHILE DEPARTING FROM LAX. THE FIRST EVENT OCCURRED WHEN I WAS PF DEPARTING FROM RWY 25L; THE CAPT CAUGHT THE ERROR AND TOLD ME NOT TO INITIATE ANY TURNS AND MAINTAIN RWY HDG. THE SECOND EVENT OCCURRED WHEN I WAS PF DEPARTING RWY 25L; NEITHER OF US CAUGHT THE ERROR. IT'S IMPORTANT TO NOTE THAT THE RIGHT-HAND TURN IS SO INSIDIOUS THAT FOLLOWING THE FD'S CAUSED A SLIGHT RIGHT-HAND TURN; HOWEVER THE RIGHT TURN IS SIGNIFICANT ENOUGH TO THE NORTH WHICH CAUSED A POTENTIAL CONFLICT WITH ANOTHER ACFT DEPARTING FROM RWY 24L; AND THE SUBSEQUENT VIOLATION. THE THIRD EVENT OCCURRED AS I DESCRIBED ABOVE; BUT THIS TIME I WAS THE PNF INSTEAD. THE ONE COMMON ELEMENT IS THE ERROR OCCURRED DEPARTING FROM RWY 25L. I'VE DEPARTED FROM RWY 25L NUMEROUS TIMES WITH NO ISSUES. HOWEVER; THIS IS JUST MY OBSERVATION. IN EACH CASE THE RWY POSITION WAS VERIFIED BEFORE DEP. THE ABILITY TO 'CATCH' THE PROBLEM HEREIN LIES WITH SOMEONE MAINTAINING THE 'BIG PICTURE.' I THINK WE'VE BEEN LULLED INTO THE BELIEF THAT IF THE ACFT POSITION IS VERIFIED AND THE CORRECT RNAV DEP IS PROPERLY LOADED THAT FOLLOWING THE 'MAGENTA LINE' IS WHAT'S EXPECTED AND WILL KEEP US SAFE ON THE DEPICTED RTE. HOWEVER; THIS HASN'T BEEN THE CASE. I AM CONFIDENT HAD WE BLINDLY FOLLOWED THE FD'S AND ANOTHER ACFT WAS DEPARTING FROM THE NORTH PARALLEL; A SIMILAR CONFLICT EVENT WOULD HAVE OCCURRED. IN EACH OF THE THREE EVENTS; ALL WERE NON-PEGASUS ACFT. AGAIN THIS IS AN OBSERVATION. ALSO; WE WERE NOT AIRBORNE LONG ENOUGH FOR GND BASED NAVAID UPDATING. THE COURSE ERROR DEPICTED ON THE MAP TO THE HIIPR WAYPOINT REMINDED ME OF THE TYPICAL 'MAP SHIFT' THAT OCCURRED AFTER COMING OFF THE NAT SYSTEM ONCE NAVAID UPDATING CORRECTED ITS POSITION. AT ANY RATE; I THINK IT IS IMPERATIVE THIS ISSUE BE BROUGHT TO THE FOREFRONT.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT FOR AN ENTIRE MONTH HE FLEW NOTHING BUT FMS DEPARTURES FROM MAJOR US AIRPORTS IN BOTH THE B757 AND B767 ACFT AND BOTH PEGASUS AND NON PEGASUS ACFT. THIS APPARENT MAP SHIFT DID NOT OCCUR IN THE PEGASUS ACFT BUT DID IN SOME BUT NOT ALL NON PEGASUS ACFT. THE FACT THAT IT OCCURRED ON NON PEGASUS ACFT MADE HIM UNCERTAIN ABOUT THE ABILITY OF THE ACFT TO RELIABLY FLY RNAV DEPARTURES WHICH REQUIRE A HIGH DEGREE OF ACCURACY.

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